Comprehensive Benefit Evaluation And Optimizing Of Direct Expansion Ground Coupled Heat Pump System

With the development of the social economy, the demand of energy is much more than before. At the same time the effect on the environment is more and more important. Additionly, the development and utilization of renewable energy are taken into consideration by more and more countries and governments. The ground source heat pump(GSHP)system has become the research focus in HVAC industry because of its’ highly efficient, energy-saving and environmentally-friendly. Hence, the ground source heat pump system has been rapidly developing and applying. The direct expansion ground coupled heat pump(DX-GCHP) system is one kind of ground source heat pump systems. It possesses the characters of simpleness, high heat transfer efficiency. Thus, it is getting more and more popular.Even though the numbers of the project exploring the ground source heat pump systems are increasing, almost all the types of the heat pump systems are the second loop ground coupled heat pump system(SL-GCHP) in the world. The DX-GCHP system is seldom utilized. It is necessary to evaluate the application effect and comprehensive benefit in defferent regions and projects for the DX-GCHP system application. This paper aims to evaluate the comprehensive benefit of the DX-GCHP system and to optimize the DX-GCHP systems for different climate zones.The evaluation system of the DX-GCHP system is established on the system performance, efficiency, energy saving and environmental protection. Taking a villa in Beijing for instance, the paper designs the DX-GCHP system and weights the indicators by the fuzzy analytic hierarchy process. The paper establishes an evaluation score system by summarizing the relevant normative standards of the ground source heat pump system, evaluates and analyzes the comprehensive benefits of the DX-GCHP system.The DX-GCHP systems are optimization designed according to the different climatic zones. Solar energy aided direct expansion ground coupled heat pump system is proposed for the cold or the severe cold climate zones. Cooling tower combined with direct expansion coupled source heat pump system is proposed for the hot-summer and cold-winter climate zones. The two kinds of systems are analyzed and evaluated.