Use of personalized ventilation for improving health, comfort, and performance at high room temperature and humidity

Melikov, Arsen Krikor; Skwarczyński, M.; Kaczmarczyk, Jan; Zabecky, J.

doi:10.1111/ina.12012

Cited by 96 publications

(46 citation statements)

References 22 publications

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“…Willem (2006) (19) examined the effect of temperature reduction on stress. According to the results of this study, the de- (22) research increased the sAA, which was consistent with the present study. Lan et al's (2011) study investigated increase of 8°C in temperature (from 22°C to 30°C) on stress, which led to no change in sAA, and was not consistent with the present study.…”

Section: Discussionsupporting

confidence: 92%

The Effect of Thermal Comfort on Stress in Female High School Students

Najafi¹,

Movahed²,

Barzegar³

et al. 2018

Int J School Health

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Background: Indoor environment, in which we are located, influences our psychological responses, like stress. Thermal comfort is one of the most important factors determining the quality of indoor environment, obtained by calculating predicted mean vote (PMV) and predicted percentage of dissatisfaction (PPD) in a steady-state approach. Several studies revealed that hot or cold temperature (°C) could increase stress. However, other climatic thermal comfort factors like relative humidity (%) and air velocity (m/s) have not been well researched in this regard. Objectives: The purpose of this study was to investigate the immediate effects of undesirable thermal comfort on stress by measuring salivary alpha-amylase levels (sAA) in female high school students. Methods: The present study was conducted in a semi-experimental design with pre-test and post-test and control group. The sample size was 390 female high school students, who were selected by multi-stage cluster random sampling, during years 2016 and 2017, in Shiraz, Iran. Students were divided to intervention and control groups. In the intervention group, thermal comfort was interfered by changing temperature, relative humidity, and air velocity for two hours. Saliva was collected by Cocorometer's strip and sAA was measured by a hand-held device, Cocorometer (Nipro Co, Osaka, Japan). The pre-test and post-test were compared with each other. Thermal comfort in classrooms was measured by a steady-state model, PMV/PPD index, and data was analyzed by Analysis of Covariance (ANCOVA). Results: Interfering in temperatures and humidity at an average of 4.8°C and 36% for two hours in the intervention group caused thermal comfort to be in an unfavorable range (PMV > +0.5) and dissatisfaction was more than desirable (PPD > 10%). In the intervention group, when the intervention took place at the temperature, relative humidity, air velocity, and the synchronous effect of these three variables (TRHAV), the mean sAA was 43.57, 42.74, 44.23, and 45.93 (KU/L) in the pre-test and 55. 91, 52.35, 44.89 and 61.99 (KU/L) in the post-test. Also, in the control group, the mean sAA was 44.73, 47.03, 43.38, 47.19, 43.83, and 43.77 (KU/L) in the post-test. The sAA was significantly increased in the intervention group when thermal comfort and its climatic variables, including temperature (P < 0.001) and relative humidity (P < 0.001), was undesirable. No Significant increase was observed in air velocity (P = 0.659). In the control group, the mean sAA did not change significantly in pre-test and post-test. Conclusions: Undesirable thermal comfort increased stress in female high school students. Stress was affected by temperature, relative humidity and the synchronous effect of temperature, relative humidity, and air velocity yet not air velocity, individually.

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Section: Discussionsupporting

confidence: 92%

The Effect of Thermal Comfort on Stress in Female High School Students

Najafi¹,

Movahed²,

Barzegar³

et al. 2018

Int J School Health

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“…One recent study investigated the effects of a personalized ventilation system on people's health, comfort, and performance in warm and humid environments (26 and 288C at 70% relative humidity). The system provided increased local air movement and improved perceived air quality (PAQ) and thermal sensation, decreased the intensity of SBS, and improved self-estimated and objectively measured performance (Melikov, Skwarczynski, Kaczmarczyk, & Zabecky, 2013). The authors of another overview of various studies of productivity concluded that robust measures such as occupant control of temperature, operable windows and providing for adaptive thermal comfort could be more effective than increased ventilation or mechanical temperature control (Leyten, Laue, & Kurvers, 2014).…”

