scholarly journals Study on thermodynamic functions of traditional building windows based on characters

2020 ◽  
pp. 251-251
Author(s):  
Yuelian Hu ◽  
Jing Zhuo
Keyword(s):  
Thermodynamic Function ◽  
Thermodynamic Functions ◽  
Indoor Environment ◽  
Building Envelope ◽  
Light Environment ◽  
Analysis Method ◽  
Interior Decoration ◽  
Heat Gain ◽  
Solar Heat ◽  
Surrounding Environment

The indoor light environment of the building has an extremely important influence on its own use function, and there are many factors that affect the indoor light environment of the building, such as the surrounding environment of the building, the interior decoration of the building, and the design of the window. The window is used as the building envelope. An important part of the structure is responsible for lighting and ventilation to meet the requirements of the indoor environment. It exists as a lighting device for the building. The lighting performance of the windows not only meets people's requirements for living comfort, but also consumes energy in the building. It will have a very important impact. A variety of window shapes start from different functional needs. The comprehensive use of these window shapes by traditional buildings together creates its unique thermodynamic function. This article analyzes cold regions based on the analysis method of thermodynamic functions. Solar heat gain from traditional building windows.

scholarly journals Development of a Reduced Order Model of Solar Heat Gains Prediction

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6316
Author(s):  
Meril Tamm ◽  
Jordi Macià Cid ◽  
Roser Capdevila Paramio ◽  
Joan Farnós Baulenas ◽  
Martin Thalfeldt ◽  
...  
Keyword(s):  
Early Stage ◽  
Gain Coefficient ◽  
Building Envelope ◽  
Reduced Order Model ◽  
National Standards ◽  
Order Model ◽  
Heat Gain ◽  
Reduced Order ◽  
Solar Heat ◽  
Solar Heat Gain

The aim of this study was to elaborate and validate a reduced order model able to forecast solar heat gains as a function of the architectural parameters that determine the solar heat gains. The study focused on office buildings in Catalonia and Spain and their physical values were taken from the Spanish Building Technical Code and European Union Directive 2018/844. A reduced order model with three direct variables (solar heat gain coefficient, shade factor, window to wall ratio) and one indirect design variable (building orientation) was obtained and validated in respect to the International Performance Measurement and Verification Protocol. Building envelope properties were fixed and the values were taken from the national standards of Spain. This work validates solar heat gain coefficient as a primary variable in determining the annual solar heat gains in a building. Further work of developed model could result in building energy need quick evaluation tool in terms of solar heat gains for architects in building early stage as it has an advantage over detailed building simulation programs in terms of instant calculation and the limited need for predefined input data.

Reducing Roof Solar Heat Gain by Using Double-Skin Ventilated Roofs

2020 ◽  
Vol 38 (3A) ◽  
pp. 402-411
Author(s):  
Mohannad R. Ghanim ◽  
Sabah T. Ahmed
Keyword(s):  
Inclination Angle ◽  
Convection Heat Transfer ◽  
Ventilation Rate ◽  
Channel Length ◽  
Air Gap ◽  
Galvanized Steel ◽  
Heat Gain ◽  
Solar Heat ◽  
Double Skin ◽  
Solar Heat Gain

Double skin ventilated roof is one of the important passive cooling techniques to reduce solar heat gain through roofs. In this research, an experimental study was performed to investigate the thermal behaviour of a double skin roof model. The model was made of two parallel galvanized steel plates. Galvanized steel has been used in the roof construction of industrial buildings and storehouses in Iraq. The effect of inclination angle (ϴ) from the horizontal and the spacing (S) between the plates was investigated at different radiation intensities. It is found that using a double skin roof arrangement with a sufficient air gap (S) can reduce the heat gain significantly. The higher the inclination angle (ϴ) the higher the ventilation rate, the lower the heat gain through the roof. In this study, increasing the air gap from 2 cm to 4 cm reduced the heat gain significantly but when the gap was further increased to 6 cm, the reduction in the heat flux was insignificant. A dimensionless correlation was also reduced between Nusselt number () and the single parameter  where L is the channel length. This correlation can be handily utilized for designing of engineering applications dealing with high temperature difference natural convection heat transfer.

