Heat pump

#1. Field of the Invention

#The present invention relates to heat pumps useful for hot water heaters, air-conditioners, and the like, and more particularly to a heat pump furnished with a mechanism for recovering energy by an expander.

#2. Description of the Related Art

#FIG. 1 illustrates one example of the configuration of a heat pump according to the present invention.

#FIG. 2 is a Mollier diagram illustrating a refrigeration cycle of the heat pump shown in FIG. 1.

#FIG. 3 is a flowchart illustrating one example of controlling the opening of an expansion valve by a control device.

#Hereinbelow, preferred embodiments of the present invention are described with reference to the drawings. In the following description, the same components and steps may be designated with the same reference numerals to avoid repetitive description.

#FIG. 1 illustrates a configuration of one embodiment of the heat pump according to the present invention. This heat pump 11 is provided with a compressor 1, a radiator 2, an expander 4, and an evaporator 6 as the primary constituent components for exhibiting the fundamental functions of a heat pump, and further is provided with piping 10 for connecting the primary constituent components so that refrigerant can circulate therethrough. A suitable displacement of the expander 4 is 5% to 20% of the displacement of the compressor 1. The compressor 1, the radiator 2, the expander 4, and the evaporator 6 are connected by the piping 10 to form a refrigerant circuit. The refrigerant circulates in the refrigerant circuit in the direction indicated by the arrows in FIG. 1, and at the radiator 2, it radiates heat absorbed at the evaporator 6.

#In the heat pump 11, a first expansion valve 3, which is a first throttling device, is disposed between the radiator 2 and the expander 4, and a second expansion valve 5, which is a second throttling device, is disposed between the expander 4 and the evaporator 6. Also disposed in the heat pump 11 are a pressure sensor 7 for measuring the pressure of the refrigerant between the expander 4 and the expansion valve 3 (the pressure PI of the refrigerant flowing into the expander 4) and a temperature sensor 8 for measuring the atmosphere temperature of the evaporator 6.