Human factors in differently ventilated office buildings

Abstract

Construction and operation of buildings are responsible for approximately 50% of global greenhouse gas emissions. Over 50% of the end-use energy in buildings are associated with heating, ventilation, air-conditioning (HVAC) and lighting. Building occupants’ tolerance of sensory stimuli is influenced by a variety of internal processors attributed to the feedback between occupants and their environment. Environment-oriented behavior related to ventilation system controls allows adaptation to indoor environment conditions. Available ventilation system controls, their performance, usability and effectiveness influences occupant’s perception of indoor environment quality (IEQ). Occupant interaction with the building systems has been linked to a sizable variation of end-use energy consumption. Hence, research on energy related occupant behavior is a promising course to set operational priorities and reduce the end-use energy demand in buildings. This research examines human factors related to design characteristics of three ventilation systems typically used in Sri Lankan office buildings. The ventilation systems are centralized air conditioning systems, decentralized air conditioning systems, and natural ventilation. The research design is a post-occupancy evaluation (POE). Nine office buildings and their 585 occupants were recruited in this research. Statistical evaluation of seventeen questionnaire items addressing the perception of IEQ reveals a significant difference in occupant’s evaluation of their indoor environments attributed to the ventilation system. The occupant’s perception of indoor air temperature, air freshness, overall lighting quality, noise, and furniture were the most significant IEQ factors which were related to the occupant’s effectiveness in this survey. Passive solar design positively influenced perceived control over indoor environment conditions and also improved occupant perception of the building’s overall comfort performance.