2. The condenser and evaporator of a refrigerator with refrigerant-134a as the working fluid work at the constant pressures of 200 psia and 25 psia respectively. The mass flow rate of the refrigerant in the cycle
is 5 lbm/min. The condenser rejects heat to cooling water that enters the condenser at 40°F at a rate of 25.297
lbm/min and leaves at 55°F. The exit of the evaporator (state 1) is saturated vaper but the exit of the condenser
(state 3) is not saturated liquid. The work consumed by the compressor is 23.48 Btu/lbm and the estimated
heat gain of the compressor from the surroundings is 0.81 Btu/lbm. Determine
(a) the enthalpy and temperature at the condenser inlet (h2 and T2)
(b) the enthalpy and temperature at the condenser outlet (h3 and T3)
(c) the refrigeration load in Btu/min
(d) the COP of the refrigerator.
Water
Water
55°F
40°F
Он
Condenser
P= 200 psia
3
2
Qin
Expansion
valve
Win
Compressor
4
Evaporator
P= 25 psia
1
QL