Study on Evaporative Cooling Effect of Porous Decorative Layer Applied to Vertical Walls

2012 ◽  
Vol 193-194 ◽  
pp. 556-561 ◽  
Author(s):  
Yan Shan Feng ◽  
Lei Zhang ◽  
Qing Lin Meng
Keyword(s):  
Thermal Resistance ◽  
Surface Temperature ◽  
Porous Materials ◽  
Horizontal Plane ◽  
External Surface ◽  
Experimental Result ◽  
Temperature Peak ◽  
Inner Surface ◽  
The World ◽  
Vertical Walls

The porous materials are more and more popular throughout the world. However most of the resent researches focus on the porous materials applying to horizontal plane. In this paper an experiment was conducted to study the applicability of porous decorative layer applying to vertical walls. The Experimental result shows that the wet porous decorative layer has a good applicability to west-facing wall by reducing the external surface temperature at least 8°C and eliminating the temperature peak of inner surface. The equivalent thermal resistance of the porous decorative layer is 0.40 m2•K/W, when using the 4-day value of the measurement. In the summer of Guangzhou, the porous decorative layer on west-facing wall is recommended to supply water once a day at 13:00.

scholarly journals Experimental Determination of the Heat Transfer Coefficient of Real Cooled Geometry Using Linear Regression Method

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 180
Author(s):  
Asif Ali ◽  
Lorenzo Cocchi ◽  
Alessio Picchi ◽  
Bruno Facchini
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Linear Regression ◽  
Surface Temperature ◽  
Transfer Coefficient ◽  
External Surface ◽  
Internal Surface ◽  
Regression Method ◽  
Thermal Transient

The scope of this work was to develop a technique based on the regression method and apply it on a real cooled geometry for measuring its internal heat transfer distribution. The proposed methodology is based upon an already available literature approach. For implementation of the methodology, the geometry is initially heated to a known steady temperature, followed by thermal transient, induced by injection of ambient air to its internal cooling system. During the thermal transient, external surface temperature of the geometry is recorded with the help of infrared camera. Then, a numerical procedure based upon a series of transient finite element analyses of the geometry is applied by using the obtained experimental data. The total test duration is divided into time steps, during which the heat flux on the internal surface is iteratively updated to target the measured external surface temperature. The final procured heat flux and internal surface temperature data of each time step is used to find the convective heat transfer coefficient via linear regression. This methodology is successfully implemented on three geometries: a circular duct, a blade with U-bend internal channel, and a cooled high pressure vane of real engine, with the help of a test rig developed at the University of Florence, Italy. The results are compared with the ones retrieved with similar approach available in the open literature, and the pros and cons of both methodologies are discussed in detail for each geometry.

Complex Protection of Pipelines Using Silicate Materials Based on Local Raw Materials of the Far East

2019 ◽  
Vol 945 ◽  
pp. 46-52 ◽  
Author(s):  
Elena A. Yatsenko ◽  
B.M. Goltsman ◽  
A.V. Ryabova
Keyword(s):  
Oil And Gas ◽  
External Surface ◽  
Raw Materials ◽  
Foam Glass ◽  
Russian Far East ◽  
Far East ◽  
The Far East ◽  
Inner Surface ◽  
Oil And Gas Pipelines ◽  
The Russian Far East

Modern trends in the development of the oil and gas infrastructure of the Russian Far East are considered. The main threats in the operation of oil and gas pipelines are described. The technology of complex protection of pipeline surfaces is proposed. Protection of the inner surface is achieved through the use of silicate enamel coatings, protection of the external surface – through the use of foam glass. On the basis of local silicate raw materials the technology of the described materials is developed, and their main properties are determined. Recommendations on the application of the developed technology for the protection of pipelines are given.

scholarly journals Experimental Study on the Thermal Behavior of Exterior Coating Textures of Building in Hot and Arid Climates

2021 ◽  
Vol 13 (8) ◽  
pp. 4175
Author(s):  
Islam Boukhelkhal ◽  
Fatiha Bourbia
Keyword(s):  
Energy Consumption ◽  
Surface Temperature ◽  
External Surface ◽  
Thermal Characteristics ◽  
Energy Performance ◽  
Building Envelope ◽  
Interior Space ◽  
Design Elements ◽  
Aesthetic Appearance ◽  
Reduction Of Energy Consumption

