Sensor location methodology for improved IEQ monitoring in working environments

In the current era, sensors in buildings have become an essential requirement for wide applications such as monitoring indoor air quality (IAQ), thermal and environmental conditions, controlling building heating, ventilation, and air-conditioning systems (HVAC). To accurately control the IAQ for all areas in the indoor space, it is necessary to obtain considerable data from different locations in the space for more precision. The airflow in a room is not uniform, which raises the question of where the environmental sensor should be positioned with regard to optimum performance of IAQ and thermal comfort. This paper uses a case study of an open-plan office in Loughborough, UK, to assess the indoor climate conditions from real-time measurements from several sensors placed in different locations in the office and investigates the potency of using ventilation effectiveness (Ez), one of the IAQ relative indicators, as a preference to locate environmental sensors. The air parameters measured by the sensors are indoor temperature (ta), relative humidity (RH), carbon dioxide (CO2), total volatile organic compounds (tVOCs), formaldehyde (CH2O) and particulate matter (PM2.5 and PM10). Computational fluid dynamics (CFD) simulations were conducted to identify the areas in the office with low Ez evaluated using the age-of-air. Results showed that the measurement of RH and CO2 levels were marginally different between the sensors. A larger difference was found for temperature, assuming local heat sources significantly influenced the measured temperatures. Also, the calculated Ez from the measured data of each sensor was found to be different for each sensor location. The results from field measurements and CFD simulations can support decision making regarding the position of environmental sensors and the collection of indoor climate data in open-plan offices.