Performance of capillary ceiling cooling panel on ceiling surface temperature and indoor thermal environment

2020 ◽  
Vol 29 (6) ◽  
pp. 881-894 ◽  
Author(s):  
Dong Xie ◽  
Chenhua Wang ◽  
Chuck Wah Yu ◽  
Yun Wang ◽  
Hanqing Wang
Keyword(s):  
Surface Temperature ◽  
Water Temperature ◽  
Thermal Environment ◽  
Ventilation System ◽  
Internal Heat ◽  
Experimental Methodology ◽  
Maximum Temperature ◽  
Air Supply ◽  
The Difference ◽  
Supply Velocity

A new experimental methodology is presented to show the effect of water supply temperature, mass flow rate and thermal load distribution on the radiant ceiling capacity and thermal comfort conditions. Computerized fluid dynamics simulated vertical temperatures and velocities profiles were validated by a comparison with experimental results and the difference was within 10%. Uniform surface temperature distribution was achieved in a 45.6 m3 test room installed with capillary ceiling radiant cooling panels by an increase in water temperature and air supply velocity. When the ventilation system was turned off, the mean ceiling surface temperature rose from 16.9 ± 0.4°C to 21.5 ± 0.3°C with a rise in the inlet water temperature to 20.1°C. The temperature difference between the head and ankle of an occupant was 2.0°C, which complies with the Chinese standard, GB/T 18049-2017. At a height of 1–1.5 m, the maximum temperature fluctuation was 2°C in the horizontal direction. When the ventilation system was turned on, with the air supply temperature and velocity at 19.8°C and 1.11 m s−1, the ceiling surface temperature was increased by 0.5°C. The indoor air temperature has a positive correlation with the air supply temperature and internal heat load but a negative correlation with air supply velocity.

scholarly journals An Analysis of Land Surface Temperature Trends in the Central Himalayan Region Based on MODIS Products

2019 ◽  
Vol 11 (8) ◽  
pp. 900 ◽  
Author(s):  
Wei Zhao ◽  
Juelin He ◽  
Yanhong Wu ◽  
Donghong Xiong ◽  
Fengping Wen ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Thermal Environment ◽  
Himalayan Region ◽  
Maximum Temperature ◽  
Temperature Cycle ◽  
Increasing Trend ◽  
Nighttime Temperatures

The scientific community has widely reported the impacts of climate change on the Central Himalaya. To qualify and quantify these effects, long-term land surface temperature observations in both the daytime and nighttime, acquired by the Moderate Resolution Imaging Spectroradiometer from 2000 to 2017, were used in this study to investigate the spatiotemporal variations and their changing mechanism. Two periodic parameters, the mean annual surface temperature (MAST) and the annual maximum temperature (MAXT), were derived based on an annual temperature cycle model to reduce the influences from the cloud cover and were used to analyze their trend during the period. The general thermal environment represented by the average MAST indicated a significant spatial distribution pattern along with the elevation gradient. Behind the clear differences in the daytime and nighttime temperatures at different physiographical regions, the trend test conducted with the Mann-Kendall (MK) method showed that most of the areas with significant changes showed an increasing trend, and the nighttime temperatures exhibited a more significant increasing trend than the daytime temperatures, for both the MAST and MAXT, according to the changing areas. The nighttime changing areas were more widely distributed (more than 28%) than the daytime changing areas (around 10%). The average change rates of the MAST and MAXT in the daytime are 0.102 °C/yr and 0.190 °C/yr, and they are generally faster than those in the nighttime (0.048 °C/yr and 0.091 °C/yr, respectively). The driving force analysis suggested that urban expansion, shifts in the courses of lowland rivers, and the retreat of both the snow and glacier cover presented strong effects on the local thermal environment, in addition to the climatic warming effect. Moreover, the strong topographic gradient greatly influenced the change rate and evidenced a significant elevation-dependent warming effect, especially for the nighttime LST. Generally, this study suggested that the nighttime temperature was more sensitive to climate change than the daytime temperature, and this general warming trend clearly observed in the central Himalayan region could have important influences on local geophysical, hydrological, and ecological processes.

