Solar thermal energy (STE) is a technology for harnessing solar energy for thermal energy (heat). Solar thermal collectors are defined by the USA Energy Information Administration as low-, medium-, or high-temperature collectors. Low temperature collectors are flat plates generally used to heat swimming pools. Medium-temperature collectors are also usually flat plates but are used for creating hot water for residential and commercial use. High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production. - Wikipedia on Solar Thermal Energy

Solar thermal applications use heat from the sun for:

• water heating
• ventilation
• industrial process heat
• water distillation and disinfection
• and many other applications

One of the most cost-effective ways to include renewable technologies into a building is by incorporating solar hot water. A typical residential solar water-heating system reduces the need for conventional water heating by nearly 67%. It minimizes the expense of electricity or fossil fuel to heat the water and reduces the associated environmental impacts.

Solar Water Heating for Buildings

Solar water heaters use the sun to heat either water or a heat-transfer fluid in the collector. Heated water is then held in the storage tank ready for use, with a conventional system providing additional heating as necessary. The tank can be a modified standard water heater, but it is usually larger and very well insulated.

Solar water heating systems can be either active or passive:

• Active solar water heaters are the most common systems. They rely on electric pumps, and controllers to circulate water, or other heat-transfer fluids through the collectors.

• Passive solar water heaters rely on gravity and the tendency for water to naturally circulate as it is heated. Because they contain no electrical components, passive systems are generally more reliable, easier to maintain, and possibly have a longer work life than active systems.

The most environmentally-friendly method of domestic hot water heating, as well as a backup/supplement for low-temperature heating purposes.

Thanks to the highly effective Sol-Titan coating, the vacuum tube collector Vitosol 300-T can even utilize diffused solar radiation. It is therefore suitable not only for domestic hot water applications, but also as a backup for central heating purposes.

• High level of operational reliability and a long service life thanks to the use of high-grade, corrosion-resistant materials such as special solar glass, copper and stainless steel. Durable, vacuum-tight glass-to-metal seal.
  
  
• High efficiency thanks to the Sol-Titan coated absorber and vacuum collector tubes.
  
  
• Energy-efficient Duotec wrap-around pipe heat exchanger, which almost completely encases the condensers to facilitate better heat transfer.
  
  
• The condenser has a flexible connection to the vacuum tube via a stainless steel corrugated pipe. The individual tubes can be adjusted for optimum alignment to the sun during original placement.
  
  
• The dry connection of the collector tubes allows for individual tubes to be mounted and disassembled without having to drain the solar heating system.
  
  
• Proven Viessmann plug-in system for connecting several collectors to form one collector panel with a total surface area of up to 65 ft2 - 6 m2.
  
  
• A fully integrated solar system package available:
  

• Vitosol 300-T vacuum tube collectors
• Vitocell 100 or 300 hot water storage tank
• Solar-Divicon pump station
• Vitosolic control unit
• Solar expansion tank, Tyfocor solar fill
• System fill manifold