Study On Variable Flow Rate Of Ground Source Water System Of Soil Source Heat Pump

With the acceleration of urbanization in recent years,the proportion of building energy consumption in the total energy consumption in China is rising.As a stable,efficient and environment-friendly new air conditioning system,soil-source heat pump has been widely used.However,the ground-source side water system usually operates at a constant flow rate.The phenomenon of"large flow and small temperature difference"is common,and the energy consumption of the ground-source side water pump accounts for a large proportion,which needs to be further optimized.In this paper,the DeST model of a typical building in an industrial park in wuhan is established and the distribution characteristics of the building load are analyzed.For the shortcomings of the heat pump unit DOE-2 model,in this paper,the correction coefficient EER_m of the influence of circulating water velocity on the unit that is missing in the DOE-2model is supplemented,and a new method for calculating EER_m is given.In view of the rationality that the circulating water on the ground source side of the soil-source heat pump adopts the variable flow mode with the same fixed temperature difference throughout the year,this paper puts forward the suggestion that different inlet and outlet temperature differences should be adopted in the refrigeration season and heating season.For this,in combination with the industrial park of heat pump system,through software simulation,above the working condition of industrial park in the summer on the source side best circulating water temperature is 4.7?,and the system energy saving rate is12.2%;the best temperature is 3.9?in winter,and the system energy saving rate is 9.9%.Due to different heat pump systems,the ratio of pump power to heat pump host power)53(t_in-out is different under the maximum load,and the R value will significantly affect the value of the optimal temperature difference.Therefore,this paper respectively explored the influence of different R values on system energy consumption under two working conditions of winter and summer.The results show that the larger the R value is,the larger the optimal temperature difference?35?t_in-outis.Therefore,when designing the inlet and outlet temperature difference)53(t_in-out of the ground source side water system,the influence of R value on the energy consumption of the heat pump system should be fully considered,and the optimal inlet and outlet temperature difference should be selected according to different R values.Finally,this paper also studies the influence of configuration mode of heat pump host and water pump on system energy consumption in view of two common variable flow modes of pump number adjustment and frequency conversion adjustment.Taking three typical combinations of unit and pump?"1 machine 1 pump","1 machine 1.5 pump","1machine 2 pump"?as an example,when the configuration of the unit and the pump changes from"one machine with one pump"to"one machine with two pumps",if the number of pumps is adjusted,the energy saving rate of the heat pump system increases from 4.5%to6.21%;if the pump adopts frequency conversion adjustment,the energy saving rate of the heat pump system is reduced from 12.01%to 8.74%.