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1. Fig 3 29 The sheet Earth with the properties from the user defined library Geologie ews Bed EWSA7 En doc 28 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 8 The sheet Extraction The load profile of the boreholes are entered in sheet Extraction see Fig 3 30 P Eingabedaten EWS l E x File Input Import Edition Windows Info hee Goreholes 9 Fluid Earth graction p Info Create new load profile with the following values Calculation if no the data from the input file will be taken 4 1 Yes C No Load profile taken out of the monthly heat extraction er if no is chosen the daily running time must be given 4 2 Yes No Daily running time or monthly heat extraction negativ for cooling ave January fi 2 h d July 2 h d Results February fi 1 h d August 2 h d March h d 4 3 September 3 h d April h d October 7 h d May E h d November s h d June 2 h d December 11 h d Heat extraction rate out of boreholes Heat extraction rate in heating case kW 4 4 0 positiv sign Heat injection rate in cooling condition kW 4 5 D positiv sign Number of days of peak load in February 4 6 2 Heat extraction rate in peak load k 4 7 00 peak load in February Simulation period Simulation period Bo max 60 years Freecooling
2. 52 5 7 Thermal resistances Ra Ry of a coaxial borehole 53 9 4 1 Modeling of the intern borehole resistance 53 5 7 2 Modeling of the borehole resistance 53 5 8 The analytical borehole ei 54 5 8 1 The concept of thermal resistances aiana a a e nennen nenn 54 5 8 2 Thermal resistance R evaporator 54 5 8 3 Thermal resistance R temperature loss along the borehole 55 9 8 4 Thermal resistance ofthe earnh Ruhe 56 5 8 5 The analytical borehole equation 0220024002400nnnnnnnnennnennnenennnonnn ann nnnn nenn nennen 56 ANNEX B Input of a particular g Tunelionzae se a 57 6 1 Example 1 The input of a g function by the values of the function 57 sense ee ee 59 7 1 Lat SVIMDOIS zieren ERE 59 7 2 CUTS Widget mE cm 60 Biscuit E T Pc mE 60 Bed EWS47 En doc 3 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 1 Software Manual 1 1 Content and use of the program EWS The basic version of the program EWS calculates the behavior of borehole heat exchangers This is
3. 23 3 7 1 Basic g 9 0 as 23 3 7 2 Input of multiple horizontal 25 3 1 3 Physical properties of the nnne nenn nenn nennen 26 3 7 4 Creation of a user defined geological library 27 oo Ne sheet 29 3 9 Th esheet Load unklare 31 3 10 She sheer za er 33 Thesheest SIMULALON iur 33 3 10 2 Input of the heat extraction rate and the borehole inlet temperature 34 Bed EWS47 En doc 2 Huber Energietechnik AG 4 5 6 T 8 Program EWS Ver 4 7 Huber Energietechnik AG 3 10 3 The active additional cooling if freecooling is not sufficient 34 3 10 4 Antifreeze minimal brine temperature und bivalent heat pump systems 34 9 19 9 TAG Tesponse een 34 3 11 dheshBeet Parameler M DEI a daten i dau Co UE ands DE rere LE 36 942 Ihewneet Pressure td en ebd metet adn tt qat md Crue du Ioa d 37 3 13 Properties of the heat pump and of the supplementary heating system 39 3 14 Direct Cooling T 40 42 4 1 Diagram of the inlet and outlet
4. N N 1 120 2 72128 ATN Ie oxxemzkk eo recon Degen ates ark gcnere io a 21 0 N i LLLLELLELLELINLLLELL E gt E 240 i 300 12 13 14 15 16 17 18 19 20 Huber Energietechnik mit Prog EWS Huber Energietechnik AG Zurich C Fig 3 21 Input of the undisturbed temperature profile in the earth out of a measurement Example from a measurement of Dr U Sch rli E Rohner 16 Bed EWS47 En doc 21 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 5 2 Automatically calculated borehole length The program EWS is able to calculate automatically the necessary borehole length according to the norm SIA 384 6 18 To do so the simulation period in field 4 8 or field 10 15 has to be set to 50 year and the minimal borehole inlet temperature in field 2 12 and the temperature difference in field 2 6 have to be set according to the norm SIA 384 6 minimal mean temperature of the brine must add up to 1 5 C e g minimal borehole inlet temperature in field 2 12 set to 3 0 C and the temperature difference in field 2 6 set to 3 0 K To start the calculation the field 2 11 must be set to Yes and the calculation can be started with the button Calculation The program EWS than calculates the minimal borehole length and the resulted length can be read in fiel
5. fpa x40 bis20 0m 2 40 woo oo pa 180 soo foooo 3 16 3 17 Close li Programm EWS Lizenz f r heim Huber Energietechnik AG Z rich Fig 3 25 The sheet Earth with a inhomogeneous filling of the borehole 3 7 3 Physical properties of the earth For each horizontal layer appears a line to enter its properties Either the properties can be entered directly into the cells or an earth type can be selected from the pull down menu The earth types in the pull down menu are linked with the appropriate physical properties see Fig 3 26 nx File Input Import Edition Windows Info DER Boreholes 2 Fluid 3 Earth Axtraction 5 into 3 1 External earth data 3 1 1 Borehole resistances x Number of horizontal layers Calculat alculation SwEWS Pipe distance 3 1 21 080 m Shank spacing Open Properties of the earth Properties of the filling 3 4 3 5 3 6 3 2 alwimk plkg m3 cp J koK 3 3 aWimk plkg m3 cp J keK Ra mK W Rb mK W Rc mK W Save Homogeneous 2 31 2560 0 81 1180 3040 0 428 0 117 0 077 if unknown leave blank 7 8 3 Results C Equal layers C Homogeneous earth Homogeneous filling Model of Hellstr m Unequal layers Inhomogeneous earth Inhomogeneous filling Input of thermal resistances Depth alW mK p ka m3 cp J kgK 200 m fiso 2200 soo ME
6. lo inner radius of the borehole pipe m outer radius of the borehole pipe m lj inner radius of the inner coaxial borehole pipe m la outer radius of the inner coaxial borehole pipe m 4 borehole radius m lp radial distance from the borehole axis variable m heat transfer resistance from the fluid to the wall of the borehole pipe Km W Ra internal borehole resistance from the upward to the downward flowing fluid Km W Rp thermal borehole resistance from the fluid to the borehole radius Km W Re thermal borehole resistance from the borehole pipe to the borehole radius Rc Rp R Km W Rr thermal resistance of the evaporator T source 0 Km W Rm thermal transportation resistance in the fluid between the depth H 2 and the earth surface Km W AT grad vertical temperature gradient in the undisturbed earth K m Tp borehole temperature in the depth z on the radius r4 T borehole temperature averaged over the borehole depth on the radius r1 T mean fluid temperature in the depth z C 1 averaged fluid temperature Toutiet Tinet C dann temperature of the downward flowing fluid in the depth 2 longtime mean temperature of the outer air mean temperature of the undisturbed earth Ting averaged annual temperature on the earth s surface Tome outlet temperature temperature of the out streaming borehole fluid C T intet inlet temperature temperatur
7. BIZenz EWS aan 8 3 1 2 DECIMal BONS ers 8 3 1 3 BIBIT 8 3 1 4 PU GOWILMENUS 8 o4 JME SMCS BONOS ns 9 3 2 1 Selection of the borehole type u2220022200200000n0nnno nenn nenne nenn nnnnennnnn nnns 10 3 2 2 Boreholes WIth double U DID6S sse e b a nein 10 3 2 3 5 stes 11 3 2 4 Selection of the borehole configuration single borehole or field of boreholes 12 3 2 5 INBULOF a parideular g mlbcotlol asse in 14 3 3 A freely designed borehole configuration The sheet Field of boreholes 16 3 3 1 Set dislocate and delete boreholes in a field of boreholes 17 3 3 2 Inserting a background map in 4 easy 18 3 3 3 Optimization of borehole 19 3 4 Calculation of a single borehole in a field of boreholes 19 9 5 TInesheerElUd nennen nee 20 3 9 1 The temperatures in the undisturbed earth 21 3 5 2 Automatically calculated borehole length 22 3 6 Theshe et Nie a een ausa cd uv at ide 22 37 le Sheet bul nosset cto tat rasta
8. The heat equation in radial direction around a borehole can be written as JT OT run en TR l OT cn eq 5 6 a thereby the thermal diffusivity a is defined with A Def a eq 9 7 Cp Earth p Earth The heat equation is linear Hence single boreholes as well as borehole fields with geometric similarity have similar thermal responses Thus the heat extraction rate from a borehole causes a temperature drop ATearn in the earth around the borehole compared to the unaffected earth 7 temperature funnel This funnel grows with the ongoing extraction The temperature drop be made dimensionless by using the specific extraction rate and the heat conductivity Agarth AT path r t 2 q Def g rt eq 5 8 5 3 2 The radial temperature funnel In the steady case the radial heat flow in the borehole close up range is constant and the following equation can be used 2 77 u Qu The integration from r to r4 gives g r g r 18 5 10 I q E 0 Earth T 0 q eq 59 This relation allows us to estimate the temperature behavior of the borehole with a single thermal response Additionally if the thermal response g on the point r4 is known it can be concluded on the thermal response g on point r But please note that the assumption of the steady case can produce major deviations for little time steps Bed EWS47_En doc 47 Huber Energietechnik AG Program EWS Ver 4 7
9. i m Shank spacing Open Properties of the earth Properties of the filling 3 4 3 5 3 6 3 2 alW mk plkg m3 cp J kgK 3 3 AIWW mk p kg m3 cp J kgK Rae mK W Rb mK W Re mK W Save Homogeneous 2 40 2600 1000 0 81 1180 3040 0 000 0 000 0 000 3 7 3 8 3 9 if unknown leave blank Results Equal layers Homogeneous earth Homogeneous filling Model of Hellstr m C Unequal layers C Inhomogeneous earth C Inhomogeneous filling C Input of thermal resistances 12 3 3 34 las plkg m3 cp J kgK 3 11 bis20 0m 2 40 3 45 Programm EWS Lizenz f r heim Huber Energietechnik AG Z rich Close Fig 3 23 The sheet Earth with a single horizontal layer 3 1 First the user defines the number of horizontal layers in the earth The calculations are executed using equal layers see below Calculations with only one horizontal layer and averaged properties save computing time but provide less accurate results because of the coarse calculation grid Nevertheless this is often precise enough for boreholes up to a depth of 100 m or for a first rough dimensioning Due to numerical reasons the program EWS calculates internally with a uniform calculation grid in the vertical direction of the boreholes even if in field 3 7 unequal layers are selected which is possible only in the full version of the program The program EWS than averages internally the physical prope
10. into a word file by clicking on the required month 4 2 The diagram of the heat extraction rate Eingabedaten EWS File Input Import Edition Windows Info lolx Calculation Extraction Jania Inlet Temp y TMin 10 6 C danyen e4h average TMax 0 8 C February Year 3 April May June July August September October November December Input Calculation Open Save Results 34 Fluidtemp Inlet Temp _ Cooling system Energy injected 0 kWh Airtemp Energy extracted 372 kWh Days 0 3 b 9 12 16 19 22 25 28 31 Probeversion mit Prog EWS Huber Energietechnik Zurich Fig 4 2 The diagram of the heat extraction rate Bed EWSA47 En doc 42 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 34 The heat extraction rate of the boreholes during each month can be viewed by clicking the button Extrac rate If the sign of the heat extraction rate is positive the heat energy is extracted from the boreholes A negative sign means that heat is injected in the borehole 35 The averaged heat extraction rate over one day is shown by clicking on the button 24h average 36 The cooling and the heating energies of the selected month are shown in the diagram Extrac rate All input parameters can be saved and opened for a new session by clicking on the button Open project 4 3 The sheet Res
11. rli U Rybach L 1999 Geothermische Eigenschaften Schweizer Molassebecken Tiefenbereich 0 500m Bundesamt f r Energie Bern Merker G 1987 Konvektive W rme bertragung Springer Verlag Werner A Bigler R Niederhauser A et al 1996 Grundlagen f r die Nutzung von W rme aus Boden und Grundwasser im Kanton Bern Thermoprogramm Erdw rmesonden Burgdorf Schlussbericht Wasser und Energiewirtschaftsamt des Kt Bern WEA Huber A Ochs M 2007 Hydraulische Auslegung von Erdw rmesondenkreisl ufen Mit der Software EWSDruck Vers 2 0 Bundesamt f r Energie Bern Scharli U Rohner E Signorelli S Wagner 2007 Thermische Leitf higkeit Eichung von in situ Messungen d h kabellose Temperatursonde mit Laborbestimmungen als Grundlage fur die geothermische Kartierung des Kanton ZH und der umliegenden Kantone Bundesamt f r Energie Bern Loose P 2007 Erdw rmenutzung Versorgungstechnische Planung und Berechnung 2 Auflage C F M ller Verlag ISBN 978 3 7880 7811 9 Norm SIA 384 6 2010 Erdw rmesonden SIA Z rich EWSA7 En doc 60 Huber Energietechnik AG
12. 10 years But the results are less precise and they should only be use for rough estimations Bed EWS47 En doc 33 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 10 2 Input of the heat extraction rate and the borehole inlet temperature The borehole inlet temperature in field 6 6 or in field 4 10 is taken as a base for the calculations of the possible heat extraction rate i e the heat extraction rate is not determined by the heat pump if in field 6 2 no is selected 3 10 3 The active additional cooling if freecooling is not sufficient If in the field 6 9 yes is selected there is an additional cooling machine installed which uses the boreholes as a back cooling The cooling machine is activated if the freecooling covers less than a certain fraction of the total cooling demand the fraction is defined in the field 6 11 In this case the boreholes have to absorb the compressor power of the cooling machine which is calculated with the heating EER 1 of the cooling machine field 6 10 3 10 4 Antifreeze minimal brine temperature und bivalent heat pump systems To ensure the anti freeze protection and to take into account of bivalent heat pump systems a minimal brine temperature can be set in field 6 13 To activate the anti freeze protection the field 6 12 must be set to Yes When now the brine temperature is falling below the minimal temperature in field 6 13 the heat pump stops to wo
13. 400 m feao zo oo v 600 m 240 foo v 800 m 240 zo oo x 4 4 4 4 4 4 Close Programm EWS Lizenz fiir heim Huber Energietechnik AG Zurich Fig 3 24 The sheet Earth with 6 horizontal layers of variable thickness Caution The depth does not indicate the thickness of the corresponding layer but the distance form the deepest point of the layer to the surface of the earth After defining the number of horizontal layers data about their properties can be entered into the suitable fields It is possible to define layers which are deeper than the borehole itself These layers are neglected as long as the borehole does not reach them Therefore it is recommended to enter the entire data of the known geology This allows a later variation of the borehole depth without a need for adjustment in geology A horizontal variation of the filling material can be entered by selecting inhomogeneous filling in field 3 9 This option is only available if the layers are equally spaced what implies the selection of equal layers in field 3 7 Similar to the division of the earth it appears a field with additional lines that can be used to enter the properties of the filling material field 3 16 as well as of the borehole resistances field 3 17 see Fig 3 25 The default values are taken from the field 3 3 and 3 4 3 6 Bed EWS47 En doc 25 Huber Energietechnik AG Program EWS
