| As people pay more and more attention to energy conservation and emission reduction,soil source heat pump as a renewable energy technology has been more and more widely used.The soil source heat pump hot water system transfers the soil low heat energy to the domestic hot water by consuming part of the electric energy of the heat pump unit.The temperature of underground soil has the characteristics of stable and high temperature,so the production of domestic hot water by soil source heat pump system has the advantages of high efficiency,energy saving and stability.This paper,taking a two sets of the university of Liuzhou city,Guangxi Province soil source heat pump hot water system as the research object,the cyclic heating type soil heat source heat pump hot water system and direct type soil source heat pump hot water system(hereinafter referred to as circulation heating system and direct heating system),in transition seasons and summer respectively in two sets of hot water system operation parameters test,compare the two sets of hot water system operation parameters,analysis of the pros and cons of two sets of soil source heat pump hot water system;FLUENT simulation software was used to conduct stratified simulation of hot water for pressure insulation storage tanks used in the recirculated heating soil source heat pump hot water system,and the structural optimization design of pressure insulation storage tanks was carried out,and a baffle was added to separate the cold and hot water to increase the efficiency of using hot water and improve the water supply temperature.Finally,the energy consumption,cost and pollutant emission reduction of the soil source heat pump hot water system and several other common hot water preparation methods are calculated briefly,and the economy and environmental protection of the soil source heat.pump hot water system are analyzed.In this paper,the main research results:1.The type of hot soil source heat pump hot water system compared with cyclic heating type soil source heat pump hot water system has a higher water temperature,the transition season average water temperature of 48.4?,1.7? higher than the circulating heating system and summer average water temperature of 48.9?,0.4? higher than the circulating heating system and the winter temperature is 47?,average water supply than cyclic heating system is 2.8?,and direct heating system water supply temperature stability,water temperature fluctuation is small,circulating heating system water supply temperature is affected by the dynamic pump working condition are volatile.2.The direct heating system has a higher COPunit,and COPsystem,with the transition season of the direct heating system being 4.8 and 4.5,the summer season being 4.9 and 4.5,the winter season being 4.7 and 4.4,the cycle heating system transition season being 4.0 and 3.5,the summer season being 4.1 and 3.4,and the winter season being 3.9 and 3.3.3.The percentage of heat loss in the hot water pipe of the direct heat system in the heat pump unit is 4.95%,3.19%and 5.75%in the transition season,summer and winter,and 12.3%,11.27%and 13.8%in the cycle heating system.The hot water pipe of the heating system adopts polyurethane foam insulation,while the hot water pipe of the circulating heating system adopts rubber plastic insulation.Therefore,the hot water pipe of the circulating heating system can be changed into polyurethane foam insulation to reduce the heat loss of the pipe.4.The direct heating system with an open insulated water tank needs to be equipped with a hot water supply pump.In the direct heating system,the hot water supply pump consumes about 0.56kwh,0.54kwh and 0.59kwh for each ton of hot water supply pump.The power pump in the circulating heating system of the pressure-insulated water tank USES the power pump energy consumption of 0.12kwh,0.21kwh and 0.08kwh for each ton of hot water.The water supply energy consumption of the pressure-insulated water tank system is 88.7%,78.5%and 92.3%less than that of the open tank system.According to the annual water supply of about 33120 tons,the water supply energy consumption is reduced by about 28443.9kWh.The hot water supply pump of the open-type water tank system consumes a lot of energy,which can be used when the user's hot water demand is large,the hot water use is centralized,and the hot water supply can be set at a fixed time every day.If the hot water is used in a scattered period of time and hot water needs to be provided to users 24 hours a day,the pressure-insulated water storage tank + circulating heating soil-source heat pump hot water system can be adopted.5.In the economy,the direct preparation of hot water heating system cost is 9.98 RMB/ton,circulating heating system is 11.91 yuan/ton,air source heat pump hot water system is 13.01 RMB/ton,gas hot water system is 17.32 RMB/ton,electric water heater and solar + electric auxiliary to 35.03 RMB/ton,compared to the air source heat pump hot water system and gas hot water system,electric water heater and solar +electric auxiliary system,hot water has a lot to the economic advantages of soil source heat pump hot water system.6.In environmental protection and energy converted into several kinds of hot water system of standard coal consumption calculation of pollutant emissions,soil source heat pump heating system and circulating heating system than the rest of the several hot water preparation system on the emissions of CO2,SO2 and dust,direct heating system annual emissions of CO2,SO2 and dust is about 5%,respectively,compared with the cyclic heating type system;7%higher than air source heat pump system;65%higher than the electric water heater;It is 11%higher than solar + air source system,and the annual water supply is about 33120 tons.Compared with electric heating,the two systems save 130.95 tons of standard coal and 122.86 tons of standard coal respectively.Compared with the solar + air source system,the two systems save 21.9 tons of standard coal and 13.81 tons of standard coal annually.Compared with natural gas heating,the two systems save 168.9 tons of standard coal and 160.81 tons of standard coal annually.7.Build pressure heat insulating water storage tank by SolidWorks physical model,the FLUENT software to simulate the temperature of the circulating water in hot water heating system runtime layering is,in the experiment of the heating tank,heating tank top outlet(3.33m)the average temperature of 49.5?,the lower inlet(0.83m),the average temperature is 46?,lower water temperature is 3.5? or so,simulate the upper-middle-class average temperature of 49.2?,46.4? lower,lower water temperature is about 2.8?,the experiment of the heat storage tank,heat storage tank top average temperature of 45.3?,Below 28.5?,16.8? from left and right sides,simulation of thermal storage tank top average temperature 45.7?,the lower the water temperature is 28.7?,a difference of about 17?,can be seen from the experiment and simulation results,during the period of system operation,heating pot and heat storage tank water stratification is obvious.8.Optimize the pressure heat insulating water storage tank structure design,increasing the block flow plate will be separated,the hot and cold water thermal storage tank inlet area(0.83m)in lower temperature before and after optimization is not obvious,but the optimized heat storage tank outlet height(3.33m)to simulate the average temperature of 47.1?,is 1.8? higher than the average temperature 45.3?,visible after optimization can effectively improve the water supply temperature. |
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