Case Model - Service.daikin.com
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1. Generally this way can be cheap Effect of cleaning can be confirmed visually in the working 3 Is cleaning necessary or unnecessary There are various ways to judge of the scale coating but it is general and certain way to judge be the degree of fall of the heat exchange efficiency That is when full load operating of the cooling refrigerating system the outlet temperature of the cooling water flowing in the condenser is compared with the condensation temperature of the refrigerant And then this difference is compared with the value at the clean time of the cooling pipe Finally it is judged by how much the former has increased Condensation temp Of retrigerant This is found by conversion to the saturation temperature of the refrigerant from the indicating pressure of the high side pressure gauge The strong point of this way is that the both temperature differences are almost constant even though the volume of cooling water changes more or less So there are few cases of misjudgement 373 Appendix Provided TC Condensation temperature TW Cooling water temp at condenser outlet t1 Temp difference when cooling pipe is clean t2 Temp difference when scale adheres Do not be confused by the sudden stop of the operating cooling refrigerating equipment even though the high pressure switch does not get to the function For this it is necessary to examine the increasing rate of t2 t1 and2. 999113T Attached to the TYPE3 Power Unit 220V Please follow Daikin s purchasing procedure e Pentinum is a registered trademark of Intel Corporation Other product names mentioned above are trademarks or registered trademarks of respective companies The above specifications may be modified for improvement without any advance notice d Note Refer to the operation manual of Service Checker Type Ill for more details 204 Si 18 7 5 Cautions for installation Before installing the unit actually at the predesigned position make sure to leave the service space indicated on the respective installation and technical manuals around the unit and at the same time examine various surrounding conditions 7 5 1 Service space In general space for installation works is over 600mm and space for service works is over 1200mm With regard to the details see the technical manual Incase two air cooled condensing units are installed in parallel Minimum service space is shown below However the minimum service space differs with models so follow the respective installation or technical manual as for the details Fig 7 20 1 In case the air suction inlets face each other Came Product Suction inlet 2 In case the air suction inlets do not face each other Ga A gu SSS AN E m Product Viste Io SN NN 1 unit Suction inlet 2 5 times Suction inlet Product Service space for
3. Thus concerning moist air a variety of numerical values are not handled for the unit weight of mixed gas of dry air and water vapor while the mixed gas of 1 kg of dry air and X kg of water vapor that is 1 X kg of air is used as one unit weight 286 Si 18 Namely the following figure represents the weight pressure and volume of the moist air by the expressions Water vapor Moisture Moist air O O O O O O O OO Weight 1 kg X kg 1 X kg Volume V V V Pressure Pa kg cm Pw kg cm P kg cm 1 03323kg cm P kPa 101 325kpa Total pressure Pa kPa Pa kPa il CN Partial pressure 11 1 3 How to represent water vapor Humidity in moist air There are different kinds of method available to represent the humidity 1 Relative humidity 6 26 The relative humidity is the ratio of the moist air specific weight to the saturated air specific weight or the ratio of the water vapor partial pressure Hw mmHg kpa in given moist air to the moisture partial pressure Hs mmHg kPa in saturated moist air at the same temperature y Specific weight kg m Specific weight 1 Specific volume This is the weight of water vapor kg contained in 1 m moist air Saturated moist air O When the temperature t of moist air is equal to the temperature t of saturated water vapor corresponding to the partial pressure Hw of the water vapor the air is called saturated moist air
4. 11 6 2 Selection of model with priority given to apparatus and airflow rate In cooling operation 1 Find the sensible heat factor From Equation 5 1 Qs SHF QstQ 2 Plot the proven conditions on the psychrometric chart Indoor condition Point 1 X4 Absolute humidity at outlet point 4 of humidifier Outdoor air condition C kg kg When outdoor air is taken in Point X5 Absolute humidity at inlet point 6 or B of heater SHE lll uiu ierit rtr o nain inne nulia SHF line found in e kg kg Fig 1 1 41 When the humidifying weight is determined specify the type from the optional accessories list in the Technical Data When selecting with evaporative plate type humidifier Type KEM104D15 Humidifying capacity 5 2 kg h and Power consumption 4 kW h Summary in heating operation The cycle is shown on the psychrometric chart Fig 11 40 3 Find the airflow rate of apparatus qs kcal n 3600 x qs Q 0 24 x VIX t1 t4 1 005 x J t1 t4 V4 Assuming the discharge point 4 of apparatus calculate the specific volume of air m kg t4 Assume the discharge point 4 of apparatus C How to assume t4 In the case of ordinary cooling operation assume that the 1 Indoor point difference t1 t4 in temperature between suction and 2 Outdoor air point discharge is 8 to 12 deg and the relative humidity at the 3 Mix
