ClimateWell DB220
Contents
1. HeatSource Distribution Heat Rejection e O I e O gt S N gt lt 2 5 2 n N 65 e e e eo O O O 40 full load 60 Figure 20 Pump duration curve for a typical Solar Cooling installation Here it is apparent that good partial load efficiency is necessary since the system is mostly operating between 20 and 80 of full capacity In order to have high overall efficiency it is important to have good partial load efficiency This can be solved by installing variable speed pumps in the collector and heat rejection circuits The temperature difference between the inlet and outlet in each circuit can be used to generate a signal to the frequency converter in the pump A temperature difference of 10 to 12 C is recommended For small pumps simpler methods can be used for varying the speed Connection with ClimateWell SolarChiller The ClimateWell units should be installed in the solar primary circuit to provide the installation with freeze protection and 50 all components in the heat source circuit must be able to sustain vapour temperatures e Install throttle bypass valves on the heat source connections of every ClimateWell unit see Figure 21 These valves are necessary for the ClimateWell units to measure the available heat source temperatu2. Figure 6 Simple harp hydraulics with four banks connected in series with each four collectors connected in parallel Simple harp is a high flow solar collector and it is recommended to have at least four collectors in series in order to obtain sufficient flow through each collector More than four collectors in parallel in one bank are not recommended because the flow is then unevenly distributed X Collector Fluid Use only reversibly evaporisable heat transfer fluid based on propylene glycol and non toxic corrosion inhibitors with pH buffering capacity for utilization in solar heating installations The fluid should be able to withstand at least 170 C without being altered Since water quality depends greatly on location ClimateWell only recommends pre mixed products Stagnation Behaviour e Use a safety algorithm for the solar pump that automatically shuts off the solar pump if the collector temperature exceeds 130 C e The solar pump must under no circumstances be turned on during collector stagnation e Install pipe work for both flow and return with a continuous upward slope towards the solar field This will give a slower and more controlled vapour transport during stagnation e sure that the vapour always has somewhere to expand There must be an unhindered path from the solar collectors to the expansi
3. OMA Normally open Input signals Output mode Toggle between heating and cooling when closed AC pump status On off 5V OV 20 mA DESIGN GUIDELINES FOR SOLAR COOLING Hydraulic Connections ClimateWell SolarChiller mm 2077 3 807 2 with screws 1211 2 with screws From SP to CW To SP from CW From HS to CW To HS from CW From AC to CW To AC from CW Connection diameter 28 mm DESIGN GUIDELINES FOR SOLAR COOLING Power Curves 1 Please Note The curves below are made for 20 C distribution return temperature ClimateWell SolarChiller CWSC Characteristic Curves for Chilled Ceiling System 80 90 100 110 8 Se Do OE ee 2 Mine IN UJ N gt c c Q Q 50 c gt lt 28 29 30 31 Recooling Temperature Appendix 2 Input and Output Signals Sensors Type T10 Collector_Out Temperature T20 CW Return Temperature T30 Tank1Lower Temperature T31 Tank1Upper Temperature T32 Tank2Lower Temperature T33 Tank2Upper Temperature T50 Tank3Lower Temperature 151 Tank3Upper Temperature T35 CWHSReturn Temperature T36 CWHSFlow Temperature 20 21 22 30 P31 P32 P34 P36 Logics Boolean Inputs Summer_Mode DESIGN GUIDELINES FOR SOLAR COOLING Required Outputs Type Settings Defaults CW Solar_Pump Rel
4. Q DESIGN GUIDELINES FOR SOLAR COOLING Solar Field M gt PN T10 ClimateWell Heat Rejection ClimateWell Heat Source Heat Rejection 1 Figure 29 Possible schematic for installations with high demand for domestic hot water The control logics in Appendix 2 have been designed for this schematic P21 must have variable flow in order work simultaneously with P20 Appendix 1 Technical Data matt SolarChilkr Triple state absorption process COP 0 68 Implemented COP Thermal COP will depend on installation characteristics typically 0 52 0 57 The Maximum Temperature to From Heat Source 120 C ClimateWell DESIGN GUIDELINES FOR SOLAR COOLING sse tnter nnne tnnt nennen tette Energy Storage Capacity Cooling 56 kWh Weight 990 kg Operational Data Heat Source Circuit 25 30 l min Typical Power Range 15 20 kW o Out 75 C 100 C perational Temperature rm 85 110 C Propylene Glycol 1 2 L 2 15 concentration Distribution Circuit 25 30 l min Out 10 C 16 C Operational Temperature 15 C 21 C Type of Fluid Propylene Glycol 1 2 L 2 15 96 concentration Heat Rejection Circuit 50 60 l min Typical Power Range 20 30 kW sperational Temperature 307004576 perational Temperature a lt 80 30 C Type of Fluid Propylene Glycol 1 2 L 2 15 concentration Electrical Connections and Control
5. H Heat Exchangers 18 Heat Rejection System e 12 Heat Source System 3 Hollow Core Slabs e 10 Hydraulic Connections 26 Hydraulic Design 16 Hydraulic Drawings 22 Input and Output Signals 27 L Logics 28 Losses e 8 Operational Data 25 Pipes 7 Power Curves 27 Preheating of DHW e 14 Pumps e 18 DESIGN GUIDELINES FOR SOLAR COOLING R Radiant Systems e 11 Reference e 31 S Safety Valves e 18 Solar Collectors e 4 Solar Cooling Installation e 3 Solar Pump Station e 16 Solar Schematics e 22 Stagnation Behaviour e 7 Strainer 18 Swimming Pool 13 Technical Data 24 Thermal Storage e 14 W Wet Cooling Tower 14 Reference ClimateWell AB Instrumentvagen 20 126 53 Hagersten Stockholm Sweden Tel 46 8 794 03 70 Fax 46 8 744 30 70 info climatewell com ClimateWell Ib rica S A U C Insula Barataria N 27 28034 Fuencarral Madrid Spain Tel 34 91 372 12 55 Fax 34 91 734 16 52 infoiberica climatewell com ClimateWell Ib rica S A U Avenida de Segovia 6 Pol gono Industrial C P 42110 Olvega Soria opain infoiberica climatewell com ClimateWell No warranty or representation is made by ClimateWell AB as to the accuracy or completeness of the information contained herein and nothing contained herein is or shall be relied upon as a promise or a representation as to the future Each and any potential partner distri
