Brief History of Water Solar Panels
Posted by admin on Aug 23, 2009
Sun and sunlight have been utilized by mankind for ages. It served to spark a fire, boil water or measure time with sundials. It was a long way from then to the modern water solar panels of these days. This article gives a brief outline of water solar panel’s history
One of the most ancient energetic use of the sunlight supposedly goes back to old Babylon of 2000 B.C.. Dark water containers were exposed to the sun to heat up the water. Later on there, sun heated pigmented water was used as a transfer fluid in one of the world’s oldest “water solar panels”.
In China, small concave mirrors were used to spark a fire around 700 B.C..
Furthermore it is said that the Grecian mathematician and inventor Archimedes of Syracus, who lived more than 2200 years ago between 285 and 212 B.C.set light to the Roma
n fleet with the aid of concave mirrors (see picture).
Picture: Copperplate engraving on the title page of the Latin edition of “Thesaurus Opticus”, which was written by Arabic academic Alhazen. The picture shows Archimedes of Syracus setting light to the Roman Fleet with the aid of concave mirrors. Source: Bavarian National Library
In 1767, Swiss natural scientist and physicist Horace-Bénedict de Saussure constructed his “capteur solaire” (sun catcher). This early form of water solar panels consisted of 5 stacked glass cases on a black base and reached temperatures up to 88°C / 190°F and, as rumor has it, even up to 110°C / 230°F.
Flat Plate Solar Collector (Flat Water Solar Panel)
De Saussure’s sun catcher is deemed to be the forerunner for today’s Flat Plate Water Solar Panels, aptly named “Thermal Solar Collectors” or in short “Solar Collectors”.
In the 1870’s, French engineers Augustin B. Mouchot and Abel J. Pifre combined concave mirrors with a thermal solar collector and built the first solar powered steam engine. They aimed the focus of a parabolic reflector at a black painted steam boiler and thus managed to drive a water pump.
Evacuated Tube Solar Collector (Vacuum Water Solar Panel)
The precursor for today’s evacuated tube water solar panels has been the thermos flask, invented by the Scotch physicist James Dewar in 1893. (So-called Dewar tubes, using Dewar’s insulation technology, are core elements in parabolic trough collectors today.) Adapted from the Dewar flask, US American electrical engineer William Le Roy Emmet developed vacuum tubes to utilize solar power. His work is the basis of today’s evacuated tube water solar panels.
Water Solar Panels – the main different types
Posted by admin on Aug 22, 2009
The core of all heat and electricity producing water solar panels is a collector. For this reason water solar panels are correctly named “Thermal Solar Collectors” or “Solar Collectors”.
Heat producing water solar panels
A distinction is drawn here between 2 types of collectors: Flat Plate Collectors and Evacuated Tube Collectors.
Flat plate collectors in water solar panels
The flat plate consists of an coated absorber to absorb solar radiation and convert them into heat. The absorber is installed in a damped case to reduce heat loss. Its faceplate, mostly glass, is transparent to let pass the solar radiation. Inside the water solar panel absorber
are tubes that are filled with transfer liquid. This liquid passes a heat exchanger to heat up water for domestic use such as heating, shower and pool heating.
Advantages of flat plate water solar panels:
- many different options of mounting
- complaisant integration into rooftops
- reasonably priced
Evacuated tubes in water solar panels
Those types are also known as vacuum tube collectors. They consist of glass tubes which are strung together. These tubes are vacuum insulated, highly reflective and weather proof metalized. Inside the evacuated tubes run tube loops, again filled with transfer liquid to pass a heat exchanger and boil domestic water for pool heating, house heating and shower.
Advantages of evacuated tube water solar panels
- higher degree of efficiency, especially at times of lower insolation
- some makings allow the replacement of single modules
- visually interesting
Electricity producing water solar panels
Electricity generating “water solar panels” are not (yet) used in private households. They are used almost exclusively in solar power generating plants. These solar collectors produce hot steam to drive electric generators. Three major types of collectors are used:
1. Parabolic dishes. They concentrate the sunlight at a narrow focus and reach the highest temperatures.
2. Parabolic troughs. These are trough shaped parabolic mirrors. They focus on an air insulated Dewar tube, filled with transfer liquid.
3. Power tower. A power tower consists of self aligning mirrors. The concentrate insolation on a receiver at the top of the tower. Power towers can be considered as a colossal parabolic dish.