5. De S M E f MN as ES e gt A c N 7 z x NS T ay WE XT h UM i AR Aur i6 P AN atk see x 3 e gt 7 x Sy N X N Wa 1 Drying no moisture There shall be no moisture in the pipe Water entering from outside such as rain Moisture due to dew condensation occurring inside the pipe Clogging of expansion valve capillary tube etc Insufficient cooling or heating Degradation of refrigerant oil Malfunction of compressor Z0186 Compressor is corroded due to moisture Pipe preparation Flushing Vacuum drying Z0137 Pipe preparation Flushing Vacuum drying ae O G amp 2 Cleaning free of contamination R407C and R410A refrigerants 3 Tightening air tightness There shall be no dust in the pipe There shall be no refrigerant leak Oxidized film generated during brazing Entering of foreign items such as dust particles and oil from outside Clogging of expansion valve capillary tube etc Insufficient cooling or heating Degradation of refrigerant oil Malfunction of compressor Not clogged Z0187 e Same as the items on the left e Do not use tools or devices previously used with a different type of refrigerant Basic brazing procedure Basic flaring procedure Z0136 Insufficient brazing Inadequate flaring or insufficient tightening torque Inadequate tightening of flange connection Gas shortage I
6. 1 unit Note J Shows service space 7 5 2 Installation of units Consider air distribution of a room based on structure of a room and arrangement of occupants and furniture Install the unit in such a place where wall or obstacles do not interrupt the air ways in and out of the unit If the air way is disturbed predesigned cooling efficiency is not obtainable and furthermore dew forms on the casing which may be resulted in water leakage Avoid installing the unit in such a place which is near the door or kitchen so as not to draw unnecessary volume of air or stale air Incase the unit is mounted in a wall carefully install it not to transmit operation vibration to the wall Leave a sufficient space for providing after sales service 217 Installation Examples of bad installation If distributed air is short circuitted cooling or heating capacity will be greatly reduced 7 6 Making a pipe hole Make a hole in the wall In case of room air conditioners suitable hole diameter is 70 80mm The location of a hole should be lower than the drain outlet so that drain water can be smoothly extracted outsides In addition the hole should be inclined downwards to the outdoor as shown in the figure below Bownword 70 80mm NClination Downward Psychrometric chart Chapter 11 Psychrometric chart 11 1 Air Atmospheric air is referred to as air which means the moist air in terms of air c
7. Service Checker FPYEIII 4 for VRV system air eal for building erial connector conversion cable Checker TYPES 9991357 Used when connecting M5 RAcable to the Service Checker RS 232C cable for personal computers D sub 25 pin male D sub 9 pin female straight Input 220VAC 50Hz AC adapter Output 9VDC 500mA Outside vi Temperature condition 10 to 35 Battery Ni Cd battery Charger 220VAC input 50 60Hz Complete charging approx 16 hours TYPES Software English 999143T Compatible with English version Windows95 98 Me NT4 0 2000 XP TYPES Instruction Manual English 999144T Instruction manual of TYPES software English Purchase the above four items total of 181 000yen TYPES Power Unit 220V 1 999142T 6 10 1 8 Optional Items Used when connecting to a Super Multi or room air conditioner via PCB M5 RA cable 1 999140T connection No need to purchase this cable if customers have TYPE2 Expansion Kit 9991 12T High temperature thermistor 30 to 150 Low temperature thermistor 30 to 70 Sensor Kit 1 999107T Air thermistor 10 to 50 High pressure sensor 0 to 30kg cm G Low pressure sensor 0 to 10kg cm G 6 10 1 9 Accessories TYPES cable for VRV system air conditioner A set of cable of VRV system air conditioner for building cable and serial for building 999141T connector conversion Attached to the Checker TYPES3 Used to drive the Serivce Checker FPYE III TYPE spare battery