6. DHW Preparation There are basically two different schools when it comes to domestic hot water preparation Either hot water for consumption is prepared and stored in DHW tanks before use or the water is heated up instantaneously at demand The main advantage with the first solution is that high peak demands can be covered with small capacities on heat exchangers but with the side effect that storing warm water 53 C may create hygienic problems The latter solution gives high hygienic standards since cold water is heated instantaneously but requires that heat exchangers are dimensioned for the peak power demand Figure 14 and Figure 15 illustrate how the two solutions can be combined with solar heating and preheating Fresh Water Station G 194 Inlet DHW Return DHW Figure 14 Domestic hot water solutions with open buffer tanks and instantaneous hot water preparation The three tanks are Starting left preheating tank tank heated by the heat rejection circuit of the ClimateWell units 20 40 C solar tank 40 70 C and boiler tank 60 C Inlet DHW Return DHW Figure 15 Domestic hot water solutions with DHW tanks The three tanks are starting left preheating tank tank heated by the heat rejection circuit of the ClimateWell units 20 40 solar tank 40 70 C and boiler tank 60 Make sure that the chosen solution follows local normative
7. P33 P3L P32 Figure 12 Connection in parallel for two rejection systems HE3 and HE 4 connected in series with a third system HE2 with highest priority Swimming Pool A swimming pool can be the only heat rejection system in the solar cooling installation but can also be used in combination with other solutions if size is not sufficient or if the pool is strictly temperature regulated Use connection in parallel with secondary heat rejection system if the pool heating season is during a short period of the year If not connection in series can be used to simplify control logic If preheating of domestic hot water is used connection in series is always recommended It is important to use a pump on the pool side of the heat exchanger that can work at ambient pressure Normal circulation pumps need a higher incoming pressure and will not work well in a non pressurized circuit It is also important to choose a heat exchanger that will withstand the corrosive environment present in pool applications The material used in the heat exchanger must be chosen depending on what chemicals are used in the pool water A heat exchanger that can withstand chlorinated water might not withstand salt treated water or seawater Figure 13 shows an example of a shell and tube heat exchanger especially designed for pool applications It can handle both chlorine water and seawater and has very low pressure drop Q
8. DESIGN GUIDELINES FOR SOLAR COOLING Figure 13 pool heat exchanger from Bowman The heat exchanger has plastic fittings on the pool side that can withstand maximum 100 C Wet Cooling Tower wet cooling tower is the most conventional way of rejecting heat in solar cooling applications The evaporative cooling allows the tower to deliver temperatures below the ambient dry bulb temperature which is a necessity for solar cooling installations in warmer climates When dimensioning the cooling tower maximum and average wet bulb temperatures for the location must be taken into account The maintenance necessary for a cooling tower consists mainly of hygienic maintenance since mechanical maintenance is minimal Sanitary standards should follow or exceed normative such as RD865 03 Some cooling tower manufacturers recommend a slow dissolution solid treatment which is a solid cleaning tablet that works both as biocide and corrosion inhibiter during a period of roughly six months Another very important parameter to determine in the design of the cooling tower is the number of concentration cycles that can be used The concentration of minerals such as Ca and Mg increases as the water evaporates and in order to avoid deposition and accumulation of minerals inside the cooling tower a certain amount of water must continuously be replaced with new water in addition to the water lost through evaporation The quality of the water at the location is what wi
9. For smaller installations with no preheating a single tank can be sufficient Q DESIGN GUIDELINES FOR SOLAR COOLING Hydraulic Design All components connected to the collector loop must have a high temperature classification Solar Pump Station The solar pump station is the connection between the solar collectors and the rest of the components in the installation There are standard pump stations for small to medium size installations existing on the market that come pre installed and leak tested with all the necessary safety equipments An example of a pump station is illustrated in Figure 16 and a list of the necessary components can be seen below For larger installations preassembled pump stations are not common and the components are normally assembled and installed on site o Variable speed circulation pump Safety relief valve Filling drain valve Pressure gauge Flow meter Air trap and vent Flow temperature gauge Return temperature gauge Insulation shell Shut off and check valves Expansion vessel connection a e 1234 I9 pu ew C at 8 Figure 16 Example of a solar pump station designed for small to medium size solar installations In Figure 17 and Figure 18 some examples of pump station components available on the market is shown Figure 18 Combined temperature gauge shut off valve and non return val
10. TERT 13 i 14 Preneating 14 Domestic Hot Water System dl a RR ER nnana 14 14 Bing Es Ps Eze POT 15 FAY CV QUIG 16 Solar PUMP gt D c UTE akah aa 16 Expansion Vessel UD mI HE d 17 Cooling VSS Se 17 17 SOE GAINS wm 18 oale VANOS 18 EX NINOI saanane anan anang a ga 18 ee 18 Connection with ClimateWell SolarChiller 19 STE ii KNA Na DENG ga 22 T 22 Communication with ClimateWell cccccssssscscsecsscsscsessssesessecsecsecssessseseeseesaesaecascasassessusansateateass 22 SOAL S Kan E TET ETOILE 22 Hydraulic DIaWINGS RERO 22 Kel a Kaga 24 Technical Du ERR 24 Operational EDU NND 25 Electrical Connections and Control sese 25 alis esae n 26 FONG Fs INVES 27
