Air Thermal To Compensate The Imbalance Of Heat Absorption In Winter And Heat Releasing In Summer Of Ground Source Heat Pump System

With energy conservation and environmental awareness increased, ground source heat pump (GSHP), as a new green energy-saving technology, is concerned by more and more people. It has many advantages, such as energy-saving and high-efficience, non-pollution, stable and reliable operation, low operating cost, and so on. However, in the application of the GSHP, the problem which uneasy to resolve is existed. It is about the soil temperature imbalance in winter and summer which caused by the limited heat storage capacity, and that problem is more serious in the hot and cold load. For example, in the cold region, the heat which is got out from the soil in winter is more than that which is got in in summer. Because of this, the temperature of the soil will decrease year by year and lead to the efficiency decrease of the system. As a result, the opinion that it is unreasonable and even impossible to use the GSHP in the hot and cold load is hold by some people.According to the soil temperature imbalance which mentioned above, this paper developed a novel and simple compensation method with remarkable economic benefit. Unlike the general system which uses supplemental cold source method (such as cooling towers), this paper presents a new method of soil temperature balance, that is"The thermal of the air to compensate the imbalance of colding and heating load of ground source heat pump (GSHP)". Using the outdoor low temperature air as the cold energy and the underground soil as the cold storage device, the outdoor Fan Coil running outside and exchanging cold with the low temperature air, the system is to store cold energy underground by U-tube heat exchanger, so as to balance the increase temperature of ground due to the big different between heat absorption quantity and heat removal quantity after system running for several years. Compared with the traditional cooling tower-ground source heat pump mixed system, this mode has a lot of benefits. It can avoid large area occupation; due to the heat exchanger underground, it runs stably and structures simply; finally, it has low operation cost and it is pollution-free. This method provides a practically and effectively way to solve the common problems of underground heat accumulation in the ground source heat pump system.In order to prove the reliable and superiority of this method, the paper uses the calculation and number of a practical project. It is a ground source heat pump system of a hotel in Wuhan, which cooling load is much bigger than the heating load.This article is mainly the theoretical study of the air thermal compensation system, and a hotel's ground source heat pump system in Wuhan as a design example. In the calculation, a physical and dynamic mathematical model of the air thermal compensation system which includes the GSHP unit, outdoor Fan Coil system, air conditioning terminal, and underground U-tube heat exchanger are made based on energy conservation law; then, the study focus on the analysis of underground temperature change of the soil, to provide a theoretical basis and basic data for the evaluation of the air thermal compensation system's efficiency and performance parameters; finally, analyze and compare the economy of the system with and without thermal compensation, make a comprehensive evaluation of economy, energy-saving and environmental protection value of the air thermal compensation system.