Designing a smart electrically heated sleeping bag to improve wearers’ feet thermal comfort while sleeping in a cold ambient environment

Abstract

In this study, a novel smart electrically heated sleeping bag was developed by incorporating a proportional–integral–derivative heating control system into a traditional sleeping bag. The smart sleeping bag was aimed to maintain human feet temperature within the thermoneutral range (i.e. 25.0–34.0℃) by automatically adjusting the heat power to the feet region based on real-time human toe temperatures. Subsequently, the performance of the newly developed smart sleeping bag in improving human thermal comfort was investigated by human trials. Eight female subjects underwent two 8-hour sleep trials, that is, the smart sleeping bag with power turned on (SleepingbagHT) and the smart sleeping bag with power turned off (SleepingbagCON). All trials were performed at an air temperature of 6.1 ± 0.5℃ (i.e. the EN 13537 defined comfort temperature for females), relative humidity of 80 ± 5% and air velocity of 0.4 ± 0.1 m/s. It was found that SleepingbagHT could maintain both the foot and toe temperatures within the thermal neutral range as well as keep the local-, and whole-body thermal and comfort sensations in thermal neutral state throughout the 8-hour cold exposure. In contrast, linearly decreasing foot and toe temperatures and aggravated local-, and whole-body thermal and comfort sensations were detected in SleepingbagCON within a 4.5-hour cold exposure. It could thus be concluded that the smart electrical heating sleeping bag was able to provide wearers an 8-hour comfortable sleep in the studied cold environment.

Smart Wireless Charging Heating Insoles: Improving Body Thermal Comfort of Young Males in an Extremely Cold Environment

“…Song et al (2016) found that warming feet was able to elevate foot skin temperatures, promote blood flow, and improve both local and whole body thermal comfort of human body while sleeping in cold environments. The results echoed to the findings of Zhang et al (2017) who also examined a novel smart heating sleeping bag with localized heating at the foot region. Keeping feet warm in a cool environment could maintain both feet and the whole body thermal comfort (Zhang et al, 2015).…”

“…However, most studies discussed the effect of heating on human body when sleeping or performing office task in indoor temperatures higher than 0 °C, whereas few studies considered the effect of heating in improving thermal comfort of occupational workers in extremely cold environments. Based on the previous studies, it was highly expected that feet heating could improve body thermal comfort in cold environments with temperatures lower than 0 °C (Song et al, 2016; Zhang et al, 2017).…”

“…Currently, more exploration has been performed in heating products such as heated gloves and clothing, which were found to be effective in improving body thermal comfort while being exposed in cold environments (Brajkovic & Ducharme, 2003;Song et al, 2015). Regarding foot heating, only few studies were conducted on its effectiveness in improving thermal comfort of human body while sleeping or performing office tasks in cool or cold environments (Ko & Lee, 2018;Song et al, 2016;Zhang et al, 2015Zhang et al, , 2017. Song et al (2016) found that warming feet was able to elevate foot skin temperatures, promote blood flow, and improve both local and whole body thermal comfort of human body while sleeping in cold environments.…”

An experiment to assess the heat transfer performance of thermoelectric-driven conditioned mattress

“…In terms of the thermoregulation, the current focus has moved to mattress manipulation [11][12], regarded as a much more efficient approach. A number of strategies have been proposed including an electric heat blanket, or electrically heated sleeping bag [13][14]. These powered temperaturecontrolled facilities may meet the human thermal requirements within the bed microclimate, but they are to some extent dangerous owing to the direct contact with the human body.…”

Thermal insulation property of graphene/polymer coated textile based multi-layer fabric heating element with aramid fabric

“…It was reported that graphene heater at upper back heating could increase the temperature and maintain the body temperature better, compared with chest heating. Zhang et al 18 have prepared a smart electrically heated sleeping bag to improve wearer’s thermal foot comfort in a cold ambient environment. The smart sleeping bag was aimed to maintain human feet within the thermoneutral range (25.0–34.0) °C.…”