Energy Saving Technology for Doors and Windows of the Building

2014 ◽  
Vol 1056 ◽  
pp. 128-130
Author(s):  
Fu Yun Yang
Keyword(s):  
Energy Saving ◽  
Indoor Environment ◽  
Energy Performance ◽  
Building Envelope ◽  
Energy Performance Of Buildings ◽  
Summer Heat ◽  
Energy Saving Technology ◽  
Heat Preservation

Doors and windows of the building is an important part of the building envelope. AS the transparent and open envelope of the building, doors and windowsare the weakest part in the winter and summer heat preservation. It directly affects the energy performance of buildings. Therefore, do a good job of building doors and windows energy saving is an important way to optimize the indoor environment and realize energy saving.

scholarly journals The Impact of Aspect Ratio on External Heat Gain of Multi-storey Office Buildings in Jakarta

2018 ◽  
Vol 16 (1) ◽  
pp. 24-31
Author(s):  
Wasiska Iyati ◽  
◽  
Eryani Nurma Yulita ◽  
Jusuf Thojib ◽  
Heru Sufianto ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Building Design ◽  
Climatic Conditions ◽  
Building Envelope ◽  
External Heat ◽  
Office Buildings ◽  
Office Building ◽  
Cooling Load ◽  
Heat Gain ◽  
The Impact

The narrow land in big cities such as Jakarta, increases the amount of high rise building, especially multi-storey office building. Office building consumes much energy to provide air conditioning to meet the thermal comfort inside the building. On the other hand, the building shape, building envelope, and building orientation to the sun's position are the main factors in building design aspects that affect the amount of cooling load. This study aims to investigate the impact of the aspect ratio or the ratio of the longer dimension of an oblong plan to the shorter, on external heat gain of multi-storey office building. Variables examined include the transparent and solid area of building envelope, the total area of the surface of the building envelope in any orientation, and the volume of the building, as well as the influence of those proportion on the external heat gain. This study uses mathematical calculations to predict the cooling load of the building, particularly external heat gain through the walls, roof and glass, as well as comparative analysis of models studied. The study also aims to generate the design criteria of building form and proportion of multi-storey office buildings envelope with lower external heat gain. In Jakarta climatic conditions, the result on rectangular building plan with aspect ratio of 1 to 4 shows that the external heat gain did not differ significantly, and the smallest heat gain is found on the aspect ratio of 1.8. Results also showed that the greater aspect ratio, the greater reduction of external heat gain obtained by changing the orientation of the longest side facing east-west into the north-south, about 2.79% up to 42.14% on the aspect ratio of 1.1 to 4. In addition, it is known that in same building volume, changing the number of floors from 10 to 50 can improve the external heat gain almost twice.

scholarly journals VEGETATION INSULATION SCREEN AS A PASSIVE COOLING SYSTEM IN HOT HUMID CLIMATE: HEAT AND MASS EXCHANGES

2021 ◽  
Vol 9 (10) ◽  
pp. 1368-1378
Author(s):  
Hodo-Abalo Samah ◽  
◽  
Magolmeena Banna ◽  
Belkacem Zeghmati ◽  
◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Cooling System ◽  
Gain Factor ◽  
Passive Cooling ◽  
Humid Climate ◽  
Heat Gain ◽  
Area Index ◽  
Solar Heat ◽  
Solar Heat Gain

Planted roofs are passive cooling techniques that reduce the thermal load of buildings. In this paper, a Dynamic mathematical model based ontime average Navier-Stokes equationsfor a plantedroof in hothumidclimates has beendeveloped for evaluating the cooling potential.Transfer equations are solved using a finite difference scheme and Thomas algorithm. The model was applied for the simulation of a planted roof in Togolese climate conditions. Results showed that, evapotranspiration and Solar Heat gain Factor are functions of the Leaf Area Index LAI which is the most important parameter when considering the foliage material. For LAI equal to 6, latent heat peak value reaches 900 W.m-2while that of sensible heat is around 350 W.m-2. Solar heat gain factor can bereducedto 15% fortheplantedroofagainst 45% forbareroof. It is clearly proved that the foliage density and hence the vegetation canopy type selection greatly influence the thermal efficiency of the bioclimatic insulation screen. A larger Leaf Area Index reduces the solar flux penetration and increases evapotranspiration which is an important parameter when considering surrounding microclimate formation.

