You have to remove 12,000 kJ/h from a refrigeration space at 4 oC and reject the heat into the surroundings at 30 oC.

a) How much work per hour (power) would you have to use if you have an ideal Carnot reverse heat engine?

b) If you have a vapor compression cycle using HCF-134a refrigerant instead, what is the minimum pressure would you have to achieve in the compressor in order to reject heat into the surroundings assuming that you need the refrigerant to be a minimum of 5 oC temperature higher than the surroundings at 30 oC throughout the condenser?

c) In class, we discussed the use of a turbine in a vapor compressor cycle instead of a throttle. If we had a non-ideal turbine, how does the fraction of vapor of the refrigerant change at the exit of the turbine compared to the use of an ideal turbine. Assume the same exit pressure. Explain answer (just a qualitative answer is sufficient.)