11. Bo E emi gt Design Guidelines for Solar Cooling Climatewell Thank you for choosing ClimateWell SolarChiller With Solar Cooling you will feel better and so will the Environment Solar energy day and night Solar powered heating and cooling both day and night This is what makes the ClimateWell SolarChiller a unique product and that will enable you to enjoy comfort cooling and heating without compromising the environment For the first time a solar powered climate solution meets the requirements both of single family homes and commercial buildings We made Solar Cooling possible and profitable Contribution Solar Cooling typical monthly savings for a single family home are 100 200 Euros per 100 of floor surface At the same time the owner contributes to a better world by reducing CO emissions by some 5 000 kilos per 100 m every year Independency With your own energy supply system installed you achieve high Independency of changes in energy prices at the same time as you get immediate savings thanks to the lower energy costs Some 25 of the world s CO2 emissions come from heating and cooling of buildings With ClimateWell this can now be done using everyone s own energy source The Sun Per Olofsson CEO ClimateWell AB Legal Notes This manual contains material which is protected by copyright All rights are reserved No part of this manual may be reproduced photocopied or translated to another language
12. ELINES FOR SOLAR Air Handling Unit An air handling unit AHU can be connected to a conventional ventilation ducting system with inlet air diffusers in each area or to a VAV Variable Air Volume system An AHU in combination with ClimateWell and a backup system with a conventional chiller must always have 2 separate cooling coils since the 2 systems operate at different chilled water temperature levels In order to maintain a high COP on the conventional chiller and a good performance from the ClimateWell units these two circuits should never be mixed For each coil inside the AHU a separate 3 way valve control the air supply temperature via the BMS system Building Monitoring System or a conventional control system Typical components in an AHU are listed below starting at the air inlet and going along the air flow Sand trap DIN std EN779 e Mixing section for inlet and return air e Filter DIN std EN779 e Pre cooling coil for ClimateWell units 12 17 Pressure drop 30 kPa on water side and 100 on air side e Cooling coil for conventional chiller boiler e Damper section Fan section with low SFP value EN 13779 SFP Specific Fan Power W m s e Silencer The air flow should be designed for maximum 2 5 m s air velocity over the cooling coil sections If not condense drop eliminators after the coil are necessary The pressure drop over the coi
13. a separation of 20 cm between each individual pipe is considered normal and for air conditioning a separation of 15 cm 15 necessary except in bathrooms with a 10 cm separation The type of distribution pipe and the separation between pipes should remain constant throughout the entire installation Parts 1 4 of UNE EN 1264 specify the design and installation requirements of radiant floor heating systems Nonetheless this standard does not cover the design of floor based cooling systems UNE EN 1264 2 establishes a characteristic base curve that determines the balance between thermal flow density q in W m2 and the mean temperature of the floor surface in C It is applicable to all types of radiant systems The proportion between these is established as follows Hot floor Cold ceiling q 8 92 x T flooriceiling Toperative Cold floor q 7 x Tsurface Toperative Hot ceiling q 6 x Tsurface Toperative Radiant floors are considered suitable when the heating load is less than 100W m and the cooling floor when the load is less than 40W m For the floor the minimum temperature recommended is 18 although it will always be necessary to take the dew point of the air into account so as not to generate condensation The theoretical minimum ceiling temperature is 8 C although the real limit will be the dew point of the air Heat Rejection System Introduction solar cooling system must always have a heat rejection syst
14. ally the total solar field flow is in the range of 20 to 50 I hr per m aperture area depending on the type of solar collector Figure 4 Figure 6 illustrate some examples on possible hydraulic configurations for different solar collectors e shut off valves at the inlet and outlet of each collector bank in accordance with Figure 4 Figure 6 This is important for start up and maintenance reasons e Install a flush out connection at the extremes of both the inlet and outlet of the collector field according to Figure 4 Figure 6 These connections can be used for purging the system as well e Install safety valves for each collector array on the inside of the shut off valves as shown in Figure 4 Figure 6 V DESIGN GUIDELINES FOR SOLAR COOLING Figure 4 Heat pipe evacuated tube hydraulics with two parallel banks with each four collectors connected in series For direct flow evacuated tube collectors the tubes must be installed horizontally gt Figure 5 Double meander hydraulics with four parallel banks with each four collectors also connected parallel Both direct flow and heat pipe evacuated tubes can be connected in a similar way with the difference that the collectors in each bank are internally connected in series instead of in parallel DESIGN GUIDELINES FOR SOLAR
15. aximum irradiation is acceptable for the different demands If all the power should be absorbed by the ClimateWell unit units then the temperature difference should be no more than 15 C In case of higher complexity such as installations with high domestic hot water demand please consult with ClimateWell technical department for help on designing the individual flows e Install reversed return hydraulics to ensure the same pressure drop in each bank in the collector array regardless of the flow This is a requisite for using variable flow in the collector loop e Install temperature sensors in each collector bank inlet and outlet These sensors are used to make sure that the same flow is passing each collector bank in the array Manual bypass flow meters can also be used in each bank e Use an immersed solar collector temperature sensor on any bank in the collector array and a second sensor close to ClimateWell unit outlet for pump control Make sure that the sensor is measuring the collector temperature and not the flow temperature in the pipes A temperature sensor attached to the pipe cannot be used for pump control since the sensor must be able to measure the absorber plate temperature even when the solar pump is off e specific collector flow rate the flow rate through one collector should be according to manufacturer specifications and the hydraulic configuration should be designed to match the flow demanded by the Climatewell units Gener
