24 June 2014

High-Performance, High-Efficiency GHP Development

The gas engine-driven heat pump air conditioner (GHP) is a gas air-conditioning system that heats and cools by means of heat-pump operation. GHP has an outdoor
compressor driven by the gas engine. Since the GHP were introduced for sale in 1987, they have been widely spread mainly in Japan because of its advantages such as savings in
electrical power consumption as well as low operational cost. The development of highefficiency GHP has steadily progressed since the product entered the market, but with the current energy conservation trend, and from the viewpoint of counteracting global warming through the reduction of CO2 emissions, there is a pressing need to improve GHP efficiency even more.
The performance of GHP has been evaluated up to now in COP (Coefficient Of Performance) at the rated point. However, GHP is hardly driven in rated point actually, and most is driven
by the partial load. APF (Annual Performance Factor) was provided for as a performance evaluation index considered the partial load driving in JIS (Industrial Standards of Japan) in
2006. It is important to maintain a highly effective operation to improve APF in the area where the air conditioning load is small.
In our development efforts, GHP system efficiency improvements were devised as the means to increase the efficiency of the gas engine driving source as well as to enhance
efficiency from the aspect of the refrigeration cycle, where the improvement of performance
at the outdoor air/heat exchanger was investigated. A comparison of the newly developed GHP to existing models indicates that reductions of primary energy up to 19% and of CO2 up
to 20% are possible. In this paper we will introduce a high-performance, high-efficiency GHP jointly developed by
Tokyo Gas, Osaka Gas, Toho Gas and the GHP manufacturers.