Energy consumption analysis intended for real office space with energy recovery ventilator by integrating BES and CFD approaches

This study aims to analyze the energy conservation performance of real office space with an energy recovery ventilator (ERV) and to investigate the effect of the arrangement of air supply and exhaust openings. Three types of ventilation systems were chosen for the analysis of coupling computational fluid dynamics (CFD) program with building energy simulation (BES) software. The adoption of mutually complementary boundary conditions for CFD and BES provides more accurate and complete information of air flow distribution and thermal performance in office space. Field measurement was also carried out in a typical office space situated in the middle story of a building to validate the numerical results by measurement data. The office space chosen for this analysis was equipped with air-conditioners on the ceiling with intake of fresh air directly via a heat recovery ventilation system. Its thermal performance and indoor air flow distribution predicted by the coupled method were compared under three types of ventilation system. When the supply and exhaust openings for ERV were arranged on the ceiling, there were no critical differences between the predictions of the CFD–BES coupled method and BES alone on the energy consumption of the HVAC system. On the other hand, discrepancy between the results simulated by the CFD–BES coupled method and BES alone could be clearly found in the case of under-floor-type ventilation system. The discrepancy emphasizes the effectiveness and impact of integrating CFD and BES approaches when non-uniform temperature distribution, that is, thermal stratification, is formed in space.