Theoretical Study Of The Evaporative Cooling Combined Air-conditioning System

Air conditioner, as the bridge which connects clients and outdoor environment, can regulate the indoor temperature, humidity and cleanliness. It has developed rapidly in recent years.In this thesis, a study of the energy consumption ratio and the present developing status of the air conditioner in computer room air-conditioning system and common room air conditioners was conducted. Afterwards, considering the service object of temperature and humidity, an evaporative cooling air conditioning system combining vapor compression refrigeration technology, separate type heat pipe technology, evaporative cooling technology was proposed, which was based on the summary of the existing energy-saving technology of the above two kinds of air conditioner(Hereinafter referred to as combined air-conditioning system).The thesis carried out a research on the evaporative cooling air-conditioning system. This research encompassed several major topics:First of all, a system was constructed, which compared with traditional computer room air-conditioning system, to analyze the energy-saving efficiency of the combined evaporative cooling air-conditioning system qualitatively. Because of the high requirement of the computer room air-conditioning system on the indoor temperature, humidity and cleanliness, the design guidelines of computer room air conditioner were chosen as the design criteria. Based on the most disadvantageous heat pipe condition, designing calculations were made for main components of the combined air-conditioning system. To ensure that the combined air-conditioning system could simultaneously satisfy every cooling mode, the design parameters were checked under the vapor compression cooling conditions. Thus the combined air-conditioning system could play the best performance in all the three cooling modes, and could guarantee the high operating reliability and energy-saving efficiency of the combined air-conditioning system.Secondly, the mathematical models for the main components of the combined air-conditioning system were established. In order to study the state changes of internal refrigerant in the two machines (air cooling evaporator and evaporative condenser), the steady state distribution parameter models for the two machines were built and solved by discrete method. For the scroll compressor and the thermal expansion valve, the lumped parameter models were established and solved using discrete method.Thirdly, based on the mathematical models of the components of the combined air-conditioning system, the complete mathematical models for every model of the combined air-conditioning system were respectively established and solved. An annual dynamic mathematical model was built and solved for the combined air-conditioning system. Taking Shenyang area as an example, an analog simulation was carried out. Comparing with the conventional air conditioning system, the thesis was to analysis energy-efficient of the complex air conditioning system.Finally, analog simulations for annual dynamical operating functions of the combined air-conditioning system in several typical climatic conditions (e.g. Shenyang, Beijing, Changsha, Guangzhou, Kunming) in China were carried out. Then on this basis, the conventional air-conditioning system was analyzed to investigate the applicability of combined air-conditioning system in different regions.This thesis proposed the evaporative cooling air-conditioning system, took fully account of characteristics of the indoor load and the outdoor cold source, and made full use of the natural cold source on the foundation of reliable operation. By the qualitatively analysis and the results of the analog simulations, it was shown that the composite air conditioning system not only could guarantee the reliability of cooling, but also had economic and energy saving benefit.