16. ay DeltaTOn 10 DHW Solar_Pump Relay DeltaT Off 4 C Solar Pump3 Relay Collector1min 60 C CWHSPump Relay Collector1max 130 C DHWSecondaryPump Relay Collector1minDHW 70 Tank1Max 90 C CoolTowerPump Relay DWHTimer 1 Min TransferPump2 Relay Tank1Hysterisis 4 TTankTransferON 12 CWHSPump_Speed 0 10V TTankTransferOFF 6 C CW Solar_Pump_Speed 0 10V TRecooling 28 C DHW Solar_Pump_Speed 0 10V Solar_Pump_Speed_Min 10 IF Summer TRUE THEN ELSE IF 10 gt T20 DeltaTOn AND T10 gt Collector1Min AND T10 lt Collector1Max 20 THEN CW Solar_Pump On IF T10 lt T20 DeltaTOff THEN CW Solar_Pump Off ELSE IF T10 lt Collector1 Min THEN CW Solar_Pump Off ELSE IF T10 gt Collector1 Max THEN CW Solar_Pump Off IF T10 gt CollectoriminDHW AND T31 lt Tank1Max Tank1Hysterisis AND T10 gt T30 DeltaTOn THEN DHW Solar_Pump ON AND DHWTimer ON IF DHWTimer 0 THEN DHWSecondaryPump ON IF T10 lt CollectoriminDHW DeltaTOff THEN DHW Solar Pump OFF AND DHWSecondaryPump OFF IF T31 lt Tank1Max TankiHysterisis AND T10 gt T30 DeltaTOn THEN DHW Solar Pump ON AND DHWTimer ON IF DHWTimer 0 THEN DHWSecondaryPump ON IF T10 gt T32 DeltaTOn AND T10 lt Collector Max AND T33 lt Tank1Max Tank1Hysterisis AND DHW Solar Pump OFF THEN Solar Pump3 ON IF T10 T32 DeltaTOff THEN DESIGN GUIDELINES FOR SOLAR COOLING ssessss
17. butor customer or investor in ClimateWell AB must conduct and rely on its own evaluation of the company its technology and products Any solution based on ClimateWell s products as shown in this document is only meant to give ideas and shall never be used as a solution for a specific project without consulting a HVAC engineer that can adapt the solution to the specific building
18. eeeeeennenenennnennnne nnne nennen nnne nnne ns Solar Pump3 OFF ELSE IF T10 gt Collector1 Solar Pump3 OFF ELSE IF T33 gt Tank1Max Solar Pump3 OFF ELSE IF DHW Solar Pump ON THEN SolarPump3 OFF END IF IF T31 gt Tank1Max THEN DHW Solar Pump OFF AND DHWSecondaryPump OFF ELSE IF T10 T30 DeltaTOff THEN DHW Solar Pump OFF AND DHWSecondaryPump OFF IF T31 gt T50 TTankTransferON THEN TransferPump2 ON IF T31 T50 TTankTransferOFF THEN TransferPump2 OFF IF T35 gt TRecooling AND CWHSPump ON THEN CoolTowerPump ON IF 35 TRecooling 1 THEN CoolTowerPump OFF IF CWHSPump OFF AND Solar Pump3 OFF THEN CoolTowerPump OFF IF T36 gt T32 DeltaTOn AND CWHSPump ON OR Solar Pump3 ON THEN PreHeatPump ON IF T36 T32 DeltaTOff THEN PreHeatPump OFF IF CWHSPump OFF AND Solar Pump3 OFF THEN PreHeatPump OFF IF T10 gt 120 AND T10 lt Collector Max THEN Solar Pump3 ON CoolTowerPump ON IF T10 110 THEN Solar Pump3 OFF Air Handling Unit 9 Appendix 1 e 24 Appendix 2 27 Chilled Beam System 10 Collector Fluid e 7 Communication with ClimateWell e 22 Connection with ClimateWell SolarChiller e 19 Control Logics e 22 Control System e 22 Cooling Vessel 17 D Deairation e 1 DHW Preparation e 15 Distribution System e 8 Domestic Hot Water System e 14 E Electric Connections and Control e 25 Expansion Vessel 17
19. em where the heat from the solar collectors and from the building is dumped The heat rejection system should be designed in such a way that the return to the Climatewell units does not exceed 35 for the design power of the circuit Generally the performance of the Solar Cooling installation improves the lower the heat rejection temperature Similarly an under dimensioned heat rejection system is likely to undermine the entire installation For these reasons high efforts should be put into the design of the heat rejection system pressure drop diagram for the heat rejection circuit can be found in Figure 10 Pressure dropfor Heat rejection flow 5 LI 5 o o Flow l min Figure 10 Pressure drop as a function of the heat rejection flow for ClimateWell SolarChiller Two or more heat rejection system can be used in a single installation and they can be connected either in series or in parallel Figure 11 and Figure 12 illustrates how different rejection systems can be coupled together DESIGN GUIDELINES FOR SOLAR HE 4 HE3 EEV N amp amp P32 Figure 11 Connection in series for three different heat rejection systems Preheating of DHW HE2 has always highest priority and is therefore placed first in the flow direction A wet cooling tower HE4 has always lowest priority and is HE4 N HE3 N HE2
20. ended in a solar cooling application For these reasons the double harp collector is not recommended by ClimateWell Direct Flow Evacuated Tube The direct flow evacuated tube collector is a high specific flow collector with poor emptying behaviour when installed with the tubes vertically and low pressure drop If installed vertically during stagnation some of the collector fluid will be trapped inside the collector similarly to the double harp collector and due to the extremely low thermal losses and hence very high stagnation temperatures in the evacuated tubes the glycol might degrade For this reason the direct flow evacuated tube collector is only recommended by ClimateWell if installed horizontally according to the right picture in Figure 3 Figure 3 Direct flow evacuated tube installed vertically to the left and horizontally to the right Heat Pipe Evacuated Tube The heat pipe evacuated tube collector is a high specific flow collector with good emptying behaviour in case of stagnation and low pressure drop Some heat pipe manufacturers even offer heat pipes with a maximum temperature in order to minimize the effects of stagnation Due to the low pressure drop many collectors can be installed in series as illustrated in Figure 4 The number of collector panels in each bank should be according to the panel manufacturer s guidelines e Design the individual collector banks so that the temperature difference between inlet and outlet at m
