Simulation And Optimization Of Solar Energy-Ground Source Heat Pump Combined System

This paper revise the polytropic index of the screw ground source heat pump unit theory model based on the experiment.established grey box model of screw ground source heat pump unit Wrote the FORTRAN simulation program of the unit based on the grey box model simulated the performance characteristics of the unit using R22as refrigerant. Analysised the influence of different evaporator inlet water temperature, condenser inlet water temperature and compressor capacity on refrigerating capacity heating capacity compressor power consumption and COP.Got the operating data of the unit on the condition of different evaporator inlet water temperature, condenser inlet water temperature and compressor capacity by the simulation.Build the unit module in TRNSYS combined with the actual control mode Aviods the repeated caculation. Accelerates the computation speed. Increases the simulation accuracyIt is closer to the actual operating condition of the unit. Makes the long time simulation of the system using small time step more quickly and accuratelySmulates the process of the thermal storage using solar energy on May1st and October1st period. Proving the useful of storing the solar energy under the ground when the solar energy is rich. Finds a way to calculate the flow rate of the solar pump on the condition of different area of the solar collectorProposes alternating solar heat storage-ground source heat pump system, using a building in Shenyang as research object. Builds a TRNSYS dynamic model of combined system include solar collector,ground source heat pump unit, ground heat exchanger, control system, meteorological parameters and building load. Simulates ground source heat pump system and combined systems with different solar collector area for9years.Simulates the instantaneous values of different systems. For example, heating capacity refrigeration capacity, heating energy consumption, refrigeration energy consumption. And integrate those values in a year. Add coal-fired boiler to those systems which can’t provide enough heat in winter. Converts the electricity consumption into coal consumption. Gets the comprehensive energy consumption energy efficiency, amount of coal-fired, the emissions of CO2,SO2and NO2There is hot and cold load imbalance problem in Shenyang. It will lead to the result that the average temperature of the ground where contains the buried pipe will decline year by year, then the ground source heat pump unit maybe stop operating to protect itself. So the system can’t fit the need of heating in winter. If combine the solar collector and ground source heat pump system in winter, the total price is very high. Because the solar energy density is lower in winter, we need more and high efficiency collectors. Flat plate solar collector can performance well when the solar energy is high. So the alternating solar heat storage-ground source heat pump system will reduce the cost.Concluded that the alternating solar heat storage-ground source heat pump system can realize the dynamic stability of underground temperature field. And improves the performance of heating in winter, but won’t reduce the refrigerating capacity. When the area of the solar collector reach400m2,the system will performance very well In the research building. It can not only supply the heating energy which the building needs in winter but also have high COP and environment benefit.