This book has a twofold purpose: to serve primarily as a college text and as a reference material for the practicing engineer.
The author attempts to present refrigeration and air conditioning in the simplest possible way without sacrificing quality. Principles and concepts are discussed thoroughly using mostly basic thermodynamics, followed by illustrative problems arranged in the order of increasing difficulty. Additional exercises are also provided at the end of each chapter to further enhance the learning process. Answers are given to all the problems so that the student himself can check the accuracy of his solutions. For the student to get the most from this book, he should solve all the problems at the end of each chapter conscientiously. This is the best way to study and learn any technical subject.
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Refrigerating Machine and Reversed Carnot Cycle SI units SI or the International System of Units is the purest form and an extension and refinement of the traditional metric system. )
Unit of Force The unit of force in the SI system is the newton, denoted by the symbol N.
1 kg f = 9.8066 N 1 lb f = 4.4484 N 1 lb, = 0.4536 kgf
Unit of Pressure The SI unit of pressure is the pascal and is denoted by the symbol Pa. 1 Pa = 1 Nzm" 1 bar = 100 kPa 1 psi = 6895 Pa 1 atm =.101.325 kPa = 1.033 kg/em" = 14.696 lb zin"
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2 Refrigeration and Air Conditioning
Refrigerating Machine and Reversed Carnot Cycle 3
Unit of Energy and Work
Heat Engine and Refrigerating Machine
The SI unit of work is the newton meter denoted by Nm or joule denoted by J.
A system operating in a cycle and producing a net quantity of work from a supply of heat is called a heat engine and is represented as shown in Fig. 11.
Hot reservoir (source of heat)
1 Btu = 252 cal = 1055 J ~
The SI uni t of power is the watt, denoted by the symbol W. It is defined as tho rate of doing 1 Nm of work per second. 1 W
Unit of Refrigerating Capacity
Cold reservoir (receiver of heat)
Fig. 11. Representation of a heat engine
The standard unit of refrigeration is ton of refrigeration or simply ton denoted by the symbol TR.
W _ QA QR QA A
One ton of refrigeration is the rate of cooling required to freeze one ton of water at 32°F into ice at 32°F in one day. In English units
1 TR = (2000 lb) (144 Btu/lb) 24 h 1 TR = 12,000 Btu/h = 200 Btu/min In Metric units
= the heat supplied
= the heat rejected
= the thermal efficiency
1 TR = (12,000 Btulh) (252 callBtu) 1 TR = 3024 kcallh =. 50.4 kcallmin
A refrigerating machine will either cool or maintain a body at a temperature below that of its surroundings. A refrigerating machine may be represented by the diagram shown in Fig. 12. The machine R absorbs heat QA from the cold body at temperature T 1 and rejects heat QR to the surroundings at temperature T 2 and, during the process, requires work W to be done on the system.
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4 Refrigeration and Air Conditioning
Refrigerating Machine and Reversed Carnot Cycle ;)
The Carnot power cycle consists of the following reversible processes: process ab: isothermal expansion, 1'" = T = 1'] b process be: isentropic expansion, SI> = S, process cd: isothermal compression, T = T = T, c
process da: isentropic compression, Sri = S, cold
= the heat absorbed from the cold body or
The performance of a heat engine is expressed by its thermal efficiency. The performance of a refrigerating m achin e is expressed by the ratio of useful result to work, called energy ratio or coefficient of performance (COPl.
Q A = the heat added by the hot body = the heat rejected to the cold body
W = the work done
e = the thermal efficiency 1']
= the temperature of the Source of heat
T 2 = the temperature of the sink or receiver of heat d
(1'1 1',,) ISh S) S a ) r 1 (S 'b
The Carnot Cycle p'
= 1'\ (S" S) 1'2 (SI> S)
refrigeration produced QR = the heat rojected to the surroundings W = the work done or mechanical energy consumed COP = the coefficient of performance
of a refrigerating machine
('arnot Cyril' Downloaded by Ice Scott ([email protected])
6 Refngeration and Air Conditioning
Refrigerating Machine and Reversed Carnot Cycle 7
The Reversed Carnot Cycle
= the heat absorbed from the cold body
the heat rejected to the hot body
COP= the coefficient of performance
The reversed Carnot cvcl« follows the same processes as in the power producing Carnot cycle, but the cycle operates in the counterclockwise or reverse direction. The reversed Carnot cycle consists of the followi ng pn)('('ss('s: process ab: isentropic compression, Sa == Sh
= the refrigeration temperature
= the temperature of heat rejection to the surroundings
(11) A refrigerating system operates on the reversed Carnot cycle. The higher temperature of the refrigerant in the system is 120°F and the lower is lOoF. The capacity is 20 tons. Neglect losses. Determine: (a) Coefficient of performance. (b) Heat rejected from the system in Btu/min. (c) Net work in Btu/min. (d) Horsepower,
process be: isothermal heat rejection, T h . T, . T 2 process cd: isentropic expansion, Se = Sa process da: isothermal heat absorption, T d == T, == T, Q A =Tj(Sa S)
T'. = 10 + 460 = 470
T, = 120 + 460 . 580
= T 2(Sa Sri) T[ ($a So)
TI(SaSa) (T 2 T I) (Sa Sa)
T) T[ Downloaded by Ice Scott ([email protected])
Refrigerating Machine and Reversed Carnot Cycle 9
1;,1'11"'1;1111111 .u u] .\11' (1III1iJll.lllIllg
QR = W + Q\ = 9:l6 + 4000 == 4936 Btu/min, W W
248 345 248 = 2.557
T] = 25 + 273 = 248 K T,~
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(2.557) (6000) = 4313kJ/min. 1 + 2.557
QR QA = 6000 4313 = 1684 kJ/min. 4313
_ (COP) (QR) 1 + COP =
(12) A refrigNation system operates on the reversed Carnot cycle. The minimum and maximum temperatures are minus 25 cC and plus 72 C. respectively. If the heat rejected at the condenser is 6000 k.l/rn in , draw the TS diagram and find, (a) power input required. n nd (b) tons of refrigeration developed.