14. Earth a m Fluid m cp Fluid g t r H H Let Two pa 7 2 ee 5 q eq 5 49 Earth 3 a m CD Um CD Fluid undisturbed borehole average fluid average fluid borehole inlet earth temperature temperature temperature at temperature in temperature at depth H 2 depth H 2 the vaporizer Tm Tb Tf Tf Tiia 0 R Rm Abb 5 9 Thermal resistance of a borehole heat exchanger The analytical borehole equation is suited perfectly as a tool to assess the dimension of a result or to check the plausibility of a result Bed EWS47 En doc 56 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 6 ANNEX B Input of a particular g function 6 1 Example 1 The input of a g function by the values of the function The g function published by Eskilson 3 with 9 boreholes in a quadratic configuration see Fig 6 1 and B H 0 10 shall be entered The borehole length is 100 m boreholes In a square rb H 0 0005 I n I I I I J g funct le o m 4 dab A p HR am PX a Oo FE 4 2 1 0 InCt t gt WME v Fig 6 1 Example of a published g function from 3 and the reading of the function value on the supporting point In t ts 2 Sel
15. H value of the selected g function the g function will automatically be extrapolated to B He This extrapolation is based on findings from Huber amp Pahud 6 Since all extrapolations are afflicted to an uncertainty always use the g function with the B H ratio as close as possible to the effective value in the field 1 6 a This extrapolated g function which is used for the calculation will be shown graphically by pressing the button 1 12 sfunc o x gfunction ts 1 5 a g function ETI BLA Fig 3 9 The Sheet Boreholes with the graph of the extrapolated g function 3 2 5 Input of a particular g function The EWS Program offers the possibility to enter a particular g function as an alternative to the selection of a borehole configuration from the library There is a big number of published g functions in the literature e g 3 Additionally new g functions can be interpolated from the existing library values For instance the borehole configuration 1 x 5 boreholes can be interpolated to a sufficient accuracy from the borehole configuration of 1x 4 and 1 x 6 boreholes In the following it is shown how the user can enter a particular g function This is only necessary if the borehole configuration can not be described by one of the options in the field 1 11 To enter a g function chose special input in the field 1 11 and then select yes in the fields 1 10 and 1 13 Thereafter the fields 1 14
16. Huber Energietechnik AG 5 3 3 The dimensionless thermal response 0 Carslaw amp Jaeger 1 solved the heat equation for infinite line sources analytically and found for g the following relation i in which y 0 5772 is the Euler constant Werner A Bigler R Niederhauser A et al 14 got an identical solution using an analogy from the water well equation In the program EWS equation eq 5 11 is implemented This equation can be used for an outer boundary condition of the simulation area as an alternative to the g function by Eskilson The approach by Carslaw and Jaeger leads to a continuous growth of the temperature funnel since for an infinite line source neither the inflow of heat from the top nor from the bottom is possible due to symmetrical reasons No equilibrium condition can be reached with the approach by Carslaw and Jaeger The University of Lund developed an approach for boreholes with a finite borehole length H This because finite boreholes use primarily the heat which is stored in the earth through the surface According to Claesson and Eskilson 2 the boreholes have a time constant t with which the temporal behavior of the ground around the borehole can be made dimensionless 2 t me eq 5 12 9a Thus the dimensionless Eskilson number Es t 9a Bere eq 5 13 S can be treated as a dimensionless time for single boreholes and fields of boreholes Further information on this topic can b
17. b _ 1 kf Hee Te T ut abd mA 2 2 1 6 2 in which the thermal resistance R of the pipe wall is calculated with r R In ae eq 5 33 5 6 2 The borehole resistance R by Hellstr m 4 The borehole resistance for a double U pipe can be calculated by Hellstr m 4 S 89 eq 8 69 with 2 Bu 1 r r r 16 I B In In o In pue 8x Fill E E r Bu ei Ta gt 1 p rf 7 1 16 1 1 T B 2 m Agy Ra Ru ri m eq 5 35 Bed EWS47 En doc 52 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 7 Thermal resistances R R of a coaxial borehole Nomenclature of a coaxial borehole The idealized coaxial borehole is shown in Fig 5 6 The borehole with the borehole radius r4 is colored in gray The filing has the heat conductivity Argi the inner borehole pipe Ay the outer borehole pipe A and the earth Agar The inner and the outer radiuses of the inner borehole pipe are and r4 The inner and the outer radiuses of the outer borehole pipe are and rs Fig 5 6 Nomenclature of a coaxial borehole 5 7 1 Modeling of the intern borehole resistance Ra The definition of the intern borehole resistance R in eq 5 28 is valid for the coaxial borehole too Hence the thermal resistance is the sum of the heat transfer resistan
18. be changed in every case independently from the pull down menu Bed EWS47 En doc 8 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 2 The sheet Boreholes The number of boreholes the borehole depth H the type of the boreholes and the configuration of the boreholes can be defined in the sheet Boreholes Eingabedaten EWS ae File Input Import Windows Info m Poreholes 2 Fluid 3 Earth 4xtraction 5 ore Borehole configuration 17 COUPES RER TEE Ja Ej 1 8 wallthickness of pipe m 0030 Ed 1 2 M cosia Files 1 9 Heat conductivity of pipe W mK eave 1 3 Number of boreholes I Results 1 4 Borehole depth o0 1 5 Borehole diameter 120 Dimensionless thermal response factor g 1 10 Boundary conditions with g functions ee dg Close Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich T UP usu sus Fig 3 1 sheet Boreholes and its default values In field 1 4 you enter the depth of the boreholes and in field 1 3 the number of boreholes Additional input fields appear see Fig 3 2 if more than one borehole is entered in the field 1 3 Furthermore the borehole distance can be entered in field 1 6 and in field 1 11 it is possible to choose the borehole configuration f Eingabedaten EWS t I n x File Input Import Edition Windows Info foreholes
19. constant borehole inlet temperature must be entered in field 6 6 This type ignores the heat extraction step field 6 5 Bed EWS47 En doc 35 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 11 The sheet Parameter Select the sheet Parameter from the pull down menu Windows in the menu see Fig 3 37 The simulation grid the simulation time steps and the stop criterion for the iteration can be defined in the sheet Parameter The time step for the calculation of the thermal borehole resistance Rp can be defined in field 7 15 Field 7 15 is set to no in the default setting In this case R is calculated with the given design mass flow rate field 2 7 at the beginning of a simulation and it remains constant for the rest of the simulation period If field 7 15 is set to yes Ry is recalculated in each time step hourly Thereby the computing time increases but the result can get more accurate Additionally the design of the output file can be set on the sheet Parameter Normally the user has not to fill in the sheet Parameter since it can be calculated with the default values for most cases P Eingabedaten EWS File Input Import Edition windows Info System Graph Horeno MeatPump brh traction Sinto nulation Parameter Input Results Sim g function Axial partition see page Earth Calculation im aber 7 1 2 50 j Parameter L 7 2 between
20. done by solving numerically the heat equation of the ground and the heat transfer from the boreholes The program calculates the outlet and inlet temperatures as well as the heat extraction rate of the boreholes single boreholes or fields of boreholes with hourly time steps up to a period of 60 years The program EWS allows to take into account all major impacts The ground can be divided into maximal 10 layers with different types of ground materials and the corresponding properties Since the program EWS is able to do unsteady calculations of the fluid it offers the possibility to calculate start up processes and thermal response tests Furthermore the full extension of the program EWS is able to calculate direct cooling systems with borehole heat exchangers where the boreholes can be placed in random arrangements direct on the screen Based on the return temperature of the building s cooling system TABS cooling ceiling and ventilation it is possible to simulate an hydraulic linking of the borehole heat exchanger with the ventilation or the hydraulic cooling system Even simulations with complex ventilation schedules are feasible Outdoor air temperatures can be read from a meteorological data base e g Meteonorm in hourly time steps 1 2 The structure of the manual The present manual guides the user through the different input masks of the program EWS and learns him how to use them properly It is presumed that the user is basically
21. ham 1 20 Borehole distance of g function fi 0 00 1 21 B H 0100 Close Input g function 1 13 ves C No Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich Fig 6 2 The sheet Boreholes example of a particular g function for a 3 x 3 borehole field with a quadratic configuration and B H 0 10 Bed EWS47 En doc 57 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG The entered g function respectively the spline interpolation which is used by the program can be checked visually and quantitatively by clicking on the field 1 12 It is necessary to adjust the ratio field 1 6 to the ratio of the g function field 1 20 if the B H ratio field 1 6a differs from the ratio of the g function field 1 21 The g function would be extrapolated from the B Her ratio if the adjustment is not done The graph of the entered g function is showed in Fig 6 3 P Gfunc e x gfunction ts 37 2 a g function Copy Init ts 7 Fig 6 3 The graph of the particularly entered g function from Fig 6 2 The program EWS uses an automatically extrapolated g function if the effective ratio B H r field 1 6a differs from 0 1 This extrapolated g function can be shown by clicking on the field 1 12 This means for the above example that if the effective borehole distance B is 8 m this value has to be entered in the field 1 6 Hence the effective B He
22. iE T EET ERR DE RES GER TR ER NI OH t d 14 E EEREEEEF 10 001 ER ET en 000 geo o opm GEER EE 187 10 c HHE ami T T T n ET A a a P E T T T e a RN EHS CHHHEERPEHHHHHHEREHHHHHHHEEHHHHHHHEEEERHHHHHHRERH Pie a ERG EB BR a ES GR ES a Ta Aa aa 0 AR aes ER T ES S Pees E EE ES B ERASER 8 Ez m mi tT tt z EEE SERRE N 10 10 0 19 9 489 30 141 pers ea pri i t n BS ES EST E DE ERR ER ee RS D m n S t Rd RD ERR RR UR T ERU Re REC E BEHHZEBERBERE oE dil 0 0 al bog SA a ESEMETE Besse fes 10 0 40 012817 20 0 40 0113 18 30 0 13_400 20 499 40 011421 60 0 HH PH Her S8 a 8 ER EE E D EE ees SE RD DE D DEN FE EBEN RR DE RB Fig 3 13 sheet Field of boreholes with 21 boreholes T
23. modes for boreholes Iteration 0 1 Cooling of the borehole outlet temperature with a given heat Temperature ola earth and fluid pump Temperature old Temperature earth and fluid 2 Heating or cooling of the borehole to a given temperature Tiniet during a process e g use of the borehole for the cooling of a building Write the borehole outlet tempertature into a file Read the borehole inlet temperature or the heat extraction rate The program EWS provides both operation modes he iteration goes towards the extraction rate if the input parameter heat ee extraction rate given is set to yes field fluid 6 2 No intern iteration is done if no is selected in the field 6 2 In this case the borehole outlet temperature Toutiet is calculated for a given borehole inlet temperature Tinet Therefore the input of the borehole inlet temperature is dt 1 Calculation of the earth idt subdt no Iteration on extraction T inlet old T inlet T inlet T outlet T_inlet cpgyig m no Iteration Iteration 1 Abs T_inlet T_inlet_old lt accuracy yes Bed EWSA7 En doc 45 necessary he entered borehole inlet temperature is only used as a first approximation for the start of the iteration if field 6 2 is set to yes Huber Energietechnik AG Program EWS Ver 4 7 Huber Ene
24. mouse button mouse wheel into the sheet field of boreholes the clipboard is pasted on the screen Ne a ogramm EWS Sondenanmendnurg BE um m 27 2216 2 Ai 157 0 44 4 4 an 2n f 4 1141 55 s 18 158 B 567 E m N 14 131 7 62115 1552 19 1943 e re A N 7 aM IN wa pee Am E fi ON aM d AO NN NC Sans ur DIR sS 4 step With the buttons S6 and S7 the map and the grid finally can be set to the favored size on the screen Now insert the borehole positions as described in 3 3 1 Note As soon as the first borehole is set the map can not be changed any more Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 3 3 Optimization of borehole fields The procedure of the optimization of a field of boreholes shall be illustrated on a example with 5 x 10 boreholes The blue colored boreholes have the highest yield Boreholes with lower yields they are located in the centre of the field where the heat hardly flows to are purple at the borders and dark red in the centre The button 1 12 shows a graph of the g function which makes the difference easily visible The g function can be reduced by 8 with the relocation of the 4 central boreholes This means that on a long term basis the borehole temperature increases 8 if the same charge of the boreholes is simulated gfunction ts 38 2 a gfunct
25. properties for the whole borehole depth In field 3 3 the properties of the filling heat conductivity X W mK density kg m and specific heat capacity cp J kgK can be entered if in field 3 9 homogenous filling is selected what usually is the case or if the calculations are done with a single horizontal layer The properties of the filling are used for the calculation of the thermal borehole resistances and R see chapter 5 6 The borehole resistances Ra Ry Re can be found in the fields 3 4 3 6 The definition of the resistances Ra Rp Re are given in chapter 5 6 The default setting of the program EWS calculates the borehole resistances by the equations given by Hellstr m see chapter 5 6 option field 3 10 In this case the inputs in the fields 3 4 3 6 are ignored there is no need for an input The borehole resistances are calculated prior to each run using the equation by Hell strom and considering the properties of the filling material field 3 3 the mass flow rate field 2 7 and the distance between the pipes in the borehole field 3 12 The calculated values for R4 Ry and R are showed in the fields 3 4 3 6 after each run The internal resistance R field 3 4 and the resistance of the borehole R field 3 5 can be entered if in the field 3 10 Input of thermal resistance is selected In this case field 3 6 must be set to zero Otherwise the value for field 3 6 is used to calcul
