Using personally controlled air movement to improve comfort after simulated summer commute

Abstract

People often feel uncomfortably warm and sweaty in their workspace after commuting there by walking or cycling in summer. This is because body heat stored during the commute takes a substantial time to dissipate. People complaining about this uncomfortable transition may cause operators to lower the thermostat setpoint, causing long-term overcooling and wasting energy. In addition, space cooling is slow, requiring minutes to take effect. This study addresses how to improve comfort in the transition by increasing the availability of convective cooling, where the response time is in seconds. Thirty-five subjects (17 men and 18 women) dressed in 0.6 clo entered a test room after exercising at 4.4 met for 15 min in 30 ºC. The exercise emulates the commute activity in summer. The test room was controlled to 24, 26, and 28 ºC, with and without the option of cooling using fan-produced horizontal airflow. Subjects were sedentary for 60 minutes, during which subjective thermal responses and physiological responses were measured. The enhanced convective and evaporative heat loss caused by fans significantly shortened the time needed to reach thermal comfort after the exerciseinduced thermal stress and improved the final comfort level. Compared to a typical indoor condition of 24 ºC and still air, 26 and 28 ºC with fans provided equal or better comfort more quickly, and inherently required much less energy to do so. Our study suggests that personally controlled air movement should be available in spaces where thermal and metabolic down-steps take place.

Ceiling-fan-integrated air conditioning: Airflow and temperature characteristics of a sidewall-supply jet interacting with a ceiling fan

“…It has also been found that a modest air speed significantly reduces a CO2 bubble that accumulates in a person's breathing zone under still air conditions in workstations [16]. Finally, higher air temperatures and air speeds have also recently been shown to be far more effective (compared to cooler temperatures and still-air) at restoring comfort to occupants who have just entered a space with elevated metabolic rate and stored body heat from walking [17,18]. Note that in each of these above cases the desirable air flows are isothermal, involving only the room air itself.…”

Test rooms to study human comfort in buildings: A review of controlled experiments and facilities

“…These rooms could be adjacent, but with independent entrances, or connected through an intermediate door. The latter configuration allows researchers to continuously monitor participants' reactions when exposed to different controlled environmental conditions [48]. Eight of the external facilities have just one room, but the possibility to work with movable internal partitions is mentioned for four of them [38,41,43,44].…”

Review of studies on thermal comfort in Indian residential buildings

“…However, the earlier versions of standards never permitted it without air control requirement of individual subject. This shows that there has been considerable understanding of occupant interaction with building attributes particularly used for ventilation effects (Aynsley, 2008(Aynsley, , 2005Cândido et al, 2010;Zhai et al, 2019;Kabanshi et al, 2019). Some recent studies (Wang et al, 2019;Zamani et al, 2019) have not used either of these approaches and used comfort simulation for producing climatic data useful in the development of thermal comfort model.…”