Refrigerating Machine and Reversed Carnot Cycle 11
10 Refrigeration and Air Conditioning
(13) The power requirement of a Carnot refrigerator in maintaining a low temperature region at 238.9 K is 1.1 kW per ton. Find (a) COP, (b) Te;' and (c) the heat rejected.
(1) A reversed Carnot cycle is used for refrigeration and rejects 1,000 kW of heat at 340 K while receiving heat at 250 K. Determine (a) COP, (b) the power required, and (c) the refrigerating effect.
Ans. (a) 2.778, (b) 264.7 kW (c) 735.3 kW
,/ (2) A reversed Carnot cycle has a refrigerating COP of 4. (a) What is the ratio Tmax/Tmin? (b) If the work input is 6 kW, what will be the maximum refrigerating effect, kJ/min and tons.
W = 1.1 kW/TR Ans. (a) 1.25,
~ 1 T R or 3.52 kW
'(3) A reversed Carnot engine removes 40,000 kW from a heat sink. The temperature of the heat sink is 260 K and the temperature of the heat reservoir is 320 K. Determine the power required of the engine.
Q A 3.52 kW =3.2 COP = W = 1.1 kW (b)
238.9 T l 2 3 8 . 9
= W + Q A = 1.1 + 3.52 := 4.62 kJ/s
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/ Simple Vapor Compression Refrigeration System 13
The pressureenthalpy (ph) diagram and the temperature entropy (T's) diagram are the diagrams frequently used in refrigeration cycle analysis. Of the two, the ph diagram is the one most commonly used. The process which comprise the standard vaporcompression cycle are:
Simple Vapor Compression Refrigeration Systems
12, reversible and adiabatic compression from saturated vapor to the condenser pressure 23, reversible rejection of heat at constant pressure de superheating and condensation 34, irreversible expansion at constant enthalpy from saturated liquid to the evaporator pressure 41, reversible addition of heat at constant pressure in evaporation to saturated vapor
III Refrigeration is that branch of science which deals with the process of reducing and maintaining the temperature of a space or material below the temperature of the surroundings. Refrigerant is the working substance in a refrigeration system.
Analysis of the Vapor Compression Cycle 1. Compressor
(a) Isentropic expa n sion 'IY-1 [ (P - 4 )~ v.. F. =kp 1 k P1 T
P I = 448kPa P 2 = 1150 kPa T 1 = 5 + 2 73 = 27 8 K T , = 25 + 27 3 = 298 K
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102 AirCycle Refrigeeration
Refrigeration and Air Conditioning 103
= T 1 [ PH ] k = 278
1550 1.41 [ ] 1.4 = 396 . 3K 448
P4 k1 448 1.41 P::3] k = 278 [1550] 1.4
(m) (cp ) (T i - T 4 ) = 50
209) = 50 m = 0.720 kg/s
(62) A 35kW refrigeration load is to be carried by an air refrigerating system with a discharge pressure of 1370 kPa and a refrigerator pressure of 345 kPa. Compression and expansion processes are polytropic with n = 1.37. The pressure at the start of expansion is 1344 kPa and the temperature is 32°C. Air temperature leaving the refrigerator is O°C and entering the compressor is 5°C. Clearance for both compressor and expander is 5%. Determine (a) the piston displacement of the compressor and expander, (b) the net work and, (c) the COP. SOLUTION
Compressor pirston displacement without clearance, V =
(0.72) (0.28708) (278) 3 3/ = 0.128 m s 448
«n w =_lrC(_2) c 1 - k L PI
448 PI = 345 kPA
= (1.4) (0 .. 72) (0.28708) (278)
(0.72) (0.28708) (209) mRT = 0.0964 m 3/s 4i4 = 448 P4
(c) Expander pistvon displacement without clearance, V
P 3 = 1344 kPa T 1 = 5 + 273 = 278 K
448 1.41 [ (1550)rr 1]
T 3 = 32 + 273 = 305 K T a
Net work = 8:,5.61 64.37 = 21.24 kW
p4 . =.! 345 !.d1. T = T [ _ ] n = 305 [ _ ] 1.37 = 211.3K 4 3 P3 1344
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= T I [ PI ] n = 278 [ 345 ] 1.37
Refrigeration and Air Conditioning 105
104 Air Cycle Refrigeration (m ) (c
(rn ) (1.0062) (273 211 .3) = 35
= 1 + 0 .05 _ 0 .05[1370J 1.:37 [ P2]n P I 345
Net work = 75.21 56.20 = 19 .01 kW
(0 .564) (0 .28708 ) (278) 345
pi ston displacement = ~
[ P3]n = 1 + 0.05 0.05 [1344J1.37 345
= 0.9151 mRT 4 volume flow rate = P4
(0. 564 ) (0 .28 708) (2 11.3) 345
= 0 .099 m 3/s . di ISP 1 acement = 0 .099 piston 0.9151
= (1.37) (0. 56 4) (0 .28 708 ) (278) [(1370) \ 1~; _ J 1 1.37
mRT 1 volume flow rate = Pl
1.371 _ (1.3 7) (0 .56 4) (0 .28708) (305) [( 345 fT37 1] 11.37 1344
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106 AirCycle Refrigeration
(1) An open air refrigeration system carries a load of 35 kW with a suction pressure of 103 kPa and a discharge pressure of 690 kPa. The temperature leaving the refrigerator is 5°C and that leaving the cooler is 30°C. The compression is polytropic with n = 1.33 and the expansion is also polytropic but with n = 1.35. Determine the power required and the COP.