8. and draw the line of the compression process by connecting the Points 1 and 2 The Point 2 represents the discharge gas state from the compressor 37 Mollier chart o Q C C QO e 2 v v Q X QO specific enthalpy kJ kg Note The compression process is drawn as theoretical adiabatic compression Therefore it may be slightly different from that in actual operation 3 Condensation process The condensation process starts from the Point 2 Heat exchange in this process is performed mostly in the condenser but the condensation process itself starts at the discharge point of the compressor At the Point 2 the condensing high pressure is 1 4MPa abs which is equal to the condensing temperature of 36 C Since the condensation process is a heat radiation process under constant pressure draw a line horizontally to the left from the Point 2 While in the condensation process the refrigerant changes from superheated vapor to moist vapor and further to sub cooled liquid thus proceeding to the expansion process In this case the temperature of liquid at the expansion valve inlet is 31 C Therefore the Point 3 of intersection of the pressure line of 1 4MPa abs with the 31 C constant temperature line that tilts toward the right by 1 C immediately before the 30 C constant temperature line is taken as the point where the condensation process is complete Pressure MPa abs Specific enthalpy kJ kg Note The pre
9. clean the scale in advance Generally when t2 t1 becomes over 3 to 5 C cleaning is necessary 4 Judgement after cleaning The simplest and the most certain way is to confirm visually the state of coming off the scale But in some cases the visual confirmation is impossible because the recent heat exchanger in a cooling refrigerating equipment has hermetic or other complicated structure For this itis important to compare the before and after cleaning using the ways mentioned above in the clause 3 when you neglect this confirmation of cleaning effect even though the high pressure is cut by other reasons than scale sometimes it may be judged that the cleaning made a mistake More the way of judgement of the state of scale adhesion only by high pressure is not proper because the state changes depending on the temperature or the volume of cooling water 5 How to select chemicals for cleaning An important factor in the chemical cleaning is to select the proper chemicals depending on the type of scales As a matter of fact analysis of composite scales should be consulted our Daikin S S or the specialist of water treatment
10. i SSNMNN Pha e Shey e Bo D P Il 4 ot te e pA LACE Smo gs roel oo Toes PER P d p rar 2 P RT MES CI TE DIC DA VT fe m IP GLI ALL NT Vu chee LPS A ONG KV GLO A INE vy oes 0 Te Bite ae whee e ee to J v 2 P v or y O DM C Receiver Inlet air Evaporating temperature qp AX Condensing t rat gt temperature S H 5 C Pressure Lowside EMEN Liquid vapor Superheated Superheated Liquid Sub mixture vapor cooled CZ Inlet air Compressor High side liquid 28 Mollier chart Chapter 2 Mollier chart The state of refrigerant in a refrigeration cycle varies with a wide range of conditions while an air conditioner or a chiller is in operation When the changes in state under these conditions are plotted on a chart each state and the numerical values of the state in every part of the equipment can be estimated Furthermore the capacity or the operating state can be estimated using these values This chart is called the P h Chart The vertical axis of the P h Chart specifies the pressure P and the horizontal axis specifies the specific enthalpy h The P h Chart is therefore sometimes referred to as Pressure enthalpy Chart Furthermore this Chart has received another name derived from the name of the inventor of the Chart that is Mollier or Morieru in Japanese Chart The P h Chart consists of 8 kinds of line
11. or saturated air in short O When pressure and temperature are determined the limit of water vapor containable in the said air is also determined This air containing water vapor up to the limit is called saturated air 2 Absolute humidity X kg kg X in Fig 1 1 represents the absolute humidity itself The weight ratio of water vapor contained in the moist air becomes X 1 kg kg to 1 kg dry air contained in the moist air In other words this is the ratio of the moisture weight to the dry air weight both of which are contained in the moist air Si 18 Example of calculation 1 From Equation 5 8 qp G h3 hs kcal h 1 Qp 3000 G hs hs kw Ln d pa 9P hs hs G h5 12xQ 2 Substituting hzarid hs into Equation 5 13 the Equation will be hs hs X BF hs hs CcF Find BF according to the technical data to calculate the he 3 Draw a straight line between Point 3 and Point 6 obtained from hs on the psychrometric chart and find ts through the intersection of the straight line and hs c Availability of model assumed If the air conditioner outlet temperature ts found in Section b 3 is lower than the design discharge temperature t4 and located below the apparatus SHF line found by Equation 5 1 the design air conditions are satisfied making it possible to proceed with calculations according to the model assumed Fig 11 28 shows that on the psychrometric cha