Potential of an air curtain system orientated to create non-uniform indoor thermal environment and save energy

2016 ◽  
Vol 26 (2) ◽  
pp. 152-165 ◽  
Author(s):  
Chong Shen ◽  
Xiaoliang Shao ◽  
Xianting Li
Keyword(s):  
Thermal Environment ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Coefficient Of Performance ◽  
Maximum Temperature ◽  
Building Energy Efficiency ◽  
Maximum Temperature Difference ◽  
Air Curtain ◽  
Discharge Velocity ◽  
Save Energy

Non-uniform indoor environment has shown its potential for building energy efficiency and improving indoor air quality compared with traditional uniform environment created by mixing ventilation. An air curtain was employed to create non-uniform thermal environment in this study. The performance of an optimal ventilation strategy between an air curtain and the background ventilation in a typical air-conditioned room was investigated numerically. The air curtain's effectiveness and coefficient of performance (COP) are proposed as evaluation indices for assessing the efficacy of air curtain for this usage. The numerical model was validated by experiments. The energy saving potential of an air curtain system for maintaining a thermal environment of a compartment was studied under different internal heat-source characteristics. The discharge velocity of the air curtain was optimized. The results show that the efficacy of an air curtain system to create a non-uniform thermal environment is high, where the maximum temperature difference between two sides of an air curtain could be as high as 7.4℃. Both the flow rate of the air curtain and background ventilation can be reduced to save energy. An air curtain is more efficient when the heat is concentrated mainly in the unoccupied room partition and the unoccupied zone contains external walls.

scholarly journals Assessment of indoor thermal environment of Aceh house based on WBGT index

2021 ◽  
Vol 881 (1) ◽  
pp. 012023
Author(s):  
Muslimsyah ◽  
A Munir ◽  
Y Away ◽  
Abdullah ◽  
K Huda ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Ventilation System ◽  
Vernacular Architecture ◽  
Maximum Temperature ◽  
Cooling Process ◽  
Temperature Index ◽  
Indoor Thermal Environment ◽  
Temperature Ranges

Abstract Thermal comfort is one of the standard assessments of building thermal environment. Air movement is an important parameter for in a naturally ventilated to achieve thermal comfort by accelerating the evaporative cooling process on the human body. Aceh House has a standard of thermal comfort with a vernacular architecture with a natural ventilation system. This vernacular architectural building has a fairly high harmonization of the environment because it has undergone a process of adaptation. In this study, observations were made at the Original House (OH), the Adaptive Reuse House (ARH), and the Aceh Modified House (AMH). By using the method of assessing changes in environmental comfort, using Wet Bulb Temperature Index (WBGT) method, the minimum and maximum temperature ranges are 25°C and 30°C. In the WBGT thermal rating, AMH has the higher thermal and is followed by ARH and OH respectively. Thus, OH has lower thermal compared to other Aceh houses.

Numerical Simulation on Effects of Air Supply Angle and Air Supply Velocity to Indoor Thermal Environment of Wall Hanging Air-Conditioning

2014 ◽  
Vol 1030-1032 ◽  
pp. 553-557
Author(s):  
Xiao Yong Peng ◽  
Lan Xia Guo ◽  
Xu Sheng Chai ◽  
Jing Jing Liang ◽  
Zhi Qiu Fu
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Temperature Fields ◽  
Air Distribution ◽  
Supply Angle ◽  
Air Supply ◽  
Supply Condition ◽  
Comprehensive Comparison ◽  
The One ◽  
Supply Velocity

A wall hanging air-conditioning office was simulated on three different air supply angle and three different air supply velocity by the AIRPAK .Based on the velocity fields, temperature fields, PMV-PPD obtained, analysis indoor thermal comfort. The result shows obvious difference of air distribution and great effect of indoor thermal under different air supply angle and different air supply velocity. By comprehensive comparison, the best air supply condition is the one of 75° downward, 3.0m/s.

scholarly journals On-site measurement and numerical investigation of thermal environment with different air distribution systems in ice arenas

2021 ◽  
Vol 2069 (1) ◽  
pp. 012096
Author(s):  
Wenyu Lin ◽  
Tao Zhang ◽  
Xiaohua Liu ◽  
Lingshan Li
Keyword(s):  
Thermal Environment ◽  
Ventilation System ◽  
Simulation Method ◽  
Extreme Condition ◽  
Air Distribution ◽  
Jet Ventilation ◽  
Displacement Ventilation ◽  
Air Supply ◽  
Temperature And Humidity ◽  
Ice Field