Ans. 23.77 kW, 1.47 (2) An air refrigeration system is required to produce 52.5 kW of refrigeration with a cooler pressure of 1448 kPa and a refrigerator pressure of 207 kPa. Leaving air temperatures are 29°C for cooler and 5°C for refrigerator. Expansion is. isentropic and compassion is polytropic with n = 1.34. Determine the COP.
IftZIdfLINB WA'I'D BITVBN
WATEll LAVEL COImloL
Fig 71. SteamJet Refrigeration System
Steam jet refrigeration is a type of water evaporative refrigeration wherein water is used as the refrigerant. The principle of operation is based on the fact that water will boil or vaporize rapidly, at a relatively low temperature, if the pressure on the surface is reduced sufficiently.
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108 Refrigeration and Air Conditioning
Cascade System 109
A steam jet refrigeration is shown in Fig. 71. An ejector sucks or draws water from the surface of the water in the evaporator or flash chamber, causing the pressure in the evaporator to drop. The ejector reduces the pressure in the evaporator to a point at which the water will vaporize at the desired temperature. In vaporizing, it absorbs heat and cools the remainder of the water in the evaporator. The steam pressure at the ejector nozzle should be about 1030 kPa.
SOLUTION DaZZle ateam
The evaporation of the water in the evaporator, reduces the temperature of the water in the evaporator. This cold water, 4°C to 21°C, is circulated by means of pumps, to the area to be cooled.
Steam jet systems are used extensively in air conditioning, and for cooling of water in certain chemical plants for gas absorption. The cooling temperatures provided by the steam jet mechanism are usually between 4°C and 21°C. Temperatures below 4°e are impractical due to the danger of freezing.
From the steam table
h, = h, at 5°C = 20.98 kJ/kg h, = h, at 10°C = 42.01 kJ/kg
h 3 = h g at 5°C = 2510.6 kJ/kg v3
= v g at 5°C = 147.12 m 3/kg
= h, at 2roC = 88.14 kJ/kg
= vapor removed from the evaporator, carried
by nozzle steam m
= mass flow rate of chilled water
Energy balance about the whole system, neglecting pump work, zh, + 175 = zh, 88.14z + 175
z = 0.07224 kg vapor/s volume of vapor removed = zV:l = (0.07224) (147.12) = 10.63 mvs Downloaded by Ice Scott ([email protected])
(71) A steamjet pump maintains a temperature of 5°C in the evaporator. The cooled water leaves at the same temperature and warms to 10 as it does its refrigeration. Makeup water is available at 2re. There are required 1.27 kg of nozzle steam per kg of vapor removed from the evaporator. For a 175:[
110 Refrigeration and Air Conditioning
Cascade System 111
kg steam kg vapor quantity of nozzle steam = (1.27 kg vapor) (0.07224 second )
(a) Energy balance about the cooled area m h , + 350 = mh,
20.98m + 350 = 54.60m m = 10.41 kg/s
Energy balance about the cooled area,
(b) Energy balance about the whole system, neglecting pump work, zh, + 350 = zh 3.
mh, + 175 = mh, 20.98m + 175 = 42.01m
134.15z + 350 = 2435.9z
m = 8.32 kg/s (72) A vacuum refrigeration system consists of a large insulated flash chamber kept at low pressure by a steam ejector which pumps vapor to a condenser. Condensate is removed by a condensate to an air vent. Warm return water enters the flash chamber at 13°C; chilled water comes out of the flash chamber at 5°C. Vapor leaving the flash chamber has a quality of 0.97 and the temperature in the condenser is 32°C. For 350 kW of refrigeration. (a) how much chilled water at 5°C does this system provide? (b) how much makeup water is needed? (c) how much vapor must the steam ejector remove from the flash chamber?
z = 0.1521 kg/s (c) vapor removed = zV 3 = (0.1521) (142.7) = 21. 7 kg/s
The diagrammatic layout of Problem 71 is used in this problem. From the steam table h, = h, at 5°C = 20.98 kJ/kg h, = h, at 13°C = 54.60 kJ/kg h, = h, at 32°C = 134.15 kJlkg h, = h rn + x 3h fg3 ='20.98 + (0.97) (2489.6) = 2435.9 kJ/kg v1
= X,1Vj(l = (0.97) (147.1> = 142.7 mVkg Downloaded by Ice Scott ([email protected])
Air Conditioning 113
112 Refrigeration and Air Conditioning
PROBLEMS (1) There are removed 3.06 mvs of vapor from the water evaporator of a vacuum refrigeration system; the warm water enters the evaporator at 18°C and chilled water leaves at 10°C; makeup water enters at 29°C. Determine the refrigerating capacity.
Ans. 68.99 kW (2) In a steam jet refrigeration system, the evaporator is maintained at 6°C. The chilled water leaves at the same temperature and warms to 11°C as it absorbs the load. Makeup water in available at 25°C. For a capacity of 50 tons, determine (a) the quantity of chilled water required, and (b) the volume of vapor removed. Ans. (a) 8.381 kg/s, (b) 10.07 m 3/s
Air Conditioning Air conditioning is the simultaneous, control of temperature, humidity, air movement, and the quantiiity of air in a space. Moist air is a binary mixture of dry air and water vapor. Dry air is the noncondensing comtponents of the mixture, mainly the nitrogen and the oxygen. Vapor is the condensable component cofthe mixture, the water vapor or steam which may exist in a sarturated or superheated state. P, = PH + P,
where P, = total mixture pressure
P, = partial pressure exerted I by the dry air P, = partial pressure exerted l by the vapor Saturated air means that the vapor in the air is saturated. Unsaturated air is containing superheated vapor. Humidity ratio (moisture content, r.mixing ratio or specific humidity) W is the ratio of the mass of vwater vapor to the mass of dry air.
