Performance Analysis And Optimization Of Energy Storage Surface Water Heat Pump System

With the rapid development of the society,the total energy consumption of buildings in China is rising rapidly,and the peak load in summer is constantly rising,so the pressure of building energy conservation and consumption reduction is huge.In addition,as the country began to vigorously promote the shallow geothermal energy as a renewable energy,the geothermal energy utilization technology based on heat pump has been in rapid development.However,it is still faced with a low proportion of the amount of exploitation and uneven regional development,especially in Shanghai,Zhejiang and other economically developed areas,where the technology is developing slowly.This paper takes the energy storage surface water heat pump system as the research object.Taking Jinghu plain river network in Shaoxing as an example,the potential of plain river network water resources for surface water heat pump system is studied.Then,this paper takes a certain energy storage surface water heat pump system in this area as a case to study and analyze,and proves the feasibility of application of the energy storage surface water heat pump system in this area through performance measurement and comparison.Finally,the optimization strategy is proposed to solve the problems found in the test results.The main research work is as follows:(1)The water resources utilization potential of Jinghu Plain river network in Shaoxing was studied through analysis of water resources quantity and water heat load bearing capacity,water intake water level safety analysis,water intake convenience analysis,water quality suitability analysis and water temperature suitability analysis.The results show that the water resources of the plain river network can be used as the cold and hot source of surface water heat pump system and the application potential is huge.(2)Take an energy storage surface water heat pump system under Jinghu Plain river network in Shaoxing as an example.By measuring the operating conditions of the system under different loads in winter and summer,the COP of heating performance,EER of refrigeration and other measured indexes were obtained,and the energy efficiency was compared with that of common systems,the results show that the surface water heat pump system produces 2 times more heat than the gas-fired boiler in the heating period when the energy consumption is converted to the same amount of standard coal.EER is superior to the control water-cooled air conditioning system in cold supply period.Through the economic comparison with the original air conditioning system scheme,it is concluded that the static payback period of increased investment is 9.1 years under the current working conditions.(3)Take the VRF system in the same building as the case system as the comparison object.Three indexes,namely energy consumption per unit area,indoor thermal environment(temperature,relative humidity)compliance rate,and user satisfaction with thermal environment,were compared.The results show that the energy storage surface water heat pump system has lower energy consumption than the VRF system in winter and basically the same energy consumption with the VRF system in summer when it has a similar indoor thermal environment compliance rate and users’ thermal environment satisfaction.(4)By comparing the actual operating condition of the air conditioning system with the design condition,it was found that the system operated under partial load for a long time,but the operation strategy was configured and executed according to the designed load,leading to the system’s long-term inefficient operation state and unbalanced energy supply and demand.To solve the above problems,this paper adopts the strategy optimization method and the pool capacity selection method.Through the simulation of the energy storage tank,the operation law of the reservoir is mastered,the causes of the existing problems are found,the optimization strategy is proposed pertinently,and feasible judgment conditions are proposed for the transformation between strategies.Through the economic analysis before and after the strategy optimization,it is concluded that after the optimization,the annual accumulative energy saving of the system can reach72,800 k Wh,and the operating cost can be reduced by 31,100 yuan,with the decrease rates of 14.9% and 14.2% respectively.