- Email: [email protected]
Derived thermodynamic design data for heat pump systems operating on R152a
Heat Recouery Systems & CHP Vol. 7, No. 4, pp. 303-306, 1987 Printed in Great Britain.
0890-4332/87 $3.00+ 0.00 Pergamon Journals Ltd
DERIVED T H E R M O D Y N A M I C DESIGN D A T A FOR HEAT PUMP SYSTEMS OPERATING ON R152a M. A. R. EISA*, S. SUPRANTO, S. DEVOTTA
and F. A. HOLLAND Department of Chemical and Gas Engineering, University of Salford, Salford M5 4WT, U.K. (Received 18 September 1986)
Almraet--Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R152a. These values are listed in tabular form for temperature lifts of 10-75°C and condensing temperatures of 20-85°C in 5°C increments. A composite plot has been drawn to illustrate the feasible operating range of RI52a heat pump systems.
NOMENCLATURE coei~cient of performance of the heat pump system [dimensionless] compression ratio of the heat pump [dimensionless] enthalpy per unit mass [El kg-I] pressure [bar] temperature [K or °C]
(COP)
(CR)
H P T Subscripts CO EV R
condenser evaporator Rankine. INTRODUCTION
R152a is difluoroethane a n d has the chemical f o r m u l a C2H4F2 . Its critical t e m p e r a t u r e a n d pressure are 114°C a n d 44.35 bar, respectively. T a b l e 1 presents some physical d a t a for R152a. 60
50 40 30
/ .
~o_~_
D3~
20
70°C
/_~L.
tk
___
.
D2
D1
_50~ . . . . . . .
e"
| e,
10
•~
/
/--4
I
-
.
~/ ..... ;,
9 8
4o°c
.... i
f
Zo:.
s#
7
#l . . . . . ,/ . . . .
4
I/
3 0
50
I
100
I
150
-~:~ ..4-~ ,o'.c _/~ I
I
200
250
I
300
II
350
I
400
Enthalpy per unit mau, H, kJ kg-1 Fig. 1. Pressure against enthalpy per unit mass for R152a. *Mahmoud Abdel Rahman EISA, (Ph.D), Cairo, Egypt. n.u. ~/~--A
303
I 450
500
304
M. A. R. EtsA et al. Table i. Physical data for R152a Density (kg m -z) Tco (°C)
Pco (bar)
liquid
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
2.673 3.176 3.752 4.409 5.152 5.987 6.922 7.965 9.128 10.412 11.834 13.392 15.096 16.967 19.007 21.210 23.603 26.206 28.990 31.980
958.3 947.1 935.6 923.8 911.7 902.0 886.4 873.0 859.2 844.8 829.9 814.3 797.9 780.4 761.9 742.1 720.7 697.1 671.1 641.5
Latent heat
vapour
PV (bar m3 kg-i)
(kJ kg-*)
8.337 9.837 I 1.357 13.494 15.699 18.208 21.048 24.266 27.866 31.938 36.547 41.757 47.658 54.320 61.941 70.713 80.964 92.966 108.084 155.321
0.32061 0.32290 0.32454 0.32664 0.32808 0.32871 0.38279 0.32817 0.32749 0.32955 0.32375 0.32062 0.31668 0.31227 0.30677 0.29986 0.29488 0.28183 0.26815 0.20584
305.004 301.375 297.472 293.108 289.349 282.809 277.896 271.956 265.587 257.688 251.320 243.397 234.833 225.580 215.532 204.516 192.346 178.299 161.880 138.197
(MJ m -z)
Enthalpy of saturated vapour (kJ kg -t)
Mass of working fluid (kg MJ -I)
2.5430 2.9645 3.4379 3.9554 4.4524 5.1494 5.8492 6.5993 7.4009 8.2299 9.8151 10.1635 I 1.1918 12.2536 13.3503 14.4620 15.5732 16.5757 17.4966 21.4650