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114 Refrigeration and Air Conditioning
Air Conditioning 115
air: mass volume
Water vapor: =mv mass volume = Vv =V
Entropy, kJlkg K
Fig.82. Isothermal process from superheated vapor to saturated vapor.
Fig. 81. A mixture of dry air and water vapor
w = mass of water vapor = mv mass of dry air
Ps V/RsT Pa V/RaT
(8-1) Compute the humidity ratio of air at 65 per cent relative humidity and 34°C when the barometric pressure is 101.3 kPa. Solution
_ PsRa _ p§Ra _ 287ps PaRs (ptPs)R s 461.5 (Ptps)
Pd = saturation pressure at 34°C = 5.318 kPa Ps = (0) (P d) = (0.65) (5.318) = 3.457 kPa
R a = 287 Jlkg.K, gas constant of dry air
R, = 461.5 Jlkg/J, gas constant of water vapor Relative humidity 0 is the ratio of the partial pressure of water vapor in the air to the saturation pressure corresponding to the temperature of the air.
(0.622) (3.457) = 0.022 kg vaporlkg 101 .3 - 3.457 drv air ryal
Enthalpy h of a mixture of dry air and water vapor is the sum of the enthalpy of the dry air and the enthalpy of the water vapor. Enthalpy values are always based on some reference condition, and the zero value of the dry air is chosen as air at O°C and the zero value of the water vapor is saturated liquid water at O°C. h = cp t + Whg kJlkg dry air
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~· rAir Conditioning 117
116 Refrigeration and Air Conditioning
where c = specific heat of dry air at constant pressure p
= 1.0062 kJfkg.K (approximately)
h = enthalpy of saturated steam at temperature t, kJfkg g
(8-2) What is the enthalpy of the airvapor mixture in Problem (8-1)?
Wet bulb temperature t w is the temperature of air as registered by a thermometer whose bulb is covered by a wetted wick and exposed to a current of rapidly moving air. Wet bulb depresssion is the difference between the readings of the wet and dry bulb thermometers. Dewpoint temperature t (Ip is the saturation t.emperature corresponding to the actual partial pressure of the steam in air or the temperature at which condensation of moisture begins when the air is cooled at constant pressure.
h = cpt + Wh g = (1.0062) (34) + (0.022) (2563.6)
Specific volume is the number of cubic meters of mixture per kilogram of dry air.
RT RT v = _p3 = _3_ m 3fkg of dry air PtPs
(8-3) What is the specific volume of an airvapor mixture at 30 and a relative humidity of 40 per cent at 101.3 kPa pressure? 0e
SOLUTION P, = saturation pressure at 30 Ps = (0) (Pd) = (0.40) (4.241)
T = 30 + 273 = 303 K
h g = h g at 34°e = 2563.6 kJfkg
Degree of saturation u is the ratio of the air humidity ratio W to the humidity ratio W s of saturated air at the same temperature.
(287)(303) 3fkg = 101,300-1696 = 0.873 m dry air
Dry bulb temperature t d is the temperature of air as registered by an ordinary thermometer.
Pt Ps _ [ Ps ] [PIPel] (0.622) (p) -p;sP~t PtPd
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118 Refrigeration and Air Conditioning
Air Conditioning 119
(84) A mixture of dry air and water vapor is at a temperature of 21°C under a pressure of 101.3 kPa. The dew point temperature is 15°C. Find (a) partial pressure of water vapor, (b) relative humidity, (c) humidity ratio, (d) enthalpy, (e) specific volume, and (f) degree of saturation.
P. LWs = 0.622 PtPd (0.622) (2.4861) = 0.01565 kglkg Ws = 101.3 _ 2.4861
W 0.01064 = 0.6799 or 67.999t W s = 0.01565
Psychrometry is the study of the properties of mixtures of air and water vapor.
Psychrometric properties are the properties of moist air.
A psychrometric chart is a graphical representation of the thermodynamic properties of moist air.
