EVACUATED TUBE SOLAR TECHNOLOGY

Australian Sun Energy is the proud distributor of "Greenlandsystems evacuated tube solar hot water system "

Single walled vacuum tubes (evacuated tubes) were developed in Germany by Daimler-Benz Aerospace mid 1980's, with support from Sunda Solar SEIDO in 1986. Over ten years of co-operative research and development by Sino-German experts have resulted in today's cutting edge design and superior solar performance for solar hot water systems.

Evacuated tube solar systems are ideal for domestic and commercial solar hot water systems, GreenLand System’s Sunda's evacuated vacuum solar tubes are also readily suited for OEM manufacturers and can be used for various kinds of commercial and industrial solar water applications.

Australian Sun Energy evacuated solar tubes absorber and heat pipe are mounted in a highly stable borosilicate single walled vacuum glass tube and are the thickest of any solar tube on the market at this time. This also prevents damage and heat loss that occurs in conventional flat plate solar water collectors.

The absorber is sputtered with aluminium nitride selective coating to ensure high absorption and highest efficiencies - this improves the efficiency by as much as 40-60% on cloudy days compared to flat plate solar hot water systems and when the evacuated tubes are recycled at the end of their life no nasty chemicals are required.

Heat Pipe Technology

Heat pipes act like a low-resistance thermal conductor. Due to their thermal-physical properties, their heat transfer rate is thousands of times greater than that of the best solid heat conductor of the same dimensions. Sunda's SEIDO heat pipe is a closed system comprised of two metres of copper tubing, an evaporator section, a capillary wick structure, a condenser section and a small amount of vaporizable fluid.

The heat pipe employs an evaporating-condensing cycle. The evaporator section is tightly bonded to the absorber plate, where it captures the heat from the absorber and evaporates the liquid to steam, which moves up to the condenser section. The condenser protrudes out from the evacuated tube and is inserted into the heat exchanger manifold. There this steam will be condensed by water flowing through the manifold. Latent heat energy will be released to the process water through this phase change of vapour to liquid. In vacuum tube solar collectors, the condensation zone is at a higher level than the evaporation zone. The transport medium condenses and returns to the evaporation zone under the influence of gravity. This process is repeated continuously thereby heating the water in the solar loop.

Advantages of Australian Sun Energy solar hot water Technology:

•  High heat transmission rate for solar hot water

•  Fast start-up for solar hot water systems

•  One-way heat conduction

•  The homogeneous heat distributing on the surface of the condenser

SELECTIVE COATING

The absorber is treated with an aluminium-nitride selective coating to achieve highest efficiency of the heat transfer. The coating is applied using a magnetic sputtering technique. This special optical coating transforms more than 92% of the incoming solar irradiation into heat and reduces it to less than 8% heat loss.

Advantages of the Technology:

•  High absorptance to guarantee the effective heat from solar irradiation

•  Low emittance against the heat loss by heat emission

HEAT PRESSURE SEALING AND EVACUATED

Heat pipes are inserted into the aluminium absorbers forming assemblies, which in turn are inserted into the glass tubes. The tubes are made of borosilicate glass which is strong and has a high transmittance for solar irradiation.

In order to reduce the convection heat loss, glass tubes are evacuated to vacuum pressure of <10-5 mbar. GreenLand Systems use a patented technique employing high heat and pressure to insure stable glass-to-metal vacuum seals. In order to keep the stability of the vacuum for a long time, a barium "getter" is used. Through evacuating air out of the glass tube the absorber material and the selective coating are protected from corrosion and other environment influences ensuring a working lifetime of optimal performance, without loss of efficiency.

•  More cost effective

•  Frost free below 800 metres

•  Fast start-up due to small thermal capacity

•  Low heat loss due to thermal diode effect

•  High vacuum with long-term stability

•  High pressure resistance

•  Reliable and durable

•  Easy installation and maintenance

•  Easy integration into buildings

Australian Sun Energy evacuated solar hot water systems efficiently deliver solar hot water all year round - even in winter, and on cold and overcast days.

These collectors are a breakthrough in solar hot water technology.

The GreenLand Systems solar collector with vacuum tube and heat pipe construction is a true four season hot water system ideal for lower temperate areas.

The Number 1 choice for domestic solar hot water. Latest technology vacuum solar water tube system and dry heat interface.

KEY BENEFITS:

•  Out performs most other collectors - even in winter for heating solar water

•  Save on power bills

•  Reduce emissions and help the environment

•  Affordable

ALL YEAR ROUND PERFORMANCE - EVEN IN WINTER

Australian Sun Energy evacuated solar tube collectors incorporate the latest in solar water technology and perform efficiently the whole year around, not just during the hot summer months across all Australian states.

By utilising a 'dry heat interface' within the vacuum tube, the GreenLand Systems solar collector tubes ensure that solar hot water is available, even in winter, or on a cloudy day when most other collectors do not collect any heat at all.

KEY BENEFITS:

•  Excellent heat transfer

•  Long life peak performance for producing solar hot water

•  Minimum maintenance

•  Quick and easy installation for plumbers

•  Australian Standards compliant

•  12 year guarantee on evacuated solar tubes

The evacuated solar collectors are made within a totally environmentally friendly manufacturing process.