Analysis of the Operation Strategy for Heat Storage Middle-deep Geothermal Heating System

The heat storage middle-deep geothermal heating system extracts geothermal energy from the underground at depths of 2000-3000 meters as a heat source, and is coupled with a thermal storage system to provide clean energy to buildings and balance the electrical grid load. The operation control strategy of the system has a significant impact on its performance. In order to study the operation control strategy of the heat storage middle-deep geothermal heating system, the thermal load models of three typical public buildings in Xi'an were established using TRNSYS software, along with a simulation process for the heat storage middle-deep geothermal heating system. Based on the thermal load characteristics of the three building types, the effects of different operation control strategies on peak shaving and load shifting of the electrical grid were explored, as well as the analysis of operational economics. The results show that for office buildings, release energy priority mode and determine proportions control mode have a good peak load shifting effect. The daily operating cost of the release energy priority mode is the lowest ¥132.35. For hotel buildings, there is a heat load demand within 24 hours of hotel building, so the control strategy is during the valley power time period and the flat power time period, the heat pump unit runs at full load. After the thermal load of the heat pump unit meets the heat load of the building, the remaining part of the thermal load of the heat pump unit is used for heat storage. During the peak power time period, the middle-deep ground source heat pump coupled heat storage system of the hotel building adopts unit priority operation mode. Using the above operation control strategy, the daily operation cost is ¥326.83. For the mall buildings, determine proportions control mode have the best peak load shifting effect, and the daily operating cost of the release energy priority mode is the lowest ¥120.49.