26. temperature of the borehole fluid 42 4 2 diagram of the heat extraction 42 AS qnesneeb mesSllls Sure dnt olt res 43 ANNEX A Desctripliron OF THE model e EL ende 44 Sek SMmUlallonared ee ee cce 44 5 1 1 The s mulation or the Ime SIED eed cia 45 92 46 5 3 Heat Equation and the thermal response 0 47 5 3 1 ICAL QUO Ni ee TM 47 5 3 2 The radial temperature funnel nenn 47 5 3 3 dimensionless thermal response Q ccccccceccseccceeeeeeeeeeeeeeeeeeeeeeeeeseeeseeeaneeaees 48 5 3 4 Thecompatrison OF tie models an ae 49 5 4 The calculation of the g function with the principle of superposition o0 5 5 borehole temperature T and the fluid temperature 50 5 5 1 THe TUG temperature en I na 51 5 6 Thermal resistances und Ry in the double U pipe 51 5 6 1 The internal borehole resistance Ra by Hellstrom 4 52 5 6 2 borehole resistance Ry by Hellstrom 4
27. the building e The cooling demand of the building is only indicated if the load profile was entered in the sheet Load chapter 3 8 Bed EWS47_En doc 43 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 ANNEX A Description of the model Extractions of the models in the EWS Program are given in the following However only the parts are shown which are required for the comprehension of the input parameters A more complete model description can be found in 5 6 and 3 5 1 Simulation area The vertical heat conduction close to the borehole 3m distance to the borehole has only a marginal influence on the ground temperature in this area when the borehole depth is more than 50 m Therefore for this area the calculations neglects the vertical heat conduction As a consequence the heat equation in cylindrical coordinates can be solved one dimensional for each layer Thus it is possible to define different layer properties This allows to calculate the common case in which the ground consists of various layers with different properties The Crank Nicholson method is used for the simulation of the ground temperatures close to the boreholes 3m The averaged fluid temperature of the corresponding layer is taken as an inner boundary condition The fluid is simulated unsteady with an explicit time step procedure Thus it is possible to calculate the start up behavior of the borehole The out
28. the inner pipe Aw field 3 3 Heat conductivity of the filling Afin Earth Fig 3 6 Coaxial pipe s nomenclatures Bed EWS47 En doc 11 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 2 4 Selection of the borehole configuration single borehole or field of boreholes P Eingabedaten EWS E lelx File Input Import Edition Windows Info oreholes 2 Fluid 3 Earth amp xtraction 5 Info Borehole configuration Falcalanen 14 1 7 Outer pipe diameter m 0 0320 1 8 Wall thickness of pipe m 0 0030 Open ae 1 2 P EUM 0558 1 9 Heat conductivity of pipe W mK 0 40 nud 1 3 Number of boreholes 1 4 Results Borehole depth 20 0 1 5 Borehole diameter 01 20 Dimensionless thermal response factor g 1 10 Boundary conditions with g functions Yes No Fig 3 7 Sheet Boreholes with its default values Each type of borehole configuration can be described by its dimensionless thermal response function g see eq 5 8 The program EWS sets the outer boundary condition of the simulation area to this thermal response For single boreholes a second possibility is the use of the analytical solution for infinite line sources described by Carslaw amp Jaeger 1 see eq 5 11 Field 1 10 defines which solution is applied The program EWS sets the boundary condition with the g function if the field 1 10 is set to yes otherwise it
29. uses the equation of Carslaw amp Jaeger The boundary condition calculated by Carslaw amp Jaeger is only adequate for single boreholes and simulation periods up to the response time from eq 5 12 Once the entered number of boreholes field 1 3 exceeds one field 1 10 is set to yes and the boundary conditions are calculated with the g functions 2 and 3 As a consequence the pull down field 1 11 appears with a choice of the borehole configurations There B H stands for the ratio of the borehole distance B and the borehole depth H JF Eingabedaten EWS single borehole a x 2 boreholes 0 05 File Input Import Edition Window boreholes 0 1 2 boreholes 0 2 3 boreholes in line 3 boreholes in a line TForeholes 2 FI 3 boreholes in a line Input 4 boreholes in a line 0 4 boreholes a line 0 Borehole cd 4 boreholes in a line Calculation 11 ter pipe diameter m 0 0320 i all thickness of pipe m 0 0030 Open 1 21 Pat conductivity of pipe W mK 0 40 Save 1 3 E J Number of 1 4 Borehole d 2 8 boreholes 0 05 Results 5x10 boreholes 0 2 10x10 boreholes 0 1 3 boreholes in a triangle 0 05 Dimensionle 5 boreholes in a triangle 0 1 boreholes in L configuration B H 0 05 boreholes in L configuration B H 0 1 1 10 Boundary ca 12 boreholes in a squ
30. 0 200 220 240 260 280 300 Huber Energietechnik AG Z rich Temperature C down Tf Abb 5 8 Temperature profile of the fluid according to 8 Thus the thermal resistance R can be defined as 1 2 3 R m CD Fluid Bed EWS47_En doc 55 eq 5 42 eq 5 43 eq 5 44 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 8 4 Thermal resistance of the earth R The thermal resistance of the earth R follows from the temperature difference between the borehole surface temperature and the temperature level of the undisturbed earth on the same depth The definition of R follows from the definition of the g function eq 5 8 q Bog Ap OPS 4 eq 5 45 The particularity of the thermal resistance R is that it is a function of the time and that it is permanently increasing under a constant heat extraction rate see chapter 5 3 5 8 5 The analytical borehole equation The analytical borehole equation follows from the combination of the different thermal resistances of the borehole and its surroundings Tous T Ry R Ry R d eq 5 46 T Ry R R d eq 5 47 Replacing Tm with eq 5 21 Rg with eq 5 45 and Rm with eq 5 44 yield to the analytical borehole equation H g t r l H H 1 Al Grad 1 29 q eq 5 48
31. 17 Graph of g function Graph of gfunction 1 12 2 10 860 1 18 3 110 80 1 16 Input g function Yes C No 1 13 Close graphic input of field f Yes No 1 22 single borehole Nr 0 all 2 1 23 Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich Fig 3 19 The calculation of a single borehole in a field of boreholes Bed EWS47 En doc 19 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 5 The sheet Fluid The data about the fluid and the filling can be entered in the sheet Fluid Eingabedaten EWS 18 x Fie Input Import Edition Windows Info Eu INE NC CN NN vM oreholes 2 Fluid Earth 5 Info Calculation _ 2 1 Properties of fluid monoethylenglykol 20 0 C Open 2 2 Heat conductivity of fluid V mK 2 3 Density of fluid kg m3 2 4 Heat capacity of fluid J kgK cn c Ii iil Save Kinematic viscosity of fluid m2 s Resulte 2 5 ty m2 s 0 000035 Mass flow rate in all boreholes ce 2 6 Temperature difference in out K Mass flow rate kg s 0 080 2 7 Temperature profile in the earth Yes No 2 13 Temperatures in the undisturbed earth 2 8 Annual mean airtemperature 2 9 Additional warming of the surface 2 10 Temperature gradient in the earth C m 0 030 2 11 Calculate borehole depth C Yes No 12 Minimal borehole inlet temperatu
32. 2 Fluid 3 Earth 4xtraction 5 Info Borehole configuration Calculation y 1 7 Outer pipe diameter m 0 0320 mm double U pipe Y 1 8 wallthickness of pipe m 0 0030 Open a E 4 Typ en auc 1 9 Heat conductivity of pipe W mK 0 40 Save 1 3 Number of boreholes 2 1 4 Results Borehole depth 20 0 1 5 Borehole diameter 01 20 1 6 Borehole distance 0 00 B Hett 0 500 1 64 rn Dimensionless thermal response factor g 1 10 Boundary conditions with g functions Yes No 1 11 g function Graph of g function 1 12 Graph of g function Input g function 1 13 c Yes No Close Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich Fig 3 2 On the sheet Boreholes additional input fields appear if 2 or more boreholes are entered in field 1 3 Bed EWS47 En doc 9 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 2 1 Selection of the borehole type By selecting one of the options in the pull down field 1 1 see Fig 3 3 the program fills in automatically the default values for the borehole type double U or coaxial pipes field 1 2 the borehole diameter 2 x r4 field 1 5 the outer pipe diameter 2 x field 1 7 the wall thickness of the pipe rs r field 1 8 and the heat conductivity of the pipe field 1 9 But these parameters can still be adjusted manually PP Eingabedate
33. 2 Thermal resistance R evaporator In a steady condition the heat balance of the evaporator and the earth can be written as Cone Tier m CPriid Oase B q eq 5 39 Considering eq 5 23 the following equation for the thermal resistance of the evaporator R can be defined as H _ gt LEE 5 40 Der epa H _ Dale Ted a 5 41 mm deg S i Bed EWSA47 En doc 54 Huber Energietechnik AG Program EWS Ver 4 7 5 8 3 Thermal resistance R temperature loss along the borehole Huber Energietechnik AG In the heat extraction case the highest average fluid temperature T is at the bottom of the borehole heat exchanger During the transportation of the fluid from the bottom the fluid yield a part of its heat energy to the down flowing fluid and sometimes also to the upper earth layers Assuming that there is a constant specific heat extraction rate for the entire borehole length which is a reasonable assumption for most boreholes the following relationship for the fluid temperature results 8 2 g t H 1 2 T z 2 T AT ga u T a H z z H z T AT Ho BUM Mt ce 2 27 T down a z b ao 2 u 2 M CP Fhia 2 CD ria H z 2 2 R M CDrwid 2 m CDrtyia Depth z 0 m 59 Tinet 13 0 Tr 14 0 T outlet 40 60 80 100 120 140 160 18
34. 29 are ignored 10 7 Duration of the peak load non stop operation at the end of February 10 8 COP of the heat pump during the full load 10 11 10 10Input of the EER of the cooling machine cooling COPz i e the ratio of the cooling energy and the consumed electric power There should be entered a high value e g 999 if the freecooling option in field 10 28 is selected 10 11The heat extraction rate during the maximal load end of February The duration is defined in the field 10 7 10 13The heat extraction rate during a part load This heat extraction rate is rounded to be equal to the total heating energy of 10 16 10 27 10 15The duration of the simulation maximal 100 years Always the last year of the period is evaluated 10 28 The cooling temperature of the borehole inlet is limited if the freecooling option is selected The coverage of the cooling demand can be seen on the sheet Results 10 29 The borehole inlet temperature in the freecooling case Attention The borehole inlet temperature mostly is lower than the return temperature of the cooling loop because of the heat exchanger 10 30 Mean COP of the heat pump in the heating period at part load 10 13 Extraction KW July oo 15 TMax 13 9 C year 9 6 3 D 3 6 9 heat energy 400 kWh cooling energy 886 kWh days 0 3 6 9 12 16 19 2 25 2 J t Huber Energietechnik AG mit Prog EWS Huber Energi
35. 3 3 freely designed borehole configuration The sheet Field of boreholes Only in the complete version of the program EWS an additional smart option is offered to enter any kind of borehole configurations up to 100 boreholes in a field To take advantage of this option choose Field of boreholes in the menu Input see Fig 3 11 P Fingabedaten EWS input Import Editon Windows Info cantiquratioan coaxinl al boreholes Fluid Eanh Exracion into Outer pipe diemeter m Wall thickness of pipe m Heat conductivity of pipe mic Dimensionloss thermal nop lnctar q Boundary condions wiht grlanelon gtunctian Graph el gstunctian Close Graph nf g function input Te Ma Programm Lie Fig 3 11 en fur amp Huber Enerqiechnik AG Zurich The selection of the sheet Field of boreholes in the menu input The full version of the program EWS now shows the sheet Field of boreholes with a grid The distance between two grid lines is one meter Every ten meter there is a thicker grid line The gird lines correspond to a net of coordinates in which the left upper corner has the coordinates 0 0 PA Programm EWS i 0 0 Bed EWSA7 En doc HH b c c co ce e ce ce Eas ae L 4 30 0 200 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 3 1 Set dislocate a
36. 4 6 2 Heat extraction rate in peak load kw 4 7 00 peak load in February Simulation period Simulation period 28 max 60 years Freecooling Freecooling by 9 d 10 neg heat extraction Yes No 4 borehole inlettemperature 20 00 B Programm EWS Lizenz f r Huber Energietechnik Huber Energietechnik AG Z rich Fig 3 31 The sheet Extraction with the input of the monthly heat extraction Bed EWS47 En doc 30 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 9 The sheet Load The full version of the program EWS offers alternatively to the direct input of the heat extraction in the sheet Extraction chapter 3 8 another possibility to enter the borehole load Thereto the sheet Load can be opened under the pull down Input see Fig 3 32 It appears the sheet Load and the sheet Extraction gets hidden see Fig 3 33 The sheet Load needs as an input the monthly heating energy to calculate the heat extraction of the boreholes using the COP of a heat pump The sheet Load can not be combined with the sheet Heat pump f Eingabedaten EWS File Input Import Edition Windows Info Boreholes Fluid Earth Fluid Ee Simulation Extraction new load proi Parameter he data from the Info Ventilation schedule Direct coooling Heat pump pressure drop rofile taken o1 s chosen the de Field of boreholes single borehole in a fiel
37. 4 and 12 open RO PETE 7 3 2 000 Save Simulation time steps Borehole time step min 60 has to correspond with input file 7 4 Results Fluid time step security 1 7 5 40 recommended 4 Earth time step security 2 7 6 2 0 recommended 2 Time step of outer boundary conditions weeks 7 7 fi recommended 1 Stop criterion for the iteration accuracy of iteration 7 8 0 01000 Number of lines in the output file m BEER File TEarth ews Write results in output file 7 9 C Yes No C Yes No Number of simulation steps per output value 7 10 730 Monitor point in axial direction 7 11l Monitor point in radial direction 7 12 Write all simulation years in output file 7 13 C Yes No Write starting conditions on file C Yes No Close 7 14 Recalculate Rb each timestep 7 15 C Yes No Programm EWS Lizenz f r Probeversion Huber Energietechnik AG Zurich Fig 3 37 The sheet Parameter In field 7 15 is defined whether the thermal borehole resistance Rb is recalculated for each calculation step The borehole resistance R thermal resistance between borehole and fluid is basically a parameter which is influenced by geometrical factors of the borehole by the properties of the filling material and by the pipes Additionally it includes the heat transfer coefficient a from the piping wall to the fluid which depends on the mass flow rate in the pipes Since the program EWS offers the option to simulate a v
38. 47 En doc 29 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 4 6 4 7 There is an option to simulate the peak load in the heating case by calculating a non stop heating period The duration of this period is defined with the input in field 4 6 The period always is simulated at the end of February which is the coolest period of the year The field 4 7 defines the heat extraction rate during this period which is normally equal the heat extraction rate in field 4 4 P Eingabedaten EWS x File Input Import Edition Windows Info 4Boreholesb Fluid 4 Earth gxrectiong Info Input Create new load profile with the following values Calculation if no the data from the input file will be taken 4 1 e Yes No Load profile taken out of the monthly heat extraction Open if no is chosen the daily running time must be given 4 2 e Yes No z Daily running time or monthly heat extraction negativ for cooling ave January 372 kWh July 62 kWh Results February 334 kWh August 62 kWh March 279 kWh 411 September o0 kWh April 0 kWh October 7 7 kWh May 93 kh November 270 kh June 60 kWh December 341 kh Heat extraction rate out of boreholes Heat extraction rate in heating case kW 4 4 0 positiv sign Heat injection rate in cooling condition k 4 5 D positiv sign Number of days of peak load in February
