| Variable Refrigerant Flow(VRF) air conditioning system has been more and more popular nowadays due to the energy saving and other significant advantages. However, the only drawback is that the VRF system doesn’t induce outside air into the air conditioned zones. With the development and popularization of the air-conditioning system, people have paid more and more attention to the above problem. This paper developed a VRF and VAV combining system to solve the problem. Based on the TRNSYS platform and related experimental rig, several simulation and experimental tests have been carried out in order to research some optimal control strategy.Since the core of the simulation platform is the variable refrigerant flow system, an economical and practical experimental rig called 1V2 VRF system has been developed. Several tests have been carried out on the experimental rig for the purpose of verifying the stable and dynamic characteristics of the simulation platform. The tests results come to be satisfied.Further optimal control study of the VRF and VAV combining system has been developed. Firstly, based on the combining system, tests under the variable outlet air conditions and indoor humidity loads have been conducted. Results show that the combining system has the potential to meet the temperature and humidity independently control request if the humidity control of the fresh air system can be guaranteed. To further study the humidity control of the direct expansion system, several simulation tests have been carried out to investigate the correlations between the compressor rotating speed and EEV openness. Several fitting formulas and regular patterns have been got which is beneficial to the design of the humidity control simulator. Meanwhile, several experimental tests based on the above regular patterns have been carried out. All of the simulation and experimental tests have laid solid foundation of the more widely application of the VRF and VAV combining system. |
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