21. heating cooling medium and the radiant panel and between the radiant panel and the indoor air These systems are thus very efficient since they require less exergy than other systems to maintain conditions of comfort The major drawback of these systems is that they will only cover sensible cooling loads In floor systems in winter the mortar absorbs the heat given off by the pipes and conveys it to the upper flooring which in turn conveys this energy towards the walls and ceiling of the room by means of radiation and to a lesser degree natural convection In summer on the other hand the flooring absorbs the heat from the walls and ceiling by radiation and partly by convection Ceiling systems are solutions based on circulation of hot cold water through panels installed in the ceilings Radiant systems adjust very well to the optimal projection of human body heat by means of radiation convection transmission and evaporation The temperature that you feel is more or less the average temperature between the radiant temperature and the dry bulb temperature illustrated in the picture below Winter Summer 24 20 Figure 9 The temperature perceived by person operational temperature is a function of the ambient air temperature and the radiant temperature from all surfaces surrounding the person This means that the ambient air temperature can be lower in winter and higher in summer with
22. ired However if a check valve is required before the pump for protection meaning that the collector field is only able to expand along the flow pipes a cooling vessel may be required In this case if the fluid volume of the pipes between the collector field outlet and the expansion vessel inlet is less than the volume to be held by the expansion vessel then a cooling vessel must be added to protect the expansion vessel The volume of the cooling vessel must be such that when added to the fluid volume of the pipes between the collector field outlet and the expansion vessel inlet the total volume exceeds the volume to be held by the expansion vessel Which method to use must be decided on a case to case basis depending on distance to solar field and stagnation behaviour of the collectors used Deairation Install at least one air purge unit APU per circuit with a residence volume 2 5 pipe diameters in length for air in T section or elbow An automatic purge valve can be used but controlled by a manual valve that should always be closed during normal operation Increase the pipe size in that section to lower the flow velocity The purge system can be placed close to the pump station for easy maintenance In larger installations several APU units are recommended Figure 19 illustrates how an APU should look like Figure 19 Example of an APU consisting of an automatic purge valve a manual valve and a residence volume for air Different co
23. lero qae 27 Input and Output Signals 27 i RI RR RR RN Rr 28 DC ocio ax ORO FREUNDE E O 30 ee 31 O ClimateWell DESIGN GUIDELINES FOR SOLAR Solar Cooling Installation Introduction This document has been developed to be used as a guideline for designing Solar Cooling installation together with ClimateWell s licensed partners The document includes key components and component configurations that are crucial for well functioning and reliable Solar Cooling installations Due to the fact that real projects might deviate more or less from the standard configurations described in the following chapters it is important to treat this document as a platform for continuous mutual communication between ClimateWell and its partner in the design of specific Solar Cooling projects More information about the installation and management of a ClimateWell SolarChiller can be found in the ClimateWell User Manual Installation Manual Hardware Manual and Software Manual Heat Source System Introduction The heat source is the driving force in a Solar Cooling installation The ClimateWell Solar Cooling products use a single effect triple state absorption cycle working with fluid driving temperatures in the range of 85 110 C High regeneration temperatures will increase
24. ll decide the number of concentration cycles where very pure water can be concentrated many times before deposition becomes a danger and water with high concentration of minerals must be replaced more often For guidelines on maintenance and dimensioning of fan speed sump volume and number of concentration cycles contact the cooling tower manufacturer Preheating of DHW Preheating of DHW is the most favourable of all heat rejection systems since the exergy levels are used very efficiently First the heat is used for producing cooling and later the same energy can heat up the tap water The disadvantage with this rejection system is that it is dependent on the tap water consumption and can therefore never be used as the only system for heat rejection It can neither be used as the sole source for heating the tap water because maximum available temperatures are below sanitary requirements The preheating of tap water should be done in a separate tank in order to allow for good stratification See the chapter on DHW preparation for further information Domestic Hot Water System Thermal Storage The use of open buffer tank is recommended in installations with both DHW and heating demand especially if high hygienic standards are required For smaller installations or if no heating is required from the solar installation domestic hot water tanks can be readily used DESIGN GUIDELINES FOR SOLAR COOLING sess nnne nnne nnn nnn
25. llector hydraulics for flat plate collectors From the left simple harp double meander and double harp Simple Harp The simple harp collector is a high specific flow collector with good emptying behaviour in case of stagnation and low pressure drop Due to the low pressure drop a very high specific flow is necessary to balance the flow through each collector and therefore the simple harp collector must be connected in series as shown in Figure 6 Double Meander The double meander collector is a low specific flow collector with good emptying behaviour in case of stagnation and low pressure drop if connected in parallel Due to the higher pressure drop compared to simple harp the meander collector is easier to balance hydraulically and can therefore be connected in long arrays in parallel as shown in Figure 5 DESIGN GUIDELINES FOR SOLAR 0 Double Harp The double harp collector is a low specific flow collector with poor emptying behaviour in case of stagnation and high pressure drop if connected in series This collector has only one inlet and one outlet and can there for only be connected in series In order not to have too high pressure drops in the collector array a low total flow must be used which results in a high deltaT over the collector field A high deltaT is acceptable in domestic hot water installation where a highly stratified storage buffer is desired but is not recomm
