scholarly journals Determination of Heat Transfer Coefficient of Two Insulated Cotton Based on Wall Framing

2019 ◽  
Vol 275 ◽  
pp. 01014
Author(s):  
Yao Lu ◽  
Wenbo Xie ◽  
Zheng Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Engineering Application ◽  
Heat Conducting ◽  
Filling Material ◽  
Wood Structure ◽  
Wood Frame ◽  
Frame Construction

The heat preservation performance of the light wood frame construction wall directly affects the energy saving effect of the light wood frame construction. In order to strengthen the research of the thermal performance of the light wood structure wall and sandwich wall, in this paper, the heat transfer coefficient of glass-insulated cotton with two kinds of materials was measured in the exterior wall of the same light-weight wooden structure through field test method for heat transfer coefficient of construction so as to compare the test value and theory of the wall insulation coefficient Value, and preferably a thermal insulation cotton filling material. The conclusion shows that the wall filling material of guardian glass insulation performance is better than the Owens Corning Glass insulation cotton, and the former is adapted to the area of hot summer and cold winter and hot in summer and warm in winter, which is suitable for the hot summer and warm winter area. This paper is helpful to promote the energy saving optimization design of the wall structure of the light wood frame construction, and the engineering application value is high. Calculating the heat-conducting value of light wood structure wall, and the calculated values of the temperature of the constituent materials are comparable with the measured values actually, and the composite material theory can be used to predict the heat-conducting property of wood structure construction. The above is mentioned help to improve the level of on-site testing technology of heat-conducting, and provide a useful reference for the energy-saving insulation design work for light wood structure wall in our country, and this study has a high engineering application value.

scholarly journals A New Energy-Efficient Building System Based on Insulated Concrete Perforated Brick with a Sandwich

2018 ◽  
Vol 4 (7) ◽  
pp. 1467 ◽  
Author(s):  
Guoqi Xing ◽  
Jing-jie Yu ◽  
Chun-gang Zhang ◽  
Jun-xi Wu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Energy Efficient ◽  
Field Tests ◽  
Insulating Layer ◽  
New Energy ◽  
Building System ◽  
Energy Efficient Building

The purpose of this research is to put forward a new energy-efficient building system that can meet the energy saving requirement of 65% for public buildings in cold areas based on modified insulated concrete perforated brick with a sandwich. Modified brick was composed of three parts and three parts can be made a whole in brick manufacturing and it was called self-thermal insulation concrete perforated brick and could avoid appearance of cracks. The tesst was done to obtain thickness of EPS for modified insulated concrete perforated brick with a sandwich in order to meet the requirement of insulation. Thickness of EPS was set to to 45, 50, 55, 60, 65 and 75 mm respectively and comparative experiments were also carried out to verify the effect of insulation for modified bricks and unmodified bricks. Field tests were carried out to obtain appropriate masonry methods for modified bricks. Based on the results of analysis and discussion, then obtained: (1) Heat transfer coefficient of wall made by modified bricks was less than heat transfer coefficient of wall made by unmodified bricks when the same for thickness of EPS, it could be reduce by up to 45%; (2) When thickness of insulating layer was 65 mm, heat transfer coefficient of wall made by modified bricks could reached minimum limit 0.45 and it could meet energy saving requirement of 65% for buildings in cold area. (3) Insulating layer, located inside of the wall, could avoid appearance of cracks on surface of wall for modified bricks.

The Analysis on the Optimum Thickness of Square Air-Interlayer in Building Materials

2014 ◽  
Vol 685 ◽  
pp. 448-453
Author(s):  
Gang Chen ◽  
Li Guo Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Building Materials ◽  
Convection Heat Transfer ◽  
Engineering Application ◽  
Heat Transfer Process ◽  
Interlayer Thickness ◽  
Variation Rate

This paper conducts a simulation study on the natural convection heat transfer process in square air-interlayer. According to the meteorological parameters in regions of hot summer and cold winter, two typical boundary temperature contrast is selected 6.5 and15 °C, using Fluent software to simulate condition of air-interlayer in 10 groups of material with thickness from 6 to 60 mm respectively to draw conclusion on how heat transfer quantity, thermal resistance and heat transfer coefficient change with different thickness of the air-interlayer. The result of simulation shows that when the square air-interlayer thickness was about 20mm, the variation rate of the total heat flux and heat transfer coefficient reach a turning point. Thermal resistance will change slowly with a small numerical value after this point. Therefore, the optimum square air-interlayer thickness is 20mm. Combined with practical engineering application, it provides better technical support for research and development of energy-saving building materials.

