SOLAR PROTECTION SYSTEMS |
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Buildings with large glass areas represent one of the symbols of modern architecture. Glass surfaces allow making the most of the natural light, and thereby they fit naturally and harmonically into the surroundings.
Buildings with luminous glass facades do look attractive, but they also have a few disadvantages because solar energy and sun emission can cause problems in the interior of the building. |
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PC Ušće - Belgrade |
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In normal conditions, glazed areas without protection transmit 88% of solar energy, where 80% penetrates directly into the interior of the building. Walls and household furniture absorb solar emission and transform that energy into long thermal waves that are retained in the interior. This exact phenomenon is the cause of the “greenhouse effect” that causes heat accumulation in rooms.
If the outside temperature does not fall under the temperature in the interior of the building, the heat accumulated in rooms remains inside, and it cannot be reduced by transmitting the heat, nor by air circulation. Double glass windows have even lower heat transmission capacity.
In buildings with 50% or more of glazed areas, where windows are only single-glazed and exposed to sunlight without protection, and in case that windows are closed – interior room temperature reaches range from 10% to 15% higher than the temperature outside. For instance, when the outside temperature is 25°C, room temperature is 35°C or 40°C.
Significant Energy Saving
The extent of glass area of a building represents an important factor that influences electrical energy consumption. Cooling devices are necessary to maintain a pleasant temperature in rooms, especially during summer months. Nevertheless, in order to reach a pleasant temperature without cooling devices, the utilization of outdoor sunscreens, that can provide quality protection and besides be easy for maintenance, becomes a necessity. |
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NLB Banka - Beograd |
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CEBTP studies have shown that, using MERMET Sunscreen Satine 5500 protection sunscreens, we can reduce the maximum room temperature in different types of buildings by up to 6°C. The research was conducted during three normal sunny days in France. The difference between high and medium room inertia was minimal.
In rooms where, using air-conditioner, the temperature range was maintained at 25°C, utilization of MERMET Sunscreen Satine 5500 protection sunscreen has shown the possible amount of electrical energy saving.
• for rooms with high inertia, when protection sunscreens are mounted, cooling devices need 2000W of maximum power, while in rooms without protection sunscreens they must have 3800W power;
• for rooms with medium inertia, let us compare following figures: 2000W with, and 4100W without protection sunscreens.
In both examples, outdoor protection sunscreen installation has reduced energy consumption by 62% (15 kW/h a day with protection sunscreens).
Outdoor sunscreens represent a necessity and an important factor in modern buildings. They contribute equally to the aesthetics of the building and to overall comfortability, as well as to a significant energy saving.
A large choice of MERMET protection sunscreens provides perfect possibilities for protection against sun and rugged outdoor factors.
Sunscreens, besides their heat-protection capacity, need to retain good outward visibility, but at the same time must protect us from the curious glares from the outside. Filtrating the natural light, they prevent the sun's glare. Sunscreens' efficiency is based on the solar factor Fs and the shading coefficient Sc.
Solar factor is the the quantity of energy that passes through the glass:
SOLAR FACTOR |
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Graphic 2 |
1) energija sunčevog zraka koja udara u staklo prozora (100 %)
2) odbijanje energije sunčevih zraka
3) absorbovana energija u staklu koja izlazi napolje
4) energija sunčevih zraka koja ulazi u prostoriju
5) absorbovana energija u staklu koja ulazi u unutršanjost
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| Fs= |
Quantity of energy that passes through the glass into the room (4+5) |
| Quantity of total energy that hits the window glass (1) |
Shading coefficient is the ratio of solar factor in case when the window is protected (glass + sunscreen) and the solar factor in case of normal glass.
| Sc= |
Fs (glass + sunscreen) |
| Fs (glass) |
Solar protection coefficient (IPS) is the percentage of sun radiation reflected by the sunscreen:
IPS = (1- Sc)
Values that determine sunscreen efficiency must be given in precise measures for a certain type of glass and only in case of closed windows.
These values are also conditioned by other favorable or unfavorable factors. Besides the thickness and nature of the glass, equally important are the position and direction of the facade, difference between outside and inside temperature, as well as the space between sunscreen and the window.
The following diagram is based on CEBTP researches, and it shows the efficiency of MERMET Sunscreen Satine (protection sunscreen) on single and double glass windows.
This fabric is mainly intended for external sunscreens, and it rejects 82% of sun radiation (80% with single glass windows). Only 14% of total solar energy and radiation passes trough windows into the interior of the room (18% in case of single glass windows). When used in the interior side, solar factor is reduced by 64%.
MERMET SCREEN FABRICS TECHNICAL FEATURES
Fiberglass yarn fabric
The fabric has unique characteristics:
1. Solar energy protection up to 88% (installed on exterior-facing glass in rooms with medium inertia, it decreases the temperature by 5-10°C, which, as a result, reduces installed power of air conditioners by 50%, while the electrical energy consumption for air conditioning is reduced by 62%);
2. UV radiation protection from 97% to 100%;
3. A wide selection of weaving types and colors provides desired level of natural light in a room, as well as good contrast (outward visibility);
4. Non-flammable, self-extinguishing and non-melting (M1, B1 Fr standard);
5. Specific weight from ± 410 g/m²;
6. Stretch resistant (1m² area resists the load of 250 kg);
7. Permanently anti-static (it repels dust and does not require special maintenance);
8. Fabric does not absorb water or other liquid (resistant to atmosphere influences);
9. Total diffusion of transmitted light, providing 100% glare protection for electronic device screens (computer monitors, etc.);
10. More than twenty years of durability.
Indoor and outdoor parameters ratio:
Outdoor temperature: + 35°C » Indoor temperature: + 25°C
Infrared radiation outdoors: 100% » Infrared radiation indoors: 6%
UV radiation outdoors: 100% » UV radiation indoors: 0%
Heat effect outdoors: 100% » Heat effect indoors: 12%
Light outdoors: 100% » Light indoors: 85 – 80%.
Manufacturing technology process
Cutting and assembling of screen fabrics is done according to cold process of ultrasound cutting technology with side welding. The process of cold welding of PVC components in screen fabric ensures durability of welded borders and prevents mechanical damage of borders on sides of the screen fabric. This process provides the accurate desired dimensions of screen fabric, that therefore can be rolled regularly even without side channel guide systems.
Pocket on the bottom part of screen fabric, into which aluminum weight rod is inserted, is made in accordance with thermal welding technology, welding PVC structure onto the screen fabric. Width of the thermal weld is 10 mm and the screen fabric is nontransparent on the welding spot.
The same technological process (thermal welding on the upper part) is used for welding the screen fabric onto PVC panel tape (keder), which is then inserted into the aluminum tube sleeve.
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