| Keywords |
Mechanical minimum ventilation rates; Airtightness; Modular building; HVAC energy usage; Indoor CO2 concentration |
| Abstract |
Educational buildings must secure the required ventilation rates for buildings (RVRB) to maintain indoor air quality. To achieve this, the ministry of education mandates the installation of mechanical ventilation systems. The RVRB is secured through natural ventilation and mechanical ventilation. Since natural ventilation rates is a fixed parameter for each buildings, the mechanical minimum ventilation rates (MMVR) must be adjusted to ensure RVRB. However, most MMVR are designed based on the reinforced concrete buildings with high airtightness. If it used in modular buildings with low airtightness, this can result in excessive ventilation.
This leads to increased indoor heating loads. Therefore, the mechanical ventilation systems of modular educational buildings need to use MMVR that consider airtightness. Accordingly, the purpose of this study was to determine the optimal MMVR. To achieve this, the study evaluated the indoor environment and HVAC energy usage by varying MMVR using EnergyPlus. Based on these findings, the optimal MMVR was identified as Case #5.
When using the determined MMVR in this study, HVAC energy usage was reduced by approximately 18.1%, without exceeding the recommended indoor CO2 concentration. This study highlights the need to MMVR that consider the airtightness of modular buildings to optimize HVAC energy usage. |