Heat pump with capillary tube-type expansion device.

摘要

A heat pump employing a capillary tube as an expansion device. The main throttle portion of the heat pump comprises a main capillary tube 312 and a by-pass 311 through which a portion of the refrigerant flows and cools the refrigerant flowing through the main capillarytube. A solenoid valve 360 for controlling the flow of refrigerant through the main capillary tube is connected to the intake of the main capillary tube, and an electrical expansion valve 350 is connected to the intake of the by-pass for controlling the flow therethrough. An auxiliary capillary tube 400 for cooling and an auxiliary capillary tube 500 for heating are connected in parallel with the main throttle portion, both capillary tubes having a higher resistance to flow than the main capillary tube. The auxiliary capillary tubes increase the range over which control of the flow of refngerant can be achieved, allowing both a smaller flow of refrigerant during under minimum cooling or heating load as well as a larger flow of refrigerant under maximum cooling or heating load.