scholarly journals Effects of Changing Air Temperature at Different Sleep Stages on the Subjective Evaluation of Sleep Quality

2019 ◽  
Vol 11 (5) ◽  
pp. 1417 ◽  
Author(s):  
Jack Ngarambe ◽  
Geun Yun ◽  
Kisup Lee ◽  
Yeona Hwang
Keyword(s):  
Control System ◽  
Sleep Quality ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Sleep Stage ◽  
Subjective Evaluation ◽  
Ambient Air ◽  
Thermal Control ◽  
Sleep Stages

The thermal environment in bedrooms is important for high-quality sleep. Studies confirm that, even during sleep, the human body remains sensitive to the ambient air temperature. This study assesses how changing indoor air temperatures at different sleep stages affects the subjective evaluation of sleep quality. We compare reports from two identical sleeping environments with different thermal control systems: an IoT-based control system that adjusts the indoor air temperature according to the sleep stage and a fixed control system that maintains a constant temperature throughout the night. Ten subjects participated in the experiments and completed a questionnaire about their sleep quality. Our results show that, overall, the subjects experienced better sleep in the room with the IoT-based control system than in the one with a fixed thermal control. The mean differences in sleep satisfaction levels between the two sleeping environments were generally statistically significant in favor of the room with the IoT-based thermal control. Our results thus illustrate the suitability of using the IoT to control the air conditioning in bedrooms to provide improved sleep quality.

scholarly journals Energy-saving potential of intermittent heating system: Influence of composite phase change wall and optimization strategy

2020 ◽  
pp. 014459872096921
Author(s):  
Yanru Li ◽  
Enshen Long ◽  
Lili Zhang ◽  
Xiangyu Dong ◽  
Suo Wang
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Phase Change ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Optimization Strategy ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Intermittent Heating

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

scholarly journals An Interactive Task Conditioning System Featuring Personal Comfort Models and Non-Intrusive Sensing Techniques: A Field Study in Shanghai

Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 90
Author(s):  
Siliang Lu ◽  
Erica Cochran Hameen
Keyword(s):  
Thermal Comfort ◽  
Field Study ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
New Paradigm ◽  
Dynamic Task ◽  
Current Task ◽  
Open Plan

Heating, ventilation and air-conditioning (HVAC) systems play a key role in shaping office environments. However, open-plan office buildings nowadays are also faced with problems like unnecessary energy waste and an unsatisfactory shared indoor thermal environment. Therefore, it is significant to develop a new paradigm of an HVAC system framework so that everyone could work under their preferred thermal environment and the system can achieve higher energy efficiency such as task ambient conditioning system (TAC). However, current task conditioning systems are not responsive to personal thermal comfort dynamically. Hence, this research aims to develop a dynamic task conditioning system featuring personal thermal comfort models with machine learning and the wireless non-intrusive sensing system. In order to evaluate the proposed task conditioning system performance, a field study was conducted in a shared office space in Shanghai from July to August. As a result, personal thermal comfort models with indoor air temperature, relative humidity and cheek (side face) skin temperature have better performances than baseline models with indoor air temperature only. Moreover, compared to personal thermal satisfaction predictions, 90% of subjects have better performances in thermal sensation predictions. Therefore, personal thermal comfort models could be further implemented into the task conditioning control of TAC systems.

Effects of indoor temperature and background noise on floor impact noise perception

2018 ◽  
Vol 28 (4) ◽  
pp. 454-469 ◽  
Author(s):  
Wonyoung Yang ◽  
Myung-Jun Kim ◽  
Hyeun Jun Moon
Keyword(s):  
Air Temperature ◽  
Noise Level ◽  
Background Noise ◽  
Room Temperature ◽  
Thermal Environment ◽  
Subjective Evaluation ◽  
Adaptation Period ◽  
Indoor Climate ◽  
Impact Noise ◽  
Background Noise Level

