Chapter 9, Problem 9.88P

Define the no refrigerator can have a higher COP than a reversible refrigerator operating between the same temperature limits.

4. A Camot heat pump with refrigerant-134a as the working fluid is used to keep a room at 78*F by absorbing heat from geothermal liquid water that enters the evaporator at 60°C at a rate of 3.78 kg/min and leaves (still as a liquid) at 40°c The refrigerant, meanwhile, enters the evaporator at 12°C with a quality of 25% and leaves at the same pressure as saturated vapor. If the compressor consumes 1.8 kW of power, detemine (a) the mass flow rate (in kg/s) of the refrigerant at the evaporator, (b) the rate of heat (in kW) supplied to maintain the room temperature, and (c) the COP. Also, what is (d) the ambient temperature at the outside, in "C, that necessitates the use of the heat pump? Assume steam properties to compute for the thermodynamic conditions of geothermal water. Outside Inside Expansion Ve Condenser Evaporator Compresser

A heat engine is operated between temperature limits of 1370 C and 260 C. Engine supplied with 14142 kJ/kW-h. Find the Carnot cycle efficiency.