A Method for On-Going Commissioning of VRV Package Systems Using a Simulation Model

Abstract

Variable refrigerant volume (VRV) systems, which have several indoor units and a single outdoor unit, have become very popular HVAC systems in Japan. However, some systems may be operated under inefficient conditions and consume excessive energy, since verification of system performance is not conducted. Although the performance of systems should be evaluated by some indices such as coefficient of performance (COP), calculating such a value is difficult, because the heat load handled by machines is not known. A simulation model based on a refrigeration cycle was proposed to evaluate system performance. Basic conditions for evaporation and condensation were defined from conditions provided in Japanese Industrial Standards (JIS). Flow rate of refrigerant was calculated from heat load under full occupancy and enthalpy difference of the evaporator. If power consumption exceeds the calculated value, malfunctions or inadequate conditions are considered to occur. The method presented here can be used for on-going commissioning of VRV package systems.