Thermal Characteristics Study Of Water-source Multi-connected Air-conditioning System

Along with the rapid development of social economy, people have higher and higherdemands for living environment, and their awareness for energy saving and environmentprotection is increasing at the same time. Water-source multi-connected air-conditioningsystem has been more and more widely used for it conbines the advantages ofmulti-connected air-conditioning system and renewable sources. Howerver, thetechnologies of water-source multi-connected air-conditioning system are mature in Japan,but the study for this system started late in China, little information is available onwater-source multi-connected air-conditioning system’s thermal properties. From thispoint, a water-source multi-connected air-conditioning system simulation platform is built,and it has been used to simulate the system’s full-year operating characteristics and toanalyses the system’s thermal characteristics.Firstly, the main parameters of the refrigerant, water and air used in the system wasprogrammed. Secondly the types of the major parts required by the system such ascompressor, expansion valves, heat exchangers etc. was reasonablely choosed, and thephysical models of these parts was created. Then the calculation process for each modelwas designed and descriped. In this paper, a new control stratage was presented, that is therefrigerant flow rate was controled by compressor frequency while thesupercooling/superheating degree of outdoor unit was controled by circulating water flowrate. After the conponents of indoor units and outdoor units was built, a water-sourcemulti-connected air-conditioning system simulation platform was built. By using thissimulation platform, the system’s full-year operating characteristics were simulated andanalyzed. The simulation results showed that in summer the water-source multi-connectedair-conditioning system has a higher efficiency with40%-70%loads, and the maximumEfficiency appeared with60%loads; in winter the system’s maximum Efficiency appearedwith50%-60%loads. This system’s customized heat capacity was bigger its customizedcooling capacity, and when the load rate was certain, the system’s heating efficiency wasalways higher than its cooling efficiency. The system’s average coefficient of performance was high both in summer and winter, and the full-year average coefficient of performanceis high, so it can be seen that the energy-saving effect of this system was good.