Vaccum-Tube-Collector

MAGNETRON SPUTTERING PLATING EVACUATED GLASS TUBE

 

MEDORS EVACUATED TUBES:

Evacuated tubes absorb solar energy and convert it into heat for use in water heating.  There are several types of evacuated tubes used in solar thermal collectors. Borosilicate Evacuated tubes are the most commonly used ones. This type of tube is chosen for its reliability, performance and cost effectiveness. Each evacuated tube consists of two glass tubes made from extremely strong borosilicate glass. Borosilicate glass is a strong glass that can withstand high internal pressure and external force. The outer tube is transparent and allows sunlight to pass through with minimal reflection. The inner tube is coated with an aluminum nitride coating.  During the manufacturing process, the air contained in the space between the two layers of glass is pumped out, while the top of the tubes are exposed to high temperatures.  This fuses the two tubes together into a single evacuated tube.  This "evacuation" of the gasses forms a vacuum, which is the most important factor in achieving the high performance of the evacuated tubes. The vacuum eliminates the physical connection between the two glass layers of the tube so that there is no loss of thermal energy. The insulation properties are so good that while the inside of the tube may be 150oC / 304oF, the outer tube remains within a few degrees of the ambient air temperature. This means that evacuated tube water heaters can perform well in cold weather, when flat plate collectors perform poorly in these conditions due to heat loss.

In order to maintain the vacuum between the two glass layers, a barium getter is used. This barium layer actively absorbs any CO, CO2, N2, O2, H2O and H2 out-gassed from the evacuated tube during it's lifetime and increases the longevity of the vacuum.  This barium layer also provides a clear visual indication of the vacuum status; the silver-colored barium layer turns white if the vacuum is lost making it easy to identify.

Individual evacuated tubes are inserted into a manifold of 10, 20 or 30 tubes in order to form a complete collector.  When oriented toward True South, a passive tracking effect is achieved in the collector due to the round absorption surface, meaning the collector is absorbing the sun's radiant energy throughout the day and not just when the sun is directly overhead.  In an East West orientation, a similar effect is achieved as the sun rises and falls across the sky over the course of the year.

The efficiency of an evacuated water heater is strongly related to the intensity of the solar radiation (known as "insulation") in your location.

Medors Solar evacuated tube collectors are one of the highest quality collectors in the market. Triple layers of extremely durable borosilicate glass maintain a vacuum layer which acts as a magnificent insulator.

With this superior insulation property, Medors evacuated tube collectors have the ability to generate heat through the winter in colder climates with overcast conditions and even during foggy weathers.

Features: Technical Specifications

Length

1500mm

1800mm

Outer tube diameter

47mm

58mm

Inner tube diameter

37mm

47mm

Weight

2.1kg

2.9kg

Glass thickness

2.2mm

2.2mm

Material

Borosilicate Glass 3.3

Borosilicate Glass 3.3

Absorptive coating

Graded CU/SS-ALN

Graded CU/SS-ALN

Vacuum degree

P<5*10 -3 Pa

P<5*10 -3 Pa

Thermal expansion

3.3*10 -6 /°C

3.3*10 -6 /°C

Insolation Temperature

>390°C

>390°C

Absorptance

>93%

>96%

Emittance

<8%

<8%

Heat loss

<0.8W/(m2°C)

<0.8W/(m2°C)

Maximum strength

0.8Mpa

0.8Mpa

Resist cold

-35 °C

-35 °C

Resist hailstone

Ø 50mm

Ø 50mm

Resist wind

50m/s

50m/s

Start-up temperature

<=25°C

<=25°C


 

Item No.

Specification

Effective collector
area m2

Diameter of solar tube

Length of solar tube

MRE4715

Ø47mm

1.5M

0.0966

MRE5818

Ø58mm

1.8M

0.1350

 

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