Question

"Ideal vapor compression cycle using R-134a with condenser and evaporator pressure of 800 kPa and 165 kPa, respectively. Find the COP of the cycle."

A 4.44

B 5.15

C 3.56

D 3.95

Answer 1

Q Griven: P = 165 kPa = 165x10²x10 s bar gil bar = 105 Pa - lits bar P, - $oo Efa - Воо что я р S рах = 8 bar To find i coop of cycle soln P-h 8 bar diagram ) libs bar t- Let us consider wet refrigerant entering the compressor and leaving it in dry saturated condition. Using Refrigeration table of R-134 a, we get! Presure 1.65 bar I Temperature , ho (x۱۴۹) -14.8554°C (180.2908) 389.689 10.9263 1.73688 (ht,) (hg) (sf) (så,) 243, 5628 415.4124 | 1.1498 1.7137 31.3°C БА T (haa) (hoz) (Spa) 15221 process 1-2 Y isentropic :. s, S = sa Stat*, (9- Sf, ) = 52 = 592

0.9263 ta, ( 1.73688- 0.9263) 5 1-7137 0.92637 0.810582, 1.7137 0.810580, 0.7878 a oi9714 :hia hf, tx, (hg, - hf.) = 180.29087 0.9714 ( 389.689 - 180 2908) - 383.70 - so, 1h, = 383.70 kg 1kg And, I " h₂=h2 = 415 4129 ks 1kg hfz = har = ha - ha = 243-5628 kJ lkg So, Coop = Refrigeration effect work done by compressor = hi ha h₂ h, 38.3.70 - 283.5628 415 4129 - 383.70 140.1372 31.7129 = 4:42 Tc.oop ~ 4.42 so, correct option (A)