Abstract It is important to strictly maintain the indoor thermal environment in ice arenas which have very different features to other commercial buildings. Separated air distribution system is widely used to create a dry and cold environment near the ice and a comfortable environment in the view stand. The warm and humid air from the view stand may lead to uneven temperature and humidity distribution in the rink, leading to extra energy consumption, even fog and frost on the ice. Unreasonable air supply in the ice rink zone will also make the spectators feel too cold and uncomfortable. Jet ventilation system is the most extensively used system in the ice rink zone. An innovative ground displacement ventilation system is proposed in the National Aquatics Centre, which will serve as the venue for the curling competition in the 2022 Beijing Winter Olympics. On-site measurement in the arena is carried out and computational fluid dynamics (CFD) simulation method is adopted in the present research. Measured thermal environment above the ice with different ventilation systems are compared and analysed. Result shows that the displacement ventilation system features a more obvious vertical stratification than jet ventilation system in this kind of large space buildings, and thus is more energy-efficient. A CFD model of the ice cube is setup and verified by measured data. The thermal environment in the ice rink with displacement ventilation under extreme condition is studied using the simulation method. The temperature and humidity in the ice field increases by 10.1 °C, 4.5 g/kg without air supply in the view stand, proving that the spectators in the view stand have a great impact on the thermal environment in the ice field.

Comparison of two air sampling methods to monitor operating room air quality and assessment of air quality in two operating rooms with different ventilation systems in the national hospital of Sri Lanka

2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Tshokey Tshokey ◽  
Pranitha Somaratne ◽  
Suneth Agampodi
Keyword(s):  
Air Quality ◽  
Sri Lanka ◽  
Operating Room ◽  
Ventilation System ◽  
Surgical Site Infections ◽  
National Hospital ◽  
Air Contamination ◽  
Acceptable Method ◽  
The Difference ◽  
Laminar Air Flow

Air contamination in the operating room (OR) is an important contributor for surgical site infections. Air quality should be assessed during microbiological commissioning of new ORs and as required thereafter. Despite many modern methods of sampling air, developing countries mostly depended on conventional methods. This was studied in two ORs of the National Hospital of Sri Lanka (NHSL) with different ventilation system; a conventional ventilation (CV) and a laminar air flow (LAF). Both ORs were sampled simultaneously by two different methods, the settle plate and sampler when empty and during use for a defined time period. Laboratory work was done in the Medical Research Institute. The two methods of sampling showed moderate but highly significant correlation. The OR with CV was significantly more contaminated than LAF when empty as well as during use by both methods. Overall, the difference in contamination was more significant when sampled by the sampler. Differences in contamination in empty and in-use ORs were significant in both ORs, but significance is less in LAF rooms. The consistent and significant correlation between settle plate and sampler showed that the settle plate is an acceptable method. The LAF theatre showed less contamination while empty and during use as expected. Air contamination differences were more significant when sampled with sampler indicating that it is a more sensitive method. Both CV and LAF ORs of the NHSL did not meet the contamination standards for empty theatres but met the standards for in-use indicating that the theatre etiquette was acceptable.

Ocular surface temperature differences in glaucoma

2021 ◽  
pp. 112067212110237
Author(s):  
Ari Leshno ◽  
Ori Stern ◽  
Yaniv Barkana ◽  
Noa Kapelushnik ◽  
Reut Singer ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Thermal Imaging ◽  
Ocular Surface ◽  
Open Angle Glaucoma ◽  
Tissue Temperature ◽  
Body Temperatures ◽  
Current Thinking ◽  
Imaging Camera ◽  
The Mean ◽  
The Difference

Purpose: Accumulating evidence suggests that neuroinflammation and immune response are part of the sequence of pathological events leading to optic nerve damage in glaucoma. Changes in tissue temperature due to inflammation can be measured by thermographic imaging. We investigated the ocular surface temperature (OST) profile of glaucomatous eyes to better understand the pathophysiology of these conditions. Methods: Subjects diagnosed with glaucoma (primary open angle glaucoma [POAG] or pseudo exfoliation glaucoma [PXFG]) treated at the Sam Rothberg Glaucoma Center (11/2019–11/2020.) were recruited. Healthy subjects with no ocular disease served as controls. The Therm-App thermal imaging camera was used for OST acquisition. Room and body temperatures were recorded, and the mean temperatures of the medial cantus, lateral cantus, and cornea were calculated with image processing software. Results: Thermographic images were obtained from 52 subjects (52 eyes: 25 POAG and 27 PXFG) and 66 controls (66 eyes). Eyes with glaucoma had a significantly higher OST compared to controls (mean 0.9 ± 0.3°C, p < 0.005). The difference between the two groups remained significant after adjustment for age, sex, intraocular pressure (IOP) and room and body temperatures. Lens status and topical IOP-lowering medication did not significantly affect OST. A subgroup analysis revealed that the OST was higher among eyes with POAG compared to eyes with PXFG, but not significantly. Conclusions: Differences in the OST between glaucomatous and normal eyes strengthens current thinking that inflammation affects the pathophysiology of glaucoma. Longitudinal studies are warranted to establish the prognostic value of thermographic evaluations in these patients.

