Shading Devices to Limit Solar Heat Gain But Increase Cold Sky Radiation

1965 ◽  
Vol 8 (4) ◽  
pp. 0470-0472
Author(s):  
L. W. Neubauer and R. D. Cramer
Keyword(s):  
Heat Gain ◽  
Solar Heat ◽  
Solar Heat Gain ◽  
Shading Devices

Hot-cool box calorimetric determination of the solar heat gain coefficient and the U-value of internal shading devices

2017 ◽  
Vol 10 (6) ◽  
pp. 1553-1571 ◽  
Author(s):  
Ayelén Villalba ◽  
Erica Correa ◽  
Andrea Pattini ◽  
Daniel Vicare
Keyword(s):  
Gain Coefficient ◽  
Heat Gain ◽  
Solar Heat ◽  
U Value ◽  
Solar Heat Gain ◽  
Shading Devices ◽  
Calorimetric Determination

scholarly journals Method of assessing the reduction of solar heat on window surface shaded by continuous vertically slanted shading devices

2021 ◽  
Vol 15 (3) ◽  
pp. 185-198
Author(s):  
Tran Ngoc Chan ◽  
Pham Thi Hai Ha ◽  
Pham Van Luong ◽  
Nguyen Thi Khanh Phuong
Keyword(s):  
Diffuse Radiation ◽  
Heat Gain ◽  
Slant Angle ◽  
Solar Heat ◽  
Solar Shading ◽  
Reduction Coefficient ◽  
Gain Reduction ◽  
Solar Heat Gain ◽  
Shading Devices ◽  
Shading Device

The research discusses calibration of the method used to calculate solar heat transfer through shaded windows with continuous vertical slanted shading devices (below is abbreviated as "vertical slanted fins") with any slant angle Θ through a radiation reduction coefficient - Kbt. In order to evaluate the reduction of solar heat on window surface shaded by shading devices, a designated coefficient β of solar heat gain reduction through glazed windows should be established. It is the ratio of the transmitted amount of solar heat (including direct and diffuse radiation) through windows with shading device QK to those without solar shading device QKo. The study also introduces two in-house software programs. These programs help calculating solar heat gain and coefficient β for vertically slanted fins with any slant angle θ for 16 window orientations. The results of this study will be applied to the implementation of the Vietnamese national code QCVN 09:2017/BXD towards energy efficiency in buildings.

scholarly journals Daylight glare mitigation by internal shading devices use and effects on building energy performance

2019 ◽  
pp. 164-184
Author(s):  
Dayan de Loyola R. Garcia ◽  
Fernando Oscar R. Pereira
Keyword(s):  
Thermal Environment ◽  
Building Design ◽  
Energy Performance ◽  
Design Guidelines ◽  
Indoor Environmental Quality ◽  
Heat Gain ◽  
Solar Heat ◽  
Solar Heat Gain ◽  
Shading Devices ◽  
Building Cooling

Daylight glare arouses buildings’ occupants to insert internal shading devices. When solving glare issues, shading strategies can increase internal temperature and building cooling energy consumption, especially in hot climates. Indoor environmental quality has been treated through architectural and engineering projects utilising spatial-temporal metrics and controls algorithms. This article focused on investigating some interactions between user behaviour, shading devices proprieties, and their effects on building’s luminous and thermal environment. This research aimed to relate daylight glare probability’s reductions through internal shading devices uses, with their effects on the window’s solar heat gain and energy cooling demand. Using building modelling and simulation approach through Rhinoceros 3D 5.0 and plug-ins Grasshopper+DIVA, Daylight Glare Probability (DGP) hourly values were generated for an occupant, 1.5 m away from the window at a side lit-room. The open-access model is a typical private office in the multi-floors building. Window’s solar heat gains and energy cooling demands were recorded using EnergyPlus 8.4 software. The model was simulated in East, West, North and South orientations, at Florianópolis. Subtropical Brazilian city. Starting from ‘without solar control’ cases, 8 controls were applied to 4 internal shading devices: blinds 50°, blinds 0°, curtains and roller shades. Clearer and darker colours were considered by two proprieties sets. From two fixed obstruction modes (100% and 50%), DGPintolerable (>45%) and direct solar radiation (>50W/m²) were applied to proposed monthly, daily and automatic controls. DGPintolerable annual frequencies at uncontrolled condition varied from 30% to 65%. These differences pointed out design guidelines according to façades. It has been confirmed that 0° blinds don’t secure daylight glare and increase energy cooling demand. Dark roller shades, curtains and blinds 50° completely solved glare problems, controlled by ‘always 100% closed’ mode and DGPintolerable based controls. Clear devices still allowed 2% of DGPintolerable frequency. However, clear roller shades contributed to reducing annual cooling demand until 11.5% while other devices achieved until 52% increase. Dark curtains indicated maximum increased in annual window’s solar heat gain (3%). Obtained results allowed identifying some design guidelines to balance daylight glare protection and energy-efficiency, contributing to sustainable building design and low impact architecture.

scholarly journals SURVEY OF THERMAL INSULATION PERFORMANCE AND SOLAR HEAT GAIN PERFORMANCE OF WINDOWS WITH SHADING DEVICES USING A FULL-SCALE EXPERIMENTAL BUILDING

2020 ◽  
Vol 26 (64) ◽  
pp. 1001-1006
Author(s):  
Keiichiro TANIGUCHI ◽  
Masayuki MAE ◽  
Siyu JI ◽  
Kozo TAKASE ◽  
Teruki KOJIMA ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Full Scale ◽  
Heat Gain ◽  
Solar Heat ◽  
Solar Heat Gain ◽  
Shading Devices ◽  
Insulation Performance

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.

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.

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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