12. 5 RH 2 Find the state at the outlet of heating coil Substituting numerical value through Equation 4 10 Fig 11 55 qH Qx vs h3 h1 2800 6000x Y x h4 8 57 ha 8 57 2900 Assume that 6000x 1 V 0 882 V 0 882 pe 8 57 44 12 SHF 0 548 12 7 kcal kg Thus make sure through the psychrometric chart 3 Find the state of air after humidification Substituting numerical value through Equation 4 11 Lw Q x 1 Xs X3 V3 2 Find the discharge point of air conditioner From Equation 5 11 hszhs T 1 1026000 x x Xs 0 0069 v 12 65 _ _ X5 0 00694 10 Assume that 242 BRUM 1 12 65 5 56 6000x V 0 875 V 7 09 kcal kg E re Write the enthalpy hs at the outlet of air conditioner on the psychrometric chart 4 Write the numerical values found in the above 1 2 and 3 on the psychrometric chart From Equation 5 13 he hs Nux 12 65 5 56 x0 1 0 0069 0 0015 Mirai O h 12 66 7 09 0 79 6 3 kcal kg Fig 11 54 In order to provide the discharge point of air conditioner on the SHF line X 0 0084 Fig 11 56 ts 31 5 C Install a re heater and determine the re heater capacity 309 Si 18 Simple cooling heating load calculation 12 3 Design Conditions Table 12 1 Composition of heat load Het mum Heat m Heat source 1 Roof wall partition floor ceiling Solar radiation night radi
13. Chart this change of phase is represented by drawing a vertical line from top to bottom from the left side of the saturated liquid line Electrical wiring Si 18 4 Thyristor SCR SCR Silicon Controlled Rectifier Thyristor is a power control element consisting of P and N Thyristor type semiconductors connected in 4 layers This is used in speed control of DC motor light control Appearances meu device of electric lamp and non contact switch utilizing its rectifying and switching functions Figure code Moreover the thyristor can turn on and off the extremely high voltage current of several thousand volts and several ir N un G Bde thousand ampere with one element which is so small that itis placed on our palm Thyristor SCR Silicon Controlled Rectifier P gate P gate A thyristor j U d Anode Cathode G gate 5 Triac Triac is a 3 polar dual direction thyristor which can flow electric current in both directions AC and functions with both positive and negative gate voltages The functions are the same as those obtained by combining thyristors in l pee Figure code parallel and in reverse direction Triac has a 5 layer structure of NPNPN which is the same as SSS and is used for AC non contact switch electric heater control light adjusting device three phase motor control and temperature control of copy machines Xerox PPC In Daikin products it is used for phase control of indoor unit fan of room air cond
14. September 5 2011 Correction of Service Manual Si 18 Air Conditioning and Refrigeration Equipment Please refer attached pages for correction of service manual Si 18 Fundamentals of refrigeration At Point B the R410A refrigerant of 0 1MPa boils at a temperature of 51 6 C Therefore at Point D if the R410A refrigerant having a temperature of 35 C is in a state of saturated vapor at the pressure of 2 12MPa it becomes refrigerant saturated liquid of 35 C by removing the condensation latent heat from the said saturated vapor By contrast at Point C that means it is required to reduce the pressure down to 0 94MPa in order to boil the R410A refrigerant at 5 C Fig 1 33 Saturated curve of R410A and Water Liquid Condensation l l mHg 20 40 60 80 100 120 Temperature C Si 18 1 3 5 Sensible heat and latent heat Fig 1 34 shows the temperatue heat content diagram for 1kg of water heated from 50 C to 150 C vapor under the atmospheric pressure 1 From A to B 105 4kJ 25 2kcal of heat were added to increase ice temperature from 50 C to O C 2 From B to C 333 2kJ 79 6kcal were added to melt ice without changing its temperature 3 From C to D 418 6kJ 100kcal were added to heat water to boiling point from 0 C to 100 C 4 From D to E 2256kJ 539kcal were added to change water to vapor without changing its temperature b From E to F 92 5kJ 22 1kcal were added to increase vapor tempera
15. ation temp difference 2 Window glass Solar radiation night radiation temp difference 3 Infiltration Temperature and humidity of infiltrated air 4 Illuminant Generated heat 5 Human body equipment Generated heat Outdoor 6 Intake fresh air air Temperature and humidity in outdoor air Table 12 2 Cooling load conditions Dry bulb temp DB Wet bulb temp WB Relative humidity RH a Note Since these conditions about indoor and outdoor are included in the coefficient B in the Cooling Heating load list the figuring out of temperature difference is not required O rq O a Cc D X LLI Indoor load Internal load Table 12 3 Heating load conditions Figure out the temperature difference from the following table Outdoor Brussels Shanghai gon Kong Tokyo Riyadh ea MS Paris Sydney temperature China China Sii Arabia MK France Australia C Note 1 These data are drawn out from ASHRAE HANDBOOK 2 When night heating is regarded as importance reduce further 2 degrees from the above temp Table 12 4 Indoor temperature C State of action Examples Seated at rest or very light work Office theater residence restaurant etc Little active Factory light work school store etc 313 Si 18 13 3 Refrigerant piping 13 3 1 Three basic rules of refrigerant piping Item D 2 v iv 2 _ Cc o gt D Yi a Remarks