The building envelope is the barrier between the interior and exterior environments. It has many important functions, including protecting the interior space from the climatic variations through its envelope materials and design elements, as well as reduction of energy consumption and improving indoor thermal comfort. Furthermore, exterior building sidings, in addition to their aesthetic appearance, can have useful textures for reducing solar gains and providing good thermal insulation performance. This research examined and evaluated the effect of external siding texture and geometry on energy performance. For this objective, a field in situ testing and investigation of surface temperature was carried out on four samples (test boxes) with different exterior textures and different orientations, under the climate zone of Constantine–Algeria during the summer period. The results indicated significant dependability between the exterior texture geometry, the percentage of shadow projected, and external surface temperature. The second part of the research involved a similar approach, exploring the effect of three types of particles with the same appearance but with different thermal characteristics. It was concluded that the natural plant aggregates “palm particles” had the best performance, which contributed to a significant reduction of external surface temperature reaching 4.3 °C, which meant decreasing the energy consumption.

Obtaining the thermal resistance of air enclosed at the interface of multilayer fabrics by simulation

2018 ◽  
Vol 89 (15) ◽  
pp. 3178-3188 ◽  
Author(s):  
Hua Shen ◽  
Lexi Tu ◽  
Xiaofei Yan ◽  
Sachiko Sukigara
Keyword(s):  
Finite Element Method ◽  
Surface Roughness ◽  
Thermal Resistance ◽  
Three Dimensional ◽  
Estimating Equation ◽  
Experimental Result ◽  
Dimensional Finite Element ◽  
Experimental Values ◽  
Three Dimensional Finite Element ◽  
Method Model

An air layer enclosed at the interface was largely responsible for the insulation results of multilayer fabrics obtained from experiments. In this study, a three-dimensional finite element method model, in which the air layer enclosed at the interface of multilayer fabrics was ignored, was developed to calculate the fabric thermal resistance, and the result obtained from the fabric model was independent of the air. A Thermolab II Tester KES-F7 was also used to measure the thermal resistance of fabrics, and the experimental results were influenced by the air layer. By comparing the simulation and experimental result, the air layer thermal resistance was determined, and then an estimating equation, which can be used to estimate the fabric and air layer thermal resistance for multilayer fabrics, was proposed. The results suggested that the surface roughness of fabrics was strongly related to the air layer thermal resistance, with a linear relationship between them. Moreover, for multiple layers stacked by different fabrics, the air layer thermal resistance at the interface was mainly decided by the fabric with the rougher surface. An estimating equation was also developed to predict the thermal resistance of multilayer fabrics and good correlation between predicted and experimental values was observed.

scholarly journals Mapping Vegetation Health Around the World

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Christine Lee ◽  
Joshua Fisher ◽  
Simon Hook
Keyword(s):  
Surface Temperature ◽  
Water Availability ◽  
Ecosystem Responses ◽  
The World ◽  
Vegetation Health

A new spaceborne sensor monitors Earth's surface temperature at a resolution higher than ever before, providing information on ecosystem responses to changes in water availability and climate stressors.

scholarly journals OPTIMASI RONGGA TERHADAP VARIASI DERAJAT KEVAKUMAN SEBAGAI ISOLATOR

2012 ◽  
Vol 11 (1) ◽  
pp. 63 ◽  
Author(s):  
MULYONO MULYONO
Keyword(s):  
Heat Transfer ◽  
Specific Gravity ◽  
Thermal Resistance ◽  
Heat Convection ◽  
Vacuum Pressure ◽  
Temperature Conductivity ◽  
Easy Task ◽  
Insulation Materials ◽  
The World ◽  
Natural Heat Convection

In the world of industry, insulation materials are often utilized to maintain the temperature,either low or high. However, since the insulation materials often need to be thick, thus,costly, they are frequently deemed impractical. Therefore, in the attempt to replace the insulationmaterials, a cavity with low vacuum pressure is opted for. Yet, to attain a total (100%) airfreecavity is not an easy task. Such, the cavity usually still bears some amount of air pressurewhich results in natural heat convection through the two surfaces making up the cavity. Thetransfer coefficient of natural heat convection (h) is influenced by some factors, such as, the temperaturedifference, geometry of the cavity, cavity orientation, and characteristics of the fluid,for instance, its pressure, temperature, conductivity, specific gravity (density), and viscosity.The purpose of the study is to find answers to the following question: “How do vacuum pressurevariation and cavity ratio affect the rate of natural heat convection through the a cavity?” Pertinentto the question, the study was aimed to find the appropriate value of the vacuum pressurewhich can function well as an insulator. This study is significant in the attempt to lower downthe rate of heat transfer taking place in a system vis-à-vis the surrounding media. The studyfound out that the degree of emptiness of -60 cm Hg and =5.96, results in a lower rate of heattransfer compared with -20 cm Hg and -40 cm Hg. This means that the vacuum pressure of-60cm Hg bears a bigger thermal resistance than the -20 cm Hg and -40 cm Hg do.

