Abstract: An improved non-stratified heat pump water heater wherein the condenser assembly of the heat pump has at least one non-vertical section and is inserted into the water tank through an existing opening in the top of the tank. The condenser assembly has either a tube-in-a-tube style or U-tube style elongated heat exchanger construction. As the refrigerant condenses along the interior surface of the condenser assembly, the heat from the refrigerant is transferred to the water. Two embodiments of the invention include a water heater having a separate sacrificial anode rod and a water heater wherein the condenser assembly acts not only as a heat exchanger but also as the sacrificial anode in the water tank by being constructed of a metal which is more likely to corrode than the metal of the tank.

Abstract: An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second refrigerant expansion device to selectively defrost the evaporator by causing warm refrigerant to flow through the evaporator.