16. densing temperature 4 Liquid temperature at expansion valve inlet or sub cooled degree Superheated degree Suction gas temperature Evaporating temperature Sub cooled degree Condensing temperature Liquid temperature at expansion valve inlet B Procedure Draw the refrigeration cycle on the R22 P h Chart based on the following operating conditions Conditions Evaporating temperature 6 C Condensing temperature 36 C Superheated degree 5 C Liquid temperature at expansion valve inlet 31 C 1 Evaporation process Even though the refrigeration cycle can be started to draw from anywhere on the P h Chart it is usually started from the compressor suction point that is the completion point of the evaporation process Since the evaporating temperature is 6 C a horizontal line is drawn from the 6 C graduations on the saturated liquid line and the saturated vapor line The starting point of the evaporation process has not yet been known at this stage Therefore the horizontal line may be tentatively drawn to the right from a point with a dryness factor of about 0 4 The evaporation process is represented with a horizontal line due to changes under constant pressure In this case the pressure is 0 6MPa abs which is referred to as the evaporating or low pressure Check the superheated degree given in the above conditions to determine the point where the refrigerant is discharged from the evaporator and sucked int
17. ead the following numerical values of the four Points 1 2 3 and 4 If the column which cannot be read from the Chart fill it with an oblique line Mollier chart 2 2 How to draw refrigeration cycle 2 2 1 Vapor compression refrigeration cycle Chiller and air conditioners consist of four major components such as evaporator compressor condenser and expansion valve The refrigerant flows through these components and the process of evaporation compression condensation expansion repeats to carry out refrigeration This process is called the refrigeration cycle Fig 2 9 Low pressure High pressure Superheated Superheated vapor Moist vapor liquid 1 Evaporation Change of phase in the evaporator The evaporation is a process in which the low temperature low pressure liquid refrigerant evaporates while removing heat from the indoor air or moisture On the P h Chart this change of phase is represented by drawing a line from left to right with a constant pressure line that is a horizontal line Evaporation o Q A D w gt o v Q QO Specific enthalpy kJ kg 2 Compression Change of phase in the compressor The compression is a process in which the compressor sucks in gases generated through the evaporation process and compresses the gases into high temperature high pressure superheated vapor This process is taken as the adiabatic compression that
18. ing point Heater suction point discharge point falls in the range of 80 to 90 4 Design discharge point Outlet point of humidifier Heater outlet point Inlet of evaporative plate type 4 Find the conditions of air at the inlet of humidifier evaporator Heater outlet point Inlet of water spray type a When outdoor air is taken in the air conditioner humidifier Find the mixing point 3 which is present on the straight line O Heater capacity hs or hs hs connecting the outdoor air point 2 and the indoor point 1 hs In the case of water spray type humidifier The point 3 is defined as the suction point hs In the case of evaporative plate type humidifier From Equation 2 1 O Indoor load ha h ts Kete 1 K ett C O Outdoor air load h hs hs Ke h2 1 K eht kcal kg kJ kg O Humidifying load ha hs O Humidifying capacity X4 Xs 304 Si 18 Psychrometric chart Answers to Exercise 8 Answers to Exercise 9 Find the mixed air D Find the sensible heat factor SHF From Equation 2 1 ts K e t 1 K t1 From Equation 4 1 SHF qs ts 0 1x0 1 0 1 x20 qs qL 18 C _ 8500 hs K h2 1 K hi 8500 7000 0 1x1 1 1 0 1 x9 4 0 548 0 1148 46 Write the SHF on the psychrometric chart and find the 8 57 kcal kg conditions of suction air of air conditioner According to the above calculation the mixed air 3 Enthalpy hi of inlet air 212 65 kcal kg reaches 18 CDB and 54