This study investigates effects of room air temperature and background noise on the perception of floor impact noises in a room. Floor impact noises were recorded in apartment buildings and were presented in an indoor climate chamber with background noise for subjective evaluation. Thirty-two participants were subjected to all combinations of three thermal conditions (20%C, 25%C, 30%C and relative humidity 50%), four background noise types (Babble, Fan, Traffic and Water), three background noise levels (35 dBA, 40 dBA and 45 dBA) and four floor impact noises (Man Jumping, Children Running, Man Running and Chair Scraping). After a 1-h thermal adaptation period for each thermal condition, the participants were asked to evaluate their thermal and acoustic perceptions. Statistically significant effects were found for the room air temperature and background noise level on the perception of the floor impact noises. Noisiness, loudness and complaints of floor impact noise increased with increasing room temperature and background noise level. Annoyance of floor impact noise showed a peak in acceptable thermal environment for general comfort. Room air temperature was a dominant non-auditory factor contributing to floor impact noise annoyance, while the floor impact noise level influenced the floor impact noise loudness and the floor impact noisiness was almost equally affected by the room temperature, background noise level and floor impact noise level. Further investigation is needed to fully understand the combined perception of floor impact noise under various indoor environmental conditions.

Utility of Activity Monitors and Thermometry in Assessing Sleep Stages and Sleep Quality

2018 ◽  
Vol 1 (3) ◽  
pp. 108-121
Author(s):  
Natashia Swalve ◽  
Brianna Harfmann ◽  
John Mitrzyk ◽  
Alexander H. K. Montoye
Keyword(s):  
Sleep Quality ◽  
Skin Temperature ◽  
Sleep Stage ◽  
Sleep Onset ◽  
Sleep Efficiency ◽  
Sleep Stages ◽  
Sleep Onset Latency ◽  
Onset Latency ◽  
Activity Monitors ◽  
Research Grade

Activity monitors provide an inexpensive and convenient way to measure sleep, yet relatively few studies have been conducted to validate the use of these devices in examining measures of sleep quality or sleep stages and if other measures, such as thermometry, could inform their accuracy. The purpose of this study was to compare one research-grade and four consumer-grade activity monitors on measures of sleep quality (sleep efficiency, sleep onset latency, and wake after sleep onset) and sleep stages (awake, sleep, light, deep, REM) against an electroencephalography criterion. The use of a skin temperature device was also explored to ascertain whether skin temperature monitoring may provide additional data to increase the accuracy of sleep determination. Twenty adults stayed overnight in a sleep laboratory during which sleep was assessed using electroencephalography and compared to data concurrently collected by five activity monitors (research-grade: ActiGraph GT9X Link; consumer-grade: Fitbit Charge HR, Fitbit Flex, Jawbone UP4, Misfit Flash) and a skin temperature sensor (iButton). The majority of the consumer-grade devices overestimated total sleep time and sleep efficiency while underestimating sleep onset latency, wake after sleep onset, and number of awakenings during the night, with similar results being seen in the research-grade device. The Jawbone UP4 performed better than both the consumer- and research-grade devices, having high levels of agreement overall and in epoch-by-epoch sleep stage data. Changes in temperature were moderately correlated with sleep stages, suggesting that addition of skin temperature could increase the validity of activity monitors in sleep measurement.

scholarly journals The effects of building layouts and envelope on indoor thermal environment of Hui style traditional buildings in Wuyuan

2020 ◽  
Vol 194 ◽  
pp. 05013
Author(s):  
Xiaowei Hong ◽  
Guangjin Zhang ◽  
Yufeng Zhang
Keyword(s):  
Quantitative Analysis ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Field Investigation ◽  
Indoor Thermal Environment ◽  
Adaptive Thermal Comfort ◽  
Thermal Comfort Model

Indoor thermal environment of Hui style traditional houses is depended on surrounding environments, building layouts and envelope. Quantitative analysis of the effects of building layouts and envelope on indoor thermal environment is of great significance for preventions of traditional houses and design of new archaized houses. A field investigation was conducted on thirty-six traditional houses from nine villages in Wuyuan, and the typical buildings’ layout and envelope were determined. Four traditional buildings in different location in Wuyuan were selected for continual recording. The four buildings with four types of building layouts and envelope were analyzed by using local adaptive thermal comfort model, and the effects of building layouts and envelope of traditional buildings were clearly revealed. The most crucial way to improve indoor thermal environment in Hui style traditional buildings was raising the indoor air temperature.

