20 September 2011


Due to worldwide demand for energy saving, many new technologies have been developed in the air conditioning field. VRF (Variable Refrigerant Flow) system is a recently dveloped air conditioning system that has some indoor units. This system has advantage
for space and cost saving. In recent year, we have to improve the annual performance of this system. In the annual performance, intermittent driving and defrost operation have to be
considered. The study based on experiment has limitations to grasp the system performance well because there are many driving and control patterns. Therefore, theoretical approach with unsteady state simulation is required. However, there are few reports concerning the simulation for VRF systems. In this study, we constructed unsteady state simulation model
and carried out unsteady simulation for VRF system. Moreover, we verified its validity by comparing the simulation results with the experimental ones using the actual system. As a result, we made sure that the constructed simulation model could predict actual behavior of systems.