Improvement of heat pump performance using an ejector | Human, Energy and Environment Laboratory, The University of Tokyo

Members
	Eiji HIHARA, Prof.
	Chaobin DANG, Asso. Prof.
	All members

Research

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CO2 heat pumps (Improvement of heat pump performance using an ejector)

Ejector has been used as a compressor or a vacuum pump for a long time. The principle of ejector is as follows. Supersonic nozzle accelerates high pressure driving flow to supersonic speed. After sharing the kinetic energy with suction flow, pressure of each flow rises in the mixing section and diffuser. With this device, expansive power, which had not been used in the conventional heat pump cycle, can reduce the compressor work. The working fluid for the ejector of this research is carbon dioxide, which has been attracting much attention as one of the most promising natural refrigerants.

In our labolatory, experimental setup of ejector cycle has been designed. The influences of a variety of parameters, from temperature and pressure to shape parameters of each section, are examined experimentally and theoretically.

See also: Ejector air conditioner


High-pressure primary fluid is accelerated, and its pressure becomes low. Sucked flow is compressed through a diffuser.	The expansion process of heat pump cycle is relaced by an isentropic process. The COP will be improved by several modification.


The fluid flow at the exit of the nozzle was visualized by a high speed camera.	The flow rate of sucked flow was dependent on the diameter of mixing section.