scholarly journals EFFECT OF THERMAL ENVIRONMENT ON SLEEP QUALITY IN ACTUAL BEDROOM IN SUMMER BY SLEEP STAGES ANALYSIS

2018 ◽  
Vol 83 (745) ◽  
pp. 277-284
Author(s):  
Yuichi AKIYAMA ◽  
Emika MIYAKE ◽  
Riho MATSUZAKI ◽  
Masayuki OGATA ◽  
Kazuyo TSUZUKI ◽  
...  
Keyword(s):  
Sleep Quality ◽  
Thermal Environment ◽  
Sleep Stages

Field Survey on Occupant Thermal Comfort of Cold Regions in Transition Season

2013 ◽  
Vol 805-806 ◽  
pp. 1620-1624 ◽  
Author(s):  
Wan Ying Qu
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Indoor Air ◽  
Field Survey ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Residential Buildings ◽  
Cold Regions ◽  
Indoor Thermal Environment ◽  
Transition Season

A thermal comfort field study was investigated in residential buildings of cold regions in transition season during which the indoor thermal environment conditions are measured, the thermal sensation value of the occupants is questioned and recorded. A seven-point thermal sensation scale was used to evaluate the thermal sensation. The statistical method was used to analyze the data and the conclusions are as follows in transition season: clothing increase in 0.1clo when the indoor air temperature is lowered by 1°C; and clothing will be a corresponding increase in 0.06clo when the outdoor air temperature is lowered by 1°C; clothing also varies with gender, age, weight and thermal history and other related; the measured thermal neutral temperature is 21.3°C; and the minimum accepted temperature is 11.4 °C in transition season in cold regions. Most people choose to change clothes, switch and other passive measures, and occasionally take active measures of heater, electric fans and others.

scholarly journals An Investigation of the Behavioral Characteristics of Higher- and Lower-Temperature Group Families in a Condominium Equipped with a HEMS System

Buildings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 4 ◽  
Author(s):  
Rajan KC ◽  
Hom Rijal ◽  
Masanori Shukuya ◽  
Kazui Yoshida
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Indoor Air ◽  
Energy Use ◽  
Thermal Environment ◽  
Indoor Thermal Environment ◽  
Home Energy Management ◽  
Temperature Group ◽  
Higher Temperature ◽  
Lower Temperature

A home energy management system (HEMS) shows the energy used indoors so that the energy waste can be easily identified and reduced. Thermal comfort is related to the trend of energy use in buildings. We conducted a survey in a condominium equipped with a HEMS to determine the indoor thermal environment and various behaviors of the occupants taken for thermal comfort adjustment. The results showed that there is a large variation of indoor air temperatures according to season, floor and flat. We categorized families into two groups, one with higher and the other with lower average indoor temperatures. The indoor air temperature of the higher temperature group in summer was found to be higher than the recommended indoor temperature during the summer season in Japan. The higher temperature group tended to adopt behaviors, such as window opening and using a fan more often, than the lower temperature group. Due to the moderately high insulating levels in the building surveyed, the indoor air temperature of both groups was not low in winter. Heating was used less and irregular. The overall results indicate that the groups of families behaved differently to adjust the indoor thermal environment even though they were equipped with the same HEMS system.

Research of Inlet Air Quantity for Mechanical Cooling Tower

2014 ◽  
Vol 1044-1045 ◽  
pp. 388-391
Author(s):  
Bo Yang ◽  
Wen Zhou Yan ◽  
Liang Cai Chen
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Air Temperature ◽  
Heat Load ◽  
Cooling Tower ◽  
Functional Relation ◽  
Ambient Air ◽  
Total Heat ◽  
Ambient Air Temperature ◽  
Temperature And Humidity

The functional relation of inlet air quantity, total heat load, ambient air temperature and humidity of the mechanical cooling tower was analyzed. The curves of inlet air quantity with total heat load, ambient air temperature and humidity were plotted by programing. The results show that the inlet air quantity will increase linearly with total heat load and with ambient humidity as well, but the influence was less. Finally the function of inlet air quantity for mechanical cooling tower is fitted. The function can calculate the inlet air quantity for automatic control system of mechanical cooling tower, to achieve the goal of energy saving.

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