Grant: Discovery Grants Program - Individual

Ventilation systems, by their very nature of design, are a means to bring in outdoor air and trap and dilute contaminants such as particulates, microorganisms and chemicals, and exhaust them to the outdoor. These typical contaminants have been recognized explicitly in the ASHRAE ventilation standard, which requires that the ventilation rate specifications be based on the contribution from occupants as well as other indoor/outdoor sources, implying that an increased ventilation rate is needed. Increased ventilation rates and outdoor air supply rates can generally enhance indoor air quality (IAQ); however, they can also result in a large increase of global energy consumption. Air purification can provide a key strategy to improving IAQ while reducing outdoor air supply with concomitant energy savings. Air cleaning technologies such as adsorption and ultraviolet photo catalyst oxidation (UV-PCO) filters are commonly applied technologies in commercial air cleaners and there are some anecdotal reports showing their usefulness for such applications. These devices, if they work properly, can play a significant role in reducing building energy consumption, and removing chemical contaminants, hence improving the well-being of occupants and building energy efficiency. There are, however a number of parameters that their impact on the performance of these systems for such applications have not been thoroughly investigated (ambient temperature, high relative humidity, high air flow rate, mixture of contaminant, etc.). Moreover, incomplete oxidation of target pollutants could result in the formation of CO and some organic by-products (i.e. formaldehyde) that are more hazardous to building occupants than the target pollutants. The proposed research work aims to solve all of the above-mentioned problems so as to make the PCO technology to be a mature and reliable option applied in an HVAC system in a changing world. Our investigation will extend to the contaminants of emerging concern not limited to traditional air pollutants. As more air cleaning devices designed for the removal of gas-phase air pollutants enter the market, it would be essential to develop a procedure to evaluate their performance and develop design tools. The long-term objective of this research is to carry out comprehensive research to minimize/eliminate the by-product generation of air cleaning systems, to improve their removal efficiency and energy efficiency, to develop an efficient technique for their regeneration, to develop design tools, and to develop universal evaluation standards.