Agas within a piston-cylinder assembly executes a carnot power cycle during which the isothermal expansion occurs at th 5 600 k and the isothermal compression occurs at tc 5 300 k. determine (a) the thermal efficiency. (b) the percent change in thermal efficiency if th increases by 15% while tc remains the same. (c) the percent change in thermal efficiency if tc decreases by 15% while th remains the same. (d) the percent change in thermal efficiency if th increases by 15% and tc decreases by 15%.

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.