Energy simulation and analysis of the heat recovery variable refrigerant flow system in winter

Heat recovery variable refrigerant flow (HR-VRF) system can supply cooling and heating for the building simultaneously and make good use of the indoor cooling and heating capacity efficiently. This system has a good energy performance and can meet the emerging requirements of modern buildings. In order to evaluate the energy features of the system, a new energy simulation module is developed and embedded in the dynamic energy simulation program, EnergyPlus. Using the program with the newly developed module, the dynamic energy simulation is performed for a simplified typical commercial building. The indoor thermal comfort of the building in winter and the setting temperature of the system are analyzed. Based on the simulation results, the energy characteristics of the system are investigated, and it is indicated that different methods of the temperature control and the percentage of the heat recovery have influence on the relative ratio of the energy saving. If the HR-VRF system adopts the same temperature control method as the heat pump VRF (HP-VRF) system, the HR-VRF system promises 15–17% energy-saving potential, when compared to the HP-VRF system.