19. is the constant specific entropy change In general the suction gas into the compressor has a superheated degree of 5 C Therefore on the P h Chart this change of phase stage is represented by drawing an upward slopping line from the right side of the saturated vapor line along the constant specific entropy line 36 Si 18 Evaporation Pressure MPa abs Specific enthalpy kJ kg 3 Condensation Change of phase in the condenser The condensation is a process in which the high temperature high pressure discharge gas from the compressor is condensed liquefied through cooling water or outdoor air in the condenser On the P h Chart this change of phase is represented by drawing a line from right to left with a constant pressure line that is a horizontal line Condensation Evaporation a O iv C a D T 3 D U D Y A Specific enthalpy kJ kg 4 Expansion Change of phase in the expansion valve or capillary tube The expansion is a process in which the pressure of the condensed liquid refrigerant is reduced through the expansion valve or capillary tube to an evaporation pressure required In this process since there is no heat transmission between the refrigerant and the surroundings the phase changes according to the constant specific enthalpy In general the liquid refrigerant at the inlet of the expansion valve is sub cooled by 5 C below the condensing temperature Therefore on the P h
20. itioners and sky air systems Photo triac Photo triac functions when light is emitted instead of Photo triac applying gate voltage and is often used as light receiving element of photo coupler It is also often incorporated into phase control circuit of fans by combining with light Fd emitting diode LED Figure code e oua a o 6 Dyac Dyac is often used as the trigger element in AC phase control circuit such as muffling access ignition device of water Dseilers etc Another name of dyae Dual direction diode thyristor Figure code 124 Si 18 Electrical wiring 7 Thermistor Thermistor has a characteristics that the resistance lowers as the temperature rises which is opposite to that of normal resistor NTC thermistor By utilizing this characteristics resistance change thermistors are incorporated into the sensors of electronic thermostats in room air conditioners Sky Air system and boilers Code and characteristics of thermistor Temperature Characteristics of thermistor 8 Regulator Regulator is an IC for power stabilization The regulator can control the output voltage to a constant level regardless of the input voltage The accuracy of regulator is higher than that of zener diode and can take a heavy power source out m UU IN OUT Constant output voltage Input voltage Comparator compares two input voltages and outputs the result as H
21. nsufficient cooling or heating Temperature increasing of discharge gas Degradation of refrigerant oil Malfunction of compressor Clogged 20188 Capillary is clogged with dust Follow the basic brazing procedure Follow the basic flaring procedure Follow the basic flange connection procedure Conduct an air tightness test gas leak check Air tightness testing procedure Gas leak check 331 Si 18 B Merits and demerits of cleaning using chemical There is selectiveness of scales but almost all scales can be removed if the chemical is selected precisely On the other hand if the mistake is made in the selection the scale cannot be removed and more in some cases abnormal corrosion is brought about n some cases neutralization treatment of drain is required after cleaning Even the cleaning of large capacity is possible in a short time Even the complicated water circuit can be cleaned Take care of metal corrosion by the cleaning chemicals Generally this way is too expensive B Merits and demerits of cleaning using brush There is selectiveness of scales comparatively a little And very hard scales cannot be removed This is almost physical work so personnel expenses are too high Incase of complicated or closed type water circuit a brush cannot be inserted that is the cleaning is impossible As the chemicals is not used there is no fear of the drain pollution
22. o the compressor In this case since Mollier chart the superheated degree is 5 C the suction gas temperature rises by 5 C from the evaporating temperature of 6 C thus reaching a temperature of 11 C The pressure is kept constant up to this point therefore the Point 1 of intersection of the extension of the constant pressure line of 0 6MPa abs and the 11 C constant temperature line that tilts toward the right by 1 C from the 10 C constant temperature line is taken as the suction point of the compressor o re A 2 o XI 5 D Q Lum a O Specific enthalpy kJ kg Note Strictly speaking the pressure varies while showing a slight drop in the evaporation process while the pressure is assumed to be constant on the P h Chart 2 Compression process The compression process starts from the Point 1 While in this process a line is drawn according to the changes of the constant specific entropy that is in parallel with the specific entropy line up to the Point 2 of intersection with the line of condensing pressure high pressure of 1 4MPa abs corresponding to 36 C condensing temperature Whereas this specific entropy line is slightly curved and the Point 1 does not always comes on the specific entropy line on the Chart Therefore it is practical to find the Point 2 according to a position on the condensing pressure line having the numerical value of specific entropy equal to that at the Point 1
