Study Of Heat Pipe Heat Exchanger Applied In Air-conditioning System

As a kind of high efficiency heat exchangers, the heat pipe heat exchanger has many merits, and can be used in some special occasions such as hospital and swimming gymnasium, where the cross infection must be prevented, so it has a bright prospect for application. However, application of the heat pipe heat exchanger applied in the air-conditioning system just begins, and there are still many flaws about it which need to be improved. In this paper, simulation calculations and optimum designs for this heat exchanger were chiefly discussed.After analyzing the characteristics of energy recovery in air-conditioning system, the author adopted an ammonia-aluminum inclined gravity heat pipe heat exchanger as the structure of the heat pipe heat exchanger applied in air-conditioning system. The evaporation section and the condensation section of the heat pipes can be changed as the temperature of the outdoor air varies, so the heat exchanger can be operated through the whole year.On the basis of theoretical analysis and documents home and aboard, the author took a method of simulation calculation for this heat exchanger and accomplished it by using a discrete calculation model, transfer units ( e -NTU) method and iteration. The reliability of the method was verified by testing a heat exchanger composed of ammonia-aluminum heat pipes. The relative errors between the test results with the analytical results were below 17%.The author established an optimum design model that regarded the maximum of annual net profit for the equipment as the object function for this heat exchanger, and solved the model by employing the exhaustion method and SUMT method. To accelerate the solution, the relations among design variables and the influence of each design variable on heat transfer and pressure drop of the fluid were analyzed in this paper.As the conclusion, an integrated design program for the heat pipe heat exchanger applied in air-conditioning system was established, which improved the design method and reduced the cost of the equipment. The study of simulation optimization would promote the popularization of this heat exchanger and facilitate the heat exchanger design for engineers and technicians.