Thermal comfort, perceived air quality, and cognitive performance when personally controlled air movement is used by tropically acclimatized persons

Abstract

TitleThermal comfort, perceived air quality and cognitive performance when personally controlled air movement is used by tropically acclimatized persons AbstractIn a warm and humid climate, increasing the temperature setpoint offers considerable energy benefits with low first costs. Elevated air movement generated by a personally controlled fan can compensate for the negative effects caused by an increased temperature setpoint. Fifty-six tropically acclimatized persons in common Singaporean office attire (0.7 clo) were exposed for 90 minutes to each of five conditions: 23, 26, and 29 °C and in the latter two cases with and without occupant controlled air movement. Relative humidity was maintained at 60%. We tested thermal comfort, perceived air quality, sick building syndrome symptoms and cognitive performance. We found that thermal comfort, perceived air quality, and sick building syndrome symptoms are equal or better at 26 °C and 29 °C than at the common setpoint of 23°C if a personally controlled fan is available for use. The best cognitive performance (as indicated by task speed) was obtained at 26 °C; at 29 °C, the availability of an occupantcontrolled fan partially mitigated the negative effect of the elevated temperature. The typical Singaporean indoor air temperature setpoint of 23 °C yielded the lowest cognitive performance. An elevated setpoint in air-conditioned buildings augmented with personally controlled fans might yield benefits for reduced energy use and improved indoor environmental quality in tropical climates.Keywords Thermal comfort; Perceived air quality; Sick building syndrome; Cognitive performance; Air movement; Tropically acclimatized person Practical ImplicationsIncreasing the indoor temperature setpoint to values in the range 26-29 °C (79-84 °F) and simultaneously providing occupants with personally controlled fans could be a cost-effective, sustainable and energy-efficient option for providing thermal comfort in new and existing buildings in the tropics. We show that this strategy can be implemented without negative influence on the well-being of occupants, and with almost 100% thermal comfort satisfaction. Cognitive tests showed the lowest performance at 23 °C and the highest at 26 °C.

Building and indoor environmental quality assessment of Nigerian primary schools: A pilot study

“…All classrooms had indoor temperatures above the maximum 23°C thermal comfort set point suggested by Andersen and Gyntelberg and between 20°C and 22°C suggested by Salthammer et al for classrooms. This is against the set point of between 26°C and 29°C suggested by Schiavon et al for improved performance, whereas according to Lu et al, an indoor temperature of about 31°C is still acceptable for a naturally ventilated room. While the study by Schiavon et al was done in an academic setting that of Lu et al was not.…”

“…This is against the set point of between 26°C and 29°C suggested by Schiavon et al for improved performance, whereas according to Lu et al, an indoor temperature of about 31°C is still acceptable for a naturally ventilated room. While the study by Schiavon et al was done in an academic setting that of Lu et al was not. The highest overall comfort for students was still achieved at 23°C without fans and 26°C–29°C with fans .…”

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“…However, not all individuals will have the same leverage or will give the same importance to controllable variables inside a building, since expectations, culture, religion, education, and experience tend to mediate our comfort perception [44,45].…”

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“…Assuming that the dry-bulb air temperature ( ) is the same as the mean radiant temperature ( ̅ ), we consider three operative temperature ( ) categories: 26°C, 27.5°C and 29°C (79°F, 82°F and 84°F). Based on the work of Schiavon et al (2016), it is expected that in tropical climate for office work conditions, 29°C is the upper acceptable limit.…”