Compare to the air conditioning cycle Heat Pump Cycle 0000 System Performance Coefficient of Performance Desired heat transfer effect(units Work required(units) COP= Heat transfer rate To indoor air Power input to pressor and fans Energy Efficiency Ratio Heat transfer rate(Btu/hr) EER= Maximum COP for a Heat-Pump Cycle as a Function of Outdoor Air Temperature Heat Pumps Outdoor air temperature(F)5 Compare to the air conditioning cycle. Heat Pump Cycle Outdoor air 20 F 10 F 72 F low temperature high temperature Indoor air 90 F System Performance Work Heat Heat Coefficient of Performance Energy Efficiency Ratio COP = Desired heat transfer effect (units) Work required (units) COP = Heat transfer rate TO indoor air Power input to the compressor and fans EER = Heat transfer rate (Btu/hr) Electrical power (Watts) 0.0 10.0 20.0 30.0 40.0 50.0 -10 0 10 20 30 40 50 60 Outdoor air temperature (F) COP (dimensionless) Indoor air temperature = 72 F Maximum COP for a Heat-Pump Cycle as a Function of Outdoor Air Temperature Geothermal Heat Pumps