scholarly journals The Value of a Decrease in Temperature by One Degree Celsius of the Regional Microclimate—The Cooling Effect of the Paddy Field

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 353
Author(s):  
Ya-Wen Chiueh ◽  
Chih-Hung Tan ◽  
Hsiang-Yi Hsu
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Paddy Field ◽  
Research Area ◽  
Paddy Fields ◽  
Cooling Effect ◽  
Field Temperature ◽  
Bare Land ◽  
The Face ◽  
The Difference

In the face of climate change, extreme climates are becoming more frequent. There were severe droughts in Taiwan in 2020, 2014–2015, and 2002. In these years, the paddy fields were kept fallow to save water and transfer agricultural water to non-agricultural use. On the other hand, with global warming, the existence of paddy fields may be one of the natural solutions to regional temperature mitigation. This study used remote sensing to quantify the difference in temperature between paddy fields and urban areas. The result of overall surface temperature deductive analysis revealed that the temperature in the whole Taoyuan research area was 1.2 °C higher in 2002 than in 2003 because of fallowing of the paddy field, while in the Hsinchu research area, it was 1.5 °C higher in 2002 than in 2003, due to the same reason described above. In terms of the difference in land use, for the Hsinchu research area, the surface temperature deductive result showed that the average paddy field temperature in 2002 was 22.3 °C (sample area average), which was 7.7 °C lower than that of the building and road point and 4.3 °C lower than that of the bare land point. The average paddy field temperature in 2003 was 19.2 °C (sample area average), which was 10.1 °C lower than that of the building and road point and 8.3 °C lower than that of the bare land point. Then this study evaluated the economic valuation of the paddy field cooling effect using the contingent valuation method. Through the paddy field cooling effect and in the face of worsening extreme global climate, the willingness to pay (WTP) of the respondents in Taiwan for a decrease of 1 °C with regard to the regional microclimate was evaluated. It was found that people in Taiwan are willing to pay an extra 8.89 USD/per kg rice/year for the paddy for a decrease in temperature by 1 °C in the regional microclimate due to the paddy field. Furthermore, this study applied the benefits transfer method to evaluate the value of a decrease of 1 °C in the regional microclimate in Taiwan. The value of a decrease of 1 °C in the regional microclimate in Taiwan is 9,693,144,279 USD/year. In this regard, the economic value of 1 °C must not be underestimated. In conclusion, more caution is needed while making decisions to change the land use of paddy fields to other land uses.

scholarly journals Seasonal Variations of Daytime Land Surface Temperature and Their Underlying Drivers over Wuhan, China

2021 ◽  
Vol 13 (2) ◽  
pp. 323
Author(s):  
Liang Chen ◽  
Xuelei Wang ◽  
Xiaobin Cai ◽  
Chao Yang ◽  
Xiaorong Lu
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Rapid Urbanization ◽  
The Impact ◽  
The City

Rapid urbanization greatly alters land surface vegetation cover and heat distribution, leading to the development of the urban heat island (UHI) effect and seriously affecting the healthy development of cities and the comfort of living. As an indicator of urban health and livability, monitoring the distribution of land surface temperature (LST) and discovering its main impacting factors are receiving increasing attention in the effort to develop cities more sustainably. In this study, we analyzed the spatial distribution patterns of LST of the city of Wuhan, China, from 2013 to 2019. We detected hot and cold poles in four seasons through clustering and outlier analysis (based on Anselin local Moran’s I) of LST. Furthermore, we introduced the geographical detector model to quantify the impact of six physical and socio-economic factors, including the digital elevation model (DEM), index-based built-up index (IBI), modified normalized difference water index (MNDWI), normalized difference vegetation index (NDVI), population, and Gross Domestic Product (GDP) on the LST distribution of Wuhan. Finally, to identify the influence of land cover on temperature, the LST of croplands, woodlands, grasslands, and built-up areas was analyzed. The results showed that low temperatures are mainly distributed over water and woodland areas, followed by grasslands; high temperatures are mainly concentrated over built-up areas. The maximum temperature difference between land covers occurs in spring and summer, while this difference can be ignored in winter. MNDWI, IBI, and NDVI are the key driving factors of the thermal values change in Wuhan, especially of their interaction. We found that the temperature of water area and urban green space (woodlands and grasslands) tends to be 5.4 °C and 2.6 °C lower than that of built-up areas. Our research results can contribute to the urban planning and urban greening of Wuhan and promote the healthy and sustainable development of the city.

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