26. lours are used for flow and return O E DESIGN GUIDELINES FOR SOLAR COOLING Strainer ltisrecommended to install a strainer of 1 1 5 mm mesh before the pump with service valves on each side The strainer is a filter with large mesh that will collect dirt in the circuit Connections for measuring the pressure over the strainer are recommended to know when it needs to be cleaned or replaced When installing a strainer it is important that maintenance is really performed and strainer is cleaned or replaced when dirty Failure to do so may lead to clogging of the system and unrepairable damage to pumps Safety Valves e Double safety valves are recommended for larger installations separated by a 3 way ball valve for easy maintenance e Choose the rated pressure for the safety valve according to the VDI6002 standard The right pressure will depend on the height of the collector field and the selection of heat transfer fluid Ifthe collector field is very large or far away from the pump station additional safety valves close to the collector field are recommended e is any risk for vapour reaching the solar pumps during stagnation a non return valve must be installed after the solar pumps on the return pipe to the collectors in order to protect the pumps A second non return valve can also be used in the flow pipe of the collector to prevent self circulation in this single pipe up to the collecto
27. ls should be as low as possible to avoid unnecessarily large circulating pumps fans Use air fans with as low SPV values W m s as possible Table 1 illustrated an example of an AHU specification Table 1 Example of design data for an air handling unit Design data Supply air m3 sec 3 80 Chilled water temp KB2 7 12 Ext static pressure Pa 350 Coil Air inlet temp RH 27 C 50 Return air m3 sec 3 50 Pre filter MERV 6 Ext static pressure Pa 225 Filter MERV 13 Coil 1 Al Copper Heat Exchanger Plate Cross Air None Capacity kW 60 Exhaust air m3 sec 0 4 Chilled water temp KB1 12 17 Frequency control Yes no Coil Air inlet temp RH 27 50 90 dBA silencer Coil 2 sound level outlet after 55 dBA silencer Capacity kW 120 Q DESIGN GUIDELINES FOR SOLAR COOLING Hollow Core Slabs The hollow core slab system offers one of the most energy efficient HVAC solutions available on the market while providing top rated comfort levels This is possible by adding a massive thermal storage to the air distribution the building itself The hollow core slab system can be combined with all types of Air Conditioning Air Handling units AHU units From the AHU unit generally placed on the roof supply air ducts run in vertical shafts down to each floor inside the building and then to horizontal ducts placed in central corridors usually within false ceiling
28. nected to different external systems They are only conceptual drawings and do not include all necessary components Heat Sink 4 Solar Circuit HS Pump oj A N Cooling 4 4 Circuit b Y v AC Pump HE3 CY ClimateWell 4 Figure 23 A single ClimateWell unit connected to a water distribution circuit without a cooling backup system Heat Sink Circuit Solar Circuit ER AC Pump SP Pump L Lot 4 n ClimateWell Figure 24 A single ClimateWell unit connected to the primary coil of an air handling unit with a secondary coil connected to a backup chiller Cooling Circuit Heat Sink Circuit lt N Solar Circuit 4 SP Pump MAN ClimateWell Figure 25 A single ClimateWell unit connected to a water circuit in series with a backup chiller The chiller flow should be close to the design flow of the ClimateWell cooling circuit Cooling Circuit HS Pump Heat Sink Circuit 4 Solar Circuit C E O Figure 26 A single ClimateWell unit connected to a water circuit in series with a backup chiller The distribution flow is higher than the design flow of the ClimateWell cooling circuit DESIGN GUIDELINES FOR SOLAR COOLING Control System Control Logics Detailed information on possible control logics suitable for the schematics in Figure 28 and Figure 29 is found in Appendix 2 The logic for the distribution system i
29. on vessel in order to avoid pressure peaks Design pipe dimensions to have 0 5 1 5 m s flow velocity but never more than 20 mm m mm pressure head per length meter pipe pressure drop e Use only copper or stainless steel pipe material in any high temperature circuit Stainless steel offers the most efficient and reliable performance for the collector loop e Always follow or exceed local or regional normative when designing the pipe work Higher flow velocities than 1 5 m s will give unnecessarily high pressure drop in the loop and lower velocities than 0 5 m s will make it impossible for air bubbles to reach the purge unit while increasing the thermal losses In order to avoid confusion when connecting the pipes the flow and return can have different colours see Figure 19 DESIGN GUIDELINES FOR SOLAR COOLING Losses Insulation should be of a sufficient thickness and standard in order to limit heat loss from the pipes to and from the collector field Less than 0 15 WIK per length meter pipe is recommended insulation must be resistant to weathering and meet or exceed the requirements of standards such as EN 483 or EN 513 Collector inclination orientation and shading affect the performance of the solar cooling installation to varying degrees e Optimum inclination is usually close to or slightly lower the latitude of the location e Always try to orient the solar field towards the equator where efficiency will be highe
30. r Heat Exchangers Use flat plate heat exchangers with approximately 3 C logarithmic temperature difference for the design power of the circuit e Amaximum of 30 kPa pressure drop over the heat exchanger is recommended If possible similar flow should be used on both sides of the heat exchanger The design power for the different heat exchanges can be obtained using the ClimateWell Solar Cooling dimensioning tool Typical heat transfer values for a single ClimateWell SolarChiller installation are 20 30 kW for heat rejection and 7 10 kW for distribution If the collector field is located far away from the machine room making costs for collector fluid unrealistically high a flat plate heat exchanger close to the collector field can isolate the primary solar side from the rest of the installation This will leave the ClimateWell units without any freeze protection and extreme care has to be taken in the design of the installation Failure to do so may lead to irreparable damage to the ClimateWell units Pumps The electrical efficiency of the system is of highest importance and fluid pumping is one of the key factors influencing this efficiency Like most solar installations a Solar Cooling system is often run at partial load off peak hours This is illustrated in Figure 20 where it can be seen that a system runs at its full capacity very few hours in a year DESIGN GUIDELINES FOR SOLAR
