| 1. |
- Yang, Bin, et al.
(författare)
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Non-invasive (non-contact) measurements of human thermal physiology signals and thermal comfort/discomfort poses -A review
- 2020
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Ingår i: Energy and Buildings. - : ELSEVIER SCIENCE SA. - 0378-7788 .- 1872-6178. ; 224
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Forskningsöversikt (refereegranskat)abstract
- Heating, ventilation and air-conditioning (HVAC) systems have been adopted to create comfortable, healthy and safe indoor environments. In the control loop, the technical feature of the human demand-oriented supply can help operate HVAC effectively. Among many technical options, real time monitoring based on feedback signals from end users has been frequently reported as a critical technology to confirm optimizing building performance. Recent studies have incorporated human thermal physiology signals and thermal comfort/discomfort status as real-time feedback signals. A series of human subject experiments used to be conducted by primarily adopting subjective questionnaire surveys in a lab-setting study, which is limited in the application for reality. With the help of advanced technologies, physiological signals have been detected, measured and processed by using multiple technical formats, such as wearable sensors. Nevertheless, they mostly require physical contacts with the skin surface in spite of the small physical dimension and compatibility with other wearable accessories, such as goggles, and intelligent bracelets. Most recently, a low cost small infrared camera has been adopted for monitoring human facial images, which could detect the facial skin temperature and blood perfusion in a contact less way. Also, according to latest pilot studies, a conventional digital camera can generate infrared images with the help of new methods, such as the Euler video magnification technology. Human thermal comfort/discomfort poses can also be detected by video methods without contacting human bodies and be analyzed by the skeleton keypoints model. In this review, new sensing technologies were summarized, their cons and pros were discussed, and extended applications for the demand-oriented ventilation were also reviewed as potential development and applications.
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| 2. |
- Li, Haimeng, et al.
(författare)
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Sleep microenvironment improvement for the acute plateau entry population through a novel nasal oxygen supply system
- 2024
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 256
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Tidskriftsartikel (refereegranskat)abstract
- Most people who have moved to high-altitude areas temporarily suffer from sleep disorders. Sleep deprivation negatively affects not only people's daytime activities but also their health. However, most of the existing nonpharmaceutical intervention methods have the problems of discomfort, restricted movement, or high cost. This study involved the use of an oxygen-rich flow of air in the breathing area during sleep to fight hypoxia and aid with altitude acclimatization when people first traveled to a highland plateau. The associated nasal breathing targeted oxygen supply system (NBTOSS) was designed and optimized by numerical simulation and full-scale experiments. Blood oxygen saturation (SaO2) and pulse rate (PR) monitoring experiments were conducted on subjects exposed to hypoxia at a high altitude (Lhasa, 3646.31 m) with or without assistance from the novel oxygen system and on a lowland plain (Xi'an, 397.5 m) as a comparison. The size of the affected area, concentration target value, and oxygen consumption were used as evaluation indices. Experiments have demonstrated the feasibility of creating an oxygen-enriched microenvironment in breathing area during sleep. The results of the testing showed that the oxygen supply area was uniformly covered and that the degree of hypoxia in subjects was effectively alleviated, with average SaO2 increasing to 95% ± 1%. Maintaining oxygen levels during sleep for temporary residents of high altitudes with less oxygen consumption and minimal oxygen supply costs is discussed to provide a healthy and comfortable oxygen-enriched environment.
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| 3. |
- Su, Wei, et al.
