Ground Source Heat Pump Operation Modes And Characteristic Research

Vigorously develop renewable energy is the only way for China to reduceenvironmental pollution and ease energy pressures. Soil source heat pump based onshallow soil of cold (hot) source, through the medium ground heat exchanger in a closedfloW between the heat exchanger and soil. It is rapidly developed as a new energy ofhigh efficiency, energy saving and environment protection, and conforming withsustainable development strategy, so this technology has been widespread concern in theinternational community at present. Current research and application of soil source heatpump systems in the Northern Regional is quite enthusiastic, While this technology isstill in the exploratory stage in the Southern District and lack the support of theexperiment data. Therefore, based on a set of soil source heat pump systems at the NanHua University platform, and the method of experimental research and simulationanalysis have been adopted in order to obtain a large amount of data and provide thebasis of research and application for ground source heat pump system. The specificresearch contents are as follows:1. Theoretical calculations and measured at different depths in the soil initialtemperature distribution. The results show that annual temperature under10m on theground is not subject to outside temperature change.2. Running performance of the soil source heat pump at winter and summerconditions are experimental research. Mainly includes import and export watertemperature changes in the ground source side, the change of buried pipe wall in soiltemperature, soil temperature recovery after the shutdown, the heat transfer capacity ofheat exchanger, heat pump units COP and systems COP.3．Priority compared to run continuously and four clearance operation mode cyclemedium temperature change, soil temperature and natural recovery, the heat transfercapacity of heat exchanger and heat pump units and the performance of the system. Theresults show that, compared with the continuous mode, operation characteristics are improved under four kinds of clearance operation mode. For instance the heat transfercapacity of the heat exchanger in the heating conditions are increased by15.1%,13.5%,8.5%and4.9%, respectively and are increased by15.03%,13.2%,9.4%and6.5%under refrigeration conditions, respectively.4. Simulation analysis under different operating mode in winter and summerconditions the change of soil temperature field, and the radius of the thermal effect ofburied tube heat exchanger. Experiments have been carried out to verify the simulationresult. Results show that the thermal effect radius increases with the running time of theheat pump system and the gap is significantly less than continuous operation mode. theradius of the thermal effect under winter and summer conditions are2m and2.3mrespectively.