355.887 359.660 363.344 366.885 370.313 373.030 376.682 379.603 382.292 384.758 386.944 388.837 390.373 391.517 392.215 392.326 391.763 390.140 387.186 380.180
3.2786 3.3181 3.3616 3.4117 3.4560 3.5359 3.5985 3.6771 3.7652 3.8806 3.9790 4.1085 4.2583 4.4330 4.6397 4.8896 5.1989
5.6085 6.1774 7.2360
DERIVED T H E R M O D Y N A M I C DESIGN DATA The theoretically ideal Rankine heat pump cycle for R152a is illustrated in Fig. 1 which is a plot of pressure P against enthalpy per unit mass H for R152a. With reference to Fig. 1, the theoretical Rankine coefficient of performance of a heat pump can be defined as HDI - - HD3
(COP)R = HDI -- Hs2"
(I)
Table 2. Theoretical Rankine coefficients of performance (COP~ for a range of gross tentperature lifts and condensing temperatures for R152a 20 5.152 10 15 20 25 30 35 40 45 50 55 60 65 70 75
24.13 15.84 11.75 9.30 7.67 6.50 5.63 4.97 4.43 4.09 3.64 3.34 3.09 2.87
25 5.987 25.09 16.54 12.23 9.68 7.97 6.76 5.85 5.14 4.60 4.14 3.85 3.46 3.19 2.96
30 6.922 26.09 17.19 12.75 10.06 8.29 7.02 6.08 5.35 4.76 4.29 3.90 3.64 3.29 3,05
35 7.965 27.06 17.83 13.22 10.46 8.60 7.29 6.31 5.54 4.94 4.44 4.04 3.69 3.46 3.15
40 9.128 28.17 18.53 13.72 10.85 8.94 7.56 6.54 5.75 5.12 4.60 4.17 3.82 3.51 3.31
45 50 10.412 11.834 29.42 19.27 14.25 i 1.25 9.26 7.85 6.78 5.95 5.30 4.76 4.32 3.94 3.64 3.36
30.61 20.06 14.79 1i.66 9.59 8.12 7.02 6.16 5.48 4.93 4.47 4.08 3.74 3.46
Table 3. Theoretical Rankine coefficients of performance (COP)a for a range of gross ternperature rifts and condensing temperatures for Ri52a
10 15 20 25 30 35 40 45 50 55 60 65 70 75
55 13.392
60 65 70 75 80 85 15.096 16.967 19.007 21.210 23.603 26.207
31.23 20.59 15.23 12.00 9.87 8.36 7.23 6.35 5.65 5.08 4.60 4.20 3.86 3.56
31.74 20.95 15.57 12.30 10.12 8.57 7.41 6.52 5.81 5.22 4.73 4.32 3.97 3.67
32.25 21,25 15.84 12.56 10.35 8.77 7.59 6.67 5.94 5.35 4.85 4.43 4.07 3.76
32.30 21.37 15.86 12.64 10.46 8.88 7.69 6.77 6.04 5.44 4.94 4.52 4.15 3.84
31.16 20.95 15.65 12.46 10.37 8.86 7.70 6.80 6.07 5.48 4.99 4.57 4.20 3.89
29.61 19.97 15.15 12.13 10.11 8.69 7.60 6,73 6.03 5.46 4.98 4.57 4.22 3.91
26.34 18.02 13.85 11.30 9.51 8.21 7.25 6.47 5.84 5.31 4.86 4.48 4.15 3.86
Thermodynamic design data for R152a heat p u m p systems
305
Table 4. Compression ratio (CR)-PcO/PEv for a range of gross temperature lifts and condensing temperatures for R152a (bar) 10 15 20 25 30 35 40 45 50 55 60 65 70 75
20 5.152 1.373 1.621 1.927 2.305 2.777 3.372 4.119 5.075 6.309 7.918 10.042 12.838 16.602 21.738
25 5.987
30 6.922
35 7.965
40 45 50 9 . 1 2 8 10.412 !1.834
1.358 1.344 1.330 !.318 1.307 1.296 1.596 1.570 1.546 1.525 1.504 1.486 1.884 1.845 1.807 1.772 1.739 1.710 2 . 2 3 9 2 . 1 7 9 2 . 1 2 3 2.070 2.021 1.977 2 . 6 7 9 2 . 5 8 9 2 . 5 0 7 2 . 4 3 3 2 . 3 6 3 2.297 3 . 2 2 7 3 . 0 9 7 2 . 9 7 9 2 . 8 7 3 2 . 7 7 5 2.684 3 . 9 1 9 3 . 7 3 2 3 - 5 6 4 3 . 4 1 4 3 . 2 7 7 3.154 4 . 7 8 7 4 . 5 3 1 4 . 2 4 4 4 . 0 8 4 3 . 8 9 4 3.725 5 . 8 9 7 5 . 5 3 5 5 . 2 1 4 4 . 9 2 1 4 . 6 5 9 4.426 7.331 6.819 6 . 3 6 9 5 . 9 7 6 5 . 6 1 3 5.295 9 . 2 0 2 8 . 4 7 7 7 . 8 4 6 7 . 2 9 9 6 . 8 1 6 6.380 !1.669 10.639 9 . 7 5 5 8 . 9 9 2 8 . 3 2 6 7.747 14.918 13.493 12.243 11.179 10.257 9.463 19.293 17.250 15.526 14.030 12.751 11.658
