Home

FAQ of the solar water heater systems

Solar energy is the cleanest and most inexhaustible of all known energy sources. Solar radiation is the heat, light and other radiant energy that is emitted from the sun. The sun's energy, although plentiful, has been hard to directly harness until recently.

Solar water heater converts solar energy into thermal energy, then heat the water step by step. The beauty of this system is it does not create pollution or harmful emissions, and is extremely economical - the fuel (sunshine) is free! Plus, they are environmentally friendly. To take full advantage of these heaters, you should ideally have an unshaded, south-facing location (a roof, for example) on your property, although they can be utilized at ground level also. This type of Solar water heater is now extremely popular in many areas of the world, are are now becoming much more popular in the Europe, due to their high efficiency.

Until now, solar panels were not particularly popular in the Europe due to their low efficiencies during the spring, autumn and winter months. Classic solar panels (flat plate collectors)  work equally well as radiators - and therefore unless ambient temperature is high, heat losses are considerable. Flat plate collectors, despite their poor performance, have remained the panel of choice until now, due to their low cost, and DIY-suitability. However, we are now able to offer much higher efficiency vacuum tube collectors at similar prices to flat plate collectors.

1. Introduction of every part of the pressurized solar water heater system with separated tank system.

1. Collector 2. Collector Sensor 3. Manual Air Valve

4. Hot Water to Taps 5. Tempering Valve 6. Collector Return

7. Check Valve 8. Hose Bibs for Filling and Flushing 9. Expansion Tank

10. Air Scoop & Air Vent 11. Circulating Pump with Flanges Or Couplings 12. Pressure Relief Valve

13. Pressure Gauge 14. Collector Supply 15. Heat Exchange Coil

16. Solar Hot Water Tank 17. Immersion Heater 18. USDT 2001 Controller

2. Introduction of the vacuum tube

The vacuum tube solar panel has been around for over 10years, and has proved to be reliable and dependable. The vacuum tubes consist of a double wall glass tube (made from strong borosilicate glass ie pyrex) with a space in the centre which contains the heat pipe. The sun's radiation is absorbed by the selective coating on the inner glass surface, but prevented from re-radiating by the silvered innermost lining. This is in effect like a one-way mirror which has been optimized for infra-red radiation. In fact it is very efficient, of the sun light's energy hitting the tube's surface, 93% is absorbed, whereas only 7% is lost through reflection and re-emission. The presence of the vacuum wall prevents any losses by conduction or convection - just like a thermos flask. Because of this, the system will work even in very low temperatures, unlike traditional flat plate collectors. This is why our system can be used to heat up water at the South Pole Antarctic Science Base - where ambient air temperatures can drop below -40°C

Heat Pipe Vacuum Tube Technical 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/T9505-1998
Copper Heater pipe: φ8×0.8×1500 or φ8×0.8×1800
Start-up temperature: no more than 25
Start-up time: no longer than 2 minutes under normal sunshine.
Low temperature resistance: no breaks at -30
Heat impact resistance: no damages after over 3 times' alternative impacts of cold water below 25 and hot water over 90.
Pressure resistance: can withstand 0.6Mpa
Hail resistance: no damage by the impact of Φ25mm hail
Appearance standard: the color of the selective absorptive coatings should be even, and the coatings should have no wrinkles and peelings. The allowed tolerance of borosilicate glad tube's diameter should be in accordance with ISO4803:1978. camber of
the borosilicate glass tube should be no more than 0.3%. The translation 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 heat transferred to the tip of the heat pipe is in turn transferred to a copper manifold in which water circulates to heat the domestic hot water tank. If a tube is placed in direct sunlight on a summer day, the tip temperature can reach 250°C - so the system easily heats domestic hot water cylinders to 60°C even in cooler weather! The manifold is heavily insulated with a 2" thickness of pre-formed rockwool to keep the heat in. Unlike flat plates, these headers are so well insulated that they should not require antifreeze in normal operation - the temperature of the header is unlikely to fall below 10°C even in very cold weather. The more advanced solar controllers include a low-temperature facility- should the temperature of the collector fall below a defined level, the pump will operate to allow the the water at the bottom of the tank to heat the collector slightly. In normal conditions, this would never be necessary - but it acts as a good safety margin.

3. The technical Specifications of the Roof-Mounted system

Solar collector technical Specifications Manifold Casing Material: 304 Stainless Steel of Powder Coated Aluminum Frame Material: C12200 Copper Insulation: Polyurethane 55mm Rubber Seals and Rings: UV stabilized high temperature silicone rubber Optimal installation angle: 30-70°Vertical,0°Horizontal Maximum Operating Pressure: 6bar-85psi Pressure Drop: 700Pa@3.3L/min for 20 tube manifold(SRCC) Optimal flow rate: 0.1L/min/tube-0.026G/min/tube Performance Data(SPF): Conversion Factor: ho=0.717 Loss Coefficients:a1=1.52,a2=0.0085

4. A Word on Flat Plates

Experienced dealers/installers do not recommend flat plates for the Northern Europe. However, there are some customers that insist on flat plate panels, usually for aesthetic reasons. If this is the case, you can fit a selective-coating flat plate panel. These are not as efficient as vacuum tube panels - so their output will suffer in cold, overcast or windy weather - but with the selective absorption coating, our panels are as good as the best flat plates on the market.

Flat plate collectors only provide a useful amount of heat during the summer months in the Northern Europe. due to their high heat losses during cold or windy weather. When the ambient temperature drops, the heat loss can easily exceed the heat gain - turning your flat plate solar collector into a radiator! The reason for the popularity of flat plate collectors is their cheap construction - you can build one yourself for a few pounds worth of scrap material, or you can buy one for $600-1000. Once upon a time, flat plate panel prices were a lot cheaper than evacuated tube panels, which typically cost $1600-2400.......We have changed all this!

Vacuum tube collectors will provide useful heat for 12months of the year, as long as the sun is shining, and can even produce heat in overcast weather. In April, an overcast day without any sunshine is still able to heat a 210litre hot water cylinder to 40°C with our vacuum tubes. A sunny day in April will warm the cylinder as high as 60C using our panels!

5. A WORD ABOUT OUR PRICES:

There are about 3000 factories to manufacture solar water heater in China and quotation of solar collector module per square is about 60~150 USD with different quality. However, quality is the first concern of our company. Therefore, we provide 10 years warranty on our solar water heater.

6. TRADE ENQUIRIES WELCOMED!

We are building a network of distributors across North America and Europe. This is quite important for us, as it is difficult to transport a single box of tubes by courier (as they all seem to throw parcels around). However, we can transport larger quantities with much less trouble. We are currently looking for potential distributors in Europe and North America.

7. BRAND NAMES:

Our panel is similar to 'Thermomax' and visually identical to the 'Apricus' brand; We are one of ISO-9001 Certified OEM manufacturers of solar water heater and would like to suit our products to your local market under your own brand name - as you will see your brand name etched into the surface of the glass. In fact our panel is identical to several other panels on the market (from the US, Switzerland and Germany). This is because our factory produces panels for some of the biggest names in vacuum tube solar panels - which are simply re-branded once they reach Europe.

8. More photos

Go Top