31. re without opening their internal valves Two or more ClimateWell units can share the same bypass valve if the TSP temperature sensors are pasted in the same place If no external signals are used to control the heat rejection and distribution pumps bypasses for these circuits are also recommended c 3 4 57 77 6 bar Figure 21 Throttle bypass valve on heat source connection of the ClimateWell unit in order to measure the heat source temperature even when the internal valves in the ClimateWell unit are closed The temperature sensor must be pasted on the flow pipe before the bypass valve e Service valves and safety valves should be installed in every connecting circuit in accordance with Figure 21 Several ClimateWell units can be installed in parallel in order to increase power output In this case follow the procedures below Q DESIGN GUIDELINES FOR SOLAR COOLING e Install a pressure operated bypass valve before the first Climate Well unit in order not to harm a powerful pump see Figure 22 e reversed return pipes on all three circuits in order to obtain the same flow through each unit U U U Figure 22 Connection with several ClimateWell units in parallel Reversed return pipes are used in order to obtain the same flow in each unit for any flow The following figures are examples of how a ClimateWell unit can be con
32. s Small branch ducts feed air into each slab and the air then enters a room via diffusers fixed to the outlet of the slab Diffusers are normally located close to external walls or evenly spread over the ceiling in the office landscape The exhaust air is normally transferred into the central corridor plenum and is returned to the AHU unit in a conventional way The main distribution ductwork in the corridor is similar in construction to that found in conventional systems The main difference with this system is that every individual structural hollow core slab is supplied with a small quantity of air from the main supply duct The system is different from conventional technologies because it is integrated with the heavy structure of the building The last part of the ductwork system for the supply air consists of hollow core concrete slabs instead of traditional steel ducts Figure 8 Air flow inside the hollow core slabs The system uses the thermal storage capacity of the structural mass in the building to regulate the internal temperatures The effectiveness of the building s thermal mass is enhanced by passing supply air through the slab before it enters the room The slabs work as heat exchangers between the supply air and the rooms see Figure 8 The floor ceiling slabs serve many purposes Besides from being the structural floor it also conveys fresh air into the building while serving as an energy store The slabs are incorporated in
33. s assumed to be done by the building monitoring system and has not been contemplated in Appendix 2 Communication with ClimateWell The ClimateWell units can communicate with the external control system through 0 5 V signals or through RS232 More information on communication with ClimateWell can be found in ClimateWell s Control System Manual Solar Schematics The recommended Solar Cooling schematics have been designed to offer robust reliable and efficient installations using only standardized solutions readily available on the market Always communicate any deviation from the recommended schematics to ClimateWell s project management department Hydraulic Drawings Solar Field ClimateWell Heat Rejection ClimateWell Heat Source 136 D Heat Rejection 1 Figure 27 Possible schematic for small installations where preheating of domestic hot water not is economically viable The residential sector is one such example An internal coil in the storage tank can be used instead of an external heat exchanger DESIGN GUIDELINES FOR nennen nter terna Solar Field ClimateWell Heat Rejection ClimateWell Heat Source Heat Rejection 1 Figure 28 Possible schematics for installations where it is desired to feed the buffer tank and the ClimateWell units simultaneously For small installation an internal coil in the storage tank can be used instead of an external heat exchanger
34. st Small deviations from the optimum azimuth will have limited or no adverse affect on performance Never install a solar field close to large obstacles that can potentially shade the collectors If mountains trees or other objects are located in a way that may shorten the daily operation time during certain periods of the year this must be taken into account during the design phase of the installation Distribution System Introduction The distribution system of the building connects to the evaporators of the ClimateWell units and is the driving force in the absorption process just as the heat source is the driving force during the regeneration of the absorbent Since water is the refrigerant in the absorption cycle no sub zero temperatures are possible The Climatewell units are designed to work with high temperature systems ranging from 10 16 C on the outlet from the ClimateWell unit and performance rapidly decreases below this range Since the products loose efficiency at lower temperatures it is not recommended to use a Solar Cooling installation for dehumidification purposes For very humid climates a backup system is highly recommended A pressure drop diagram for the distribution circuit can be found in Figure 7 Pressure drop for Distribution flow o LJ 5 LI 5 o o Flow l min Figure 7 Pressure drop as a function of the distribution flow for ClimateWell SolarChiller DESIGN GUID