Table 5. Compression ratios ( C R ) - PcoJPEv for a range of gross temperature lifts and condensing temperatures for RI52a ~ c o (bar) 55 (Tco - Tev) ( ° C - ' ) - ~ 13.392
60 65 70 75 80 85 15.096 16.967 19.007 21.210 23.603 26.206
i
10 15 20 25 30 35 40 45 50 55 60 65 70 75
1.286 1.467 1.681 1.935 2.237 2.599 3.037 3.569 4.215 5.009 5.992 7.220 8.766 10.708
_m
17
•,p
le
1.276 1.450 1.654 i.895 2.181 2.522 2.930 3.434 4.024 4.752 5.646 6.755 8.139 9.883
1.267 1.434 1.629 1.859 2.130 2.451 2.834 3.293 3.848 4.522 5.430 6.346 7.592 9.147
1.259 1.419 1.606 1.825 2.082 2.386 2.746 3.175 3.689 4.311 5.066 5.982 7.109 8.054
1.250 1.405 1.584 1.792 2.037 2.323 2.663 3.064 3.543 4.117 4.810 5.653 6.676 7.933
1.242 1.391 !.563 1.762 1.994 2.267 2.586 2.963 3.410 3.942 4.581 5.353 6.291 7.429
1.236 1.379 1.544 1.736 1.957 2.214 2.517 2.871 3.290 3.786 4.377 5.087 5.944 6.985
ss Lift
14
12
20°C (CR)., 2
10
9
o
8
30°C
(CR) = 3
6
50oC /
"~
5 21
30
I
40
~
60°C
(CR) - 7 i
50
I
60
I
70
I
80
Condensingtemperature Tco, °C Fig. 2. Theoretical Rankine coefficient of performance against condensing temperature for RI52a for various compression ratios and gross temperature rifts.
306
M . A . R . EIsA et al.
The (COP)R values for any desired condensing temperature Tco and gross temperature lift (Tco-TEv) can be calculated from the saturated properties of R152a [1]. The theoretical Rankine coefficient of performance (COP)R and the compression ratio (CR) which is the ratio of the corresponding saturation pressures in the condenser and evaporator, Pco/PEv, have been calculated for R152a for temperature lifts of I0-75°C and for condensing temperatures for 20-85°C in 5°C increments. Tables 2 and 3 list the calculated (COP)R values and Tables 4 and 5 the calculated (CR) values. Figure 2 is plotted from the data listed in the tables. The basic data has been taken from published tables [2]. Figure 2 shows the relationship between the theoretical Rankine coefficient of performance (COP)R, the condensing temperature Tco, the temperature lift (Tco-TEv) and the compression ratio (CR). If any two of these four parameters are fixed, then the other two are determined automatically. In practice the condensing temperature Tco and temperature lift (Tco-TEv) are usually fixed thus determining the values of (COP)R and (CR). REFERENCES 1. F. A. Holland, F. A. Watson and S. Devotta, Thermodynamic Design Data for Heat Pump Systems. Pergamon Press, Oxford (1982). 2. ASHRAE Handbook, Fundamentals and Product Directory. American Society of Heating Refrigerating and Air Conditioning Engineers, New York (1977).