scholarly journals Effects of diagonal bracing on thermal insulation of wood-frame walls

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 517-528
Author(s):  
Mingbin Liu ◽  
Feng Lu ◽  
Xuedong Zhang ◽  
Xiaolin Yang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Insulation ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Expanded Polystyrene Foam ◽  
Cold Area ◽  
Wood Frame ◽  
The Heat Transfer Coefficient

The influence of various diagonal-bracings arrangements on the heat transfer coefficient of wooden walls was studied with the goal of improving the thermal insulation performance of the walls. Through the reliability verification of the theoretical value of the heat transfer coefficient, this study found that a larger proportion of wood frame area resulted in larger theoretical and test values for the heat transfer coefficient. The heat transfer coefficient of the wall with expanded polystyrene foam sheet (EPS) was 5.90% to 6.10% higher than that with extruded polystyrene foam sheet (XPS), and the tested value was 4.75% to 8.60% higher. The maximum value of the average heat transfer coefficient of 12 diagonal-braced walls was 0.366 W·m-2·K-1, which met the thermal level of the severe cold area. The test value of the heat transfer coefficient was larger than the theoretically calculated value, and the linear correlation was up to 0.978.

scholarly journals Research on Energy-Saving Design of Rural Building Wall in Qinba Mountains Based on Uniform Radiation Field

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Qin Zhao ◽  
Xiaona Fan ◽  
Qing Wang ◽  
Guochen Sang ◽  
Yiyun Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Energy Consumption ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Radiation Field ◽  
Thermal Environment ◽  
Residential Buildings ◽  
South Wall ◽  
Heating Energy Consumption

How to create a healthy and comfortable indoor environment without causing a substantial increase in energy consumption has become a strategic problem that the development of all countries must face and solve. According to the climatic conditions of Qinba Mountains in China, combined with the characteristics of local rural residential buildings and residents’ living habits, the field survey and theoretical analysis were used to study the thermal environment status and the heating energy consumption condition of local rural residential buildings. The thermal design method of walls for the local rural energy-saving buildings based on the indoor uniform radiation field was explored by using the outdoor comprehensive temperature function expressed by the fourth-order harmonic Fourier series as the boundary condition of the wall thermal analysis. ANSYS CFX was adopted to study the suitability of the energy-saving wall structure designed by the above method. The results show that the indoor thermal environment of local rural residential buildings in winter is not ideal and the heating energy consumption is high, but this area has the geographical advantage to develop solar energy buildings. It is proposed that the indoor thermal comfort temperature of local rural residential buildings in winter should not be lower than 14°C. When the internal surface temperature of the external walls in different orientations are equally based on the design principle of uniform radiation field, the heat transfer coefficient of the east wall, the west wall, and the north wall of the local rural residential buildings is 1.13 times, 1.06 times, and 1.14 times of the south wall heat transfer coefficient, respectively. The energy-saving structural wall with KPI porous brick as the main material and the south wall heat transfer coefficient of 0.9 W/(m2·K) is the most suitable energy-saving wall for local rural residential buildings.

The Energy Saving Effect Evaluation for Outside Wall with Different Material in Island District

2011 ◽  
Vol 301-303 ◽  
pp. 377-383 ◽  
Author(s):  
Yan Zhang ◽  
Xi Wu Gong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Brick Wall ◽  
Insulating Layer ◽  
Aerated Concrete ◽  
Saving Effect ◽  
Insulation Performance ◽  
The Heat Transfer Coefficient

In order to evaluate the energy saving effect for building outside wall under the damp island environment, the heat insulation performance of brick wall, MU10 concrete brick wall and aerated concrete are tested. The testing method is combined of infrared photos and heat flow meter. The results showed that the insulation performance of clay brick is worst, its heat transfer coefficient is 60% more than that required by energy saving standard. Although the concrete brick has painted 25mm polystyrene granule outside, the heat transfer coefficient is still smaller than energy saving standard required. The economic thickness of polystyrene granule is 79mm , which makes the both heating cost and insulating layer minimum during the life cycle of heat insulating layer. Among the three types of outside wall, only the aerated concrete can satisfy the energy saving standard for hot summer and cold winter district, it constitutes the self-insulating system.