(författare)
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Infection probability under different air distribution patterns
- 2021
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 207:Part B
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Tidskriftsartikel (refereegranskat)abstract
- Infectious diseases have caused significant physical harm to humans as well as enormous economic losses over the years. Effective ventilation and distribution of fresh air could help to reduce indoor cross-infection. The computational fluid dynamics (CFD) method was used in this paper to investigate airborne transmission with seven different air distribution methods. The revised Wells-Riley model, which took into account the non-uniform air distribution generated with the methods, was used to calculate the infection probability in an office room shared by ten occupants for 4 h. One of the occupants was an infector. The significance of the infector's location was studied. The obtained infection probability was compared to that obtained in the case of complete air mixing, which is uncommon in practice. Under specified conditions of this study, personalized ventilation (PV) performed the best in terms of preventing cross-infection, followed by displacement ventilation (DV), impinging jet ventilation (IJV), stratum ventilation (SV) and wall attachment ventilation (WAV). The number of infected occupants was reduced below the number obtained under the complete mixing assumption by using these air distribution methods. Mixing ventilation (MV) and diffuse ceiling ventilation (DCV) exhibited the worst performance. In comparison to the case of complete mixing the infection probability for seven out of nine susceptible occupants was higher with MV and for all occupants in the case of DCV. In SV, the position of the infector had a clear impact on the infection probability of susceptible individuals. WAV may perform better in practice if the system is well designed. The location of the exhaust outlets had a significant impact on the infection probability for DCV.
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| 4. |
- Yang, Bin, et al.
(författare)
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Enhanced effects of footwarmer by wearing sandals in winter office : a Swedish case study
- 2021
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Ingår i: Indoor + Built Environment. - : Sage Publications. - 1420-326X .- 1423-0070. ; 30:7, s. 875-885
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Tidskriftsartikel (refereegranskat)abstract
- Human-centred thermal environment conditioning can guarantee thermal comfort needs of human occupants in their micro-environments by using localized heating/cooling devices. Meanwhile, less intensified thermal conditioning of unoccupied surrounding environments can achieve heating/cooling energy efficiency. The concept was originated from task/ambient conditioning, which was developed for personal comfort systems. Most of the localized heating/cooling devices are workstation based or chair based. Task conditioning would become more closely to targets (human bodies) by using special clothing materials or thermoelectric elements. From thermal physiological viewpoints, thermal stimulus to thermally sensitive body parts may generate better results for not only local thermal comfort but also for whole body thermal comfort. Thermal stimulus to the extremities (feet) has demonstrated good thermal comfort effects. Scandinavians are accustomed to outdoor harsh environments and prefer wearing heavy shoes' outdoors in winter. They have the habit of changing heavy shoes to sandals when entering offices, which give the opportunity to enhance localized heating effects of footwarmers by reducing shoes' thermal resistance. Climatic chamber tests with 32 Nordic subjects were performed under different indoor ambient heating temperatures with/without the aid of footwarmers. With footwarmers and sandals, indoor heating temperature at 16°C was acceptable, which achieved energy efficient thermal comfort.
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| 5. |
- Yang, Bin, et al.
(författare)
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Influence of relayed fans and low level exhausts on performance of attachment ventilation under heating mode
- 2021
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Ingår i: Journal of Building Engineering. - : Elsevier. - 2352-7102. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- Compared with displacement ventilation, attachment ventilation characterized by high supply air momentum has the potential to generate warm air lake on the floor under winter heating mode. However, the airflow can not keep attaching to the floor and moves upwards by thermal buoyancy. The influence of relayed fans and low level exhausts on performance of attachment ventilation under heating mode was explored. One/two relayed fans and five dimensionless exhaust heights were investigated. Performance evaluating index include vertical temperature gradient, temperature efficiency, predicted mean vote (PMV), predicted percentage of dissatisfied (PPD) and Draught risk (DR). Simulation results showed that relayed fans and low level exhausts effectively increase the attachment length of warm air lake in winter. Operation of relayed fans reduces vertical temperature difference, maintaining the head and foot temperature difference less than 3 °C. Low level exhausts effectively increase occupant zone temperature, reduce airflow short circuit and improve temperature efficiency. The operation of relayed fans slightly increase the temperature efficiency under high level exhausts. Two relayed fans decrease the temperature efficiency under low level exhausts. Better performance can be achieved by using only one relayed fan.