39. 47 En doc 40 Huber Energietechnik AG 19 20 21 22 23 24 Program EWS Ver 4 7 Huber Energietechnik AG The program offers the option to protect the heat exchanger to the borehole loop against freezing by controlling the flow rate in the intermediate loop between the air heat exchanger and the borehole heat exchanger To activate this put the Antifreeze option button field 19 to on The return temperature of the cooling system in the building in function of the outdoor air temperature can be defined in field 20 Set the value for the return temperature if the outdoor air temperature is 20 C and if it is 30 C In between the system interpolates linear Below 20 C outdoor air temperature und above 30 C outdoor air temperature it is assumed a constant return temperature of the cooling system In field 21 is defined whether it is calculated without a limit of the direct cooling rate or with the maximal cooling rate from the input file or if the maximal heating and cooling load should be calculated with data from the sheet Extraction This option should always be checked calculating variants If yes is selected in field 22 all calculations are done with the data from this input mask If no is selected the inputs of this sheet are ignored Click on the button Ventilation schedule to define a ventilation schedule File Input Import Edition Windows Info Fig 3 44 The input mask
40. 5 The geometrically maximal limit of the eccentricity bya is b E min 525 Max 2 r r eq The geometrically minimal limit of the eccentricity for not centered borehole pipe is r Did eq 5 26 r The conductivity parameter c is defined as a pure substance property by Arin B A Barth Gon eq 5 27 A gin F A arth 4 The intern thermal borehole resistance Ra Km W is a characteristic value for the thermal losses Aq W m related to the length of the upward flowing fluid to the downward flowing fluid Ra is independent of the depth of the borehole Def R 2 5 28 2 Bed EWS47 En doc 51 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG The thermal borehole resistance R is defined by the mean fluid temperature T in the borehole and the borehole temperature T Def R RL q The borehole resistance R is independent of the borehole depth and consists of the resistance of the borehole filling R and the resistance of the heat transfer from the filling to the borehole fluid R R R R eq 5 30 The resistance of the heat transfer R can be calculated for double U pipes with 1 R eq 9 31 5 29 5 6 1 The internal borehole resistance R4 by Hellstr m 4 According Hellstr m 4 1991 S 147 9 149 the internal borehole resistance R for double U pipes with a symmetric configuration of the pipes can be calculated with b 2
41. E v 60 0 m 240 2600 fiooo Piute 3 44125 m f feo o 150 0 m 2 0 2600 1000 fine sandstone OSM 200 0 m 240 2600 1000 fine sandstone OMM fine sandstone USM middle sandstone OS middle sandstone UE rough sandstone OSk Y Close i Programm EWS Lizenz f r heim Huber Energietechnik AG Z rich Fig 3 26 The sheet Earth offers a selection of rocks in the pull down menu Bed EWS47_En doc 26 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG The program EWS also offers the option to enlarge the library in the pull down menu by adding new earth types with their own names and physical properties see Fig 3 27 This can easily be done by entering manually the data into the suitable cells After a run the new defined earth types appear at the bottom of the pull down menu lolx File Input Import Edition Windows Info m Boreholes 2 Fluid Earth amp xraction 5 info npu External earth data 3 11 Borehole resistances Number of horizontal layers fe 31 SWEWS Pipe distance 3 12 0 080 m em Shank spacing Open Properties of the earth Properties of the filling 3 4 3 5 3 6 3 2 alwimk p kg m3 cp J kgK 3 3 alW mK p ka m3 cp J koK Rb mK W Re mK W Gave Homogeneous 2 61 2555 1023 0 81 1180 3040 0 424 0117 0 078 if unknown leave blank 3 7 3 8 3 9 Results C Equal layers C Homogeneous earth Homo
42. Freecooling by en C Yes No 4 9 borehole inlet temperature 20 00 4 10 Programm EWS Lizenz f r Huber Energietechnik Huber Energietechnik AG Z rich Fig 3 30 The sheet Extraction with the input of the daily running time of the heat pump 4 1 If the question create new load profile with the following values is answered with yes a load profile with the input data from this sheet is created If the answer is no the program uses the hourly input data from an external input file 4 2 There are two option to create a load profile The input of a daily running time of the heat pump or the input of the monthly heat extraction 4 3 The field 4 3 requires a daily running time for each month If no is selected in the field 4 2 a minus must be added to the running time in the months in which the boreholes are used for cooling what implies that heat is transferred to the borehole 4 11 If yes is selected in the field 4 2 the field 4 11 requires a monthly heat extraction as an input see Fig 3 31 The cooling load must be written with a minus in this option too 4 4 The heat extraction rate in the heating case must be noted with a positive sign If the heat extraction rate is changed the mass flow rate in field 2 7 the sheet fluid is adjusted automatically see description 2 6 2 7 4 5 The heat injection rate in cooling condition must be noted with a positive sign too Bed EWS
43. Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 2 3 Coaxial pipe systems The additional input fields 1 22 1 23 and 1 24 appear if coaxial pipes are selected in field 1 2 Eingabedaten EWS E E e x File Input Import Edition Windows Info npr i 3 Earth traction 5 Info Borehole configuration Calculation 3 1 7 Outer pipe diameter m 0 0320 hd 1 1 1 8 Wall thickness of pipe m 0 0030 Open E 1 2 Typ 1 9 Heat conductivity of pipe W mK 0 40 S n 1 3 Number of boreholes fi For coaxial boreholes Results 1 4 Borehole depth 20 0 1 22 Diameter of inner pipe m 0 0250 1 5 Borehole diameter 0 120 1 23 wallthickness of inner pipe m 0 0025 1 24 Heat conductivity of inner pipe W mK 0 4000 Dimensionless thermal response factor g 1 10 Boundary conditions with g functions ANA Close Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich Fig 3 5 sheet Boreholes selecting of coaxial pipes in field 1 2 The borehole disposition can be entered as following field 1 5 Borehole diameter 2 x field 1 7 Outer pipe diameter 2 x field 1 8 Wall thickness of the pipez rs ro field 1 9 Heat conductivity of the pipe A field 1 22 Diameter of the inner pipe 2 x ra field 1 23 Wall thickness of the inner pipe field 1 24 Heat conductivity of
44. Software Manual Program EWS Version 4 7 Calculation of Borehole Heat Exchangers P A Proa A EWS Sondenanordnung m NS sw 1 4 43 4 644 p Lir ee 6 eed ar 9007 pair PE V oua N ZZ TE WA i GH u NAN SAS vers a RN E Ie GE Nai 2N 7 T Ya 2 mE E 121 0 om 13 0 137 8 I Arthur Huber September 2011 Huber Energietechnik AG Ingenieur und Planungsb ro Jupiterstrasse 26 CH 8032 Z rich Tel 044 227 79 78 Fax 044 227 79 79 http www hetag ch Email mail hetag ch Program EWS Ver 4 7 Huber Energietechnik AG Table of contents 1L DOWIE NNUA 4 1 1 Content and use of the program 4 1 2 a A 4 Lo What is new in the version 4 T essen 4 kA EE sinis MI en e Umm 4 2 Installation and ll6elsill boat oae hte i et onere ea edat e hd cO i Dae 5 2 1 OVS lOM regure IM GINS cca es see 5 2 2 Programm delivery oc 5 2 9 SEAN GUAGE Verson Sen fL cal Ced UE 5 2 4 Program licenses tas de out oca 5 257 2 2 T Um 6 2 6 IHBULOFtherlicense numbers een 6 5 MENS EU seen nel ll ee ass 8 3 1 ASICS Ore data pU esc en elie ac a seien 8 3 1 1 MISSING
45. Ventilation schedule The program EWS is able to generate a ventilation schedule It exists also the possibility to define an hourly ventilation schedule for the whole year in the input file Without defining a schedule the Ventilation rate is kept constant with the values given in field 16 Bed EWS47_En doc 41 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 4 Calculations 4 1 Diagram of the inlet and outlet temperature of the borehole fluid Eingabedaten EWS File Editon Windows Info Inlet Temp December TMin 10 6 C Fluid temp Calculation February March anar April May Save June July August te q see sen MU Air temp Copy Print Close Days 0 3 6 9 12 16 19 22 25 28 31 Probeversion mit Prog EWS Huber Energietechnik Zurich Fig 4 1 Diagram of the inlet and outlet temperature of the fluid in January 32 Ifall fields are completed correctly the simulation is executed and illustrated by clicking on the button Calculation The red line outlet temperature and the blue line inlet temperature in the diagram give the fluid temperature of the corresponding month The two extreme values given in the right upper corner represent the minimal and the maximal temperature Tmin and Tmax during the hole simulation period 33 The results for each month can be viewed printed or copied e g
46. Ver 4 7 Huber Energietechnik AG 3 16 The physical properties of the filling material can be entered directly into these cells 3 17 The procedure to set the values of the borehole resistances R Rp and R is analog to the one for the fields 3 4 3 6 in chapter 3 7 1 3 3 3 6 The arithmetic averages of field 3 16 and 3 17 are shown after each run in the fields 3 3 3 6 P Eingabedaten EWS lolx Fie Input Import Edition Windows Info Boreholes 2 Fluid 3 Earth Axtraction Bio External earth data 3 1 1 Borehole resistances Number of horizontal layers c 3 1 Calculation SWEWS Pipe distance 3 12 0 080 m Shank spacing Open Properties of the earth Properties of the filling 3 4 3 5 3 6 3 2 AM mk p kg m3 cp J koK 3 3 p kg m3 cp J kgK Rb mK W Rc mK W Save Homogeneous 2 40 2600 1000 0 81 1180 3040 0 000 0 000 0 000 if unknown leave blank 13 8 9 3 10 Results Equallayers Homogeneous earth C Homogeneous filling Model of Hellstr m rege 3 C Inhomogeneous earth e Inhomogeneous filling C Input of thermal resistances 12 3 13 3 14 AlW mK plkg m3 cp J kgK AIW mkK plka m3 cp J koK Re mK W Rb mK W Rc mK W 3 11eis33m 2 40 ew ow 3 45 pst Po oo bis6 7m 240 poo oo fost fo bis10 0m 2 40 woo oo v pa 180 soo ooo bist amp 2m 240 oo
47. action rate per borehole length 9 it is possible to calculate the mean borehole temperature over the borehole depth T with T T_ eR T 6 Im Rg g Im Ina g t r4 eq 5 20 thereby is H T dos EAT EI eq 5 21 Bed EWS47 En doc 50 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 5 1 The fluid temperature The mean fluid temperature T is defined as the arithmetic mean of the upward and downward flowing borehole fluid T T Def T z E up z E down z Hence the fluid temperature T is a function of the depth z in the borehole The mean fluid temperature T is defined as eq 5 22 Def Outlet eq 5 23 5 6 Thermal resistances R und R in the double U pipe An idealized double U pipe with the borehole radius r1 and 4 borehole pipes with an inner radius r and an outer radius r is shown in the picture on the left In two borehole pipes the borehole fluid is flowing downward while in the other pipes the fluid flows upward The heat conductivity of the filling is Agi the one of the borehole s and the surrounding earth s heat conductivity is Agarn The exact position of the 4 borehole pipes can be described with the eccentricity parameter b hey Be Bu E eq 5 24 Fig 5 5 The nomenclature on the double U pipe The eccentricity parameter b is defined by the pipe distance Bu shank spacing see Fig 5
48. are B H 0 05 12 boreholes in a square B H 0 1 1 11 g function v Graph of g function 1 12 Graph of gfunction Input g function 1 13 c ves No Close I Fig 3 8 The sheet Boreholes with the borehole configurations to choose from in field 1 11 Bed EWS47 En doc 12 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG In the following the options for the borehole configuration in field 1 11 are explained e single borehole The g function for single boreholes by Eskilson is used 1 x n boreholes e g 1 x 4 boreholes m x n boreholes e g 2 x 3 boreholes 3 boreholes in a triangle 7 boreholes in a L shape 12 boreholes in a square around a building 10 boreholes in a U shape not defined Each borehole is calculated with the equations by Carslaw amp Jaeger eq 5 11 single infinite line sources e special input Description see chapter 3 2 5 Bed EWS47 En doc 13 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG Please pay attention to the following The number in field 1 3 will not be adjusted automatically if the number of boreholes in the field 1 3 is not consistent with the selection in field 1 11 All calculations are always based on the value in field 1 3 Each g function is only valid for a special ratio of the borehole distance B to the borehole depth H If the effective B H r ratio field 1 6a differs from the B
49. ariable mass flow rate the user gets two options Either the heat transfer coefficient a and thereby the thermal borehole resistance R is recalculated for each calculation step or Ry is kept constant for the hole simulation If the field 7 15 is left on the default setting Ry is calculated at the beginning of the simulation on the basis of the design mass flow rate field 2 7 Bed EWS47 En doc 36 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 12 The sheet Pressure To open the sheet Pressure open the pull down menu Windows from the menu bar and select the sheet Pressure or open the pull down menu Input from the menu bar and select Pressure drop see Fig 3 39 This option is only available in the complete version of the program EWS x A Diese Option steht nur in der EvvS volversion zur Verf gung Fig 3 38 Error message if no full version of the EWS Program is available In the sheet Pressure it is possible to calculate the pressure drop in the borehole Additionally the flow regime is calculated laminar or a turbulent flow regime in the pipes A more detailed description of the used model is given in reference 15 P Eingabedaten EWS File Input Import Edition Windows Info Boreholes Fluid Earth Fluid 2 Earh3 Exractiod Info 5 Simulat n ParameiZr Druck 8 Simulation Extraction Parameter drop 8 1 Calculate Info ure drop to be
50. ate R eq 5 30 and the input of Ry will be replaced by this new R In case of any adjustment of the mass flow rate Ra and Ry but not R are set to zero and recalculated with the new mass flow rate eq 5 30 since Ra and Rp depend on the flow velocity of the fluid by the heat transfer rate a The detailed calculation and all possible options are given in 5 There is no need to enter the values of the thermal resistances in the field 3 4 3 6 if Model of Hellstr m in field 3 10 is selected In this case the program EWS calculates the thermal resistances in the next run But the distance between the up going and down going pipe shank spacing field 3 12 must be entered see chapter 3 2 2 using the Model of Hellstr m Generally the default value for the pipe distance can be used The default value for the pipe distance is calculated from the borehole diameter and the pipe diameter under the assumption that the pipes are placed at the borehole s wall However a later adjustment of the borehole diameter does not fit automatically the pipe distance With button 3 11 earth data can be imported from the program SwEWS 11 Caution The number of horizontal layers must always be entered before property data from a SwEWS are imported Bed EWS47 En doc 24 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 7 2 Input of multiple horizontal layers The earth is divided into multiple horizontal layers by
