What Are Solar Collectors?
Although solar panels are the most known device when it comes to solar energy, Solar thermal collectors are also very efficient and are used to collect heat by absorbing sunlight. Solar thermal is also used for capturing solar radiation, which is energy in the form of electromagnetic radiation consisting of both infrared and ultraviolet waves. This can occur due to the huge quantity of sunlight that hits Earth’s surface on a daily basis.
Solar collectors can be either non-concentrating or concentrating. The difference between them is that concentrating collectors have a bigger interceptor than the absorber, while the non-concentrating collectors have them both with same sizes. Flat-plate and evacuated-tube solar collectors are used for domestic purposes, such as space heating, hot water or cooling.
Flat-plate solar collectors are the most common ones. They consist of an absorber, a transparent cover and insulation.The main use of the technology is usually in residential buildings where the demand for hot water is big and affects bills. Commercial application of flat-plate collectors is usually seen in car washes, laundromats, military laundry facilities or restaurants.
Solar water heating systems are expected to be much more cost efficient, especially for facilities with huge hot water demand (kitchens, laundries and etc.) Flat-plate solar collectors show a good price-performance ratio and also give a lot of mounting options (on the roof, within the roof itself or standalone).
This is a type of a vacuum collector, its absorber strip is placed in an evacuated and pressure proof glass tube. The heat transfer fluid flows directly the absorber into a U-tube or in a tube-in-tube system. The heat pipe collector integrates a special fluid, which evaporates even at low temperatures, thus the steam rises in the individual heat pipes and warms up the fluid in the main pipe, generating heat. Thermodynamic panels are also based on such a refrigerant fluid but are exploiting the heat in the ambient air, and, therefore, are only suitable for hot water.
The technology is very reliable as it has an estimated lifespan of 25 years. The vacuum that surrounds the outside of the tubes greatly reduces the risk of heat loss, therefore efficiency is greater than it is with flat-plate collectors.
There are also solar collectors that can be used for generating electricity. Parabolic troughs, solar parabolic dishes and power towers are used in solar power stations or for research purposes.
This specific type of solar collector is mainly used in solar power plants. The technology utilises trough-shaped parabolic reflector to concentrate sunlight on an insulated tube or a heat pipe, placed in the focal point. Thus the generated heat is transferred to the boilers in the power station.
What differentiates this technology is that with this solar collector, a few dishes can be utilised and they can concentrate solar energy at the same focal point. Like the other collectors, it’s mainly used in solar power plants and also for researchers. The dish is aligned in a way that allows it to collect almost all of the solar radiation that hits Earth’s surface. Most efficiency losses come because of slight imperfections in the shape of the dish. Losses due to weather conditions are usually minimal, however, on a rainy foggy day, sun rays are usually distributed in all directions.
A power tower is a big tower fenced by tracking mirrors called heliostats. They align themselves in order to track the sunlight, collect it and transfer it to the top of the tower, where the receiver is, the received heat is transferred to a power station below. The power tower makes it cheaper to cover much larger area with relatively inexpensive mirrors opposed to the traditional solar cells.
However efficiency can be a problem as the power tower needs perfect weather conditions at almost all the time, while solar cells still produce very good amount of energy even when the sky is completely cloudy.
Solar Collectors or Solar Cells
Solar collectors are a great invention, however they are not quite perfect for the regular customer who just wants to generate his own electricity. The collectors need perfect weather conditions, which is hard to get in many parts of the world. On the other hand solar cells and panels are a perfect solution for the people who want to generate their own eco friendly energy. Even though price-wise they could end up costing you more, the government has launched schemes that benefits people who are willing to go solar.
So if you are considering going solar yourself, you can receive quotes by filling in the form on the right. You will receive the best quotes from suppliers nearby you and you will be free to choose! This serive is free and non-binding.