The Effects of Vertical Air Temperature Defferences on Thermal Comfort and Physiological Responses

Bohgaki, Kazuaki; Imagawa, Nozomu; Ohmori, Masato; Yamada, Shigeru

doi:10.3130/aijax.417.0_31

Cited by 4 publications

(7 citation statements)

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“…The results obtained by Wyon et al, Bohgaki et al, and Hori et al indicate that the PD constantly increases, while the data obtained by Palonen et al and Yu et al display no clear tendency. Vertical temperature gradients of 4 K/m or 5 K/m are likely to be acceptable.…”

Section: Literature Reviewmentioning

confidence: 87%

“…Vertical temperature gradients of 4 K/m or 5 K/m are likely to be acceptable. In contrast to Olesen et al, Wyon et al and Hori et al have investigated temperature gradients up to 4 K/m, and Bohgaki et al up to 6 K/m. Test persons could not adjust their preferred mean room temperature.…”

Section: Literature Reviewmentioning

confidence: 96%

“…Percentage of dissatisfied persons depending on the temperature gradient. We have summarized 10 publications by Eriksson and Domier, Olesen et al, Bohgaki et al, Wyon and Sandberg, Palonen et al, Hori et al, and Yu et al into seven studies on local and global comfort. Differences regarding the time of the survey as well as the experimental conditions were also considered…”

Section: Literature Reviewmentioning

confidence: 99%

“…In summary, vertical temperature gradients of up to 4 K/m (Wyon et al, Bohgaki et al, Hori et al), up to 5 K/m (Palonen et al, Ilmarinen et al, Yu et al), and even up to 8 K/m (Liu et al and Schiavon et al) are accepted by the users. The results obtained by Olesen et al can neither be confirmed nor be clearly refuted with the available data.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Regarding users’ comfort, critical body parts for local discomfort are the head and feet. Several authors have investigated the effect of thermal comfort in vertical temperature gradients: Eriksson and Domier, Olesen et al, Tanaka et al, Bohgaki et al, Wyon and Sandberg, Palonen et al, Ilmarinen et al, Mayer, Hori et al, Loveday et al, Hodder et al, Kawahara et al, Yu et al, Cheong et al, Melikov et al, Matsuo et al, Hashiguchi et al, Liu et al, and Schiavon et al . In the following chapters, we present a literature review on recent research on thermal comfort and the effect of vertical temperature gradients.…”

Section: Introductionmentioning

confidence: 99%

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Thermal comfort in environments with different vertical air temperature gradients

et al. 2018

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The use of displacement ventilation for cooling environments is limited by the vertical temperature gradient. Current standards recommend a temperature difference of up to 3 K/m between the head and the feet. This paper reviews the scientific literature on the effect of vertical temperature gradients on thermal comfort and compares this to the results of our own experiments. Early experiments have demonstrated a high sensitivity of dissatisfied test subjects to changes in the temperature gradient between head and foot level. Recent studies have indicated that temperature gradients of 4‐5 K/m are likely to be acceptable, and the mean room temperature may have a greater sensitivity on the percentage of dissatisfied (PD). In new experiments, test subjects have evaluated the thermal comfort of different vertical air temperature gradients in a modular test chamber, the Aachen comfort cube (ACCu), where they have assessed vertical temperature gradients of ΔT/Δy = 1, 4.5, 6, 8, and 12 K/m at a constant mean room temperature of 23°C. The results of the different temperature gradients are in contrast to ANSI/ASHRAE Standard 55 (Thermal Environmental Conditions for Human Occupancy, Atlanta GA, American Society of Heating, Refrigerating and Air Conditioning Engineers, 2013) as the PD increases almost constantly with higher vertical air temperature gradients. The PD for the overall sensation increases by approximately 7% between gradients of 1 and 8 K/m. The evaluation of our own tests has revealed that vertical temperature gradients of up to 8 K/m or higher are likely to be acceptable for test subjects.

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Section: Literature Reviewmentioning

confidence: 87%

Section: Literature Reviewmentioning

confidence: 96%