Energy efficient strategies for reduced cross-contamination between occupants in office spaces -

Abstract

IAQ in indoor environments is one of the major concerns of public health organizations. People constitute one of the main sources of particles carrying contaminants in indoor environments by exhalation resulting from the different respiratory activities. The HVAC system should be effectively designed to reduce disease transmission between occupants at a minimal energy cost. This work aims towards investigating by modeling and experimentation the effectiveness of two localized air conditioning systems in decreasing the risk of cross-infection: displacement ventilation (DV) system assisted by chair fans (CF); and ceiling personalized ventilation (CPV) system equipped by desk fans (DF)- chair fans (CF). Computational fluid dynamics (CFD) and simplified numerical models are developed and validated experimentally and by literature data to simulate disease transmission in office spaces under different ventilation configurations. Simplified multi-zonal models incorporating the main physics affecting particle transport including particle deposition and gravitational effect were developed to assess the effectiveness of the standalone DV system in terms of providing good IAQ and to come-up with recommendations to enhance its performance. CFD models were used to simulate more complex situations when fans were equipped to the DV and the CPV systems. Optimization of the fans flow rate was conducted to increase the energy savings for both configurations and use the space more efficiently for the CPV system. Implementing fans with DV and CPV systems was shown to be very efficient in decreasing cross-contamination between occupants in office spaces with an acceptable comfort level and reduced energy cost.