Flat plate collectors
Flat-plate solar collector is one type of the solar collectors. The other major types are evacuated tube collectors and batch solar heaters. It is the most familiar solar collectors to use in solar water-heating systems and mostly use for homes and small office buildings for solar space heating. It is basically included of “an insulated metal box with a glass or plastic cover (the glazing) and a dark-colored absorber plate.”
- Tubular collectors
Different principals of evacuated tubular calculator are heat pipe evacuated tubular calculator and all glass evacuated tubular calculator. The simplest modules are made of two connected tube. The selective surface on the outer side of the inner tube is vacuumed incased. The fluid to extract heat must be passed in and out at the same end of the inner tube. One major of disadvantage of this collector compare to others is the necessity of using cylindrical shape.
- Compound parabolic collectors
If we want to stay away from the need of keeping the collector aperture pointed to the sun we are able to simply use compound parabolic collector. We can collect and concentrate solar energy from multiple directions to the one point. By using this technique when the sun moves across the sky we can accept and concentrate the solar thermal energy all day.
- Parabolic concentrators
Increasing solar energy capture can be reached by employing longer curved reflectors to take larger areas for sunshine and redirect that solar energy to a smaller center. The parabolic collectors can produce more solar energies at the focal plane or focal line. Because of the geometry and aperture of the collector it must directly face the sun to avoid loss of collection efficiency and maintain the location so the collector need complex and expensive mechanical tracking devices to keep it pointed to the sun all the time.
- Dish concentrators
Dish concentrators using parabolic dish formed mirrors to focus the received solar radiation onto a receiver that is situated at the focal point of the dish. The fluid in the receiver is heated to very high temperatures and then used to generate electricity in a small sterling engine which is attached to the receiver. Parabolic dish systems are the most efficient of all solar technologies “at approximately 25% efficient compare to around 20% for other solar thermal technologies.”
- Heliostat fields
The middle receiver solar power plant is composed to the lots of independently stirred mirrors which is called heliostat. They are focusing the solar radiation onto a tower mounted receiver. The amount of the energy which is received all depends on three different things. “First the characteristic angles of individual heliostats, second the incidence angle of the sun rays striking individual heliostats and the third the blocking and shading effect of each heliostat.”