Evaluation of Natural Ventilation Potential for Indoor Thermal Comfort in a Low-Rise Building in Arid and Semi-arid Climates of India

Abstract

Natural ventilation potential (NVP) has been evaluated for two climate-specific Indian cities New Delhi and Jodhpur in terms of pressure difference Pascal hour (PDPH), under various indoor conditions. Indoor temperature, indoor heat gain, and natural ventilation rate because of both buoyancy and wind effect have been evaluated for a conceptualized low-rise building using an analytical model for NVP. Thermal comfort in these stations has been evaluated in terms of percentage of time the indoor temperature falls within the thermal comfort zone. Qualitative assessment of NVP has been carried out through the cumulative frequency curves for adequate pressure variation throughout the indoor and outdoor environment of the building. The thermal comfort assessment shows that New Delhi and Jodhpur have indoor thermal comfort for 40% of the time in a typical year. Thermal comfort is found to exist for 45–90% of the time during the months of July, August, and September, whereas least thermal comfort period of 20–40% is observed during winter months of December, January, and February and PDPH curves confirms the fact that natural ventilation alone does not provide indoor thermal comfort. To achieve thermal comfort in the building during the rest of the time, an active system or complex passive systems are required to be employed.