SCGV specifications

Technique specifications

Super Heat Conduction Metal Vacuum Tube
for pressurized and un-pressurized tanks/ manifolds

Making full use of natural energy is the global permanent energy trend. The latest and most advanced series of Super Heat Conduction Metal Vacuum Tube is a totally new generation of hi-tech solar collector instead of all-glass evacuated solar collector tube. With the advantages such as high thermal efficiency, quick start-up, good anti-freezing function, excellence in resistance to cold and hot shock, all the year round operationand long lifetime, the SCGV tube will not be broken and will seldom be effected by the variation of the climate. Its working temperature ranges from -50 c ~ 420 c . The SCGV tube is not only the core part of the new generation solar water heater, but can also be widely used in many fields, for example, household space-heating, cooling and air-conditioning system, sea water desalination, aquiculture, material drying, swimming pool heating, etc.
The heat absorbing material for SCGV tube is the specially formed aluminum plate, on which the solar energy selective absorptive coatings are sputtered by the way of magnetic control. The SCGV tube has solved perfectly the stress problem of medium & high temperature hot-press seal for glass-metal joint by adapting laser welding technique and the special metal connection.

Technical data

Model type	SCGV Tube
Structure	Super Heat Conduction Metal Vacuum Tube
Glass material	High-quality borosilicate glass
Glass tube diameter	70mm
Wall thickness	2.5mm
Diameter of heat exchanging end	</span>14.5mm
Single tube weight	2.2kg
High vacuum, long-term stability	5.0-3Pa
Absorber material	Aluminum
Coating	Aluminum Nitride
Absorption coefficient	0.94 %
Emission coefficient	0.08 %
Wind resistance	30m/s
Freezing tolerance	-50c
Hail resistance	impact from up to 35mm hail
Insolation temperature	+ 250c
Start up temperature	+25c
Power output	76 watts per tube / 760watts-10 tube unit (3.414425 BTU/watt) per 10 tube unit, in 800 watts average sunshine.

Introduction II
    The new SCGV Tube is a revolutionary breakthrough in solar thermal-collecting technology as well as the symbol of a great leap in solar thermal technology.
    The very name of the SCGV tube suggests that the tube is a advanced solar thermal collector by the way of metal heat conduction, vacuum heat insulation, and super heat conduction by gravity. The tube is assembled with red copper pipe core of high efficiency in heat conduction, specially formed thermal absorbing aluminum plate, high-quality borosilicate glass, high temperature selective absorptive coatings sputtered by magnetic control and the medium & high temperature hot-press seal technology of the metal-glass connection. These are the most advanced usages and the perfect combination of so many technologies such as optics, thermodynamics, chemistry, metallography, electromagnetism, material science and environment-energy science inside the tube's slim body of 70mm/span>700mm.
   At present, many defects are found out in all-glass evacuated solar collector tube that used in common solar water heater after 10 years of service. The new generation of SCGV tubes successfully gets rid of these defects by the following advantages:

1. Heat-pipe conduction, no water inside,thus it is successfully prevented from the defects of tube block and low power output caused by water fouling and deposits of dust and sand.
2. It prevents the tube from being easily broken caused by the volume expansion when the water in tube freezes in the frigid seasons.
3.Low thermal capacity makes the tube start up quickly. Energy inside tube can be taken out within only 2 minutes under sunshine. The insulation temperature of the heat-pipe can reach 250c. The average heat efficiency can still be more than 50% even under -50c.
4.High efficient selective absorptive coatings and vacuum heat insulation technology ensure the tube to get higher heat output in cloudy weather and in moist area, especially in winter.
5.Solar collecting plate is installed and sealed inside the tube of high-quality borosilicate glass with 5/span>0-3Pa of vacuum, so it cannot be corroded even in moist area.
6. It perfectly solve the fatal defect of the common all-glass vacuum tube solar water heater, which will not run if one of the tubes is out of work.

SCGV tube is not only a leap and breakthrough in the technology of solar thermal utilization, but also the sign of the times. It has many advantages of high thermal absorbing efficiency, quick heat conduction, wide usages and long lifetime. With its excellent quality, metal heat exchanging end, crystal-like translucent borosilicate glass tube, equipped with the unique and perfect formed aluminum heat absorbing plate, SCGV tube stands out majestically from the others.

Structure feature:

SCGV tube is mainly assembled with heat-pipe, borosilicate glass tube, heat-collecting plates, metal cover, getter, heat exchanging end and aluminum safety-protection cap, etc. The magnetic-control sputtering selective absorptive coatings on the heat-collecting plates has a high absorption coefficient of more than 94%, and the emission tube is more than 5/span>10-3Pa, equipped with long effective air degassers to keep the setting vacuum degree inside the tube a constant. The structure and name of the parts are shown in illustration.
Operation principle: When sunshine and infrared ray reach the heat absorbing plate of SCGV tube, the inner X agent of heat-pipe is vaporized at 40c, the vapor flows to the heat exchanging end continuously, conducting the heat energy to the water in the tank or other low temperature object. Thus the vaporized X agent turns into liquid, returns to the original position and completes an operation circle.
Technique specification:
Material: borosilicate glass according to ISO3585: 1991; transmittance of borosilicate glass:? 0.92. Absorbance of solar selective absorptive coating: 0.94;
Hemispherical emittance : 0.08; Getter according to GB/T 9505-1998.
Start-up temperature : No more than 25 c .
Start-up time: no longer than 2 minutes under normal sunshine.
Isothermal performance: The temperature tolerance between any 2 random points does not exceed 2?after 5 minutes of working.
Low temperature resistance: No breaks at -50c.
Air pressure: P?5?/span>10-3Pa.
Heat impact resistance: No damages after over 3 times' alternative impacts of cold water below 25c and hot water over 90c.
Pressure resistance: can withstand 0.6 Mpa.
Hail resistance: no damage by the impact of +35 mm hail.
Appearance standard: the color of the selective absorptive coatings should be even, and the coatings should have no wrinkles and peelings. The support parts inside the tube should be correct and tight.
The allowed tolerance of borosilicate glass tube's diameter should be in accordance with ISO4803: 1978.
Camber of the borosilicate glass tube should be no more than 0.3%.
The transection of the borosilicate glass tube, which is 40-60mm away from flange end, should be round. The ratio of the longest to the shortest radial dimensions of the borosilicate glass tube should be no more than 1.02.
The diameter of the heat exchanging end is 14mm, and should be matched with the standard.