| With the development of economy and the increasingly demanding of indoor environment by people, the air conditioning system of independent controlling of temperature and humidity is proposed. The system has secondary energy loss between refrigerant and water for small air conditioning system of independent controlling of temperature and humidity, which deduces the poor performance of the system. The dual-temperature air conditioner system is proposed in this paper, which utilizes direct expansion refrigerant heat exchangers form to overcome the shortcoming of secondary heat loss existing in the traditional air conditioning system of independent controlling of temperature and humidity. An office in Xi’an is selected to analyze. Some analysis is done to the dual-temperature air conditioner from the aspects of the processing of indoor air, the recycling state and the performance of the system under the refrigeration conditions., and some contrast has been made with the theoretical performance of conventional refrigeration cycle air conditioner with fresh air, which proves that its theoretical refrigeration cycle coefficient could be increased by 16% to 7.54.When number of the indoor people increasing from 4 to 8, the refrigeration coefficient of the dual-temperature air-conditioner would reduce, which still be higher 5.21% than the conventional air-conditioner. For another side,the conculsion that dual-temperature air-conditioner is more energy efficient than conventional air-conditioner is verified from the point of exergy.Secondly, the choosing of main components of radiation equipment is very important for that the end of the radiation device is the mainly used to handling the room temperature. After comparing the conventional end processing temperature of the device, the metal radiation plate is used to processing the temperature and the basis device of the metal radiation plate is determined. The aluminum material is used to be the metal radiation plate and brass is used to be the metal pipe. The heat transfer model from the pipe to the indoor is built and the correlation between the refrigeration in the pipe and the pressure dropping is also identified. The degree of deviation between the heating correlation and the pressure dropping correlation is verified by experiment. Matlab software is also used in this paper. The average temperature, pressure dropping and heating coefficient and so on are used as the parameters in the Matlab to choose the optimal value of radiation panel tube spacing, radiant panel degrees, evaporation temperature and flow number. And the result shows that the refrigeration flow is 18.200 g/s under the condition that the diameter of the metal brass is 5mm and the wall thickness is 0.2mm; The refrigerant evaporation temperature had better be low for the case of condensation happening on the radiation panel; The recommended value of the radiation plate thickness is 3-5mm; the recommended value of tube spacing is 20mm; the flow number is 10.Ejector is another important component to dual-temperature air-conditioner, and it has many advantages such as simple structure, stable, no rotating equipment and widely using and so on. The working principle is described in this paper. and the size of ejector nozzle,the outlet of ejector, the inlet of the mixture room, the mixture room and the diffuser segment on the condition of using the Classical thermodynamics and experience coefficient method.The numerical simulation method is used in this paper. The CFD software in this paper is used to simulate the distribution of indoor temperature in order to verify the indoor environment effect when the dual-temperature air-conditioner is in the design conditions. The result shows that using the air supplying way of sending back down with the radiation metal would control the indoor temperature better. |
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