Design And Energy Saving Strategy Of River Water Source Heat Pump System

With the emergence of the energy crisis and high oil prices,concerns about climate change,the country pays more and more attention to the problem of high energy consumption,and has issued a series of policies and related regulations to deal with the current energy and climate problems.Including the use of renewable energy,such as solar energy,wind energy,hydropower,geothermal energy,ocean energy and other non-fossil energy sources.After a lot of research by scholars,hydropower and geothermal energy have been widely used in regional centralized cooling and heating technology.The heat is discharged from the cold source during the cooling season and heat is taken from the heat source during the heating season.but in the actual application process,due to the lack of corresponding theoretical research support,the energy efficiency of the heat pump system is often not up to the ideal state,and it often results in waste of energy.This paper takes the river water source heat pump system as the research object,and systematically analyzes the performance of the river water source heat pump system in the regional centralized energy supply technology.Specifically,It is divided into the following contents:First of all,this paper summarizes the research results of river water temperature obtained by the predecessors.Based on the data in the literature,the relationship between river water temperature and air temperature is analyzed,and the data is corrected,and the method of this paper to study river water temperature is proposed.The daily average temperature data of the air-conditioning season and the Cubic third-order model are used to establish the prediction models of the river water temperature in the cooling season and the heating season.The simulation results show that the daily average water temperature has a strong relationship with the daily average temperature,and the accuracy of the model is high.The average relative error of seasonal simulated water temperature is within 1.24%,and the average relative error of simulated water temperature during heating season is within 3.33%.Secondly,in order to study the annual load characteristics of various functional buildings,the De ST software was used to establish energy consumption models for residential buildings,commercial buildings,and office buildings,and to analyze the hourly load changes of three typical buildings throughout the year.From the simulation results,it is found that the air-conditioning load of the above three types of buildings all exhibit cyclical changes.The air-conditioning load is greatly affected by outdoor weather parameters and indoor personnel’s work and rest,so that the air-conditioning load has a large dispersion and is in a low load rate state(0%,60%] most of the time.In actual engineering,it is necessary to fully consider the system energy efficiency of the building under partial load,and propose an air-conditioning system operation strategy,which has far-reaching significance for the energy-saving operation of the air-conditioning system.Furthermore,in order to study the relationship between the operating energy consumption of the water source side equipment of the heat pump system and external influence factors during the heating season,relying on a river water source heat pump system project,two heat extraction schemes with different heat exchange forms(Plate heat exchanger takes heat,SPI immersion heat exchanger takes heat).Using the "black box" of the unit and the "multiple regression analysis" model of the water pump,the energy consumption model of the heat pump unit and the energy consumption model of the water pump are established.Parameter identification of the energy consumption model of the heat pump unit was carried out to verify the usability of the model.The verification result showed that the model had a good prediction accuracy with a relative error of less than 5%,which could be used to calculate the energy consumption of the water source side system of the actual project.After further analysis of the energy consumption of the heat pump unit,it was found that when the condenser outlet water temperature is constant,the heat generated by the unit has a greater impact on the energy consumption of the heat pump unit than the evaporator inlet water temperature.In addition,the applicability of the composite river water source heat pump system using Jialing River water and lake water as cold and heat sources is analyzed.Establish a lake water temperature model to simulate natural water temperature and dynamic water temperature under load.The simulation results show that in the natural state,the water temperature of the lake meets the design of the inlet water temperature of the heat pump unit.However,when the heat pump system is running,the water temperature at certain times in the cooling season cannot meet the design requirements.Therefore,in view of this,a system control strategy is proposed to alleviate the change of lake water temperature,which provides a reference for the control design of the river water source heat pump system.Finally,Take a regional energy station project in Chongqing as an example,with the goal of optimizing the heating system during the heating season.the hourly heat load of the building complex throughout the year is simulated,and the maximum heat load of the building complex is determined to be 69.24 MW.Calculating the energy consumption of the water source side system for two different heat extraction schemes,the results are: the operating energy consumption of the plate heat exchanger heat extraction scheme is 18.86 million k Wh,and the operating energy consumption of the SPI immersion heat exchanger heat extraction scheme is 17.98 million k Wh.Combining the operation energy consumption and the actual project,determine the final heat extraction plan for the plate heat exchanger.Based on the principle of load supply and demand balance,combined with Chongqing’s “peak-valley time-of-use electricity price” policy,the energy-saving operation strategy of heat pump units in the cooling and heating seasons is proposed,the operation control process of the heating system is compiled,and Matlab software is used to solve the problem and get Optimal control strategy.