Simulation And Experimental Research On Thermal Substation With The Electrical Heat Pump And Heat Storage System

Central heating technology is the main development direction of heating technology in China.With the rapid development of urbanization,the contradiction between the limited heating capacity of the central heating system and the increasing heating demand is becoming more and more obvious.At present,reducing the temperature of primary net return water is an effective way to improve the heat transfer capacity.Adding an electric heat pump unit in a heat substation can reduce the temperature of the primary network return water to a level lower than that of secondary network return water,thereby greatly increasing the transmission capacity of the pipeline network and reducing the irreversible loss in the heat exchange process of the heat substation.The thermal substation system of electric heat pump combined with thermal storage is studied in this dissertation.The system can switch the heat storage and heat release mode in the peak-to-valve period of the power grid to realize the intermittent operation of electric heat pumps.Therefore,it is less expensive to operate than a thermal substation that only increases the electric heat pumps.EES(Engineering Equation Solver)software is used to establish the steady-state mathematical model of the thermal substation system and analyzes the variable conditions.This dissertation first analyzes the influence of different inlet parameters on the performance of the thermal substation system,and simulates the flow process of the electric heat pump system using a single-stage heat pump or a two-stage heat pump.In addition,in order to improve the accuracy of the evaporator and condenser calculation,the distribution parameter method was used to simulate the condensation and evaporation process in the plate heat exchanger.At last,the experimental substation of the thermal substation system was set up.Experimental research is conducted on different working conditions of heating user's terminal using the radiator or the radiant floor and compares it with the simulation calculation results.The study will provide a few value for the design of thermal substation system using electric heat pumps.