Flex House

2011 ◽  
Author(s):  
Stanley Russell ◽  
Mark Weston ◽  
Yogi Goswami ◽  
Matthew Doll
Keyword(s):  
Closed System ◽  
State Of The Art ◽  
Building Envelope ◽  
Passive Cooling ◽  
Optimum Level ◽  
Seasonal Temperature ◽  
Zero Energy ◽  
Humid Climate ◽  
Heat Gain ◽  
Hot Humid Climate

Flex House is a flexible, modular, pre-fabricated zero energy building that can be mass produced and adapted easily to a variety of site conditions and plan configurations. The key factor shaping the design is central Florida’s hot humid climate and intense solar radiation. Flex house combines the wisdom of vernacular Florida houses with state of the art Zero Energy House technologies (ZEH.) A combined system of photovoltaic panels and solar thermal concentrating panels take advantage of the region’s abundant insolation in providing clean renewable energy for the house. Conservation is achieved with state of the art mechanical systems and innovative liquid desiccant dehumidification technology along with highly efficient lighting and appliances. The hybrid nature of the Flex house allows for both an open and closed system to take advantage of the seasonal temperature variation. Central Florida buildings can conserve energy by allowing natural ventilation to take advantage of passive cooling in the mild months of the year and use a closed system to utilize mechanical cooling when temperatures are too high for passive cooling strategies. The building envelope works equally well throughout the year combining an optimum level of insulation, resistance to air infiltration, transparency for daylight, and flexibility that allows for opening and closing of the house. Flex House is designed with a strong connection between interior spaces and the outdoors with carefully placed fenestration and a movable wall system which enables the house to transform in response to the temperature variations throughout the year. The house also addresses the massive heat gain that occurs through the roof, which can generate temperatures in excess of 140 degrees. Flex House incorporates a parasol-like outer structure that shades the roof, walls and courtyard minimizing heat gain through the building envelope. To be implemented on a large scale, ZEH must be affordable for people earning a moderate income. Site built construction is time consuming and wasteful and results in higher costs. Building homes in a controlled environment can reduce material waste, and construction costs while increasing efficiency. Pre-fabricating Flex House minimizes preparation time, waste and safety concerns and maximizes economy, quality control, efficiency and safety during the construction process. This paper is an account of the design and construction of Flex House, a ZEH for central Florida’s hot humid climate.

Effects of solar radiation and wind speed on metabolic heat production by two mammals with contrasting coat colours.

1995 ◽  
Vol 198 (7) ◽  
pp. 1499-1507 ◽  
Author(s):  
G E Walsberg ◽  
B O Wolf
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Heat Production ◽  
Metabolic Heat Production ◽  
Heat Gain ◽  
Solar Heat ◽  
Wind Speeds ◽  
Convective Heat Loss ◽  
Metabolic Heat ◽  
Solar Heat Gain

We report the first empirical data describing the interactive effects of simultaneous changes in irradiance and convection on energy expenditure by live mammals. Whole-animal rates of solar heat gain and convective heat loss were measured for representatives of two ground squirrel species, Spermophilus lateralis and Spermophilus saturatus, that contrast in coloration. Radiative heat gain was quantified as the decrease in metabolic heat production caused by the animal's exposure to simulated solar radiation. Changes in convective heat loss were quantified as the variation in metabolic heat production caused by changes in wind speed. For both species, exposure to 780 W m-2 of simulated solar radiation significantly reduced metabolic heat production at all wind speeds measured. Reductions were greatest at lower wind speeds, reaching 42% in S. lateralis and 29% in S. saturatus. Solar heat gain, expressed per unit body surface area, did not differ significantly between the two species. This heat gain equalled 14-21% of the radiant energy intercepted by S. lateralis and 18-22% of that intercepted by S. saturatus. Body resistance, an index of animal insulation, declined by only 10% in S. saturatus and 13% in S. lateralis as wind speed increased from 0.5 to 4.0 ms-1. These data demonstrate that solar heat gain can be essentially constant, despite marked differences in animal coloration, and that variable exposure to wind and sunlight can have important consequences for both thermoregulatory stress experienced by animals and their patterns of energy allocation.

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