Entropy, kJIkg . K
(a) P, = saturation pressure at 15°C = 1. 7044 kPa
= saturation pressure at 21°C = 2.4861 kPa
_ 1.7044 P, 2.4861 = 0.6856 or 68.5691:
(d) h g = h g at 2PC = 2540 kJ/kg Drybulb temperature
h = c p t + Whg = (1.0062) (21) + (0.01064) (2540) = 48.16 kJ/kg (e) T = 21 + 273 = 294 K
Fig. 84 Constant property lines on a psychrometric chart
P, = PtPs = 101.3 1. 7044 = 99.6 kPa
R;,T _ (0.287)(294) = 0.847 mvkg dry air 99.6
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'- (1.30) (114 kg) (3.35 k.I/kg.C") (29 7) Co ;:: 10,992 kJ 10,922 kJ ;:: 29.33 kg/24 h mass of ice;:: 372.4 kJ/kg
(114) Four hundred kilograms of poultry enter a chiller at 6°C and are frozen and chilled to a final temperature of 16°C for storage in 12 hours. Compute the product load. specific heat above freezing specific heat below freezing latent heat freezing temperature
3.18 k.I/kg.C" 1.55 kI/kg.C'' 246 kJ/kg 3°C
(10 h) (3,600 sth) (3.52 kW/ton) (113) A mass of ice at 4°C is needed to cool 114 kg of vegetables in a bunker for 24 hours. The initial temperature of the vegetables is assumed to be 29°C. It is also assumed that the average temperature in the bunker is 7°C, within the 24hour period. If the heat gained per hour in the bunker is 30% of the heat removed to cool the vegetables from 29°C to 7°C, what would be the required mass of ice? specific heat of ice specific heat of vegetables
Q I = (400 kg) (3.18 kI/kg.C") [6 (3)] Q 2 = (400 kg) (246 kJ/kg) Q3 . (400 kg) (1.55 kI/kg.C'') [(3) (16) ] Co
1.9387 kI/kg.C" 3.35 k.I/kg.C" Downloaded by Ice Scott ([email protected])
;:: 11,448 kJ . 98,400 kJ . 8,060 kJ Q. 117,908 kJ
117,908 kJ . 2.73 kW Q. (12 h) (3,600 s/h)
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186 Refrigeration and Air Conditioning
Table 1 (continued)
Table 2 Refrigeration 11 1"'''1)( -rt ics of liquid and saturated vapor
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
886.57 915.03 944.18 974.03 1004.6 1035.9 1068.0 1100.7 1134.3 1168.6 1203.7 1239.6 1276.3 1313.9 1352.2 1391.5 1431.5 ·1472.4 1514.3 1557.0 1600.6 1645.1 1690.6 1737.0 1784.3 1832.6 1881.9 1932.2 1983.5 2035.9 W89.2 2143.6 2199.1 2255.6 2313.2
SO 51 52 53 54 55
298.527 303.300 308.081 312.870 317.667 322.471 327.284 332.104 336.933 341.169 346.614 351.466 356.326 361.195 366.072 . 370.957 375.851 380.754 385.666 390.587 395.519 400.462 405.416 41fr.382 n5.362 420.358 425.369 430.399 435.450 440.523 445.623 .50.751 455.913 461.112 466.353
1410.41 1411.11 1481.17 1482.53 1483.18 1483.81 1484.42 1485.01 1485.59 1486.14 1486.67 1487.18 1487.66 1488.13 1488.57 1488.99 1489.39 1489.76 1490.10 1490.42 1490.11 1490.98 1491.21 1491.41 1491.58 1491.72 1491.83 1491.88 1491.91 1491.89 1491.83 1491. 73 1491.58 1491.38 1491.12
1.34452 1.360S5 1.37654 1.39250 1.40843 1.42433 1.44020 1.45604 1.47185 1.48762 1.50337 1.51908 1.53477 1.55042 1.56605 1.58165 1;59722 1.61276 1.62828 1.64317 1.65924 1.67470 1.69013 1.70554 1.72095 1.73635 1.75174 1.76714 1.78255 1.79798 1.81343 1.82891 1.84445 1.86004 1.87571
" 5.3626 5.3512 5.33'9 5.3286 5.3175 5.3063 5.2953 5.2843 5.2733 5.2624 5.2516 5.2408 5.2300 5.2193 5.2086 5.1980 5.1874 5.1768 5.1663 5.1558 5.1453 5.1349 5.1244 5.1140 5.1036 5.0932 5.0827 5.0723 5.0618 5.0514 5.0409 5.0303 5.0198 5.0092 4.9985
1.6426 1.6466 1.6507 1.6541 1.6588 1.6630 1.66i2 1.6714 1.6757 1.6800 1.6844 1.6888 1.6932 1.6977 1.7023 1.7069 1.7115 1.7162 1.7209 1.7257 1.7305 1.7354 1.7404 1.7454 1.7504 1.7555 1.7607 1.7659 1.7712 1.7766 1.7820 1.7875 1.7931 1.7987 1.8044
144.578 140.214 136.006 131.950 128.037 124.261 120.619 117.103 113.708 110.430 107.263 104.205 101.248 98.3913 95.6290 92.9579 90.3743 87.8748 85.4561 83.1150 80.8484 78.6536 76.5276 74.4678 72.4716 70.5365 68.6602 66.8403 65.0746 63.3608 61.6971 60.0813 58.5114 56.9855 55.5019
Specific volume, L/kg t,OC
30 25 20 15 10 8
9.24 12.15 15.78 20.25 25.71 28.20 30.88 33.76 36..86 40.18 41.92 43.73 45.60 47.54 49.53 51.60 53.73 55.93 58.21 60.55 62.97 65.4 7 68.04 70.70 73.43 76.25 79.15 82.14 85.21 H8.38 91.64 94.99
2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28' 29 30 32 34 36 38 40
101.98 105.62 109.37 113.21 117.16 121.22 125.38 134.05 143.18 152.78 162.87 173.46