51. ation deco AT orad W m eq 3 2 Directly entering the temperature profile in the undisturbed ground fields 2 15 The surface temperature will in this case be extrapolated linearly out of the first two inserted values To change from method 1 to method 2 field 2 13 must be set to Yes In this case the input fields 2 8 2 10 will disappear and the fields 2 15 and button 2 14 Graph will appear instead With these the temperature profile in the earth can be defined Temperatur 12 13 14 15 1 17 18 19 20 l 1 P Eingabedaten EWS Fie Input Import Edition Windows Info 9 m Borehole Fluid J Earth Exrecionl Info a 4 Properties of fluid monoethylenglykol 20 0 C Open j 2 Heat conductivity of fluid W mK 050 Density of fluid kg m3 fi 037 Save 4 Heat capacity of fluid J kgK 3905 oe 5 Kinematic viscosity of fluid m2 s 00000035 EBENEN b Resu Mass flow rate in all boreholes 2 6 Temperature difference in out K 3 0 Mass flow rate kg s 0 080 27 amp Temperatures in the undisturbed earth gt earth temperatura at 40 earth temperaffire 3 at 50 69 9550 rn e4at 95 Depth m Temperature Profile in the Earth t5 at Li pen d m m a n earth temperature t i 0 30 earth temperature 8 at o m 158 v emer I s
52. calculated 8 2 Yes C No Ventilation schedule Direct coooling pressure drop in evaporator Pa 8 3 fi 0000 mass flow in evaporator kg s 8 4 39 000 339 429 m3 h Pressure drop TE pressure drop in manifold Pa 8 5 5000 72199 Field of boreholes mass flow in manifold kg s 8 6 93 000 339 429 m3 h Single borehole in a field pressure drop in counter 8 7 fo nominal mass flow in counter kg s 8 8 gg 000 339 429 m3 h nominal pressure drop in valve Pa 8 9 D nominal mass flow in valve kg s 8 10 93 000 339 429 m3 h length of inlet pipe m 8 11 number of inlet pipes 6 12 I inner diameter of inlet pipes m 8 13 0 0367 number of bows 8 14 number of immersion sleeves 8 15 EN Pressure drop 8 16 Pa bus turbulent flow regime 8 17 laminar Programm EWS Lizenz f r Probeversion Huber Energietechnik AG Z rich Fig 3 39 The sheet Pressure 8 1 After each change of the input data the button Calculate must be clicked to calculate the new results 8 2 If field 8 2 is set to yes the pressure drop in the borehole pipes without the supply pipes is calculated for each time step and written into the result file one per hour Hence the pressure drop in the result file represents only the pipe itself without the supply pipe and without the pressure drop in the evaporator etc Bed EWS47 En doc 37 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energiet
53. ces of the upward flowing fluid to the inner borehole pipe 1 term of the thermal resistance of the inner borehole pipe 2 term and of the heat transfer resistance from the inner borehole pipe to the downward flowing fluid 3 term R Lb d CE SN eq 5 36 2 mr n 0 2 2 7 r 0 es 5 7 2 Modeling of the borehole resistance R In the case of a coaxial borehole R is defined as the thermal resistance of the outer borehole fluid normally the downward flowing fluid to the wall of the borehole on the radius r 1 1 T 1 R In In eq 9 37 227050 wo SA Lo 25s T Bed EWS47 En doc 53 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 8 The analytical borehole equation 5 8 1 The concept of thermal resistances The concept of thermal resistances is based on a steady condition and postulates a linear relationship between the temperature gradient and the specific heat loss Toser 1 Hestsautes YR q Gl 5 38 The thermal resistance of borehole heat exchanger systems can be split up as follows drilling depth H T Tm R O R R Ja undisturbed borehole average fluid average fluid borehole inlet earth temperature temperature temperature at temperature in temperature at depth H 2 depth H 2 the vaporizer Tm Tb Tf Tf Tic Abb 5 7 Thermal resistance of a borehole heat exchanger systems 5 8
54. d April 21 0 30 Fig 3 32 The selection of the sheet Load f Eingabedaten EWS File Input Import Edition Windows Info goreholes 2Fluid sito Create new load profile with the following values Calculation if no the data from the input file will be taken Yes C No 10 1 heating energy without tap water 800 kWh COP atfullload 3 80 full load heating rate 3 kw Open 10 2 10 8 0 11 10 3 heating energy for tap water 600 kWh COP for tap water 2 80 10 9 tap water heating rate 3 kV 0 12 Save 10 4 load heating energy o wh COP for heating 420 40 30 heating power part load 3 KM 0 13 40 5 cooling energy without base load 200 kWh EER for cooling 3 00 40 1 0 cooling capacity 25 0 kw 10 14 pos 40 6 base load cooling energy D kh 10 7 days of peak load Simulation period years EE max 60 years 10 15 Monthly heating and cooling energy without tap water always as positive number heating cooling heating cooling 10 16 January 3 D kWh July 0 kwn 10 22 10 17 February 270 D kw August Bea kwn 10 23 10 18 March 252 fo kWh September 20 kwh 10 24 10 19 April 171 D kWh October a0 D 010 25 10 20 27 feo kh November 252 0 kwh 10 26 10 21 June E po kWh December 315 bp kwh 10 27 LU Freecooling C Yes e No 10 28 borehole inlet temperature 20 00 c10 29 Close Programm EWS Li
55. d 1 4 3 6 The sheet Info This sheet helps to specify the project to describe the variant and to name the author as well as to add some remarks Eingabedaten EWS ol File Input Import Edition Windows Info Boreholes 2 Fluid Aload 5 Info Project info 5 1 Projekt Erdwaermesonden Description 5 2 Programm EWS Ver 3 9 mit Default Werten BER Author B 3 Huber Energietechnik AG Zuerich Comment Save 5 4 Results Close i Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich Fig 3 22 The sheet Info Bed EWS47 En doc 22 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 7 The sheet Earth On the sheet Earth the thermal properties of the ground and the filling material can be defined Furthermore the number of horizontal layers in the earth are defined on this sheet field 3 1 maximal 10 layers The thermal borehole resistances R and R are entered in the fields 3 4 and 3 5 If the borehole resistances are unknown they can be calculated from the borehole geometry and the properties of the filling material see chapter 5 6 3 1 Basic Inputs f Eingabedaten EWS E e x File Input Import Edition Windows Info em PB Fluid 3 Earth MExraction 5 External earth data 3 1 1 Borehole resistances Number of horizontal layers 3 1 Calculat alculation SwEWS Pipe distance 3 12 0 080 m
56. dels are published in very detailed manner sometimes even with source code of the program in scientific reports and publications An overview of the publications can be found in the reference list The program EWS contains the EWS module which was supported by the Swiss Federal Office of Energy ref 5 6 8 Bed EWS47_En doc 4 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 2 Installation and licensing 2 1 System requirements The following requirements must be fulfilled to ensure a smooth use of the program EWS on your personal computer e processor at least Pentium 800 MHz e operating system Windows 2000 Windows XP Windows Vista Windows 7 e free disk space at least 20 MB e screen resolution at least 1024 x 768 pixel 2 2 Program delivery For legal reasons the program EWS will not be delivered on a physical data medium It can only be downloaded from the internet or sent by email It must be unlocked with a license number 2 3 Language versions The program EWS is available in different language versions English German French Italian Spanish The language can be changed anytime by selecting the favored language in the pull down menu info 2 4 Program licenses The acquisition of a program license authorizes to the installation of the program EWS on one computer of the client It is feasible to obtain a second license number for a second working station e g laptop h
57. do not fulfill eq 3 1 if the last of the four entries concerned field 2 7 In such a case the program neglects the entry in field 2 6 and calculates with the value of the field 2 7 But be aware that if the heat extraction rate field 4 4 is entered after the designed mass flow rate field 2 7 the program adjusts the value of the field 2 7 and calculates no longer with the wanted mass flow rate Thus check the mass flow rate after the three other variables are entered and correct the value if necessary Furthermore it is recommended always to enter the designed temperature difference field 2 6 Bed EWS47 En doc 20 Huber Energietechnik AG Tiefe m u OKT 3 9 1 Program EWS Ver 4 7 Huber Energietechnik AG The temperatures in the undisturbed earth There exist 2 methods to insert the data for the undisturbed temperature in the earth starting condition for the simulation 1 Entering the annual mean air temperature field 2 8 the additional warming of the surface field 2 9 and the temperature gradient the earth field 2 10 With the mean air temperature the dependency of the altitude must be taken into account reduction of some 0 47K at every 100m higher altitude The mean air temperature and the additional warming of the surface are simply added in the program For the temperature gradient AT the geothermal heat flux q and the thermal conductivity of the earth Xga4 exists the following correl
58. e Lizenz ews into the current program folder or enter the license number once more according to chapter 2 6 3 1 2 Decimal points It is important that inputs are always entered with decimal points and never with decimal commas All input information after a decimal comma is ignored by the program and may produce the error message Floating point division by zero EWS Modul x e Floating point division by zero 3 1 3 Default values A default value is allocated for each parameter at the start up of the program These values were chosen carefully with the aim to represent the most common cases Generally it can be calculated with the default value if a simulation parameter is unknown or the sense of a parameter is unclear 3 1 4 Pull down menus Various input fields offer a pull down menu as a help for the data input Normally several input parameters are set to the corresponding values by the selection of an option in the pull down menu Nevertheless please note that these input values can be changed manually afterwards In such a case it may happen that the input values do not agree anymore with the pull down menu The EWS Program deals with this inconsistency by using the manually entered values and by ignoring the pull down selection gt Generally the EWS Program does not calculate with the values from the selection in the pull down menu but always with input field associated to the input parameter These input fields can
59. e see Fig 3 40 In the following the sheet heat pump appears see Fig 3 41 The sheet Heat Pump can not be combined with the sheet Load Eingabedaten EWS Fie Input import Eadhon wiekkws Info Syster raph Boreho Exrar on Info Sir Ing Bec ire Pre Cadculetion Liston i amp ETT calculated m cenare Fa mss Bow in evaporator Kg s Fig 3 40 The opening of the sheet heat pump W rmepumpe E a x Heat pumpe properties and supplementary heating system Calculate heat extraction rate with heat pump properties 9 1 C ves No Heating power of heat pump at 0 C fi 5 9 5 lw 9 2 COP at 5 C 2 50 Minimal borehole inlet temperature 0 0 96 9 3 COP at 0 C 3 00 COP at 10 C 4 00 9 7 optional input 9 4 COPat5 C 350 COP at 15 C 450 9 8 optional input Borehole circulation pump El power consumption of borehole pump 50 W 99 Bivalent heating system 91 C Yes No Power of supplementary heating system 0 0 kw 9 1 9 1 Calculation 9 1 Graph 9 1 Fig 3 41 The input mask of the heat pump properties and the additional heating system 9 1 The inputs from this mask are used for the calculation if the question Calculate heat extraction rate with heat pump properties is answered with yes In a first step the program checks the consistency of the input data in field 9 5 heating power o
60. e found e g at Loose 18 Especially for unbalanced annual heat extraction balances the knowledge of the time constant t is fundamental The equilibrium condition between heat extraction and heat inflow from the surrounding earth is reached after approximately Es 10 For a single borehole the dimensionless thermal response g g function by Eskilson 1987 is only a function of the dimensionless time Es and the dimensionless borehole distance ry H This is based on the assumption of a constant specific heat extraction rate per borehole length 9 Bed EWS47_En doc 48 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG For single boreholes within a range of 5r a lt t lt t the g function can be approached with a maximal deviation of 7 by H g t 1 nt s 0 5 In Es eq 5 14 1 For time periods longer than t the single borehole converge to the following equilibrium condition H zn g r a eq 5 15 As an example the g function of two boreholes in a distance B between the boreholes is shown in Fig 5 3 As a comparison the g function of a single borehole is illustrated with a dashed line Other thermal responses for borehole fields can be found in the ANNEX 2 boreholes rb H 0 0005 a funct ion 5 4 3 2 2 3 4 Inck t Fig 5 3 The dimensionless thermal response g for 2 boreholes with a distance B by 3 5 3 4 The comparison of the models In Fig 5 4 t
61. e of the inflowing borehole fluid Tup temperature of the upward flowing fluid on the depth z C f borehole time constant 5 Bed EWS47 En doc 59 Huber Energietechnik AG Program EWS Ver 4 7 N YTS Hd QR N earth Aisol As Aw 8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Bed_ Huber Energietechnik AG flow velocity m s wall thickness of the inner pipe of a coaxial borehole ra ri m depth in the earth measured from the earth s surface m Greek symbols heat transfer coefficient of the borehole fluid W m K dimensionless thermal resistance from the borehole pipe to the fluid dimensionless pressure loss coefficient pipe friction number often Euler constant 0 5772 kinematic viscosity of the borehole fluid m s heat conductivity of the earth W mk heat conductivity of the borehole filling W mk heat conductivity of the isolated borehole pipe W mk heat conductivity of the borehole pipe W mk heat conductivity of the inner pipe of a coaxial borehole W mk conductivity parameter of the borehole filling Literature Carslaw H S Jaeger J C 1959 Conduction of heat in solids 2 ed Oxford Univers Press London Claesson J Eskilson P 1987 Conductive Heat Extraction by a Deep Borehole Analytical Studies Dep of Mathematical Physics University of Lund Eskilson P 1987 The
