| In recent years,with the development and promotion of low temperature air source heat pumps,low temperature air source heat pump storage radiant floor heating system is gradually popular in the cold regions of China because of its comfort,energy saving and environmental protection features,and the stability and economic energy saving of the system is also gradually attracted attention.However,the mismatch between the storage tank volume and the unit capacity and heating operation strategy has resulted in poor system stability and high energy consumption,and the problem of how to match the storage tank volume and the system operation regulation strategy needs to be solved.In order to promote the energy-efficient operation of heating systems and the application of the air source heat pump thermal storage floor radiation method in cold regions of China,this paper focuses on the storage tank volume and system operation regulation strategy to study the feasibility and energy-saving economy of the system.The paper is based on the following research work: the theory and results of low temperature air source heat pump systems and heating operation strategies are sorted out,and the feasibility and importance of the research is discussed.The operation principle of the heating system and the heat balance equations of the radiant floor end,heat storage tank and pump part of the building are analysed,the heating system simulation software is selected,the meteorological characteristics of Shijiazhuang city are analysed,and the dynamic annual heat load of an energy-efficient residential building is simulated and analysed by building a simulation platform,and the heating system is selected for the characteristics of the heat load of energy-efficient buildings in cold regions,A simulation model of a low temperature air source heat pump heating system is built in the software to simulate and analyse the effect of the volume of the thermal storage tank on the operation of the system during the heating season,then four heating strategies are proposed in terms of heat load characteristics,heat pump supply and return water temperature difference,circulating water pump flow control and peak and valley electricity price control.The results of the study show that the smaller the volume of the storage tank,the more drastic the change in the water supply temperature of the users and the more frequent the start and stop of the unit,and with the gradual increase of the tank volume,the average heating performance of the heat pump unit gradually increases,and the tank volume has little influence on the average temperature of the water supply of the users.When the water tank volume is 6m~3,the heating energy consumption is the lowest,and the heat pump starts and stops infrequently,and the user water supply temperature changes smoothly.Under the premise of stable operation of the system during the heating season,the strategy of controlling the start and stop of the heat pump through the characteristics of the heat load can effectively avoid the losses caused by the start and stop of the heat pump,and the energy saving rate is the highest among the four operation regulation strategies,reaching 18.1%,and under the heat pump inlet water temperature control strategy,the energy consumption does not change significantly,and the energy saving rate is 5.8%.Compared with constant flow strategy,variable flow strategy reduces energy consumption by 7.7%.Under the strategy,energy consumption increased by 10.9%,but the heating cost savings were 39%.Comparing the six different clean heating methods,it was found that the annual operating costs of the multi-source complementary heating system were lower than those of the single energy heating system.The annual cost of air source heat pump is the lowest and the economy is better.The research of this paper provides theoretical basis for the practical application of low temperature air source heat pump thermal storage heating systems in the Shijiazhuang area. |
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