Solar-termal technology
Warmth through solar energy
Everyone has at one point seen how quickly a garden hose filled with water heats up when left lying in the sun! Solar heating functions similarly. The sun is utilized to heat up potable water, swimming pools or for backup heating.
Solar heating is heat recovery through solar energy.
The beginnings of solar termal
The flat-plate collector principle
The historical roots of the flat-plate collector date back to the Swiss naturalist, de Saussure, who in 1767 developed a glass "heating box", the precursor to today's flat-plate collector.
On this basis, the French engineer Augustin Mouchot combined the collector principle with the well-known concave mirrors to produce the first concentrated collectors that, with high temperatures, could transform water to steam and propel a small steam engine.
Evacuated tube collectors
The historical roots of the evacuated tube collectors go back to the invention of the thermos flask. The Scottish physicist, James Dewar, invented in 1893 a double-walled receptacle with a vacuum between the receptacle walls - the thermos flask.
Based on the principle of the thermos flask, Emmet developed evacuated tubes to utilize solar energy back in 1909. His patents from way back then are today still the basis for state-of-the-art evacuated tube technology.
The historical roots of the flat-plate collector date back to the Swiss naturalist, de Saussure, who in 1767 developed a glass "heating box", the precursor to today's flat-plate collector.
On this basis, the French engineer Augustin Mouchot combined the collector principle with the well-known concave mirrors to produce the first concentrated collectors that, with high temperatures, could transform water to steam and propel a small steam engine.
Evacuated tube collectors
The historical roots of the evacuated tube collectors go back to the invention of the thermos flask. The Scottish physicist, James Dewar, invented in 1893 a double-walled receptacle with a vacuum between the receptacle walls - the thermos flask.
Based on the principle of the thermos flask, Emmet developed evacuated tubes to utilize solar energy back in 1909. His patents from way back then are today still the basis for state-of-the-art evacuated tube technology.
Collector systems
The heart of a thermal solar heating system is the collector. Collectors are basically divided into flat-plate collectors and evacuated tube collectors.
Flat-plate collectors
A flat-plat collector consists of a selectively coated absorber plate that absorbs the sun’s radiation hitting the plate and transforms it into heat. In order to minimize heat loss, these absorbers are embedded in heat-insulated enclosures with a transparent cover (most commonly glass). The above-described heating medium flows through the tubes integrated in the absorber.- Cost effective
- Wide variety of assembly and mounting options
- Harmonic roof integration
Evacuated tube collectors
An evacuated-tube collector consists of parallel rows of glass tubes. These glass tubes are vacuum-isolated, highly reflecting and weather resistant. The heat carrier fluid inside these glass tubes, usually a mixture of water and ecologically sound anti-freeze, serves to transform the sun's radiation into heat.- High efficiency, particularly during periods of low radiation (e.g. during winter)
- Interesting look
- Some manufacturers enable the exchange of individual elements
Storage technologies
Besides the heart of the thermal solar system, the collector, there is the storage technology. In this sense, we basically differentiate between warm water tanks and solar combi-systems.
Warm water tank systems
The warm water tank system is larger than the conventional warm water storage tanks as it holds solar heat for about 2 – 3 days. It stands upright and has a narrow construction in which water layers with varying temperatures form. The warm water is lighter and rises upward to the upper part of the tank, ready for use. Once it is removed, colder water below flows upward, and being heated in the process continues to rise.The solar warmth is transferred to the drinking water via the lower heat exchanger. Once the temperature in the upper section of the tank is high enough, the water is heated to the desired temperature with the upper heat exchanger of the central heating boiler.
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