The evacuated (vacuum) tube:
Each evacuated tube is composed of two concentric glass tubes ; the inner one is coated with highly selective layer and it converts solar radiation into thermal energy, as for the outer one, it is a cover to keep the vacuum . Both tubes are fused together and the gap between them is evacuated to achieve excellent thermal vacuum insulation .
Technical Info Specifications:
Glass material | borosilicate glass |
Glass thickness | 1.6mm |
Coating | graded AL-N/AL |
Degree of vacuum | >5x10-3 Pa |
Hail proof | 25mm |
Absorption coefficient | >0.92 |
Emittance | <0.08 |
Average heat loss coefficient | < 0.6 W(m2.C° )-1 |
Maximum temperature | 200C |
Service life | 15-20 years |
Size of single tube | 58x1800 mm |
Structure | Dual layered water cylinders |
Inner tank material | stainless steel 304 Food grade |
Inner tank thickness | 0.4mm |
Outer tank material | PVDF Coated galvanized steel |
Outer tank thickness | 0.4mm |
Tank insulation | 50mm polyurethane |
Silicon rubber | UV stabilized high temperature |
Working pressure | non pressure system |
Testing pressure | 2 Bar |
Cold Water Inlet | ½” |
Hot Water Outlet | ½” |
Packing | Recycled Card Board (Export) |
Manufacturer Warranty | 5 years |
Material | Coated galvanized steel |
Thickness | 1.2 mm |
Tilt angle | 45 Degree |
Dimensions | (W,L,H) 170-155-130CM |
Weight | 61.88 Kg |
Why vacuum tubes?
Vacuum (evacuated) tube works like well-known, a thermos flask, which uses vacuum to provide thermal insulation; once the evacuated tube absorbs the radiation from the sun and converts it to heat; the vacuum helps keep the heat. The vacuum insulation makes evacuated tube collector excel the traditional flat plate collector in performance.
What are the main advantages of evacuated tube over flat plates collectors?
1. Increased efficiency: Due to the tabular shape of the evacuated tubes, the sun is always perpendicular to the surface of the glass for most of the day. Flat plate reaches maximum efficiency only at noon time.
2. Minimal heat loss: Since air is evacuated from the glass tubes to form a vacuum, it reduces the heat loss from the tube. This means that wind and colder temperatures have less effect on the collector’s efficiency.
3. Freeze protection: Evacuated tube collectors can be used in freezing conditions without the system being damaged. Flat plates require more sophisticated antifreeze systems which increases maintenance costs and lowers efficiency
