| A ground-coupled heat pump (GCHP) is a machine or device that consumes less high-grade energy to obtain more low-grade energy. The systems are highly efficient, environmental protection, well-balanced running, low operating cost and so on. The varied absorption of heat and heat release in soil under earth result in unsteady running of systems due to the great difference of building cooling load or heating load, therefore the heat pump technology has more drawbacks in promotion and application. By way of enhancing efficiency of systems, it will be thermal balance analysis and feasible controlling methods.The paper shows situation of energy use, advantages and principles of ground source heat pump systems, researches and applications of ground-coupled heat pump systems. According to the characteristics of more cooling load than heating load, using existing control strategies to simulate and analyze combined ground-coupled heat pump with cooling tower systems in contrast with series connection and parallel connection are essential.A College of Women and Children Health Care in Changsha as for case study, in the first place, calculated dynamic hourly cooling load all year actualized DeST software and selected methods of existing combined ground-coupled heat pump with cooling tower systems and utilized existing test data and referred to previous hourly cooling load, it has confirmed main equipments as well as amounts and forms and depth of ground-couple what the systems need. Above mentioned these points aim to satisfy heating load in winter. At the same time established three kinds of operating modes combined ground-coupled with cooling tower:series connection and parallel connection, conventional heat pump operating mode. conventional heat pump operating mode is simulated by Simulation software, proved that a cooling tower needs to be used in difference of cooling load and heating load, to ensure that the well-balanced systems run for a long time. The balance of absorption and release heat in soil under earth may be achieved when the cooling tower runs from6a.m to20p.m everyday through simulated series connection.Finally, it analyzed four kinds of operating ways and controlling condition of parallel connection. It has proved that the parallel connection also could keep the balance of absorption and release heat in soil under earth by simulated example three and four. |