0890-4332/87 $3.00+ 0.00 Pergamon Journals Ltd
DERIVED T H E R M O D Y N A M I C DESIGN D A T A FOR HEAT PUMP SYSTEMS OPERATING ON R152a M. A. R. EISA*, S. SUPRANTO, S. DEVOTTA
and F. A. HOLLAND Department of Chemical and Gas Engineering, University of Salford, Salford M5 4WT, U.K. (Received 18 September 1986)
Almraet--Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R152a. These values are listed in tabular form for temperature lifts of 10-75°C and condensing temperatures of 20-85°C in 5°C increments. A composite plot has been drawn to illustrate the feasible operating range of RI52a heat pump systems.
NOMENCLATURE coei~cient of performance of the heat pump system [dimensionless] compression ratio of the heat pump [dimensionless] enthalpy per unit mass [El kg-I] pressure [bar] temperature [K or °C]
(COP)
(CR)
H P T Subscripts CO EV R
condenser evaporator Rankine. INTRODUCTION
R152a is difluoroethane a n d has the chemical f o r m u l a C2H4F2 . Its critical t e m p e r a t u r e a n d pressure are 114°C a n d 44.35 bar, respectively. T a b l e 1 presents some physical d a t a for R152a. 60
50 40 30
/ .
~o_~_
D3~
20
70°C
/_~L.
tk
___
.
D2
D1
_50~ . . . . . . .
e"
| e,
10
•~
/
/--4
I
-
.
~/ ..... ;,
9 8
4o°c
.... i
f
Zo:.
s#
7
#l . . . . . ,/ . . . .
4
I/
3 0
50
I
100
I
150
-~:~ ..4-~ ,o'.c _/~ I
I
200
250
I
300
II
350
I
400
Enthalpy per unit mau, H, kJ kg-1 Fig. 1. Pressure against enthalpy per unit mass for R152a. *Mahmoud Abdel Rahman EISA, (Ph.D), Cairo, Egypt. n.u. ~/~--A
303
I 450
500
304
M. A. R. EtsA et al. Table i. Physical data for R152a Density (kg m -z) Tco (°C)
Pco (bar)
liquid
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
2.673 3.176 3.752 4.409 5.152 5.987 6.922 7.965 9.128 10.412 11.834 13.392 15.096 16.967 19.007 21.210 23.603 26.206 28.990 31.980
958.3 947.1 935.6 923.8 911.7 902.0 886.4 873.0 859.2 844.8 829.9 814.3 797.9 780.4 761.9 742.1 720.7 697.1 671.1 641.5
Latent heat
vapour
PV (bar m3 kg-i)
(kJ kg-*)
8.337 9.837 I 1.357 13.494 15.699 18.208 21.048 24.266 27.866 31.938 36.547 41.757 47.658 54.320 61.941 70.713 80.964 92.966 108.084 155.321
0.32061 0.32290 0.32454 0.32664 0.32808 0.32871 0.38279 0.32817 0.32749 0.32955 0.32375 0.32062 0.31668 0.31227 0.30677 0.29986 0.29488 0.28183 0.26815 0.20584
305.004 301.375 297.472 293.108 289.349 282.809 277.896 271.956 265.587 257.688 251.320 243.397 234.833 225.580 215.532 204.516 192.346 178.299 161.880 138.197
(MJ m -z)
Enthalpy of saturated vapour (kJ kg -t)
Mass of working fluid (kg MJ -I)
2.5430 2.9645 3.4379 3.9554 4.4524 5.1494 5.8492 6.5993 7.4009 8.2299 9.8151 10.1635 I 1.1918 12.2536 13.3503 14.4620 15.5732 16.5757 17.4966 21.4650
355.887 359.660 363.344 366.885 370.313 373.030 376.682 379.603 382.292 384.758 386.944 388.837 390.373 391.517 392.215 392.326 391.763 390.140 387.186 380.180
