TYPES OF SOLAR ENERGY TECHNOLOGY

There are two major types of solar energy technology; the Photovoltaic Solar Technology and the Solar Thermal Technology.

Photovoltaic Solar Technology

The photovoltaic solar technology converts sunlight into electricity by using panels made of semiconductor cells. When Photons (light particles) from the sun hit the panels, it excites the outermost electrons of the atoms of semiconductor elements present in the panel thereby creating electricity. In a photovoltaic cell, this semiconductor is generally silicon. The solar panels produce direct current which must then be converted into alternating current by an inverter in order to safely provide electricity to a building.

There are various kinds of Photovoltaic Solar Technology, they include:

• Crystalline Silicon : Monocrystalline , Polycrystalline
• Thin-Film Solar Panels
• Biohybrid Solar Cells.

 

 

 

 

 

 

 

 

 

 

 

Solar Thermal Technology

Solar Thermal Technology captures the sun’s heat and this heat is used either directly (low temperature solar thermal) or converted into mechanical energy which in turn produces electricity, known as concentrated solar power. There are two types of Thermal Solar Technology:

• Low-Temperature Solar Thermal Power.
• Concentrated Solar Power. 

Low-temperature solar thermal power

     Low-temperature solar thermal power technology produces heat from the Sun’s rays and uses it directly. Operating at temperatures below 100°C, the installations cater to residential and commercial applications (hot water and heating) as well as to a wide variety of industrial needs. This technology accounts for the lion’s share of solar power generated worldwide. Solar thermal collectors are used to absorb the heat from the Sun’s rays and transfer it to a heat transfer fluid, such as air, water or antifreeze, which in turn transports it to the areas to be heated. Most widespread are flat-plate collectors, which are made up of a dark surface area that absorbs the Sun’s rays and a layer of thermal insulation topped with a sheet of glass that generates a green house effect. Collectors operate at up to 70°C above ambient temperature.

Solar thermal is a simple and cost-effective way of heating your water and will typically convert around half of the solar energy falling on the solar collectors into heated water. The best location for a flat solar collector is on a sloping roof, preferably facing south, but east/west systems work well. The solar collector is connected to your hot water tank by a flow and return pipe, and the glycol (antifreeze), is circulated around this system by a small electric pump controlled by a pump station. This glycol is heated by passing through the solar collectors and in turn passes through a coil in your hot water tank, heating the water.

The two types of Low-Temperature Solar Thermal Power are:

 

 

 

 

 

 

Concentrated Solar Power

The second type of thermal solar power technology concentrates the warmth of the Sun’s rays using collectors to heat a transfer fluid (gas, oil or molten salt, for example) to a high temperature . The fluid heats a network of water, which produces steam and drives a turbine (mechanical energy), thereby generating electricity. Heat from the Sun’s rays is collected in large power plants where flat or curved mirrors are installed over vast areas. The technology is best suited to countries where the sunlight is intense, for example in desert regions.

Determining the exact type of Solar technology to adopt for our home should depend on your specific energy demands. Looking at a common home where hot water is needed and electricity is needed, it is advised to combine both the Photovoltaic Solar Technology and the Solar Thermal technology (Low-Temperature Solar Thermal). The Photovoltaic Solar Technology should be installed strictly for electricity generation while the Low Temperature Solar Thermal should be installed for water heating and space heating purposes.

In choosing the exact type of these technologies to adopt, Two types of Photovoltaic Solar Technology that can be widely chosen are the Monocrystalline and Polycrystalline technologies and they are learnt to be more practical to use. Monocrystalline solar panels are the panels with the highest efficiency rates as it is manufactured from highest grade silicon and it has highest power outputs even at low light conditions.

For the Solar Thermal Technology, the Concentrated Solar Power requires a lot of space and is more useful in very hot regions for electricity generation, therefore it would not be needed in a household. However, the Low Temperature Solar Thermal would help provide hot water for a household. In choosing between the two types of Low Temperature Solar Thermal identified,  the Evacuated Tube Solar Collector would be recommended for adoption in a household because it has several advantages over the Flat Plate Collector. Some of the advantages of the Evacuated Tube Solar Collector include; its ability to capture sunlight better as it has a greater surface area exposed to the sun at any time, it is more efficient in transferring heat, up to 163%, it is durable and if a tube should be broken, it can easily and cheaply be replaced, it provides excellent performance in overcast conditions, it requires a smaller roof area than comparable flat plate collectors and it does not have the same level of corrosion problems as flat plate collectors.