scholarly journals Tropical and Extratropical predictions of the summer and autumn Niño3.4 Index: a comparison

2016 ◽  
Vol 42 ◽  
pp. 73-81
Author(s):  
Miguel Tasambay-Salazar ◽  
María José OrtizBeviá ◽  
Antonio RuizdeElvira ◽  
Francisco José Alvarez-García
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Linear Models ◽  
Southern Oscillation ◽  
Heat Content ◽  
Sea Surface ◽  
South Pacific Convergence Zone ◽  
Lead Times ◽  
Convergence Zone ◽  
The World

Abstract. The El Niño-Southern Oscillation (ENSO) phenomenon is the main source of the predictability skill in many regions of the world for seasonal and interannual timescales. Longer lead predictability experiments of Niño3.4 Index using simple statistical linear models have shown an important skill loss at longer lead times when the targeted season is summer or autumn. We develop different versions of the model substituting some its variables with others that contain tropical or extratropical information, produce a number of hindcasts with these models using two different predictions schemes and cross validate them. We have identified different sets of tropical or extratropical predictors, which can provide useful values of potential skill. We try to find out the sources of the predictability by comparing the sea surface temperature (SST) and heat content (HC) anomalous fields produced by the successful predictors for the 1980–2012 period. We observe that where tropical predictors are used the prediction reproduces only the equatorial characteristics of the warming (cooling). However, where extratropical predictors are included, the predictions are able to simulate the absorbed warming in the South Pacific Convergence Zone (SPCZ).

Development of Inverse Analysis of Heat Conduction and Thermal Stress for Elbow: Part I

2013 ◽  
Author(s):  
Seiji Ioka ◽  
Shiro Kubo ◽  
Mayumi Ochi ◽  
Kiminobu Hojo
Keyword(s):  
Heat Conduction ◽  
Thermal Stress ◽  
Transfer Function ◽  
Surface Temperature ◽  
Outer Surface ◽  
Inverse Analysis ◽  
Temperature History ◽  
Analysis Method ◽  
Inner Surface ◽  
Inverse Analysis Method

Thermal fatigue may develop in piping elbow with high temperature stratified flow. To prevent the fatigue damage by stratified flow, it is important to know the distribution of thermal stress and temperature history in a pipe. In this study, heat conduction inverse analysis method for piping elbow was developed to estimate the temperature history and thermal stress distribution on the inner surface from the outer surface temperature history. In the inverse analysis method, the inner surface temperature was estimated by using the transfer function database which interrelates the inner surface temperature with the outer surface temperature. Transfer function database was calculated by FE analysis in advance. For some patterns of the temperature history, inverse analysis simulations were made. It was found that the inner surface temperature history was estimated with high accuracy.

Impact of Common Sea Surface Temperature Anomalies on Global Drought and Pluvial Frequency

2010 ◽  
Vol 23 (3) ◽  
pp. 485-503 ◽  
Author(s):  
Kirsten L. Findell ◽  
Thomas L. Delworth
Keyword(s):  
South America ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Central America ◽  
Sea Surface ◽  
The World ◽  
The Impact ◽  
Drought Occurrence ◽  
Central South ◽  
Sst Anomalies

Abstract Climate model simulations run as part of the Climate Variability and Predictability (CLIVAR) Drought Working Group initiative were analyzed to determine the impact of three patterns of sea surface temperature (SST) anomalies on drought and pluvial frequency and intensity around the world. The three SST forcing patterns include a global pattern similar to the background warming trend, a pattern in the Pacific, and a pattern in the Atlantic. Five different global atmospheric models were forced by fixed SSTs to test the impact of these SST anomalies on droughts and pluvials relative to a climatologically forced control run. The five models generally yield similar results in the locations of drought and pluvial frequency changes throughout the annual cycle in response to each given SST pattern. In all of the simulations, areas with an increase in the mean drought (pluvial) conditions tend to also show an increase in the frequency of drought (pluvial) events. Additionally, areas with more frequent extreme events also tend to show higher intensity extremes. The cold Pacific anomaly increases drought occurrence in the United States and southern South America and increases pluvials in Central America and northern and central South America. The cold Atlantic anomaly increases drought occurrence in southern Central America, northern South America, and central Africa and increases pluvials in central South America. The warm Pacific and Atlantic anomalies generally lead to reversals of the drought and pluvial increases described with the corresponding cold anomalies. More modest impacts are seen in other parts of the world. The impact of the trend pattern is generally more modest than that of the two other anomaly patterns.

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