| As the pace of urbanization gets faster and faster,the contradiction between energy demand and supply has become increasingly prominent,and the importance of building energy efficiency has gradually emerged.At present,common air source heat pump,ground source heat pump,water source heat pump and chiller&boiler have some disadvantages or restrictions in the application in hot summer and cold winter areas.Under such a background,the heat source tower heat pump air-conditioning technology,which is suitable for the climate hot in summer,cold and humid in winter,emerged and gradually spread.This paper takes the open heat source tower heat pump as the research object,the main work is as follows:Firstly,the heat and mass exchange model of the open heat source tower is established in winter.The traditional assumption that the Lewis number is 1 is abandoned in the model.Discrete equations are established by the method of region discretization,and numerical solutions are made by using MATLAB programming software.Using this program,the effects of imported humid air temperature,imported humid air moisture content and imported solution temperature on the heat transfer performance of the open heat source tower were analyzed.Secondly,based on the energy efficiency model of heat pump unit and the open heat source tower winter heat and mass exchange model,the heating energy efficiency coupling model of the open heat source tower heat pump system is established,which can calculate the hourly energy efficiency and the hourly energy consumption.Taking an office building in Guiyang City as the research object,the heating performance of the heat source tower heat pump in winter was analyzed,and compared with the air source heat pump and gas boiler heating,the economy and energy saving performance were compared.Compared with the air source heat pump system,the heat source tower heat pump system saves operating costs by 5.78% and saves energy by 8.25%.Compared with gas boilers,it saves 37.61% of operating costs and saves energy by 26.51%,which has a high energy saving advantage.Thirdly,the heating energy efficiency coupling model of the heat source tower heat pump system was used to analyze the changes of solution temperature,heat exchange capacity,and condensed water volume in the heat source during the heating season,and a regeneration control strategy of the antifreeze solution was proposed.During the entire heating period,the lowest temperature of the solution in the heat source tower is-8°C and there is a risk of icing.In order to ensure the stable and safe operation of the system,a reverse osmosis solution regeneration device is used to regenerate the solution.When the temperature sensor detects the outdoor air temperature is lower than 13.7 °C,and the solution density sensor detects the solution density is less than 1120kg/m3,start the solution regeneration device;when the temperature sensor detects the outdoor air temperature is higher than 13.7 °C,the use of open type The heat source tower operates under partial conditions to achieve natural regeneration of the system solution concentration.Finally,taking into account the “peak-to-peak electricity price” policy of Guiyang City and the problem of low energy efficiency of heat source tower heat pumps operating at low or high temperatures,a method of auxiliary heating for phase-change heat storage tanks was proposed.Then,the optimization mathematical model with the lowest objective function is established,and the optimal control strategy is obtained by using MATLAB software.Compared with the conventional system,the thermal storage system has increased the initial investment of ?411376.4,the annual operating cost savings of ?201289 yuan,a decrease of 25.9%,and the investment recovery period is 2.04 years.The annual peak electricity transfer rate of the thermal storage system is 46.05%,which is 31.7% higher than that of the conventional system. |
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