Effect of Indoor Environment on Occupant Air Comfort and Productivity in Office Buildings: A Response Surface Analysis Approach

Indoor air quality is a significant factor influencing occupant comfort, health and productivity. Indoor air comfort and its relationship to occupant comfort and productivity are widely documented. Statistical correlation between the two has been highlighted in scientific literature. This paper investigates any unique correlations between non-air quality parameters (such as lux level, temperature, and noise level) and indoor air comfort and presents a study investigating the effect of indoor environmental quality on occupant air comfort and productivity. This study was conducted by collecting data on indoor environmental parameters using remote sensors and an online survey for occupant responses for twelve months. Data analysis was performed using Response Surface Analysis to present mathematical relationships between indoor environmental quality parameters and occupant air comfort. Results show that carbon dioxide up to 600 ppm, VOC up to 25 (by volume) and humidity up to 60 have a positive impact on occupant air comfort and productivity. Our research highlighted that some non-air quality parameters, such as outdoor temperature and lux levels, affect occupant air comfort. These results would enable built environment professionals to design and operate offices (subtropical desert climate) conducive to occupant comfort and productivity

Post occupancy evaluation to assess multifamily residential building energy performance in India

Post-Occupancy Evaluation (POE) is defined as the process of systematically comparing a building's actual performance measures with explicitly stated performance criteria. POE is widely recognised as being central to addressing the performance gap between design intentions and the actual outcomes of an occupied building. This performance gap is often arising from miscommunication and over-prediction of the building's performance targets in the design stage. This gap also arises due to incorrect methods, tools, and input data for modelling and simulation. Conventionally, the evaluation of housing performance consisted of either physical monitoring or user satisfaction surveys, except that these two do not provide a comprehensive picture. POE is a systematic process for collecting and analyzing occupant feedback. Past research has highlighted occupant's behaviour as a major issue i.e. how occupants operate equipment and how they adjust to the internal conditions that may vary from design assumptions. The primary goal of this research is to evaluate the application of POE to assess an Indian Green Building Council's (IGBC) Green Homes Certified multifamily residential building in India. The building is in the city of Jaipur, a composite climate zone, and its performance gap was assessed one-year post-occupancy. The methodology comprised of performing energy simulation of three cases on eQuest: a Base-case model based on IGBC Green Homes base-case parameters, as-constructed case based on Green Homes Certification parameters, and as-occupied case based on POE data analysis. The annual energy consumption from the simulation of the three cases is compared to measure the performance gap. The findings indicate a very interesting departure from the general observation of the majority of literature which states a negative 'performance gap' or overutilization between base-case, and as-constructed and as-occupied buildings. In this study, a positive performance gap emerges, i.e. the as-occupied building performs better than the as-constructed. The positive performance gap mainly emerges due to variations in occupancy numbers, and occupancy schedules, equipment usage, equipment power density (EPD), and artificial lighting usage and schedules. These indicate a certain change in urban lifestyles. The concept of positive performance gap is an unexplored area of research in residential sector which indicates the significance of occupant feedback. This study provides a basis to further analyze post-occupancy behavioural studies to understand this positive performance gap