62. echnik AG 8 3 8 10 The input of the nominal pressure drop of single components at nominal mass flow rates The nominal mass flow rate can vary for each component The conversion to the effective pressure drop is done with the parable approach 8 11 The length of the supply pipe normally from the head to the manifold of the pipe The program EWS calculates the total pressure drop from the pressure drop of the borehole plus the sum of the single components from the borehole loop plus 2 times the pressure drop from the supply pipe from and to the borehole 8 12 The number of parallel inlet pipes for the pressure drop calculation from the head of the pipe to the manifold E g if the pipes of a double U pipe go separately towards the manifold the input in field 8 12 should be 2 but if the pipes are united at the head of the pipe the correct input is 1 It is the same behavior if two boreholes are entering the house by a manifold If the pipes of two double U pipes are going separately to the manifold the correct input in the field 8 12 is 4 If the pipes are united at each head of the two double U pipes a 2 should be entered If the manifold is very close to the two double U pipes and there is a long supply pipe to the house the input is 1 8 13 The inner diameter of the supply pipes normally from the head of the pipe to the manifold The inner diameter of the inlet pipe DN 40 usually is 0 032 m for DN 50 it is 0 037 m 8 14 8 15 The nu
63. ect the last option in the field 1 11 which is special input Then select yes in the fields 1 10 and 1 13 The function values of the g function are read from the graph in Fig 6 1 on the supporting points In t ts 4 2 0 2 3 The values are g In t ts 4 5 09 g In t ts 2 7 00 g In t ts 0 10 86 g In t ts 2 14 68 g In t ts 3 14 91 These function values are to be entered in the fields 1 15 to 1 19 The borehole distance must be adjusted in field 1 20 in a way that the B H ratio in field 1 21 is equal to 0 1 This means that the input in field 1 20 must be 10m since the length of the borehole H is given 100m PP Eingabedaten EWS lolx File Input Import Edition Windows Info fforeholes ZFiuic 3 Earth Attraction 5 Info Borehole configuration lenken 1 7 Outer pipe diameter m 0 0320 1 1 32 mm double U pipe 1 8 Wall thickness of pipe m 0 0030 Open P 1 2 Typ oor 1 9 Heat conductivity of pipe W mK 0 40 nn 1 3 Number ofboreholes 1 4 SERI Borehole depth 100 0 1 5 Borehole diameter 0 120 1 6 Borehole distance 000 1 6a Dimensionless thermal response g function 1 14 1 H 0 0005 1 10 Boundary conditions with g functions o cc 1 15 ints 4 5 03 l 1 16 In t ts 2 700 a function i EEE T 1 17 ntits 0 o6 Graph of g function 1 12 Graph of g function 1 18 In t ts 2 fi 4 68 1 19 3
64. entering the corresponding number gt 1 in field 3 1 see Fig 3 26 The maximal number of layers which can be defined is 10 The layers are equally spaced if equal is selected in field 3 7 The option unequal in field 3 7 must be selected to enter layers with variable depths available only in the full version The selected number of layers also corresponds to the number of layers in the numerical calculation but these layers are always equally spaced over the borehole depth see chapter 3 7 1 The depth of the deepest geological layer must always be gt the borehole depth JP Eingabedaten EWS m a x File Input Import Edition Windows Info mm Boreholes 2 Fluid Earth Axtraction 5 Info 3 1 External earth data 3 1 1 Borehole resistances Number of horizontal fel Iculat E Calculation SwEWS Pipe distance 3 12 oos0 m i A Shank spacing Open Properties of the earth Properties of the filling 3 4 3 5 3 6 3 2 p kg m3 cp J kgK 3 3 ADW mk plkg m3 cp J kgK Ra mK W Rb mK W Re mK W Save Homogeneous 2 40 2500 1000 0 81 1180 3040 0 000 0 000 0 000 if unknown leave blank 7 3 8 59 3 40 Results C Equal layers Homogeneous earth Homogeneous filling Model of Hellstrom Unequal layers C Inhomogeneous earth dong d C Inhomogeneous filling C Input of thermal resistances Depth a W m 13 3 11f200 m 240 feso oo 3 15
65. er boundary condition is calculated with the dimensionless thermal response factor g functions see 5 3 3 There is the option to chose between the method of Carslaw amp Jaeger 1 or the one of Eskilson 3 The problem of the inconstant heat extraction rate and the regeneration of the earth can be solved by the superposition of an optional number of constant heat Simulation extraction rates which start at different times area The chosen method allows us to use different time Outer boundary condition with thermal response steps within the program The shortest time step is used for the unsteady calculation of the fluid while the Crank Nicholson calculation in the simulation area is done with a larger time step Even a time step of one week is sufficient for the calculation of the ground with the g functions outside of the simulation area The different time steps are plausible because of the following reasons The smallest time step is needed close to the boreholes since temperature disturbances always come from the boreholes Farther from the boreholes only averaged heat extractions or inputs are observed The use of different time steps allows us to simulate the boreholes with less computing time compared to other methods and without a loss of accuracy Bed EWS47 En doc 44 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 1 1 The simulation of the time step Basically there are two operation
66. etechnik Zurich Fig 3 34 The extraction rate profile of an intermittent mode created with the sheet Load Bed EWS47 En doc 32 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 10 The sheet Simulation 3 10 1 The sheet Simulation Various special calculations can be done with the sheet Simulation Open the sheet Simulation with the pull down menu Windows from the menu bar and select Simulation see Fig 3 35 Eingabedaten EWS File Input Import Edition Windows Info System Aorehole Graph Input Results h Aload 5 Info S ulation culation of the fluid Calculation 6 1 Yes C No pressure Input of borehole inlet temperature or heat extraction rate Save Iteration of borehole heat extraction rate heat extraction rate given Yes No 6 2 Results Antifreeze C Yes N ES 6 12 at minimal borehole temperature 3393 00 6 14 Minimal borehole inlettemper ture 3 00 c6 13 supplementary heating system D 6 4 5 Calculation of thermal response Thermal response Yes e No 6 3 Heat extraction step 1 00 kw6 5 Duration ofthermal response Cth 1month 6 4 Temperature step 20 00 C 6 6 Size of input file Number oftime steps on the input file 8760 6 7 Simulation period Estimate the temperature starting condition Yes No 6 8 fast calculation with less precisi
67. f the heat pump in field 9 3 COP at 0 C borehole outlet temperature and in field 4 4 evaporator power extraction rate In the case of inconsistent input data the program EWS asks if the input in field 4 4 should be adjusted If then the field 4 4 is not adjusted field 9 5 is ignored for all further calculations The extraction rate field 4 4 is taken as the evaporator power at 0 C if yes is selected in field 9 1 In each calculation step the effective evaporator power is adapted to the effective COP Thereby the program EWS assumes a constant heating power corresponding to the input in field 9 5 9 2 9 4 9 7 9 8 In these fields the COP of the various fluid temperatures are entered The inputs in field 9 7 and 9 8 are optional If these values are not known these fields can be set to zero and the program calculates them by a linear extrapolation 9 9 The electric power consumption of the borehole pump ought to be entered in this field 9 10 9 11 In case of a bivalent heating system the power of the supplementary heating system can be entered in the field 9 11 The field 9 10 must be set to yes applied only in the case of a complete system simulation Bed EWS47 En doc 39 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 14 Direct cooling The complete version of the program EWS offers the option to enter data about the direct cooling Select the sheet System from the pull down me
68. fined in the example given below see Fig 3 28 The table must be saved as a text file txt with the name Geologie txt in the same folder as the program EWS In a next step it must be renamed to Geologie ews Thereafter the created library is available in the pull down menu see Fig 3 29 Caution The program EWS can only deal with decimal points no decimal commas Entries with decimal commas cause an error Bed EWS47 En doc 27 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG E Microsoft Excel 1 _ inix Ses Ses Bee 210 Qe m Mi lce emaa o 2 Limestone Baden 26 240 31100 _ 3 Limestone Jua 28 2500 1350 4 rok3 24 80 2200 5b jrck4 24 800 220 6 rck5 24 80 3 220 T rok6 24 80 220 8 frock 24 80 32200 Q 8 rck8 24 80 X 220 rok9 24 A 800 X 220 AU Mjockit 24 80 X 220 12 rok1l 24 80 _ 220 13 rock12 1 24 800 3 220 14 rock13 _ 24 80 _ 3220 Asrock 24 680 A 3220 _16 rock 15 224 80 220 AT jrock 16 24 8002200 2 4 Lo 4 Lo rock 17 19 rock 18 2 Klal IN Tabelte Tabele2 Tabeles 1 NNI Eingabedaten EWS
69. for a specific B H ratio The B H ratio in the field 1 21 is calculated from the borehole distance B field 1 20 and the borehole depth H field 1 4 First the field 1 21 must be harmonized with the B H ratio of the favored g function This can be done by adjusting the field 1 20 The borehole depth in the field 1 4 must not be changed Thereafter the function values of the favored g function on the data points In t ts 4 2 0 2 3 are entered in the fields 1 15 to 1 19 The g function is now completely defined by the fields 1 15 to 1 21 Remarks e Field 1 14 shows the ratio of the borehole radius and the borehole depth H This ratio is 0 0005 for all g functions in the program library and for most of the published g functions It can not be changed and it is published to the sake of completeness e 15 still the effective ratio from the field 1 6a and not the ratio from the field 1 21 that defines the result of the calculation During the next calculation the EWS Program will automatically extrapolate the entered g function to the effective B H ratio e If g function was entered under special input in the field 1 11 as described above this g function can be saved and later be reloaded from the option special input e More detailed information about the g function can be found in the ANNEX Bed EWS47 En doc 15 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG
70. geneous filling Model of Hellstr m Unequal layers Inhomogeneous earth C Inhomogeneous filling C Inputofthermal resistances 3 12 3 13 3 14 Depth p kg m3 cp J kgK 3 11 fso m 2200 900 humid rubble 200 m fiso 2200 soo humid clay z 60 0 m 3 40 2500 1200 granite 3 15 300 m x10 2700 1000 special granite z i00 m 240 2600 ioo z 2000 m 2 40 260 z Programm EWS Lizenz f r heim Huber Energietechnik AG Z rich Fig 3 27 The sheet Earth nomenclature of rocks and the input of their property data 3 7 4 Creation of a user defined geological library The program EWS offers the possibility to create a user defined geological library with a maximum of 30 different earth types and their physical properties Once the library is established it is loaded automatically when the program is started and the entries appear in the pull down menu field 3 15 The first step to establish a library is to create a table in excel with the name of the earth types and the appropriate physical properties see Fig 3 28 The names and the properties must be entered below the header row 2 31 The names must be entered in the first column the A values in the second column the p values in the third column and the specific heat capacity in the forth column There are two different types of limestone limestone region Baden and limestone region Jura de
71. grounded in physic values Therefore the physical values are not introduced In the first part the user will be familiarized with the input data In the second part the manual gives information about the calculation procedure 1 3 What is new in the version 4 7 The following new features are implemented in the version 4 7 Possibility to insert a scaled background map to simplify the input of the borehole configuration optimal borehole length is calculated automatically according to the norm SIA 384 6 the undisturbed temperature profile in the earth can be entered starting condition for the simulation in up to 10 layers possibility for a free arrangement for up to 100 boreholes in a field calculation of the pressure loss for the hole borehole heat exchanger system new worksheet load profile that allows the input of the monthly heating and cooling energy demand as well as the heat demand for the tap water of the building new input for geological profiles with unequal layers and the possibility to create a user defined library of geological data 1 4 Further literature During the elaboration of the program EWS it was paid highly attention to the fact that users with no deeper comprehension of the models should be able to use the program Hence a default value for each set of input is provided In most cases these default values lead to reasonable results The manual does not present all the models that are used in the code But these mo
72. he blue boreholes give a higher yield the red boreholes give a lower yield Bed EWS47 En doc 17 Huber Energietechnik AG Program EWS Ver 4 7 4 Huber Energietechnik AG 3 3 2 Inserting a background map in 4 easy steps In the full version of the program there exists the possibility to insert a background map This map can be scaled The picture of the map has to be in the BMP format and must be stored in the clipboard first e g by getting a printscreen of one of the existing GIS browsers and can than be pasted into the sheet field of boreholes by pressing on the middle mouse button mouse wheel In the next step the grid must be scaled to fit to the inserted map To do so with the button S8 scale a well known distance can be inserted in field S9 and defined on the map by marking the starting point Mp1 and the ending point Mp2 with the left mouse button With the buttons S6 and S7 the map and the grid finally can be set to the favored size on the screen Now we are ready to define the positions of the borehole as described in 3 3 1 As soon as the first borehole is set the background map can not be changed any more In the following pictures the 4 steps to insert a background map are shown in detail SE KANTON Z RICH nto e GIS BROWSER N BASISKARTEN LANDESKARTEN Een N X Online Karten des Kantons Z rich http www gis zh ch Zentrum 690477 247643 Bildbreite ca 165 m Ma
73. he approach by Carslaw amp Jaeger for an infinitively deep borehole is compared to the approach by Eskilson for a borehole with a depth of 10m 100m and 500m respectively There is almost no deviation of the models observed until the time constant t is reached dimensionless thermal response g from various references 0 0 001 0 010 0 100 1 000 10 000 100 000 1000 000 10000 000 years a 0 000001 m2 s rb 0 06m Werner Eskilson borehole depth 500m Eskilson borehole depth 100m Eskilson borehole depth 10m Carslaw amp Jaeger Fig 5 4 The dimensionless thermal response g by Carslaw amp Jaeger 1 and Eskilson 3 Bed EWS47 En doc 49 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 4 The calculation of the g function with the principle of superposition Normally each borehole in a field of boreholes is fed with a fluid of the same borehole inlet temperature by a manifold Hence the load is attached parallel to all boreholes In this case the g function of a borehole field can be approached by the superposition of various single boreholes We do not have to think about a deviation for shorter time steps unsteady effects since the program EWS only uses the g functions as an outer boundary condition w