23. onditioning 11 1 1 Properties of moist air Moist air is a mixture of dry air and 1 to 396 mass of water vapor 1 Properties of dry air The composition of dry air in the standard state temperature 0 C pressure 760mmHg 101 325kPa acceleration of gravity g 9 80655 m S is as follows Nitrogen Oxygen Araon Aa 2095 093 Table 11 1 omposition Pu Va Volumetric 96 e 75 53 23 14 1 28 1 Constant pressure specific heat of dry air Cpa 0 240 kcal kg deg 2 Enthalpy of dry air ha 0 240t kcal kg 1 005t kJ kg This means the enthalpy of dry air at arbitrary temperature and pressure based on the condition that the enthalpy of dry air is O at a temperature of 0 C and standard atmospheric pressure 1 005 kJ kg K 2 Properties of water vapor Constant pressure specific heat of water vapor Cow 0 441 kcal kg deg 1 85 kJ kg K Evaporation latent heat of water vapor 597 3 kcal kg 2501 kJ kg Enthalpy of water vapor hw r Cpwt 597 3 0 441t kcal kg 2501 1 85t kJ kg Water vapor enthalpy hw at arbitrary pressure and temperature is shown as a function of temperature t C alone under the condition that the enthalpy of saturated water at 0 C is 0 and the pressure and temperature are not so high 11 1 2 Moist air It is convenient to assume that the moist air is an ideal gas that is mixture of dry air of 1kg in a certain composition and water vapor of X kg variable with state
24. or L The input terminal has positive side and negative side and if the voltage input to positive side l is higher than that input to negative side the results is Figure output as H while L is output in the opposite case code The figure below shows this function using a relay as an example 10 Ope amp Ope amp is an integrated circuit called as calculation amplifier It is used for 1 calculation 2 Impedance change 3 measurement control and 4 oscillator etc by connecting to an appropriate external circuit Figure code 125 TYPE Basic works Si 18 6 10 1 6 Specifications of Service Checker TPYE III Item Specifications External dimensions excluding projecting sections 180 width x 150 depth x 45 height mm Power supply 9VDC 300mA Outside Use an AC adapter or battery of TYPES3 Power Unit 220V Battery drive time oy hours after complete charging when using a battery attached to TYPES Power Unit Temperature and humidity conditions 10 to 55 C 10 to 35 C for AC adapters 95 RH or less no condensation HS232C interface Asynchronous 19200bps D sub 25 pin female straight connection to a personal computer Temperature at 6 pone point for discharge pipe pressure at 2 points high pressure and Sensor input section low pressure Two out of the 6 points can be switched to receive to voltage signals 0 to 1V or 0 to 5V TYPE 6 10 1 7 Standard configuration
25. ressure gauge shows 0 5MPa G and the high pressure gauge shows 1 7MPa G Show each of these pressures on the P h Chart using horizontal lines 2 1 2 Specific enthalpy h kJ kg The specific enthalpy is graduated on the horizontal axis Therefore constant specific enthalpy lines are shown with vertical lines This scale is proportionally graduated Therefore the numerical values must be read as accurately as possible The specific enthalpy is the sum of internal energy and work energy which can be defined as the total amount of heat held by the refrigerant in a given state On the P h Chart the specific enthalpy of 1 kg mass of saturated liquid at O7C is defined as 200 kJ kg 400 500 m saturated liquid TT 400 aie enthalpy Note The specific enthalpy is scientifically defined as h ue Pv h Specific enthalpy ue Internal energy P Absolute pressure v Specific volume Si 18 Condensation Expansion N Evaporation o Q iv C A D _ D o D Y a opecific enthalpy kJ kg 2 2 2 How to draw actual operating state on P h Chart In order to draw the refrigeration cycle on the P h Chart the following four operating conditions are required In other words if the four conditions are known the refrigeration cycle can be drawn on the P h Chart Conditions 1 Evaporating pressure or evaporating temperature 2 Suction gas temperature or superheated degree 3 Condensing pressure or con
