Study On Operation Optimization Of Hybrid Ground Source Heat Pump And Energy Storage System

GSHPs(Ground-Source Heat Pump system)has been widely used for geothermal resources are widespread,moderate,stable,environmental friendly,etc.Because the energy efficiency ratio of traditional GSHPs will drop with soil temperature increasing or decreasing year by year,research of hybrid GSHPs is becoming hot,less in HyGSHPESs(Hybrid Ground Source Heat Pump and Energy Storage System)however.Therefore,energy efficiency ratio and operation optimization of HyGSHPESs get much attention.Firstly,a HyGSHPESs project in Tianzhou is introduced and a test to the project aimed at energy efficiency evaluation is implemented then.The results show that energy efficiency ratio of the project is 4.0 in summer,3.47 in winter,which is lower than expected but higher than traditional individual system.However,there are problems such as high loss rate of heat transfer,high loss rate of energy storage,low load rate and insufficient operation level.Secondly,a water-to-water heat pump module Type202 is developed,which makes up for the lack of TRNSYS simulation software in large-scale water-to-water heat pump module.Then,according to the energy conservation equation,hourly surface water temperature in dynamic changes is calculated based on numerical solution,as an input to the TRNSYS simulation platform.Following,a simulation platform in TRNSYS for the HyGSHPESs in Tianzhou is built.Operating strategy in actual typical winter day and summer day is simulated.The annual energy consumption of the system is simulated.The results show that annual power consumption is 5545 MWh and comprehensive energy efficiency ratio is 4.52,providing support in preferred design and refined operation strategies for designers and operators.In the end,a two-stage operation optimization concept with a goal of minimum operating cost in one day is proposed for HyGSHPESs adopted water storage technology to improve actual operation level.The first stage optimization takes energy supply of heat pumps and the reservoir at each moment as independent variables.Branch and bound method is used to solve the optimal load distribution in the first stage.The second stage optimization based on first stage takes water supply temperature and pump flow rates at both sides of heat pumps as independent variables.The genetic algorithm is used on the second stage.The actual project is applied to the two optimization model.Compared with actual operating data,energy consumption and operating cost with optimal strategy is reduced by 19.9% and 28.0% in summer,by 31.6% and by 33.8% in winter.The methods work well in similar heat pumps with water storage technology.