174.25 178.53 182.81 187.09 191.39 193.11 194.83 196.55 198.27 200.00 200.86 201. 73 202.59 203.46 204.32 205:19 206.05 206.92 207.79 208.65 209.52 210.39 211.26 212.13 213.00 213.87 214.74 215.61 216.48 217.35 218.22 219.10 219.97 220.84 221.72 222.59 223.47 224.34 225.22 226.10 227.85 229.61 231.37 233.13 234.90
373\1 37611 37866 381.12 38371 384.80 385.82 386.84 387.86 388.89 389.40 389.91 390.42 390.93 391.44 391.95 392.46 392.97 393.47 393.98 394.49 395.00 395.51 396.02 396.52 397.03 397.54 398.04 398.55 399.05 399.56 400.06 400.57 401.07 401.57 402.07 402.57 403.08 403.58 404.08 405.07 406.07 407.06 408.05 409.04
0.90099 0.91824 0.93517 0.95179 0.96813 0.97459 0.98100 0.98738 0.9937.1 1.00000 1.00313 1.00625 1.00936 1.01246 1.01555 1.01863 1.02170 1.02476 1.02782 1.03086 1.03389 1.03692 1.03994 1.04294 1.04594 1.04893 1.05191 1.05488 1.05785 1.06080 1.06375 1.06669 1.06961 1.07254 1.07545 1.07838 1.08125 1.08414 1.08702 1.08989 1.09561 1.10130 1.10696 1.11259 1.11819
1.72074 1.71447 1.70885 1.70377 1.69922 1.69753 1.69592 1.69438 1.69291 1.69150 1.69082 1.69018 1.68951 1.68888 1.68826 1.68766 1.68707 1.68650 1.68594 1.68539 1.68486 1.68434 1.68383 1.68333 1.68285 1.68238 1.68193 1.68148 1.68105 1.68062 1.68021 1.67982 1.67942 1.67905 1.67868 1.67832 1.67798 1.67764 1.67731 1.67699 1.67638 1.67581 1.67527 1.67476 1.67429
Specific volume, L/kg vf
0.62466 0.62894 0.63331 0.63777 0.64234 0.64419 0.64606 0.64795 0.64985 0.65178 0.65275 0.65372 0.65470 0.65568 0.65667 0.65.7t>6
0.65866 0.65966 0.66067 0.66168 0.66270 0.66327 0.66475 0.66578 0.66682 0.66786 0:66891 0.66997 0.67102 0.67209 0.67316 0.67424 0.67532 0.67641 0.67750 0.67860 0.67971 0.68082 0:68194 0.68307 0.68533 0.68763 0.68995 0.69230 Q.69468
1581.77 1225.53 960.954 761.949 610.466 560.196 514.840 473.883 436.764 403.130 387.493 372.593 358.366 344.792 331.859 319.500 307.698 296.427 285.648 275.347 265.483 256.063 247.037 238.396 230.130 222.205 214.614 207.332 200.361 193.665 187.245 181.089 175.166 169.485 164.034 158.786 153.754 148.903 144.246 139.768 131.305 123.462 116.135 109.430 103.151
J 188 Refrigeration and Air Conditioning
Table 2 (continued)
Table 3 Refrigeration 12: properties of liquid and saturated vapor
45 50 55 60 70 80
202.28 234.64 270.83 311.10 405.15 519.21
239.32 243.75 248.21 252.68 261.68 270.79
411.49 413.93 416.34 418.73 423.42 427.98
1.13206 1.14576 1.15929 1.17267 1.19898 1.2~479
1.67324 1.67237 1.67165 1.67109 1.67031 1.66992
Specific volume, L/kg vg
22.62 29.98 39.15 50.44 64.17 80.71 100.41 109.27 1.18.72 128.80 139.53 150.93 163.04 175.89 189.50 203.90 219.12 227.04 235.19 243.55 252.14 ~ 5 260.96 4 270.01 3 279.30 2 288.82 1 298.59 0 308.61 1 318.88 329.40 2 340.19 3 4 351.24 363.55 5 374.14 6 1 386.01 398.15 8 9 410.58 10 423.30 436.31 .11 12 449.62 13 463.23 14 477.14 15 491.37 16 505.91 520.76 17 535.94 18 551.45 19 20 567.29 Downloaded by Ice Scott ([email protected])
0.70074 0.70700 0.71346 0.72014 0.73421 0.74937
89.2884 77.6428 67.8040 59.4543 46.2114 36.3872
55 50 45 40 35 30 28 26 ..24 22 20 18 16 14 12 10 9 8 7
146.463 150.808 155.169 159.549 163.948 168.369 172.810 174.593 ! 76.380 178.171 179.965 181. 764 183.567 185.374 187.185 189.001 190.822 19"1 :734 192.647 193.562 194.477 195.395 196.313 197.233 198.154 199.076 200.000 200.925 201.852 202.780 203.710 204 ..6 42 205.575 206.509 207.445 208.383 209.323 210.264 211.207 212.152 213.099 214.048 214.998 215.951 216.906 217.863 218.821
324.236 326.567 328.897 331.223 333.541 335.849 338.143 339.057 339.968 340.876 341.780 342.682 343.580 344.474 345.365 346.252 347.134 347.574 348.012 348.450 348.886 349.321 349.755 350.187 350.619 351.049 351.477 351.905 352.331 352.755 353.179 353.600 354.020· 354.439 354.856 355.272 355.686 356.098 356.509 356.918 357.325 357.730 358.134 358.535 358.935 359.333 359.729
