Avertical piston-cylinder device contains water and is being heated on top of a range. during the process, 65 btu of heat is transferred to the water, and heat losses from the side walls amount to 8 btu. the piston rises as a result of evaporation, and 5 btu of work is done by the vapor. determine the change in the energy of the water for this process.

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.