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| 6. |
- Zhang, Yinping, et al.
(författare)
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Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China
- 2013
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Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 58:34, s. 4182-4189
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Tidskriftsartikel (refereegranskat)abstract
- Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children's asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1-8 years old in 10 Chinese cities during 2010-2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3-6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study.
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| 7. |
- Li, Angui, et al.
(författare)
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Ventilation and environmental control of underground spaces : a short review
- 2019
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Ingår i: E3S Web of Conferences. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- More and more underground spaces were used in 21st century because of rapid urbanization, traffic problems, etc. Underground city, metro, tunnel, mine, industrial and agriculture engineering, civil air defence engineering need large underground spaces. Underground spaces with different thermal, ventilation and lighting environments may cause comfort, health and safety problems. Concrete problems include excessive humidity, heat transfer specialty, excessive CO caused by blockage in long distance traffic tunnels, difficulty in smoke exhaust and evacuation during fire, harmful microorganism, radioactivity pollutants, psychological problems, and so forth. Air quality control technologies for underground spaces, including ventilation technology, dehumidification technology, natural energy utilization technology, smoke extraction technology and ventilation resistance reduction technology, will be reviewed. Ventilation for smoke-proof/evacuation and ventilation will also be reviewed.
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| 8. |
- Su, Wei, et al.
(författare)
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A novel convection and radiation combined terminal device : Its impact on occupant thermal comfort and cognitive performance in winter indoor environments
- 2021
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 246
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Tidskriftsartikel (refereegranskat)abstract
- Personal comfort systems usually use a single heat transfer mode to improve local thermal comfort by only stimulating one local body part. A novel hybrid convection and radiation combined terminal device, which could be used both in summer and winter, was proposed. A total of sixteen human subjects took part in a winter subjective experiment to test its performance on the improvement of occupants’ thermal comfort and cognitive performance in winter. Occupants’ thermal comfort, air movement perception, eye dryness and cognitive performance were investigated. The results showed that 88% of the subjects accepted 16℃ room temperature. 0.4 m/s air speed to face and abdomen parts is acceptable when convective airflow temperature is 4.5℃ higher than room temperature. No dry eye discomfort was reported while using a controllable device. Furthermore, subjects’ cognitive performance, including self-evaluate work performance, math (mental performance) and typing performance (dexterity), could be significantly improved by using the novel device. Energy efficient thermal comfort can be achieved by less intensifying ambient heating temperature to 16℃ in winter.
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| 9. |
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| 10. |
- Xiong, Jing, et al.
(författare)
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Probing the historic thermal and humid environment in a 2000-year-old ancient underground tomb and enlightenment for cultural heritage protection and preventive conservation
- 2021
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 251
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Tidskriftsartikel (refereegranskat)abstract
- The development and utilization of urban underground space have contributed to more excavation of ancient tombs in recent years. The microclimate in the burial environment is crucial for the sustainability of historical artifacts. In this paper, the variation in thermal and humid conditions during the burial time from the closure of a tomb to excavation was investigated by field testing and computational fluid dynamics (CFD) modeling. The selected object is the famous M1 tomb chamber of the mausoleum Zhang An-shi, which has a 2000-year history. It was found that the average air temperature (T) and relative humidity (RH) of the M1 tomb chamber before excavation were 12.7 °C and 93.0%, respectively. The results of the CFD simulation suggest that the burial time of an ancient tomb consists of a very short variable phase and a long stable phase. The very beginning phase may be as short as 0.3 h. The dramatic changes in temperature and RH were more than 10 °C and 20%, respectively. Consequently, dramatic changes in the thermal and humid environment will trigger the deterioration of historical artifacts. Current findings further suggest that the local annual average temperature is optimal for the conservation of underground artifacts excavated from the soil thermostatic layer. This study paves the way for characterizing the environment of an ancient tomb chamber, as well as museum design, energy savings that support cultural heritage protection and preventive conservation.
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