Suntask and the Environment!
Owning a Suntask is a practical way to help reduce greenhouse gas emissions in our atmosphere. Occasionally,the sun's radiation needs a helping hand to maintain your hot water temperature. This mainly occurs during continual cloudy days in the winter season...
Exper direction
Exper direction
Evacuated Tube solar water heaters are made up of rows of parallel, glass tubes. There are several types of evacuated tubes (sometimes also referred to as Solar Tubes).

Type 1 (Glass-Glass) tubes consists of two glass tubes which are fused together at one end. The inner tube is coated with a selective surface that absorbs solar energy well but inhibits radiative heat loss. The air is withdrawn ("evacuated") from the space between the two glass tubes to form a vacuum, which eliminates conductive and convective heat loss. These tubes perform very well in overcast conditions as well as low temperatures. Because the tube is 100% glass, the problem with loss of vacuum due to a broken seal is greatly minimized. Glass-glass solar tubes may be used in a number of different ways, including direct flow, heat pipe, or U pipe configuration. Shentai uses a high efficiency heat pipe and heat transfer fin design to conduct the heat from within the evacuated tube up to the header.

Type 2 (Glass-Metal) tubes consist of a single glass tube. Inside the tube is a flat or curved aluminium plate which is attached to a copper heat pipe or water flow pipe. The aluminium plate is generally coated with Tinox, or similar selective coating. These type of tubes are very efficient but can have problems relating to loss of vacuum. This is primarily due to the fact that their seal is glass to metal. The heat expansion rates of these two materials. Glass-glass tubes although not quite as efficient glass-metal tubes are generally more reliable and much cheaper.

Flat-Plate collectors comprise of an insulated, weatherproof box containing a dark absorber plate under one or more transparent or translucent covers. Water or heat conducting fluid passes through pipes located below the absorber plate. As the fluid flows through the pipes it is heated. This style of collector, although inferior in many ways to evacuated tube collectors, is still the most common type of collector in many countries.For more information about effciency of all other colledtor. please contact me:

Solar Energy
The energy required to raise the temperature of a substance is a physical property known as the specific heat of the particular substance. The specific heat of water is 4.2J/g/ , i.e. 4.2 joules of energy are required to raise the temperature of one gram of water by one degree centigrade. Using larger and more familiar units:

Step1 : Energy required (kJ) = 4.2 x volume (litres) x temperature rise (

Energy required (MJ)= Energy required (kJ)/1000

Energy required (Kwh)= Energy required (MJ)/3.6

Step2 : Collector area required() = (Energy demand)/[(Solar energy per ) x (collector efficiency)]

Thus, in order to consider energy sources for water heating, the parameters that must be known are the volume of water required in a given time period (hour, day), the temperature of the 'cold' water, and the required delivery temperature. Hot water may be used for a variety of purposes, but as an example, domestic use is considerable. Here usage varies widely; in industrialised countries an average of around 50 litres per person per day is normal, in developing countries the more wealthy inhabitants may use this amount or more, while the poor may not use hot water at all. For more information about Solar Energy or Solar Efficiency , please contact me with
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Shentai Solar Inc @ 2010 Zhejiang Shentai Solar Energy Co., Ltd. professionally manufactures solar water heater,solar collector.
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