Energy-Efficient Active Reflectors with Improved Mechanical Stability and Improved Thermal Performance

Author(s):  
Samuel C. Bradford ◽  
Douglas C. Hofmann ◽  
Scott N. Roberts ◽  
John B. Steeves ◽  
Charles S. Wojnar ◽  
...  
Arsitektura ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 129
Author(s):  
Sri Yuliani ◽  
Wiwik Setyaningsih

<p class="Abstract"><em>The surface temperature of the building material may release a heat load in the micro-environment. The largest building envelope receives the heat load of solar radiation is the roof. The strategic roof position at the top of the building has the opportunity to radiate heat received into the environment. Heat emissions lead to rising temperatures, so it is necessary to lower the temperature in micro-environment. When the heat of the building is not lowered will lead to an increase in the urban heat island (UHI). The objective of the study was to find the relationship between the thermal performance of the roof of the building and the energy efficiency in the high-rise building, in order to establish efficient thermal comfort. The research method uses experimental way in real model which is in Surakarta City, as humid tropical climate area. The result of the study is a comparison of the heat performance of three roofing materials which would later recommend the criteria of energy efficient roof for high buildings.</em><em></em></p>


Buildings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 95
Author(s):  
Khaled Tarabieh ◽  
Ahmed Aboulmagd

The demand for energy-efficient housing is on the rise in Egypt. The information about the individual materials used in the construction of typical residential wall assemblies are known in the literature. However, data from lab tests to validate the performance for whole composite walls are limited. Three typical wall types were constructed and tested utilizing a standard experimental evaluation procedure based on thermal convection loads. A research framework combining the validated thermal performance data from the experimental test and the simulated data was developed. The experimental tests were performed utilizing a state-of-the-art guarded hotbox apparatus and following the guidelines of the ASTM C1363-11 standard. The solar radiation load was taken into account in the calculations according to the standard, and the error estimation and uncertainty analysis for the experimental tests are reported. The results of the experimental testing are described and a recommendation of the best wall type is noted. The output of this research will help to initiate a material database of the thermal performance of typical residential wall types used in Egypt that have been validated in the lab. This will be useful for the building industry as a whole to understand the performance of the materials in composite assemblies and their impact on energy efficiency.


Author(s):  
John Kie-Whan Oh ◽  
Jeffrey S. Haberl ◽  
Larry O. Degelman

Abstract The goal of this study was to develop a computer model for solar radiation calculation and display and a shaded fenestration design system that can be used by architectural and engineering designers. This computerized model calculates the amount of insolation and transmitted solar radiation through a shaded window as well as the heat transfer through it. The computer model, called Shaded Fenestration Design (SFD), contains various functions relating to solar simulation such as: display of the sunpath diagrams and the accompanying shading mask protractor, display of the hourly intensity of solar radiation onto the path of the sun for horizontal and vertical surfaces at varying off-south azimuths, and simulating the thermal performance of a shaded fenestration. The model also provides graphical aids for energy-efficient shading device design with use of various kinds of sunpath diagrams and solar radiation diagrams. The model performs solar radiation simulation using the methods developed in the ASHRAE Handbook, Duffie and Beckman, and Kreider and Rabl. An anisotrophic sky model was applied for the calculation of solar radiation on a titled surface and the transmitted solar radiation through a single-glazed window. A part of the model was validated experimentally using a physical test box and was also compared to simulated results from the DOE-2 program; however, the validation is not included in this paper.


2019 ◽  
Vol 13 (3) ◽  
pp. 513-532
Author(s):  
Javad Asad Poor ◽  
David Thorpe ◽  
Yong Wah Goh

Purpose Regarding the contribution of Australian small-size housing in the enhancement of total energy consumption of the country and the roles of the occupants’ preferences in successful implementation of action plans, the purpose of this study is to identify the Australian occupants’ collaborative image of housing energy efficiency. The two main objectives are, therefore, to address the main energy-related housing physical factors that have the potential in representing the housing image of Australian occupants and to explain the causal factors that make the physical factors critical to their energy efficiency perception. Design/methodology/approach This study has been developed through a qualitative approach. Given that the images encompass a wide range of information expressing human perceptions, an online photo-based qualitative survey was developed based on previous research works. The survey includes respondents’ demographic profiles and the evaluation of images, asking for their perception of overall housing energy efficiency, the impacts of building envelope physical attributes on the energy efficiency of the houses and the reasons behind the selection of different attributes. Findings This study has developed a set of attribute-based factors, explaining occupants’ collective perception of energy efficient small-size housing of Brisbane in the area of exterior aspects of the buildings. Specifically, the collaborative image of small-size housing of Brisbane is about the thermal performance of the buildings provided through passive climatic principles by using more efficient envelope features, e.g. material, colour, transparency, texture, openings, balconies and shadowing devices, while ignoring the impacts of architectural composition principles along neighbourhood quality. The key attributes in assessing the small-housing energy efficiency are ventilation, thermal performance and shadowing. The housing images in old traditional architectural style with rural face, built by stone, brick and concrete in high dense vegetation were evaluated to be more energy efficient than those with modern architecture, built by large glass panel and metal cladding with light or no vegetation. Research limitations/implications The main limitation of the paper is related to the nature of an image-based survey, which leads to ignoring some aspects of real spaces such as odour, temperature and noise. Practical implications This research has the potential for developing a practical methodology for assessing housing-resident fit using computer-based methodology and neural networks. Social implications This research has the potential for developing a methodology, assisting the end users in meeting their desires and motivations by helping them in assessing how a housing unit fits with their expectations and preferences. Originality/value This research provides a reliable conceptual platform for dealing with the complexity of occupants’ housing perceptions. This is achieved by establishing a collective conceptual picture of these environmental perceptions, namely, housing image, which is a platform for transferring abstract data related to human perception into measurable and quantitative scales.


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