Deaeration Of The Low-Temperature Radiant Cooling Air-Conditioning Water System: Experimental Research And Simulation

In recent years, rapid growth of economy in China has led to the significant increase of energy consumption particularly in building sector such as air conditioning systems. The reduction of energy consumed by air conditioning systems is therefore important and necessary. In addition, traditional air-conditioning system is unable to provide people with comfortable indoor environment. In this case, research on"energy-saving, healthy, and comfortable"air conditioning systems is being paid increasing attention. Low-temperature Hydronic Radiant Cooling Air conditioning Systems (LHRCASs) is one of such system and is therefore the focus of this work.The LHRCASs is characterized by the complex structure, long-distance pipeline, and most of the systems are horizontal arrangement with low velocity of water flow. Under this condition, it is very sensitivity to dissolved gas and the function of traditional exhaust valve is subject to limitation. This paper is aiming at developing a new deaeration system which should be of convenient use, easy operation, and high efficience. According to Henry's law, the dissolved gas in the water is released when water undergoes low press or vacuum conditions. The deaerated water is unsaturated and has very strong absorbency either to dissolved gas or to non-dissolved gas (free gas).This thesis analysed, in the physical nature, the dynamic process of deaeration system, and afterwards built a rational reduced model. Using Simulink software package of MATLAB, simulation was carried out and based on the simulation results the effect of operating variables on system pressure and deaerated capability was analysed.An experimental system of deaeration system was established in order to validate the simulation results. A series of experimental testing was subsequently made, including the influence of incoming water height,vacuum degree and flux. Experimental results were compared with theoretical model results, showing a good accordance. Based on those results, the optimized operating condition was determined. Results of this paper have a very positive influence on improving LHRCASs in particular in terms of energy performance and reliability of long-duration operation.