Abstract: A gas-liquid contactor for varying the mixing ratio of a non-azeotropic refrigerant circulated through a refrigeration cycle, wherein each of pieces of a filler filled in a filler bed of the gas-liquid contactor is composed of a substantially cylindrical member with a peripheral surface having convexities and concavities. This form of the filler provides a voidage in the bed of the filler suitable for upward flow of the gaseous phase of the refrigerant through the filler bed and, at the same time, provides a large area for the contact between the gaseous phase and the liquid phase of the refrigerant by virtue of the presence of many convexities and concavities.

Abstract: A gas-liquid contactor for varying the mixing ratio of a non-azeotropic refrigerant circulated through a refrigeration cycle. A liquid returning pipe leading from a liquid refrigerant reservoir has a lower end which is opened downward into the container of the gas-liquid contactor at a position substantially on the axis of the container, so that the returned liquid refrigerant can be uniformly distributed over the entire region of the filler bed so as to enhance exchange of heat between the gaseous phase and the liquid phase of the refrigerant. A lower filler holder defining the lower end of a bed of filler in the gas-liquid contactor is convexed upward at its central portion so as to smoothly guide the flow of gaseous phase of the refrigerant into the filler bed.

Abstract: A heat pump apparatus is provided with a multiple-constituent refrigerant mixture which includes a major constituent refrigerant which is above 50% by weight of total refrigerant enclosed in the refrigerating circuit provided with a variable frequency compressor, and a minor constituent refrigerant which has lower critical pressure than that of the major constituent refrigerant.