Geothermal Heat Pump System for Air Conditioning in Hong Kong

Abstract

In Hong Kong, electrical energy consumption for air conditioning of buildings is very high. Since most central air conditioning systems are air-cooled, there has been much concern about the need for appropriate energy conservation strategies and solutions for the "heat island effect" due to heat dissipation from the air conditioning condensers of the crowded buildings. Although experience in cold climate countries has shown that geothermal heat pump systems are more efficient than other types of systems for building environmental control, there has never been any study or project of geothermal heat pump systems carried out for the sub-tropical environment of Hong Kong.
Recently, the Hong Kong government has initiated a pioneering project for the Wet Land Garden in the New Territories in which a geothermal heat pump system is employed for central cooling and heating of the associated buildings. In order to predict the performance of the geothermal system under Hong Kong weather conditions, a computer modelling and simulation study is carried out using the TRNSYS software package and a vertical U-tube ground loop heat exchanger model. Useful results are obtained for the long-term performance for cooling only and combined cooling and heating throughout the year. Great improvements in performance are achieved for the latter case. Further analyses of the results can help determine whether geothermal heat pump systems are economically viable and environmentally friendly in Hong Kong.