35. the same level of comfort compared to a system based on convection resulting in significant energy savings In addition they take advantage of the structural systems of the building floor ceiling walls as elements that accumulate energy thermal mass and this cushion temperature variations and lower peak demands The active contact area of the air volume under temperature control is the entire floor ceiling This means that thermal exchange 15 uniform throughout the surface making the movement of air by convection imperceptible The distribution circuits depart from the supply and return manifolds From there the circuits are hydraulically balanced and the circulation of the water projected is regulated in accordance with the thermal needs of each space The manifolds are placed centrally with respect to the areas to which they provide service At least one electronic valve is necessary for every thermostat controlled space and each manifold has a maximum of 12 circuits For maximum comfort it is recommended to use one thermostat for each space bedroom kitchen etc For optimum temperature control the advisable circuit design is either double coil or spiral The supply and return pipes should always be contiguous so that the warmer pipe is always next to the colder pipe This design ensures homogenised thermal distribution and increased comfort O E DESIGN GUIDELINES FOR SOLAR COOLING For heating
36. the vapour flow and hence the charging velocity but it may not always increase the efficiency of the entire cycle To find out the optimal driving temperatures and powers for a specific system please use the ClimateWell Solar Cooling simulation tool or ask for a detailed transient simulation from the ClimateWell Customer Support department A pressure drop diagram for the heat source circuit can be found in Figure 1 DESIGN GUIDELINES FOR SOLAR COOLING Pressure dropfor Heat source flow T a Ld 5 o iz Flow l min Figure 1 Pressure drop as a function of the heat source flow for ClimateWell SolarChiller Solar Collectors Use only certified highly efficient solar collectors with selective absorber plates Both flat plate and evacuated tube collectors can be used although evacuated tubes generally offer higher efficiencies for high temperature ranges There are a few aspects besides the thermal performance of the collector that have to be taken into consideration for adequate performance and robustness The most important ones are the pressure drop through the collector and the stagnation behaviour and both have to do with the internal collector hydraulics For flat plate collectors there are three main internal hydraulic configurations seen in Figure 2 and for evacuated tubes there are two different types direct flow and heat pipes Figure 2 Internal co
37. to the building and the main supply duct would normally be situated in the corridor No ducts and therefore no false ceilings are required in individual rooms This allows total freedom for the interior designer to locate or re locate in the future the internal wall partitions Chilled Beam System In application with an AHU in areas rooms with higher heat load like meetings or conference rooms a chilled beam system is highly recommended Chilled beams are very effective and easy to install and connect to the Climatewell chilled water circuit since the chilled beams require higher water temperatures in order to avoid condensation inside the units The base load into these areas is supplied by the AHU Ventilation system and the top load is supplied by the chilled beams often in combination with air supply inside the chilled beams DESIGN GUIDELINES FOR SOLAR COOLING sse nennt The chilled beams are controlled by a separate room sensor control opening the valve for the extra chilled water into the coil for maintaining the room temperature under high load conditions Some chilled beams are designed to be a part of a suspended ceiling and are very easy to install retrofit No noise from the chilled beams themselves is another great advantage Radiant Systems Radiant systems are typically designed to work at temperatures close to the indoor air temperatures This is possible because of the large contact area between the
38. ve for pumps stations DESIGN GUIDELINES FOR SOLAR entree tenet Expansion Vessel Make sure that the expansion vessel pre pressure and the final system filling pressure are measured with a digital instrument The expansion vessel should be of high temperature rating for solar applications and be installed before the solar pumps In small installations it can be installed after the non return valve on the flow pipe to the solar collector e Design expansion vessel in accordance with VDI6002 or local standards ClimateWell can provide support on expansion tank dimensioning according to VDI6002 service valve should be installed between the expansion vessel and the safety valves equipped with a lockable handle The expansion vessel should be placed below the pump station in order to stop hot water rising in the pipes from reaching the vessel Failure to correctly dimension the size and the pre pressure of the expansion vessel and the filling pressure of the installation can lead to air leaking into the system during cold nights or to glycol degradation during high thermal stress Cooling Vessel A cooling vessel may be required depending on the hydraulic design of the system If the location of the pump is sufficiently distant from the collector field and during a standstill event the collector field can expand equally along both the flow and return pipes without vapour reaching the pump then a cooling vessel is not requ
39. without the expressed written permission of ClimateWell AB ClimateWell amp Solar Cooling and Fr o Solar are registered trademarks of ClimateWell AB ClimateWell AB 2010 06 30 Article no 700015 Version v9 33 2 EN Copyright 2010 ClimateWell AB All rights reserved DESIGN GUIDELINES FOR SOLAR COOLING Table of Contents Solar Cooling InstallallORL aurae ere eee he 3 HOM PANG NE NAN NANG 3 Heat Source Syste vl E CU IR E CUR RD n EV 3 PATO GU o naen taa awana sakawan aan RT 3 eto PIRE RR 4 CONE eso la Oo RR RR RR RR 7 Stagnation a oan pee cone 7 TGS NG BEG ANGANTU GA KE 7 MEGS O Severe TM 8 DIST UEION VS socer ni 8 WOM ANA AN RT 8 Ar naka aga DA EN A Aa AA GAN AKAN EA AN BAG EN AN AA ak ANA 9 Hollow Slabs 10 Chilled Beam System 10 Mes bol M NETT 11 Heat Rejection SySleli nai adno V Cra tl E nu rv tl EL cna AA 12 Jgiigore U IESE aaa ban eag aas RR PC 12 Ser n TII OO MERA
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