A heat pump with refrigerant-134a as the working fluid is used to keep a space at 25°C by absorbing heat from geothermal water that enters the evaporator at 50°C at a rate of 0.051 kg/s and leaves at 40°C. The refrigerant enters the evaporator at 12°C with a quality of 15 percent and leaves at the inlet pressure as saturated vapor. If the compressor consumes 1.9kw of power, determine
a) The mass flow rate of the refrigerant
b) the rate of heat supply
c) the COP
d) the minimum power input to the compressor for the same rate of the heat supply