74. hich usually is calculated in time steps of one week Thus the accuracy of the steady equation is sufficient to approximate the influence of the borehole field on a single borehole x The borehole distance A between the borehole x and the borehole y is used instead of r4 MOORE FOR 25 eq 5 16 1 1 1 With a parallel operation of the boreholes the g function of the whole borehole field can be calculated with the average value of all n boreholes a se n x 1 y l n 5 5 The borehole temperature T and the fluid temperature T The thermal response AT has to be subtracted from the undisturbed earth temperature at the beginning Tm to get the temperature in the earth principle of superposition The temperature on the border of the borehole Tearn r 7borehole temperature can be calculated from g and Tm with T 2 Tm z Ry nl giri eq 5 18 art Tm Is the averaged earth temperature in the depth z under undisturbed conditions It is calculated with the averaged annual surface temperature of the earth Tmo and the temperature gradient AT eraa The averaged annual surface temperature is equal to the averaged air temperature plus a mean surface warming which usually is between 0 8 and 2 C The temperature gradient ATcraa typically ranges from 0 025 to 0 045 K m The mean borehole temperature over the borehole depth T is defined as lt j Def T TE dz eq 5 19 In the case of a constant heat extr
75. ion ts 38 2 a LLL 27 24 24 21 21 Ag 8 18 18 Tee Sil i ati i i A A Mg 15 15 12 12 9 9 3 3 Init ts H Init ts H 0 0 gt amp amp 453 2 d 2 3 7 6 5 4 3 2 4 2 3 Fig 3 18 The comparison of 2 borehole fields with 50 borehole of 100m depth and 10m distance 3 4 Calculation of a single borehole in a field of boreholes There exists the possibility to calculate the g function of a single borehole in a field of boreholes see Fig 3 19 if the borehole field was defined according to the en in chapter 3 3 Eingabedaten EWS Mp Fie Input Import Edition Windows Info Boreholes de T Fluid F 1s Earth Fluid 2 Earth 3 Exracti A Info 5 A ol Simulation AE Extraction e configuration ar A LL EEE coool Parameter IEEE ule pips cometan Mania BEHEEHSHBBBEBH info ouble U pipe wWaliticinsesof eit Se SE E Direct cooolin Heat conductivity of g C coaxial U pipe B UBER EEE ggg Heat pump y pressure drop of boreholes 5 HH ine HERB REG 100 0 IN IEEE nn 0 135 BERR oo ee A EE EN H 4 Dimensionless thermal HHH _ E Hour Boundary conditions with g functions Yes C No 1 10 IEEE rnc HHHHEHEHHHEEHH In t ts 2 6727 1 16 g function Special input 1 11 nee 0 fo 090 1
76. k AG The classical case of the thermal response test extracts or adds the ground a constant heat rate This rate must be entered in field 6 5 Thereby it must be paid attention to the convention of the signs e positive sign gt heat extraction from the earth e negative sign gt heat induction to the earth The temperature step field 6 6 is ignored in this type of response test Do not forget to enter or readjust the correct mass flow rate field 2 7 Fig 3 36 illustrates the first 60 minutes of the thermal response of a borehole 40mm double U pipe depth 150 m mass flow rate 0 7 kg s of 33 monoethylenglykol heat input of 10kW The first temperature maximum after 6 5 minutes is clearly visible This maximum is a consequence of the piston effect of the fluid an Inlet Temp Temperature C thermal response TMin 142 C 30 borehole outlet temperature 22 7 1 minutes 0 b 12 18 24 30 3 4 48 54 P0 Von Huber Energietechnik AG mit Prog EWS Huber Energietechnik Z rich Fig 3 36 The example of the thermal response of a borehole during the first hour There is another type of the thermal response test which is less frequently used In this type the borehole inlet temperature is constant and the borehole outlet temperature and the borehole heat extraction rate is analyzed For this type of response test field 6 2 Iteration of borehole heat extraction rate must be set to no and the
77. m ofthe supply air 0 00 Energy gain of heat recovery system fo kh El power consumption of borehole pump W Total heat demand 2416 kwWh Power of supplementary heating system d Not coverd by heat pump Do kWh COPF of heat pump at 5 C covered by supplementary heating COP of heat pump at 0 C Electrical power consumption of heat pump kWh COP of heat pump at 5 C Electrical power consumption of circulation pump E kWh COP of heat pump at 10 C Average COP of heat pump ooo COP of heat pump at 15 C Seasonal performance factor of heat pump oo Annual running time of heat pump 2418 h Pressure drop in borehole 610 Pa Fig 4 3 The sheet Results The following points must be taken into account e The indicated pressure loss for the designed mass flow rate considers only the borehole heat exchanger without the pressure loss in the supply pipe and in the vaporizer The pressure loss of the hole borehole heat exchanger loop and information about laminar or turbulent flow in the borehole can be found in the sheet Pressure chapter 3 12 Additionally the result file shows hourly pressure loss values e The total heat demand If the load was defined with the sheet Extraction chapter 3 7 this field shows the sum of the heat extraction of the borehole during the last year If the load was defined with the sheet Load chapter 3 8 the field total heat demand indicates the heat demand of
78. mber of immersion sleeves and bows in the borehole loop enter the number of the total loop add the bows in the inlet and outlet pipe The pressure drop is calculated with Ap e eq 3 3 in which amp 2 is entered for each bow and 1 for each immersion sleeve 8 16 The pressure drop for the hole borehole loop Please note that after each change of any input data the button Calculate must be pressed to adjust the result The pressure drop Ap of the flow in the borehole and in the inlet pipe is calculated with B P sole 2 D 2 eq 3 4 In the laminar case Re lt 2 300 is calculated with 64 eq 3 5 T q In the turbulent case Re gt 2 300 the approach by Petukhov is used E 0 790 In Re 1 64 eq 3 6 All other pressure drops are converted from the nominal mass flow to the effective borehole mass flow using the parabolic approach 8 17 Information about the flow regime in the borehole laminar or turbulent The transition between laminar and turbulent flow occurs at a Reynolds number of 2 300 Bed EWS47 En doc 38 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 13 Properties of the heat pump and of the supplementary heating system The complete version of the program EWS is able to include additional information about the heat pump as well as about the additional heating system Select the sheet Heat pump from the pull down menu Windows in the menu bar
79. me of the company by e mail to mailghetag ch The individual license number will be sent back to you within 48 hours Lizenznummer x This program is licensed for Installation number 133333 Y our license number number of trial version is 4701 Close Installation number OK The license number and the company name should be entered into the designated fields Keep the license number safe since after a certain time it might be necessary to enter the license number again Lizenznummer Installation number 333333 Yaurlieense number 8888888888 number of trial version is 4701 Close Installation number C After the finalization of the installation it is necessary to do one calculation with the program EWS by using its unchanged default values Only now it can be continued with the data input Bed EWS47 En doc n Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 3 Data input 3 1 Basics of the data input 3 1 1 Missing file Lizenz ews There is no license number entered yet see chapter 2 6 if the following error message appears during the start up of the program xl A Noch keine Lizenznummer eingegeben Oeffnen Sie INFO If you have already entered the license number and the error message still appears please assure that the file Lizenz ews is in the same folder as the program Ews exe Is this not the case copy the fil
80. n EWS 1 lo x Fie Input Import Edition Windows Info oo Porenoles 2 Fluid 3Earth amp kraction 5 Info Borehole configuration Calculation 1 7 Outer pipe diameter m 0 0320 ac mm doubie U nipe 1 8 Wall thickness of pipe m 0 0030 ELLE ee 1 9 Heat conductivity of pipe W mK 0 40 40 mm double U pipe Save 50 mm double U pipe 1 1 53 mm coaxial pipes Geowatt Results 75 mm coaxial pipes Geowatt 80 mm coaxial pipes Geowatt 32 mm single U pipe 40 mm single U pipe Dimensionless thermal response factor g 1 10 Boundary conditions with g functions Yes No Close Programm EWS Lizenz f r Huber Huber Energietechnik AG Zurich Fig 3 3 The sheet Boreholes with its options to choose in field 1 1 Especially for the borehole diameter there can be bigger deviations from the default value depending on the ground properties and the used drilling technology Check the borehole diameter carefully field 1 5 3 2 2 Boreholes with double U pipes The borehole disposition can be entered in the following manner field 1 5 Borehole diameter 2 x r4 field 1 7 Outer pipe diameter 2 x rs Lm field 1 8 Wall thickness of the pipe rs ro Bu field 1 9 Heat conductivity of the pipe A x field 3 11 Shank spacing Bu CES field 3 3 Heat conductivity of the filling A Earth Keil Fig 3 4 Double U pipe s nomenclatures Bed EWS47 En doc 10
81. nd delete boreholes in a field of boreholes It is possible to freely locate up to 100 boreholes on a field of boreholes by clicking with the left mouse button Directly below each of the boreholes appears the borehole number counting up from one in the order of the borehole setting followed by the x coordinate and the y coordinate of the borehole The x coordinate and the y coordinate correspond to the distance in meter from the left upper corner of the grid With the button S4 the grid spacing can be changed from 1 m to 10 m Each borehole can be set with a precision of 10 cm and can be dislocated anytime To dislocate the borehole select the centre of the borehole with the eft mouse button and dislocate it still pressing the left mouse button It is also possible to delete boreholes To do so select the centre of the borehole with the right mouse button and remove the borehole still pressing the right mouse button Thereby the corresponding borehole disappears Immediately all other boreholes are newly numerated Clicking on the button S3 3 concentric circles around the boreholes appear whereof the colors give a hint at the g value of the field of boreholes Red indicates a high g value and blue stands for a low value The color scale is not an absolute scale but a relative The highest value in the field of boreholes always has the same red while the lowest value has the same blue The colors give a hint at the relative distribution of the
82. nu Windows in the menu bare see Fig 3 42 In the following the sheet System appears see Fig 3 43 15 16 17 18 Eingabedaten EWS File Input Import Edition Windows Info Graph Boreho Heat Pump Input Results Bor function Calculation Simulation j Parameter Open Typ Fig 3 42 Selection of the input mask System of the direct cooling rth Extraction Info Simulation pressure C coaxial U pipe 9 Meteo data Fig 3 43 The input mask System for direct cooling systems without HP The following data must be entered in field 15 top down The degree of the efficiency of the heat recovery system the temperature rise in the supply air ventilator the desired temperature of the supply air maximum supply temperature the condensation limit minimum supply temperature and the installed cooling power of an additional chiller not shown The regular air flow and the air flow in cooling condition are entered here Field 17 requires the characteristics of the various heat exchangers in the system 3 units Additionally there are 4 pumps available for which the mass flow rate must be entered The input in field 18 defines the heating and cooling limits If the outdoor temperature is higher then the cooling limit the system is in cooling mode if the outdoor temperature is lower then the heating limit the system is in heating mode Bed EWS
83. ome computer without additional charge if the computer is exclusively used by one person In the case of the substitution of the old computer it can be applied for a third license In all other cases supplementary program licenses must be purchased for additional installations Program licenses are unassignable and must not be resold Schools get special conditions School licenses are not allowed to be used for commercial calculations Bed EWS47 En doc 5 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 2 5 Installation The program EWS requires no installation Just copy the file Ews exe into your favored program folder on the computer The program EWS can be unlocked by the entry of the license number Thereby 3 types of license numbers are distinguished 1 license number for test version 4701 2 license number for a basic installation 3 license number for full version According to the license number a different functional range is available 2 6 Input of the license number The test version as well as the basic version and the full version must be unlocked by the input of a license number The corresponding procedure is described in the following Huber Energietechnik AG Ingenieur und Planungsb ro Jupiterstrasse 26 CH 8032 Z rich Calculation of borehole heat exchangers huber hetag ch Open project Information Program EWS Version 4 7 Sep 2011 Autor Arthur Hube
84. on 8 additional cooling COP heating of add coolin 6 1 0 Close if freecooling is not enough C Yes No 6 9 9 a On if coverage is beneath 0 70 0 604 Programm EWS Lizenz f r Huber Energietechnik Huber Energietechnik AG Z rich Fig 3 35 The opening of the sheet Simulation The following special calculations can be executed with the sheet Simulation The unsteady calculation of the fluid field 6 1 The default setting of the program does steady state calculations of the fluid like it can be found in ref 5 and 6 The input of the extraction rate e g forced by the heat pump or the borehole inlet temperature e g direct cooling For these cases the field 6 2 must be selected yes The default setting calculates the needed outlet and inlet temperature of the borehole fluid to generate the wanted extraction rate of the heat pump More detailed information can be found in chapter 4 1 The calculation of the thermal response response test field 6 3 More details can be found in chapter 5 3 3 The size of the input file field 6 7 The default setting calculates 8760 steps of 60 minutes But it is possible to calculate a time period of less than one year and hence to calculate with a smaller input files Note There are max 8760 time steps possible The estimation of the start temperature field 6 8 This option results in a shorter calculation time for long simulation periods gt
