| As a new air-conditioning technology using shallow geothermal energy in the field of HVAC,soil source heat pump system has become a building energy-saving technology widely used at home and abroad.However,due to the unequal strength of the construction heat and cold load in most cases,the reliability and economy of pure soil source heat pump system can not be guaranteed in long-term use,so the coupled soil source heat pump system with auxiliary cold(hot)source is proposed,and the coupling system has great advantages in improving the performance deterioration of soil source heat pump system caused by the imbalance of soil temperature field caused by uneven heat and cold load.However,due to the complex structure of soil source heat pump coupling system,the high initial investment and the operation of the key equipment buried tube heat exchanger are affected by multiple factors,which cause the complexity of the design to become the restriction of the popularization and application of the soil source heat pump coupling system.In system design and engineering application,it is the general direction of the whole work to ensure the stability and economy of soil source heat pump coupling system operation.In the long-term operation of the system,soil as the main heat source(heat sink)of the system,due to the fluctuation of meteorological parameters,unreasonable design and other factors,its deviation from the expected accumulation of heat(cold)will have an important impact on the stability and economy of the system operation.This requires that in the early stages of system design,the operating characteristics of the coupling system in its full life cycle should be as objective as possible to make accurate predictions.Therefore,it is very necessary to carry out dynamic simulation and optimization analysis of the soil source heat pump cooling tower coupling system during the life cycle.Based on the soil source heat pump cooling tower coupling system of a residential building,this paper takes a city in the hot summer and winter cold areas as an example,and makes a model,verification model,optimization design and economic analysis.First of all,using TRNSYS software to model the coupling system,through the software preprocessor program TRNBuild to the target building time-by-time hot and cold load simulation calculation,to obtain the year-round time-by-time hot and cold load,and the hot and cold load analysis,further explained the soil heat accumulation effect,the need to add auxiliary cold source.Secondly,according to the engineering example,based on the existing data of the cloud monitoring platform of the air conditioning system,TRNSYS software is called for simulation,and three equipment parameters of refrigeration and heating conditions are selected to compare,and the correctness of the model is verified.Then,according to the geotechnical thermal response test of engineering examples,several geotechnical thermal property parameters,including the initial average soil temperature and the average thermal conductivity coefficient of the soil,are obtained.Through the test parameters,the heat exchange of the buried pipe unit extension meter in the project site is calculated,and then the preliminary design of the buried pipe heat exchanger is carried out.The full life cycle simulation operation of the system is carried out,which shows that there is room for further optimization of the design of the ground buried tube heat exchanger parameters and the start-up of the cooling tower,and four system variables and corresponding target functions,including heat exchanger parameters and cooling tower start-up parameters,are set up in combination with the starting method of the cooling tower.Finally,based on the soil source heat pump cooling tower coupling system model as the platform,the optimization design of the buried pipe heat exchanger and the starting of the cooling tower of the soil source heat pump cooling tower coupling system was carried out by using the coupling simulation and optimization software.Based on the full life cycle cost of the soil source heat pump cooling tower coupling system,including initial investment and operating cost,the paper optimizes the soil source heat pump coupling system of engineering examples,and analyzes the influence of construction load and ground buried pipe outlet temperature on the system’s full life cycle cost.On this basis,by calculating the full life cycle cost(LCC)of the six combined corresponding systems,and comparing the initial design of the system LCC,it is concluded that the minimum combination of the system LCC values is: the number of drilling holes in the buried tube heat exchanger 554,the depth of the drilling 78 meters,the buried pipe spacing 5.2m;The cooling tower is activated by the load determination when the load value is greater than 29% of the total cooling capacity of the heat pump unit.The whole life cycle cost of the optimized coupling system is 28,829,200 yuan,which is 12.12% less than that before optimization. |
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