Question

Tt

(12 points) A refrigerator using refrigerant-134a as the working fluid operates on the vapor compression cycle. The cycle operates between 200 kPa and 1.2 MPa. The refrigerant flows through the cycle at a rate of 0.015 kg/s. The actual) refrigerator has a compressor with an isentropic efficiency of 82%. The refrigerant enters the compressor slightly superheated by 6.2°C (hint: add this to the saturation temperature). The refrigerant leaves the condenser slightly subcooled by 1.8°C. What is the rate of heat removal from the refrigerated space for the actual refrigerator? 2.568 kW What is the power supplied to the compressor for the actual refrigerator? 2.74689 kW What is the COP for the actual refrigerator? 3.144 Under the ideal vapor compression cycle, for a refrigerator operating between these pressures and with the given refrigerant flow rate, what is: the rate of heat removal? 2.037 kW the power supplied to the compressor? kW the COP? (Hint: remember for an ideal cycle the evaporator does not superheat the refrigerant and the condenser does not subcool it either.)

Answer 1

for actual cycle from suble of R-1349 Valves of sp. enthalpy at vornom points Hampa hi - 2016 4 0:2 ms : 8 = 0.950 kg 1914 1-2 (isentopie) S,S': 0.958 at S'= 0.958 l A chual Cycle P ar: 1:2 MPG Par: 1:2 Tegy t 0.82= 289.250 B: 282 TOK th, hihi The 115 ks (subcooled State) h2-250 297:56 lg 1 To at 3 h 1 @ Rate of Meat Removel Roten e n Chaha) t h, hạ - Us 1 ( 6 H 4 ) Q- Orois (250-115) 19 2.025 kw ? Power supp do Comp. P: mche-hi)= 0.018 +(297:56 - 250) IP: 0.7134 kw ] ®

Сореф COPE Cop: 21025 07134 COP= 2.8385 h = 244 ks 8 = 0.938 m 70k 1:2 MP, :: B = 8, 01938 kr P2 = 120014Pq 2050 PS in hy = 282 kr Ideal Cycle hy - 118 h = hq = 118. Ig (schrottlig ) . Heat removed from refrigerated place Dr. Mich ha) - 01015x (244-118) TO 1085 km] Power Suph to complem Chi-hi) - 0.015 (282-244) Re: 0:57 kw? COP = Or 189 31316 pi? 0:57