Answer: A geothermal heat pump operating at steady state

Chapter 10, Problem 42P

(choose chapter or problem)

A geothermal heat pump operating at steady state with Refrigerant-22 as the working fluid is shown schematically in Fig. P10.42. The heat pump uses \(55^{\circ} \mathrm{F}\) water from wells as the thermal source. Operating data are shown on the figure for a day in which the outside air temperature is \(20^{\circ} \mathrm{F}\). Assume adiabatic operation of the compressor. For the heat pump, determine

(a) the volumetric flow rate of heated air to the house, in \(\mathrm{ft}^{3} / \mathrm{min}\).

(b) the isentropic compressor efficiency.

(c) the compressor power, in horsepower.

(d) the coefficient of performance.

(e) the volumetric flow rate of water from the geothermal wells, in gal/min.

For \(T_{0}=20^{\circ} \mathrm{F}\), perform a full exergy accounting of the compressor power input, and devise and evaluate a second law efficiency for the heat pump system.