Development of an indoor environment evaluation model for heating, ventilation and air-conditioning control system of office buildings in subtropical region considering indoor health and thermal comfort

Office occupants spend most of their time in an enclosed indoor environment, controlled by heating, ventilation and air-conditioning (HVAC) systems especially in subtropical regions owing to the hot and humid climate. A reasonable indoor environment evaluation model is necessary to achieve the reliable control of HVAC systems that satisfies the occupants' health and comfort needs. However, traditional HVAC systems are controlled based on a simple index that does not consider the synthesis of indoor air quality, thermal comfort and occupant preferences. In this paper, we develop a comprehensive evaluation model that encompasses these three aspects based on field survey. Field surveys were conducted to investigate indoor environmental conditions and preferences of the occupants. Collected data were then verified for model hypothesis rationality and reviewed to identify weighting factors using Pearson and regression analysis. Results showed that these parameters had significant correlations without noticeable collinearity and can be integrated using regression method. The weighting factors of each parameter were calculated using occupants' sensation and expectation to reflect the subjective preferences in model. Finally, an evaluation model expressing the indoor thermal, air quality and occupant preferences was developed to provide an HVAC intelligent control system that is more responsive to occupant needs.