Refrigerant 134a enters a heat exchanger in a steady state refrigeration system as saturated vapor at 0 °F and exits at 20 °F with no change in pressure. A separate liquid stream of Refrigerant 134a passes in counterflow to the vapor stream, entering at 105 °F, 160 psia and exiting at a lower temperature while experiencing no pressure drop. The outside of the heat exchanger is well insulated, and the streams have equal mass flow rates. Neglecting kinetic and potential energy effects, determine the exit temperature of the liquid stream in degrees F.© BrainMass Inc. brainmass.com October 24, 2018, 8:26 pm ad1c9bdddf
Please see the attached file...Solution:.
The heat transfer from vapor stream must all be received by the liquid stream:
Vapor stream in: Saturated vapor at 00F (21.2 psia): h1 = 101.75 (Btu/lb)
Vapor stream out: Superheated ...
The solution provides detailed explanation and calculations for the problem.
Refrigerant 134a leaves the evaporator as saturated vapor
Refrigerant 134a leaves the evaporator as saturated vapor at 1.4bar and is heated at constant pressure to 20 degrees C before entering the compressor. After isentropic compression to 12bar, the refrigerant passes through the condensor exiting at at 44 degrees C, 12 bar. The liquid then passes through the heat exchanger, entering the expansion valve at 12bar. The mass flow rate of refrigerant is 6 kg/min, determine:
a. coefficient of performance
b. compressor power input