Solar energy is the beam of light and heat from the sun which is bound together using a range of continuously developing technologies.
Types of solar energy
Technology to produce solar energy can be active or passive depending on how it is captured, converted and distributed.
Passive solar energy is when the orientation of the building is such that the structure itself uses sun by using favorable thermal or light dispersing materials to achieve desired results and also designing the building in such a way that it has natural circulation of air. Thermal materials like stone, cement and water have been used in warm temperate regions to keep buildings cool by absorbing solar heat during the day and radiating stored heat to cool the structure at night. They can also be used in cold temperate areas to maintain warmth as well.
The size and placement of thermal materials depend on several factors such as climate, daylighting and shading conditions. When adequately used, these can maintain space temperatures in a comfortable range and reduces the need for other heating and cooling equipment. One can also use dark colors as they absorb more heat than light ones. One can designs home in such a way that 60% of the windows face south as this reduces heating requirements by approximately 25%.
A solar chimney is an example of passive solar ventilation system. As the chimney warms, the air inside is heated causing hot air to move up through the building.
For passive solar energy it has to be planned at the designing stage. If not done in advance then it becomes a costly and difficult proposition.
Solar thermal heaters and solar water heaters are used to heat water and spaces by using solar panels to absorb heat and distribute it throughout the house, through radiators. Solar water heaters are commonly used in area where the average temperatures are below 40-degree celsius. It can easily provide 60% or more of your heating and hot water requirement in the winter and summer. You can get 20 to 25 years from the system.
Active solar energy is when photovoltaic systems is used to make electricity from sunlight, and it is simple, effective, and durable. A solar electric system is very cost effective for home and offices. It uses the mid-day sun to convert into electricity and this electricity can be used when day light is minimum or nil. Clean energy gives us clean environment. Many government and non-government agencies give subsidies up to 50% for household solar system installation. The solar panels convert approximately 15% to 40% of the sun’s energy into electricity depending on the complexity of the photovoltaic cells. China is the world leader in its use.
Israel and Cyprus are leaders in per capita use of solar water heaters. In USA, Canada and Australia the main use of this energy is to heat pool water. Remote areas are getting cheap electricity through solar power. Solar panels are installed on lamp post for street lighting and traffic lights.
Large buildings and residences are also using solar power for electricity and heating. By the year 2050 solar power will become the world’s largest source of electricity of the global consumption producing 16% through photovoltaic cells and 11% through concentrated solar power.
In 2016 solar power generated was 1.3% of the global power. According to CNBC, approximately 1.3 million homes in America have installed rooftop solar panels and centralized solar farms contributing to 40 gigawatts. Worldwide, 75 gigawatts energy is produced through these. Germany and Scandinavian countries are leader users of household solar panels.
Household solar panels save cost, reduce carbon footprints and you do not depend on power companies. Always use power efficient or power saver electrical equipment at home and in offices so that no solar energy gets wasted. When planning for residential solar installation, estimate your requirement and budget. Many devices and tools are there to help assess your home’s solar energy requirement. A technical person will accurately assess and suggest you the best option and will also provide you with an estimate.
Types of residential solar panels
There are several types of residential solar installation panel:
- Monocrystalline solar panel
- Polycrystalline solar panel
- Thin film solar cells
- Amorphous silicon solar cell
- Concentrated photo voltaic cells
- Bio hybrid solar cells
- Cadmium telluride solar cells
Monocrystalline solar panel are the purest and expensive panels. These are most efficient, converting 20% of the sunlight to energy, space saving and have life expectancy of 25 years. They can even perform in cloudy weather.
Polycrystalline solar panel are made from multiple pieces of silicon melted together. This process makes them less efficient, they convert only 15% of sunlight into energy. These take up more space to install.
Thin film solar cells are also known as thin film amorphous silicon solar panels. These are much less efficient (7-10%) than crystalline ones. These are easy to make so mass production is possible. Fluctuation in weather does not affect them. These require lots of space, so if you have space constraint then these are not suitable for you. Their life expectancy is less than 25 years.
Concentrated photo voltaic cells have very high performance and efficiency rate. These can convert 41% of sun energy. For their high efficiency solar tracking and cooling system is required.
Bio hybrid solar cells are still under research. Trying to produce energy through the simple process of photosynthesis i.e. taking advantage of this simple process to generate electricity and heat.
Cadmium telluride solar cells are produced at a low cost but are toxic in nature so people are apprehensive to use it.
For residential solar system installation, one has to calculate average daily electricity usage. This can be easily calculated from the monthly electricity bill. There are certain advantages in using this source of energy as it is renewable source, reduces electricity bills, one source can be used to generate both electricity and heat and maintenance cost is low.
Disadvantages are high installation cost, low efficiency in cloudy weather, expensive storage of energy and requirement of large open space for installation.