3.2786 3.3181 3.3616 3.4117 3.4560 3.5359 3.5985 3.6771 3.7652 3.8806 3.9790 4.1085 4.2583 4.4330 4.6397 4.8896 5.1989
5.6085 6.1774 7.2360
DERIVED T H E R M O D Y N A M I C DESIGN DATA The theoretically ideal Rankine heat pump cycle for R152a is illustrated in Fig. 1 which is a plot of pressure P against enthalpy per unit mass H for R152a. With reference to Fig. 1, the theoretical Rankine coefficient of performance of a heat pump can be defined as HDI - - HD3
(COP)R = HDI -- Hs2"
(I)
Table 2. Theoretical Rankine coefficients of performance (COP~ for a range of gross tentperature lifts and condensing temperatures for R152a 20 5.152 10 15 20 25 30 35 40 45 50 55 60 65 70 75
24.13 15.84 11.75 9.30 7.67 6.50 5.63 4.97 4.43 4.09 3.64 3.34 3.09 2.87
25 5.987 25.09 16.54 12.23 9.68 7.97 6.76 5.85 5.14 4.60 4.14 3.85 3.46 3.19 2.96
30 6.922 26.09 17.19 12.75 10.06 8.29 7.02 6.08 5.35 4.76 4.29 3.90 3.64 3.29 3,05
35 7.965 27.06 17.83 13.22 10.46 8.60 7.29 6.31 5.54 4.94 4.44 4.04 3.69 3.46 3.15
40 9.128 28.17 18.53 13.72 10.85 8.94 7.56 6.54 5.75 5.12 4.60 4.17 3.82 3.51 3.31
45 50 10.412 11.834 29.42 19.27 14.25 i 1.25 9.26 7.85 6.78 5.95 5.30 4.76 4.32 3.94 3.64 3.36
30.61 20.06 14.79 1i.66 9.59 8.12 7.02 6.16 5.48 4.93 4.47 4.08 3.74 3.46
Table 3. Theoretical Rankine coefficients of performance (COP)a for a range of gross ternperature rifts and condensing temperatures for Ri52a
10 15 20 25 30 35 40 45 50 55 60 65 70 75
55 13.392
60 65 70 75 80 85 15.096 16.967 19.007 21.210 23.603 26.207
31.23 20.59 15.23 12.00 9.87 8.36 7.23 6.35 5.65 5.08 4.60 4.20 3.86 3.56
31.74 20.95 15.57 12.30 10.12 8.57 7.41 6.52 5.81 5.22 4.73 4.32 3.97 3.67
32.25 21,25 15.84 12.56 10.35 8.77 7.59 6.67 5.94 5.35 4.85 4.43 4.07 3.76
32.30 21.37 15.86 12.64 10.46 8.88 7.69 6.77 6.04 5.44 4.94 4.52 4.15 3.84
31.16 20.95 15.65 12.46 10.37 8.86 7.70 6.80 6.07 5.48 4.99 4.57 4.20 3.89
29.61 19.97 15.15 12.13 10.11 8.69 7.60 6,73 6.03 5.46 4.98 4.57 4.22 3.91
26.34 18.02 13.85 11.30 9.51 8.21 7.25 6.47 5.84 5.31 4.86 4.48 4.15 3.86
Thermodynamic design data for R152a heat p u m p systems
305
Table 4. Compression ratio (CR)-PcO/PEv for a range of gross temperature lifts and condensing temperatures for R152a (bar) 10 15 20 25 30 35 40 45 50 55 60 65 70 75
20 5.152 1.373 1.621 1.927 2.305 2.777 3.372 4.119 5.075 6.309 7.918 10.042 12.838 16.602 21.738
25 5.987
30 6.922
35 7.965
40 45 50 9 . 1 2 8 10.412 !1.834
1.358 1.344 1.330 !.318 1.307 1.296 1.596 1.570 1.546 1.525 1.504 1.486 1.884 1.845 1.807 1.772 1.739 1.710 2 . 2 3 9 2 . 1 7 9 2 . 1 2 3 2.070 2.021 1.977 2 . 6 7 9 2 . 5 8 9 2 . 5 0 7 2 . 4 3 3 2 . 3 6 3 2.297 3 . 2 2 7 3 . 0 9 7 2 . 9 7 9 2 . 8 7 3 2 . 7 7 5 2.684 3 . 9 1 9 3 . 7 3 2 3 - 5 6 4 3 . 4 1 4 3 . 2 7 7 3.154 4 . 7 8 7 4 . 5 3 1 4 . 2 4 4 4 . 0 8 4 3 . 8 9 4 3.725 5 . 8 9 7 5 . 5 3 5 5 . 2 1 4 4 . 9 2 1 4 . 6 5 9 4.426 7.331 6.819 6 . 3 6 9 5 . 9 7 6 5 . 6 1 3 5.295 9 . 2 0 2 8 . 4 7 7 7 . 8 4 6 7 . 2 9 9 6 . 8 1 6 6.380 !1.669 10.639 9 . 7 5 5 8 . 9 9 2 8 . 3 2 6 7.747 14.918 13.493 12.243 11.179 10.257 9.463 19.293 17.250 15.526 14.030 12.751 11.658