0.77977 1.61373 0.79990 1.60552 0.81964 1.59810 0.83901 1.59.142 0.85805 1.58539 0.86776 1.57996 0.89516 1.57507 0.90244 1.57326 0.90967 1.57152 0.91686 1.56985 0.92400 1.56825 0.93110 1.56672 0.93816 1.56526 0.94518 1.56385 0.95216 1.56250 0.95910 1.56121 0.96601 1.55997 0.96945 1.55938 0.97287 1.55897 0.97629 1.55822 0.97971 1.55765 0.98311 1.55710 0.98650 1.55657 0.98989 1.55604 0.99327 1.55552 0.99664 1.55502 1.00000 1.55452 1.00335 1.55404 1.00670 1.55356 1.01004 1.55310 1.01337 1.55264 1.01670 1.55220 1.02001 . 1.55176 1.02333 1.55133 1.02663 1.55091 1.02993 1.55050 1.03322 1.55010 1.03650 1.54970 1.03978 1.54931 1.04305 1.54893 1.04632 1.54856 1.54819 1.04958 1.54783 1.05284 1.54748 1.05609 1.05933 1.54713 1.54679 1.06258 1.54645 1.06581
Specific volume, L/kg
vf 0.63689 0.64226 0.64782 0.65355 0.65949 0.66563 0.67200 0.67461 0.67726 0.67996 0.68269 0.68541 0.68829 0.69115 0.69407 0;69703 0.70004 0.70157 0.70310 0.70465 0.70622 0.70780 0.70939 0.71099 0'.71261 0.71425 0.71590 0.71756 0.71924 0.72094 0.72265 0.72438 0.72612 0.72788 0.72966 0.73146 0.73326 0.73510 (,.73695 0.73882 0.74071 0.74262 0.74455 0.74649 0.74846 0.75045 0.75246
vg 637.911 491.000 383.105 302.683 241.910 195.398 159.375 147.275 136.284 126.282 117.167 108.847 101.242 94.2788 87.8951 82.0344 76.6464 74.1155 71.6864 69.3543 67.1146 64.9629 62.8952 60.9075 58.9963 57.1579 55.3892 53.6869 52.0481 50.4700 48.9499 47.4853 . 46.0737 44.7129 43.4006 42.1349 40.9137 39.7352 38:5975 37.4991 36.4382 35.4133 34.4230 33.4658 32.5405 31.6457 30.7802
190 Refrigeration and Air Conditioning
Table 3 (continued)
Table 4 Refrigeration 22: properties of liquid and saturated vapor
Entropy, kJjkg' K
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 52 54 56 58 60 62 64 66 68 70 75 80 85 90 95 100
37.48 49.47 64.39 82.71 104.95 131.68 163.48 177.76 192.99 209.22 226.48 244.83 264.29 284.93 306.78 329.89 354.30 367.01 380.06 393.47 407.23 421.35 435.84 450.70 465.94 481.57 497.59 514.01 530.83 548.06 565.71
134.763 139.830 144.,959 150.153 155.414 160.742 166.140 168.318 170.507 172.708 174.919 177.142 179.376 181.622 183.878 186.147 188.426 189.571 190.718 191.868 193.021 194.176 195.335 196.497 197.662 198.828 200.000 201.174 202.351 203.530 204.713 205.899 207.089 208.281 209.477 210.675 211.877 213.083 214.291 215.503 216.719 217.937 219.160 220.386 221.615 222.848 224.084
379.114 381.529 383.921 386.282 388.609 390.896 393.r38 394.021 394.896 395.762 396.619 397.467 398.305 399.133 399.951 400.759 401.555 401.949 402.341 402.729 403.114 403.496 403.876 404.252 404.626 404.994 405.361 405.724 406.084 406.440 406.793 407.143 407.489 407.831 408.169 408.504 408.835 409.162 409.485 409.804 410.119 410.430 410.736 411.038 411.336 411.629 411.9J8
219.783 583.47 220.746 599.98 616.84 221.712 222.680 634.05 223.650 651.62 669.54 224.623 687.82 225.598 706.47 226.576 725.50 221.557 744.90 228.540 764.68 229.526 230.515 784.85 805.41 23.1.506 826.36 232.501 847.72 233.498 869.48 234.499 891.64 235.503 914.23 236.510 937.23 237.521 960.65 238.535 984.51 239.552 " 240.574 1008.8 1033.5 241.598 1058.7 242.627 1084.3 243.659 1110.4 244.696 245.736 1136.9 1163.9 246.781 1191.4 241.830 1219.3 248.884 1276.6 251.004 1335.9 253.144 1397.2 255.304 1460.5 257.486 1525.9 259;690 1593.5 261.918 1663.2 264.172 1735.1 i66.452 1809.3 268.762 1885.8 271.102 2087.5 277.100 2304.6 283.341 2538.0 289.879 2788.5 296.788 3056.9 304.181 3344.1 312.261
Specific volume, L/kg
360.122 360.514 360.904 361.291 361.676 362.059 362.439 362.817 363.193 363.566 363.937 36'4.305 364.670 365.033 365.392 365.749 366.103 366.454 366.802 367.146 367.487 367.825 368.160 368.491 368.818 369.141 369.461 369.777 370.088 370.396 370.997 371.581 372.145 372.688 373.210 373.707 374.180 374.625 375.042 375.427 376.234 376.777 376.985 376.748 375.887 374.070
1.06904 1.07227 1.07549 1.07871 1.08193 1.08514 1.08835 1.09155 1.09475 1.09195 1.10115 1.10434 1.10753 1.11072 1.11391 1.11710 1.12028 1.12347 1.12665 1.12984 1.13302 1.13620 1.13938 1.14251 1.14575 1.14894 1.15213 1.15532 1.15851 1.16170 1.16810 1.17451 1.18093 1.18738 1.19384 1.20034 1.20686 1.21342 1.22001 1.22665 1.24347 1.26069 1.27845 1.29691 1.31637 1.33732
1.54612 1.54579 1.54547 1.54515 1.54484 1.54453 1.54423 1.54393 1.54363 1.54334 1.54305 1.54276 1.54247 1.54219 1.54191 1.54163 1.54135 1.54107 1.54079 1.54051 1.54024 1.53996 1.53968 1.53941 1.53913 1.53885 1.5'3856 1.53828 1.53199 1.53770 1.53712 1.536'51 1.53589 1.53524 1.53457 1.53387 1.53313 1.53235 1.53153 1.53066 1.52821 1.52526 1.52164 1.51708 1.51113 1.50296