26. rt It is good if the air conditioner outlet temperature ts falls in the shaded area in the above figure If there is too large difference between the air conditioner outlet temperature ts and the design discharge temperature ta it is required to use a model of smaller capacity and reexamine the planning since the capacity of the assumed model is too large Psychrometric chart 2 When a model is not assumed Generally speaking in this case set up conditions and proceed with planning with a concept to newly produce an air conditioner conforming to the apparatus Namely Referring to information in Section 5 1 3 b When the airflow rate has not been determined tentatively determine the airflow rate then take this airflow rate as a reference to determine the model of air conditioner Example When finding a cooling load required to maintain the conditions of a given room at 26 CDB and 50 RH qs 8 000 kcal h 9 30kw and qL 2 000 kcal h 2 32kw Find the SHF of this room When the bypass factor BF of the evaporator is 0 11 what is the dry bulb temperature required to discharge air at a point on the SHF line Solution From Equation 5 1 ds 8 000 Ld Qstq 8 000 2 000 Use the psychrometric chart of discharge temperature to find the SHF 0 8 SHF qs 9 32 geti 9304 2 92 99 Fig 11 29 1 BF CF 0 89 CDB 26 CDB Discharge temperature 14 2 CDB Psychrometric chart Si 18
27. s in all saturated liquid line saturated vapor line constant temperature lines constant specific volume lines constant dryness lines and constant specific entropy lines as well as constant pressure lines and constant enthalpy lines It looks like a map which shows the refrigerant properties diagrammatically The methods of drawing the lines vary to some extent with the types of refrigerants while the basic method of reading the lines does not vary In this textbook the R22 refrigerant fluorocarbon HCFC22 most often used for air conditioning is used as the teaching material Furthermore SI unit International System of Units is used to represent the unit 2 1 Composition of P h Chart 2 1 1 Pressure P MPa abs In the P h Chart pressure is graduated on the vertical axis Therefore horizontal lines represent constant pressure lines and all points on the same horizontal line show the same pressure The scale is logarithmic but not required to be bound for use The pressure scale is expressed in the value of absolute pressure Absolute pressure Gauge pressure Atmospheric pressure MPa abs MPa G 0 1 MPa abs Note Under normal conditions the abs of MPa abs is often omitted In this textbook however the abs consciously remains shown for ease of understanding P h Chart R407C 32 Si 18 0 6 o P pa o Q9 x A Chiller is operating with the use of R22 refrigerant The low p
28. ssure also varies while showing a slight drop in the condensation process while the pressure is assumed to be constant on the P h Chart 38 Si 18 4 Expansion process The expansion process starts from the Point 3 While in this process a line is drawn according to the changes of the constant specific enthalpy that is in parallel with and perpendicular to the specific enthalpy line up to the Point 4 of intersection with the line of the evaporating pressure of 0 6MPa abs The distance between the Point 4 where the evaporation starts and the Point 1 represents the evaporation process The expansion process is performed according to the constant change of the specific enthalpy Even though there are no external heat exchanges the temperature of the liquid refrigerant falls from 31 C to 6 C The reason is that when the liquid refrigerant pressure is reduced due to the frictional resistance while passing through the expansion valve or capillary tube part of the liquid instantaneously vaporizes to decrease the liquid temperature a Q iv C a D Se D o D Y A 250 Specific enthalpy kJ kg Note It is understood that even though the refrigerant is in the low temperature low pressure liquid state when it is discharged from the expansion valve actually moist vapor having a dryness factor of 0 16 enters the evaporator Draw a refrigeration cycle on the P h Chart under the above mentioned conditions Then r
29. ture from 100 C to 150 C In this example e The heat which was required to increase the ice temperature is called sensible heat A to B e The heat which was required to change the ice to water is called latent heat of melting B to C e The heat which was required to increase the water temperature is also called sensible heat C to D e The heat which was required to change the water to steam is called latent heat of vaporization D to E If the process is reversed e The heat which must be rejected to change the steam to water is called latent heat of condensation E to D The heat which must be rejected to decrease the water temperature is called sensible heat D to C e The heat which must be rejected to change the water to ice is called latent heat of solidification C to B e The heat which must be rejected to decrease the ice temperature is called sensible heat B to A Fig 1 34 u EN MMEENENNET X Temperature C Fundamentals of refrigeration Si 18 Fig 1 53 Outlet air Outlet air fT Condenser CT TAVIT UU T pera OLOLA ENTER ORs Lond att P5 saf e LAL Lene GIL SORELY TY 044 ah p ee ee e 9 Flow control A An DM RA N 1 SN RS x MNT OS RCS TATUS gt AN N RUUAT ANEUS NADAN Nes e SAY SRS NS SYN SOUT PAPO PMNS RR UK KASON S Ay ASAE SATE 971 d VN ess NA NAA eee EJ pee Fee Her ot IPPPED ef ANS Peto
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