85. r Huber Energietechnik AG Copyright Rechenmodul EWS Bundesamt f r Energie BFE Bern Programm EWS Huber Energietechnik AG Jupiterstrasse 26 CH 8032 Zurich Ingenieur und Planungsb ro Tel 41 44 22 79 78 Fax 41 44 227 79 79 mail hetag ch Literatur Berechnungsmodul fur Erdw rmesonden ENET Nr 9658607 1 1997 Erweiterung des Programms EWS f r Erw rmesondenfelder ENET Nr 3819227 1999 This program contains the EWS module developed by mandate of the Swiss Federal Office of Energy Lizenz Nr 64701 EWS Ver4 fur Probeversion Bed EWS47 En doc 6 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG Test version The word Probeversion must be written in the designated field instead of the company name to unlock the test version The license number of the test version is 4701 _lolx This program is licensed for Ben Probeversion Installation number Your license number number of trial version is 4701 Close Installation number The test version offers to everybody the complete functional range of the full program version But there are some restrictions to a part of entries that can not be changed e g length of the boreholes substance properties Basic and full version The installation number is shown by pushing the button Installation number This number has a particular value for each personal computer This number has to be sent together with the na
86. ratio is 0 08 The extrapolated g function using the value in field 1 12 is shown in Fig 6 4 TT gfunction ts 37 2 a g function Copy Fig 6 4 The graph of the g function in Fig 6 2 extrapolated from B Her 0 08 Bed EWS47 En doc 58 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 7 Table of symbols 7 1 Latin symbols a thermal diffusivity m2 s b eccentricity parameter of a double U pipe B distance between different boreholes m Bu shank spacing between the pipes of the upward and the downward flowing fluid m CPsole specific heat capacity of the fluid J kgK D inner diameter of the borehole pipe m DimAxi number of calculation nodes in axial direction DimRad number of calculation nodes in radial direction Es Eskilson number dimensionless time f grid factor for the calculation grid in radial direction 9 g function dimensionless thermal response of the earth by Eskilson H borehole length borehole depth m m mass flow rate mass flow rate in the boreholes kg s m number of calculation nodes in the radial direction DimRad Nu Nusselt number Pr Prandtl number Ap pressure drop Pa q specific heat extraction rate of the borehole per length W m 0925 natural undisturbed geothermal heat flow W m2 Ag heat loss of the upward flowing fluid to the downward flowing fluid W m O extraction rate injection rate power IW Re Reynolds number
87. re 3 C Close Programm EWS Lizenz f r Huber Energietechnik Huber Energietechnik AG Z rich Fig 3 20 The sheet Fluid field 2 1 By selecting one composition of the fluid in the pull down field 2 1 all corresponding data the heat conductivity the density the specific heat capacity and the kinematic viscosity of the fluid are entered automatically If the used fluid is not listed in the pull down field 2 1 there is the possibility to select not defined and to enter the values of fields 2 2 to 2 5 manually fields 2 6 2 7 The required input in field 2 7 is the designed mass flow rate cumulated mass flow of all boreholes If this mass flow rate is unknown there exists the possibility to enter the temperature difference between the borehole inlet and the borehole outlet temperature in field 2 6 Immediately the program adjusts the mass flow rate field 2 7 using the eq 3 1 and the inputs of the heat extraction rate field 4 4 the temperature difference field 2 6 and the heat capacity of the fluid field 2 4 It is important to know that the program does all calculation using the value of the mass flow rate field 2 7 The value in field 2 7 can be changed anytime without causing an adjustment of other variables while changes of the other variables fields 2 4 2 6 4 4 result in an adjustment of the mass flow rate m T eq 3 1 Hence it is possible that the four variables are inconsistent and
88. rgietechnik AG 5 2 Calculation grid The calculations are done in an axially symmetric grid The ground is divided in the axial direction into equal segments of the length dl borehole diameter Dy The grid is variable in the radial direction The grid is defined by the grid factor f borehole r lj length Gitterfaktor f earth j eq 5 1 Lj ja The grid can be calculated as given in eq 5 2 to eq 5 4 if the simulation area is set to the maximal calculation radius rm whereof m represents the number of calculation point in the radial direction gt p 7 eq 5 2 D borehole diameter p ES mn eq 5 3 he for jz2 ee eq 5 4 TEarth i 4 A grid factor of 2 doubles the difference of the radius between two calculation volumes Earth The mass balance point which is important for the determination of the thermal resistance can be calculated as showed below Filling eq 5 5 Fig 5 2 The calculation grid of the borehole Bed EWS47_En doc 46 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG 5 3 Heat Equation and the thermal response g 5 3 1 Heat Equation For the following considerations it is assumed that the dominant heat transport mechanism in the earth is the heat conductivity Hence the convective heat transport by water flows in the earth is negligible The problem of the heat conductivity of the earth around a borehole is axially symmetric
89. rk and there is no heat extraction any more from the borehole In order to be able to calculate the missing heat when the heat pump stops to work the COP of the heat pump at the minimal brine temperature must be given in field 6 14 In field 6 15 the missing heat production of the heat pump is added up after the calculation of the system 3 10 5 The response test Open the sheet Simulation menu bar Windows to check the thermal response test see Fig 3 35 Select the thermal response on the sheet Simulation field 6 3 This changes automatically various default values Itis only possible to calculate reasonable results for the unsteady borehole fluid Therefore field 6 1 is set to no e The calculation of the thermal response must be done with the maximal number of ground layers Thus the number of horizontal layers in the earth is set to 10 field 3 1 e The time steps for the simulation of the fluid and of the earth are reduced For this purpose the time step factor of the fluid field 7 5 security 1 is changed from 4 to 40 and the one of the earth field 7 6 security 2 from 2 to 20 e The time step to calculate the boreholes is set to 1 minute if the duration of the thermal response is set to 1 h field 6 4 e The size of the input file for the thermal response field 6 7 is adapted to the duration of the thermal response Bed EWS47_En doc 34 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechni
90. rmal Analysis of Heat Extraction Boreholes Department of Mathematical Physics Lund Institute of Technology Lund Sweden ISBN 91 7900 298 6 Hellstrom G 1991 Ground Heat Storage Thermal Analyses of Duct Storage Systems Theory Dep of Mathematical Physics University of Lund Sweden ISBN 91 628 0290 9 Huber A Schuler O 1997 Berechnungsmodul fur Erdwarmesonden Forschungsprogramm Umgebungs und Abwarme Warmekraftkopplung Bundesamt fur Energie Bern Huber A Pahud D 1999b Erweiterung des Programms EWS fur Erdw rmesondenfelder Schlussbericht Bundesamt fur Energie BFE Bern Huber A 1999 Hydraulische Auslegung von Erdwarmesondenkreislaufen Schlussbericht Bundesamt fur Energie BFE Bern Huber A 2005 Erdwarmesonden fur Direktheizung Phase 1 Modellbildung und Simulation Schlussbericht Bundesamt fur Energie BFE Bern Huber A 2006 Rechenmethode WPesti Modellbeschrieb Verein MINERGIE http www minergie ch AWEL http www energie zh ch FWS http www fws ch Z rich 31 Mai 2006 Huber A 2006 Planung von gekoppelten K lte und Warme Erzeugungsanlagen mit Erdw rmesonden Weiterbildungskurs 235 Hochschule f r Technik Architektur Luzern Leu W Keller G Megel Th Scharli U Rybach L 1999 Programm SwEWS 99 Berechnungsprogramm f r geothermische Eigenschaften der Schweizer Molasse 0 500m Schlussbericht Bundesamt f r Energie Bern Leu W Keller G Matter A Sch
91. rties of the earth for every vertical calculation layer The averaging is done prior to every calculation run Thus even in the case of a variation in the borehole depths there is no need for adjustments of the earth s definition field 3 11 3 15 3 2 Properties of the earth The averaged physical properties of the earth heat conductivity W mK density kg m and specific heat capacity cp J kgK can be entered in the field 3 2 if in the field 3 7 equal layers and in the field 3 8 homogeneous earth are selected In this case the values are transferred automatically to the fields 3 12 3 14 The program EWS always computes internally with the values from the fields 3 12 3 14 If the user adjusts the values in Bed EWS47 En doc 23 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG SN 3 4 3 6 3 10 3 12 3 11 the fields 3 12 3 14 in a later phase it might happen that the inputs field 3 2 and fields 3 12 3 14 are no longer consistent In such a case the values in the field 3 2 are ignored and they are adjusted in the next calculation run Furthermore the program EWS calculates for each run the arithmetic mean of the properties of the earth for the whole borehole depth The results are showed after the run in field 3 2 Hence on the one hand field 3 2 is an input assistance and on the other hand it is an output field for the arithmetic mean of the physical earth
92. ssstab 1 1000 Kanton Z rich Diese Karte stellt einen Z mtlichen Daten erschiedener Stelle n da r Kei MP ios f r Rio sheet Volt Ud dem nd Aktualit t Rechtsve rb ndi che Ausk nfte aids ilen allein die zust ndigen Be 2 aw a ar RN Fig 3 14 1 step Store an appropriate map in the clipboard e g by getting a printscreen of one of the existing GIS browsers as www gis zh ch Programm EWS Soncenanordnung NB el NO WALT NER IE VANS CZ S vum m EE N 2 Ml N x N MN XN NS Al CNC KEN ES Lu Fig 3 16 gy AN ES known points on the map define the distance of these 2 points field S9 and mark the 2 points by pressing the left mouse button on this points Finalize this step by just clicking into the map Bed EWSA7 En doc Programm EWS AM Ss NES Ua ENGEL ERE wes SU GP SE Ba NE NEBSUMR 77 FE NA QI M Fe Fig 3 15 D RT DA chs m MANI EN ZZ EV Nr 3 step scaling the map Choose 2 well Fig 3 17 Sondenan ds E wo ED um Lm AM m E FT ee en XD ter Ll mz Ml SRM UNS Ld b BU A A NEA LANA TANN 66 NS KEIN p 2 step pressing the middle
93. temperature in the ground around the borehole It is possible to zoom in button S7 and to zoom out button S6 of the borehole field if the field of boreholes is bigger than the displayed range Thereby the left upper corner always keeps the coordinate 0 O The button delete S5 deletes all boreholes By pressing the button S2 the whole sheet can be copied into the clipboard and thus be used for reporting in other programs as Word The sheet Field of boreholes can be quit with the button S1 whereby all input data will be saved number of boreholes coordinates of the boreholes distances of the boreholes g function The values of the g function are transferred to the fields 1 15 to 1 19 of the sheet Boreholes and can be checked there Programm EWS Sondenanordnung ap a PEGG eee EIS eee ETE ESSET EESTI oe ES ET EE ES ET ee eae FIER H I hes pos ER IE eat ge ol 14 m ma aoe m ERE EE DE ED RAPA eee eee S00 S66 SEE Bid b GIC HE DEB HII ES yy zu RE DER a DT LES a 08 FE E o IER ET 28 1 40 0 10 0 AH 2500100 13 600 100 A uu ma an mas iE EE ee E EIER EE Ree Re ee ps pe esp Ee delete E LE d S ERI Fl EU Rf ES ERI BH 387 I E ES 8 E EZ ES DENT I DM 9 mars mem es mm d
94. to 1 21 see Fig 3 10 appear on the right hand side Bed EWS47_En doc 14 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG P Eingabedaten EWS E ol x File Input Import Edition Windows Info Boreholes Fluid Earth Extraction Info Input Borehole configuration 1 7 Outer pipe diameter m 0 0320 1 1 32 mm double U pipe 1 8 Wall thickness of pipe m 0 0030 Open T P 1 2 Typ coaxial gu 1 9 Heat conductivity of pipe W mK 0 40 eave 1 3 Number of boreholes Results 1 4 Borehole depth 100 1 5 Borehole diameter 01 20 1 6 Borehole distance fi 0 00 B H eff 0 1001 6a Dimensionless thermal response factor g 1 14 rb H 0 0005 1 10 Boundary conditions with g functions C No 1 15 Intits 4 i020 1 16 invts 2 6 1 11 atunction Special input 4 17 intits 0 Graph of g function 1 12 Graph ofg function 1 18 Init ts 2 6 570 1 19 3 soo Input g function 1 13 Yes C No 1 20 Borehole distance of g function o ooo 1 21 0 100 Close Programm EWS Lizenz f r Huber Huber Energietechnik AG Z rich Fig 3 10 The Sheet Boreholes during the input of a particular g function The fields 1 15 to 1 19 describe the g function by giving the function values of the data points In t ts 4 2 0 2 3 Published or self calculated g functions are always valid
95. ults Instead of viewing the results in a diagram the results can be shown in a table too The sheet Results is opened by selecting the sheet Results from the pull down field Windows in the menu bar Resultate Programm EWS 1 E el x Programm EWS Lizenz von Probeversion Huber Energietechnik Zurich Case description Graph Projekt Erdwaermesonden Modify Programm EWS Ver 3 9 mit Default Werten Calculate Input data Results Heat conductivity of the earth 2 4 W mK Energy injected in earth Do kWh Number of boreholes 1 Energy extracted out of earth 2416 kWh Borehole depth 200 m Cooling demand of TABS NEN kWh Borehole distance m Cooling demand of building kWh Outer pipe diameter 32 mm Coverage ofthe cooling demand by the boreholes Heat extraction rate in heating condition 1 0 kw Min inlet temperature to the borehole 106 C Heat injection rate in cooling condition 1 0 kw Max inlet temperature to the borehole C Number of days of peak load in February 4 Max cooling rate of boreholes foo ki Heat extraction rate in peak load 1 0 kw Max heating rate of boreholes o ky Max needed cooling rate 0 0 kw Medium borehole load in July and August joo Wm Max needed heating rate 0 0 kw Number of hours above cooling temperature limit Do h DT Supply Air Ventilator 0 0 je Cooling energy produced by chiller kh Eta heat recovery syste
96. zenz f r Huber Energietechnik Huber Energietechnik AG Z rich Fig 3 33 The sheet Load with the input of the heating energy Bed EWS47_En doc 31 Huber Energietechnik AG Program EWS Ver 4 7 Huber Energietechnik AG In the sheet Load the monthly heating and cooling energy demand is defined In contrast to the sheet Extraction the heating and the cooling energy in the sheet Load are in kWh and with a positive sign The program EWS calculates a load profile for an intermittent mode under consideration of the COP and the heating and cooling power of the heat pump Excluded of this intermittent is the base load field 10 4 and field 10 6 which influences the load profile independently of the installed heating or cooling power In the heating case the borehole heat extraction rate is reduced by the compressor power which can be calculated with the COP The heat injection rate in cooling condition is increased by the compressor power and is calculated with the EER COP 1 The mass flow rate field 2 7 is adjusted to the heat extraction rate considering the eq 3 1 and the temperature difference field 2 7 this means a variable mass flow rate 10 1 If the question Create a now load file with the following values is answered with yes the load profile is calculated with the values from the fields 10 2 10 27 If the answer is no the load profile is taken from the input file and the inputs 10 2 10

here - Huber Energietechnik AG

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