The ventilation rate is an essential parameter that affects the indoor air quality and energy consumption of buildings. Inadequate ventilation is a common problem in existing buildings that may affect the health and productivity of occupants. Furthermore, occupants of under-ventilated buildings are largely unaware of the problem. Current tools and methods for commissioning and measuring building ventilation rates are not a cost-effective way to identify problem areas in existing building ventilation systems because they are time and labor intensive. Thus, it can be challenging to effectively prioritize areas that require more intensive testing or recommissioning.

The UC Davis Western Cooling Efficiency Center, with funding from the Office of Naval Research, is developing a high accuracy, low cost ventilation verification tool that measures the carbon dioxide decay rate building-wide on a per-zone level and automatically calculates the current air exchange rate. The tool has been tested in a multi-zone office building and the results were within 5% of tests performed using traditional testing and balancing methods.

In addition to directly measuring the building air exchange rate per zone, this tool will enable building managers or occupants to quickly identify problem areas in existing buildings or verify measurements performed by testing and balancing professionals. These additional benefits could provide building managers and occupants with more quantitative data to support efforts to reduce the risk of airborne transmission of COVID-19 in buildings.

Lesson Objectives:

• People are not good indoor air quality sensors
• Operating principle for various air measurement tools
• How carbon dioxide decay can be used to measure the zone air exchange rate
• How carbon dioxide decay can be used to measure the zone air exchange rate