0.75449 0.75655 0.75863 0.76073 0.76286 0.76501 0.76716 0.76938 0.77161 0.77386 0.77614 0.77845 0.78079 0.18316 0.78556 0.78799 0.79045 0.79294 0.79546 0.79802 0.80062 0.80325 0.80592 0.80863 0.81137 0.81416 0.81698 0.81985 0.82277 0.82573 0.83119 , 0.83804 0.84451 0.85121 0.85814 0.86534 0.87282 0.88059 0.88870 0.89716 0.92009 0.94612 0.97621 1.01190 1.05581 1.11311
29.9429 29.1327 28.3485 27.5894 26.8542 26.1422 25.4524 24.7840 24.1362 23.5082 22.8993 22.3088 21.735'9 21.1802 20.6408 20.1173 19.6091 19.1156 18.6362 18.1706 17.7182 17.2785 16.8511 16.4356 16.0316 15.6386 15.2563 14.8844 14.5224 14.1 ?01 13.4931 lZ.8509 12.2412 11.6620 11.1113 10.5872 10.0881 9.61234 9.15844 8.72502 7.12258 6.82143 6.00494 5.25759
40 35 30 28 26 24 22 20 18 16 14 12 10 9 8 7 ~
5 4 3 2 1 0 1 2 3 4 5
602.28 7 621.22 640.59 8 660.42 9 10 680.70 11 701.44 12 722.65 13 744.33 14 766.50 15 789.15 3 16 812.29 17 835.93 4.563~ 18 860.08 3.90280 884.75 19 \, 20 909.93 Downloaded by Ice Scott ([email protected]) ~
Entropy, kJ/kg • K sf
0.73254 0.75599 0.77919 0.80216 0.82490 0.84743 0.86976 0.87864 0.88748 0.89630 0.90509 0.91386 0.92459 0.93129 0.93997 0.94862 0.95725 0.96155 0.06585 0.97014 0.97442 0.97870 0.98297 0.98724 0.99150 0.99575 1.00000 1.00424 1.00848 1.01271 1.01694 1.02116 1.02537 1.02958 1.03379 1.03799 1.04218 1.04637 1.05056 1.05474 1.05892 1.06309 1.06726 1.07142 1.07559 1.07974 1.08390
's 1.87886 1.86389 1.85000 \.83708 1.82504 1.81380 1.80329 1.79927 1.79535 1.79152 1.78779 1.78415 1.78059 1.77711 1.77371 1.77039 1.76713 1.76553 1.76394 1.76237 1.76082 1.75928 1.75775 1.75624 1.75475 1.75326 1.75279 1.75034 1.74889 1.74746 1.74604 1.74463 1.74324 1.74185 1.74047 1.73911 1.73775 1.73640 1.73506 1.73373 1.73241 1.73109 1.72978 1.72848 1.72719 1.72590 1.72462
Specific volume, L/kg vf
0.68208 0.68856 0.69526 0.70219 0.70936 0.71680 0.72452 0.72769· 0.73092 0.73420 0.73753 0.74091 0.74436 0.74786 0.75143. 0.15506 0.75876 0.76063 0.76253 0.76444 0.76636 0.76831 0.77028 0.77226 0.77427 0.77629 0.77834 0.78041 0.7824Q 0.78460 0.78673 0.78889 0.79107 0.79327 0.79549 0.79775 0.80002 0.80232 0.80465 0.80701 0.80939 0.81180 0.81424 0.81671 0.81922 0.82175 0.82431
537.152 414.827 324.557 256.990 205.745 166.400 135.844 125.563 116.214 107.701 99.9362 92.8432 86.3546 80.4103 74.9572 69.9478 65.3399 63.1746 61.0958 59.0996 57.1820 55.3394 53.5682 51.8653 50.2274 48.6517 47 .13~4 45.6757 44.2702 42.9166 41.6124 40.3556 39.1441 37.9759 36.8493 35.7624 34.7136 33.7013 32.7239 31.7801 30.8683 29.9874 29.1361 28.3131 27.5173 26.7477 26.0032
", 192 Refrigeration and Air Conditioning
Table 4 (continued) Enthalpy, kJjkg t,OC
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
935.64 961.89 988.67 1016.0 1043.9 1072.3 1101.4 1130.9 1161.1 1191.9 1223.2 1255.2 1287.8 1321.0 1354.8 1389.2 1424.3 1460.1 1496.5 1533.5 1571.2 1609.6 1648.7 1688.5 1729.0 1770.2 1812.1 1854.8 1898.2 1942.3 2032.8 2126.5 2223.2 2323.2 2426.6 2533.3 2643.5 2757.3 2874.7 2995.9 3316.1 3662.3 4036.8 4442.5 4883.5
225.324 226.568 227.816 229.068
412.202 412.481 412.755 413.025 413.289 413.548 413.802 414.050 414.293 414.530 414.762 414.987 415.207 415.420 415.627 415.828 416.021 416.208 416.388 416.561 416.726 416.883 417.033 417.174 417.308 417.432 417.548 417.655 417.752 417.838 417.983 418.083 418.137 418.141 418.089 41 '.978 417.802 417.553 417.226 416.809 415.299 412.898 409.101 402.653 38'6.708
49 50 52 54 56 58 60 62 64 66 68 70 75 80 85 90 95
234.115 235.387 236.664 237.944 239.230 240.520 241.814 243.114 244.418 245.727 247.041 248.361 249.686 251.016 252.352 253.694 255.042 256.396 257.756 259.123 260.497 261.877 263.264 266.062 268.891 271.754 274.654 277.594 280.577 283.607 286.690 289.832 293.038 301.399 310.424 320.505 332.616 351.767
Entropy. kJjkg • K Sf
1.08805 1.09220 1.09634 1.10048 1.10462 1.10876 1.11290 1.11703 1.12116 1.12530 1.12943 1.13355 1.13768 1.14181 1.14594 1.15007 1.15420 1.15833 1.16246 1.16659 1.17073 1.17486 1.17900 1.18315 1.18730 1.19145 1.19560 1.19977 1.20393 1.20811 1.21648 1.22489 1.23'333 1.24183 1.25038 1.25899 1.26768 1.27647 1.2i535 1.29436 1.31758 1.34223 1.36936 1.40155 1.45222