Fly Ash Autoclaved Aerated Concrete Self Thermal Insulation Building Envelope Energy Saving Research

2013 ◽  
Vol 448-453 ◽  
pp. 1243-1247 ◽  
Author(s):  
Li Bai ◽  
Ying Li ◽  
Shu Ming He
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Fly Ash ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Thermal Insulation ◽  
Building Envelope ◽  
Exterior Wall ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete

This article takes an actual public building in Changchun City as an example to field test the heat transfer coefficient of fly ash autoclaved aerated concrete exterior wall. By analysis the field test value, theory calculation value, and the maximum value of the design standard for energy efficiency of public building (GB50189-2005), I concluded that fly ash autoclaved aerated concrete self-thermal insulation building envelope exterior wall fully meet the energy-saving standard requirements, which does not need additional insulation material. And further as heat transfer coefficient of wall test and energy saving standard maximum heat transfer coefficient as the main parameter, I used DeST-c software simulation to calculate the building energy consumption. The simulation results showed that the heating energy consumption of fly ash autoclaved aerated concrete self-thermal insulation building envelope is 16.32% lower than the standards required value, which has the advantage of energy saving property.

Multi-Factors Analysis of Condenser Vacuum under Overall Working Conditions

2014 ◽  
Vol 654 ◽  
pp. 109-112
Author(s):  
Ning Ling Wang ◽  
Feng Ming Chu ◽  
Peng Fu ◽  
Zhi Ping Yang ◽  
Yong Ping Yang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Water Flow ◽  
Working Conditions ◽  
Thermal Power ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Circulating Water

It is of great significance to determine an optimal condenser vacuum for energy-saving diagnosis, for the vacuum means a lot to the safe and economic operation of thermal power units. The key parameters were calculated by the practical data, such as the cleanliness factor. The condenser heat transfer coefficient is affected by both the dirty of condenser water side and other factors on the basis of the method of adjusting the circulating-water flow unilaterally to get the optimal vacuum of condenser in this paper. The impacts of the exhausting steam resistance, the oxygen content of condensate caused by the change of the circulating-water flow were considered in this paper. The practical operation data was analysed with the results from HEI. The simulations were examined in the comparison of heat transfer coefficient. The impacts of unit energy consumption characteristics under overall working conditions caused by condenser vacuum were obtained in the approach based on the theory of energy specific fuel consumption (ESFC). The variation of auxiliary specific consumption as the temperature of circulating-water changing was obtained. The results indicated that the optimal condenser vacuum determined by the method aiming at maximum output power and many factors under overall working conditions accounted for played an important role in the energy saving diagnosis of thermal power units.

Evaporation of lignin-lean black liquor

TAPPI Journal ◽  
2015 ◽  
Vol 14 (7) ◽  
pp. 441-450
Author(s):  
HENRIK WALLMO, ◽  
ULF ANDERSSON ◽  
MATHIAS GOURDON ◽  
MARTIN WIMBY
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Black Liquor ◽  
Salt Content ◽  
Solubility Limit ◽  
Lignin Removal ◽  
Kraft Black Liquor ◽  
Black Liquors ◽  
The Heat Transfer Coefficient

Many of the pulp mill biorefinery concepts recently presented include removal of lignin from black liquor. In this work, the aim was to study how the change in liquor chemistry affected the evaporation of kraft black liquor when lignin was removed using the LignoBoost process. Lignin was removed from a softwood kraft black liquor and four different black liquors were studied: one reference black liquor (with no lignin extracted); two ligninlean black liquors with a lignin removal rate of 5.5% and 21%, respectively; and one liquor with maximum lignin removal of 60%. Evaporation tests were carried out at the research evaporator in Chalmers University of Technology. Studied parameters were liquor viscosity, boiling point rise, heat transfer coefficient, scaling propensity, changes in liquor chemical composition, and tube incrustation. It was found that the solubility limit for incrustation changed towards lower dry solids for the lignin-lean black liquors due to an increased salt content. The scaling obtained on the tubes was easily cleaned with thin liquor at 105°C. It was also shown that the liquor viscosity decreased exponentially with increased lignin outtake and hence, the heat transfer coefficient increased with increased lignin outtake. Long term tests, operated about 6 percentage dry solids units above the solubility limit for incrustation for all liquors, showed that the heat transfer coefficient increased from 650 W/m2K for the reference liquor to 1500 W/m2K for the liquor with highest lignin separation degree, 60%.

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