Practical Strategies for Achieving IAQ in Green Buildings and High Performance Buildings

Different ventilation strategies can have an enormous impact on both exposures to contaminants of concern (COCs) and energy use in commercial buildings. To test various strategies, we implemented two pollutant exposure control strategies in several commercial buildings in the US and the Middle East. Buildings type covered include wellness center/gym, university, office building, and a bank. The first control strategy was the conventional ventilation strategy (conventional mode). The outside air dampers were open according to the design conditions all the time. The second strategy consisted of using air cleaning along with ventilation (air cleaning mode). In each of the buildings tested, we installed a module composed of innovative sorbent materials that can efficiently remove gaseous contaminants of concern. The sorbents employed self-regenerating capabilities. The module is equipped with smart software and set of sensors that actively and automatically manage HVAC load and indoor air quality. The outside damper was set to a minimum position (minimum outdoor air is set to maintain a positive pressure in the building) unless outdoor conditions were favorable (economizer mode). In order to compare energy usage and indoor air quality, we operated the building alternatively in conventional mode and air cleaning mode. For each, we measured electrical and/or thermal energy by installing an energy meter on the air handling units. Also, for each period, we tested speciated VOCs, aldehydes, CO₂, and PM_2.5. The outcomes of these tests showed that using the air cleaning mode - employing a pollutant exposure strategy with air cleaning and minimum ventilation coupled with smart controls - realized double digit energy savings (20-40%) compared to conventional modes, while at the same time maintained or improved the air quality in the space. Formaldehyde is one of the key contaminants that was identified as a COC. Formaldehyde was successfully maintained below 33 ug/m³. For the pollutants measured, we calculated emission rates and gave examples of using time-averaged mass balance equations to show compliance with ASHRAE Standard 62.1 Indoor Air Quality Procedure (IAQP). Field measurements in this study, which compared conventional and air cleaning modes, demonstrated that efficient air cleaning is a superior option delivering both IAQ and energy savings.