JAUE2018-027 A Study on Fungus Removal Rate and Cleaning Frequency in Geothermal Ventilation System

Abstract

Recently, Zero Energy Building (ZEB) and Zero Energy House (ZEH) are attracting attention. In order to reduce the energy consumption of buildings, not only high insulation and airtightness but also utilization of regenerative energy and high efficiency of mechanical system are required. Furthermore, the use of renewable energy is required. In particular, geothermal energy with less temperature change throughout the year is drawing attention. On the other hand, the geothermal ventilation system is concern that pollutants from the 
outside air adhere to the inner surface of the pipe and settle down to the bottom of it. In this study, we measured the fungi concentration of air in the geothermal ventilation system, and predicted the fungus removal rate from the geothermal pipe and the cleaning frequency on it. As a result, the fungus removal rate by the geothermal ventilation system was 12% to 30%. However, after 3 days from the beginning of the measurement, the fungus concentration in the air increased after passing through the geothermal ventilation system from outside air. We propose to clean the geothermal pipe within 72 hours in order to supply fresh air lower than the fungal concentration from the outside into the room.