Re ECF Project: 2008-19

Project Title: Waste Heat Powered Air-conditioning System for Automobile

Applicant: City University of Hong Kong (Prof. LAI Chi-keung)

Total Approved Grant: $249,135

Duration: 15/10/2009 to 14/10/2010

Project Status/Remarks: Completed

This project aims to promote the sustainable energy use in transportation in Hong Kong by developing an experimental adsorption-type automotive cooling system that uses waste exhaust gas as heat (energy) input. This proposal also examines heat transfer properties of the system, develop control and instrumental facilities of the test rig, evaluate the coefficient of waste heat cooling, calculate the performance of the prototype including cooling power, size, cost and saving of fuel use aspects.

Summary of the Findings/Outcomes:
In this project, an adsorption cooling system using exhaust gas as heat input was designed and manufactured. Based on the current working conditions, results show that the total cooling production changes significantly with variation of the number of working adsorbers. Besides, different final temperature of condensing/regenerating phase also leads to different cooling production. If more adsorbers are working and higher final temperature of condensing/regenerating phase is set, larger cooling is produced.

The exhaust gas temperature varies with the output electric power of the generator changes. This leads to a different heat transfer rates in the adsorbers. The diesel oil consumption only depends on the output electric power of the generator and the time-consuming of condensing/regenerating phase, but has no relationship with other parameters.

The COPs are in the range of 0.37-0.44. They are not as high as an ideal cycle as the experiments are conducted in non-equilibrium cycles. The specific cooling power varies from 35 to 45 W/kg. It is not an extremely high value for adsorption cooling cycles using zeolite 13-X. The lowest WCOP is only 0.06, which is not as high as expected.