Measurement of the evaporative cooling effect: Oscillating misting fan

Farnham, C; Zhang, L; Yuan, J; Emura, K; Alam, A M and Mizuno, T (2017) Measurement of the evaporative cooling effect: Oscillating misting fan. Building Research & Information, 45(7), pp. 783-799. ISSN 0961-3218

Abstract

To determine the thermal effects of an oscillating mist fan (spraying 86L/h of droplets with 25 mu m mean diameter) on worker comfort, its effects on the thermal environment were measured in a large indoor space (37,500m(2)/525,000m(3)). It was found that the temperature dropped by 0.2-2.5K, with local humidity increasing by 5%. Ventilation air-exchange calculations indicate that in hot summer conditions, an 8-h shift could be continuously cooled without creating high humidity, recovering to initial values after 16 h of ventilation at 0.3 ach. The cooling effect of the mist and fan was measured and compared with that of the fan. The mist and fan-cooling effect exceeded 100W/m(2) in all cases, while the mist and fan cooling exceeded the fan alone by 18W/m(2) on average, 24W/m(2) at the peak values and 11W/m(2) average during oscillation. The ASHRAE 55-2013 model is modified to include this additional cooling. Standard effective temperatures (SETs) are calculated with and without the mist fan-cooling effect. Linear approximations for reduction in SET were developed as a function of air temperature and mist-cooling effect. The deployment of this technology would improve thermal comfort for factory workers on hot summer days.;To determine the thermal effects of an oscillating mist fan (spraying 86 L/h of droplets with 25 µm mean diameter) on worker comfort, its effects on the thermal environment were measured in a large indoor space (37,500 m2/525,000 m3). It was found that the temperature dropped by 0.2-2.5 K, with local humidity increasing by 5%. Ventilation air-exchange calculations indicate that in hot summer conditions, an 8-h shift could be continuously cooled without creating high humidity, recovering to initial values after 16 h of ventilation at 0.3 ach. The cooling effect of the mist and fan was measured and compared with that of the fan. The mist and fan-cooling effect exceeded 100 W/m2 in all cases, while the mist and fan cooling exceeded the fan alone by 18 W/m2 on average, 24 W/m2 at the peak values and 11 W/m2 average during oscillation. The ASHRAE 55-2013 model is modified to include this additional cooling. Standard effective temperatures (SETs) are calculated with and without the mist fan-cooling effect. Linear approximations for reduction in SET were developed as a function of air temperature and mist-cooling effect. The deployment of this technology would improve thermal comfort for factory workers on hot summer days.;To determine the thermal effects of an oscillating mist fan (spraying 86 L/h of droplets with 25 µm mean diameter) on worker comfort, its effects on the thermal environment were measured in a large indoor space (37,500 m 2 /525,000 m 3 ). It was found that the temperature dropped by 0.2-2.5 K, with local humidity increasing by 5%. Ventilation air-exchange calculations indicate that in hot summer conditions, an 8-h shift could be continuously cooled without creating high humidity, recovering to initial values after 16 h of ventilation at 0.3 ach. The cooling effect of the mist and fan was measured and compared with that of the fan. The mist and fan-cooling effect exceeded 100 W/m 2 in all cases, while the mist and fan cooling exceeded the fan alone by 18 W/m 2 on average, 24 W/m 2 at the peak values and 11 W/m 2 average during oscillation. The ASHRAE 55-2013 model is modified to include this additional cooling. Standard effective temperatures (SETs) are calculated with and without the mist fan-cooling effect. Linear approximations for reduction in SET were developed as a function of air temperature and mist-cooling effect. The deployment of this technology would improve thermal comfort for factory workers on hot summer days.;

Item Type: Article
Uncontrolled Keywords: alternative technology; cooling; heat flux; thermal comfort; evaporative; mist; evaporation cooling; system; construction & building technology; climate; spraying; indoor environments; cooling effects; summer; evaporative cooling; temperature effects; workers; air temperature; humidity; ventilation; acetylcholine
Index terms: summer, humidity, evaporative cooling, temperature effect, spraying, indoor environment, thermal comfort, building technology, standard effective temperature, thermal effect, comfort, mist, evaporation cooling, thermal environment, ventilation, air temperature, alternative technology
Subjects: climate science, engineering systems, environmental engineering, energy systems, building construction, factor and component analysis, thermal systems, environmental science, air quality, occupational health and safety management
Topics: Design Practice, Engineering Principles, Sustainability, Health and Safety
Descriptive scope: 2 PC

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