Section: Cost Of Comfortmentioning

confidence: 99%

Evolving opportunities for providing thermal comfort

Brager

Zhang

Arens

2015

Building Research & Information

137

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The building industry needs a fundamental paradigm shift in its notion of comfort, to find low-energy ways of creating more thermally dynamic and non-uniform environments that bring inhabitants pleasure. Strategies for providing enriched thermal environments must be conjoined with reducing energy; these are inseparable for any building striving for high performance. The objective of current comfort standards is to have no more than 20% of occupants dissatisfied, yet buildings are not reaching even that scant goal. A significant energy cost is incurred by the current practice of controlling buildings within a narrow range of temperatures (often over-cooling in the summer). If building designers and operators can find efficient ways to allow building temperatures to float over a wider range, while affording occupants individual control of comfort, the potential for energy savings is enormous. Five new ways of thinking, or paradigm shifts, are presented for designing or operating buildings to provide enhanced thermal experiences. They are supported by examples of research conducted by the Center for the Built Environment, and include shifts from centralized to personal control, from still to breezy air movement, from thermal neutrality to delight, from active to passive design, and from system disengagement to improved feedback loops.

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“…16 Personalized ventilation (PV) is one of the solutions that supply clean air close to the breathing zone of the user. 20 Studies show that PV improves occupants' health (reduces sick building syndrome and eye symptoms), perceived air quality, thermal comfort, and work performance, 21,22 and reduces energy consumption. 23,24 A personalized exhaust system with diffusers in the seat headrest has been shown to improve inhaled air quality and reduce exposure to airborne infection in aircraft cabins.…”

mentioning

confidence: 99%

Local body cooling to improve sleep quality and thermal comfort in a hot environment

et al. 2017

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The effects of local body cooling on thermal comfort and sleep quality in a hot environment were investigated in an experiment with 16 male subjects. Sleep quality was evaluated subjectively, using questionnaires completed in the morning, and objectively, by analysis of electroencephalogram (EEG) signals that were continuously monitored during the sleeping period. Compared with no cooling, the largest improvement in thermal comfort and sleep quality was observed when the back and head (neck) were both cooled at a room temperature of 32°C. Back cooling alone also improved thermal comfort and sleep quality, although the effects were less than when cooling 1,2 Disturbed nocturnal sleep also has consequential effects on health, increasing the risk of obesity, Type 2 diabetes, and cardiovascular disease. 3,4 The thermoregulatory system and the sleep regulating mechanisms have been shown to be strongly linked in humans, 5,6 and this was later confirmed by many studies that show high or low air temperatures, even moderately different from the neutral temperature, could significantly decrease sleep quality. 7-10 However, in many areas with long and hot summers, indoor air temperatures are very high. For example, in southern China, the indoor air temperature was found to be higher than 34°C in natural ventilated buildings during the summer season. 11 A survey in Indonesia found that the indoor air temperatures were higher than 32°C in naturally ventilated residential buildings. 12 Global warming that leads to higher temperatures will create still hotter indoor conditions. Attention is now being paid to how climate change may degrade the indoor thermal environment in buildings.13 It has been reported that heat-related deaths correlate, not just with daytime temperature, but also with nighttime temperatures. The highest risk factor for heat-related death is a bedroom located on the second floor without air-conditioning. 14 A study in 79 households in Greenland showed that in summer 19% of all bedroom temperature were above 26°C although the outside temperatures averaged no more than 9.5°C. 15Full air-conditioning may be one of the easiest ways to improve thermal environment. However, large amounts of cool air (often recirculated room air, for residential buildings) must be supplied to maintain indoor temperatures at acceptable levels in the entire building (including unoccupied areas), leading to increased energy consumption. 16Thus, especially in areas with hot summers, the long summer period

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Use of personalized ventilation for improving health, comfort, and performance at high room temperature and humidity

Cited by 96 publications

References 22 publications

The Effect of Thermal Comfort on Stress in Female High School Students

The Effect of Thermal Comfort on Stress in Female High School Students

Evolving opportunities for providing thermal comfort

Local body cooling to improve sleep quality and thermal comfort in a hot environment

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