Figure F.2 is a Pressure Enthalpy Diagram of Tetraflouroethane, unfortunately it is too big to attach.

Table 9.1:

T(oC)	P(bar	Vl(m^3/kg)	Vv(m^3/kg)	Hl(kJ/kg)	Hvl(kJ/kg)	Sl(kJ/kgK)	Sv(kJ/kgK)
-40	.512	.000705	.361080	148.14	374	.796	1.764
-35	.661	.000713	.284020	154.44	377.17	.822	1.758
-30	.844	.00072	.22594	160.79	380.32	.849	1.752
-25	1.064	.000728	.18162	167.19	383.45	.875	1.746
-20	1.327	.000736	.14739	173.64	386.55	.9	1.741
-18	1.446	.00074	.13592	176.23	387.79	.91	1.74
-16	1.573	.000743	.12551	178.83	389.02	.921	1.738
-14	1.708	.000746	.11605	181.44	390.24	.931	1.736
-12	1.852	.00075	.107440	184.07	391.46	.941	1.735
-10	2.006	.000754	.09959	186.7	392.66	.951	1.733
-8	2.169	.000757	.092422	189.34	393.87	.961	1.732
-6	2.343	.000761	.085867	191.99	395.06	.971	1.731
-4	2.527	.000765	.079866	194.65	396.25	.98	1.729
-2	2.722	.000768	.074362	197.32	397.43	.99	1.728
0	2.928	.000772	.069309	200	398.6	1	1.727
2	3.146	.000776	.064663	202.69	399.77	1.01	1.726
4	3.377	.00078	.060385	205.4	400.92	1.02	1.725
6	3.62	.000785	.056443	208.11	402.06	1.029	1.724
8	3.876	.000789	.052804	210.84	403.2	1.039	1.723
10	4.146	.000793	.049442	213.58	404.32	1.049	1.722
12	4.43	.000797	.046332	216.33	405.43	1.058	1.721
14	4.729	.000802	.043451	219.09	406.53	1.068	1.72
16	5.043	.000807	.04078	221.87	407.61	1.077	1.72
18	5.372	.000811	.038301	224.66	408.69	1.087	1.719
20	5.717	.000816	.035997	227.47	409.75	1.096	1.718
22	6.079	.000821	.033854	230.29	410.79	1.106	1.717
24	6.458	.000826	.031858	233.12	411.82	1.115	1.717
26	6.854	.000831	.029998	235.97	412.84	1.125	1.716
28	7.269	.000837	.028263	238.84	413.84	1.134	1.715
30	7.702	.000842	.026642	241.72	414.82	1.144	1.715
35	8.87	.000857	.023033	249.01	417.19	1.167	1.713
40	10.166	.000872	.019966	256.41	419.43	1.191	1.711
45	11.599	.000889	.017344	263.94	421.52	1.214	1.709
50	13.179	.000907	.015089	271.62	423.44	1.238	1.707
55	14.915	.000927	.01314	279.47	425.15	1.261	1.705
60	16.818	.00095	.011444	287.5	426.63	1.285	1.702
65	18.898	.000975	.00996	295.76	427.82	1.309	1.699
70	21.168	.001004	.008653	304.28	428.65	1.333	1.696
75	23.641	.001037	.007491	313.13	429.03	1.358	1.691
80	26.332	.001077	.006448	322.39	428.81	1.384	1.685

.11. A refrigerator with tetrafluoroethane ( ( Table 9.1, , Fig. F.2) as refrigerant operates with an evaporation temperature of 25C and a condensation temperature of 26C. Saturated liquid refrigerant from the condenser flows through an expansion (throttle) valve into the evaporator, from which it emerges as saturated vapor. (a) For a cooling rate of 5kJs1, what is the circulation rate of the refrigerant? (b) By how much would the circulation rate be reduced if the throttle valve were replaced by a turbine in which the refrigerant expands isentropically? (c) Suppose the cycle of part (a) is modified by the inclusion of a countercurrent heat exchanger between the condenser and the throttle valve in which heat is transferred to vapor returning from the evaporator. If liquid from the condenser enters the exchanger at 26C and if vapor from the evaporator enters the exchanger at 25C and leaves at 20C, what is the circulation rate of the refrigerant? (d) For each of parts (a),(b), and (c), determine the coefficient of performance for isentropic compression of the vapor