Table 5. Compression ratios ( C R ) - PcoJPEv for a range of gross temperature lifts and condensing temperatures for RI52a ~ c o (bar) 55 (Tco - Tev) ( ° C - ' ) - ~ 13.392
60 65 70 75 80 85 15.096 16.967 19.007 21.210 23.603 26.206
i
10 15 20 25 30 35 40 45 50 55 60 65 70 75
1.286 1.467 1.681 1.935 2.237 2.599 3.037 3.569 4.215 5.009 5.992 7.220 8.766 10.708
_m
17
•,p
le
1.276 1.450 1.654 i.895 2.181 2.522 2.930 3.434 4.024 4.752 5.646 6.755 8.139 9.883
1.267 1.434 1.629 1.859 2.130 2.451 2.834 3.293 3.848 4.522 5.430 6.346 7.592 9.147
1.259 1.419 1.606 1.825 2.082 2.386 2.746 3.175 3.689 4.311 5.066 5.982 7.109 8.054
1.250 1.405 1.584 1.792 2.037 2.323 2.663 3.064 3.543 4.117 4.810 5.653 6.676 7.933
1.242 1.391 !.563 1.762 1.994 2.267 2.586 2.963 3.410 3.942 4.581 5.353 6.291 7.429
1.236 1.379 1.544 1.736 1.957 2.214 2.517 2.871 3.290 3.786 4.377 5.087 5.944 6.985
ss Lift
14
12
20°C (CR)., 2
10
9
o
8
30°C
(CR) = 3
6
50oC /
"~
5 21
30
I
40
~
60°C
(CR) - 7 i
50
I
60
I
70
I
80
Condensingtemperature Tco, °C Fig. 2. Theoretical Rankine coefficient of performance against condensing temperature for RI52a for various compression ratios and gross temperature rifts.
306
M . A . R . EIsA et al.
The (COP)R values for any desired condensing temperature Tco and gross temperature lift (Tco-TEv) can be calculated from the saturated properties of R152a [1]. The theoretical Rankine coefficient of performance (COP)R and the compression ratio (CR) which is the ratio of the corresponding saturation pressures in the condenser and evaporator, Pco/PEv, have been calculated for R152a for temperature lifts of I0-75°C and for condensing temperatures for 20-85°C in 5°C increments. Tables 2 and 3 list the calculated (COP)R values and Tables 4 and 5 the calculated (CR) values. Figure 2 is plotted from the data listed in the tables. The basic data has been taken from published tables [2]. Figure 2 shows the relationship between the theoretical Rankine coefficient of performance (COP)R, the condensing temperature Tco, the temperature lift (Tco-TEv) and the compression ratio (CR). If any two of these four parameters are fixed, then the other two are determined automatically. In practice the condensing temperature Tco and temperature lift (Tco-TEv) are usually fixed thus determining the values of (COP)R and (CR). REFERENCES 1. F. A. Holland, F. A. Watson and S. Devotta, Thermodynamic Design Data for Heat Pump Systems. Pergamon Press, Oxford (1982). 2. ASHRAE Handbook, Fundamentals and Product Directory. American Society of Heating Refrigerating and Air Conditioning Engineers, New York (1977).