Solar Energy Applications
Solar energy technologies use energy from the sun to produce heat, light, hot water, electricity, and even cooling, for homes, commercial and industrial.
There are a variety of technological applications that have been developed to take advantage of solar energy. Technology can be read further below.
Photovoltaics System
Solar cells work by converting sunlight directly into electricity. The electrons in the semiconductor material, the material used to capture sunlight, will move when the sun’s energy in the form of photons hit it. Solar energy is forcing the electrons to move, occur continuously, and consequently there is also a continuous electricity production. Process, which turns sunlight (photons) into electricity (voltage), called the photovoltaic effect.
Solar Cell Module
Solar cells are usually organized into modules that each module can consist of 40 solar cells. Some modules can be arranged to form a PV line fitted with a fixed angle facing south. Or even could be placed in a sun-tracking device, to get more solar energy throughout the day. Several rows of PV could produce enough power for a house. As for industrial applications or power companies, hundreds of lines of PV can be linked to form one large PV systems and sufficient to meet the electricity needs.
Thin Film Solar Cell
Thin film solar cells use several layers of semiconductor material with a thickness in the micrometer scale. Technology allows to create solar cells integrated into rooftops to the skylights. Even solar cells are designed for applications having the same power with actual roof.
Concentrated Solar Cell
Some solar cells are also designed to work with concentrated sunlight. Solar cells are integrated into the sunlight collector which usually uses a lens to focus it onto the solar cells. There are several advantages and disadvantages by using this technique when compared with flat plate solar panels. Its main objective is to use a minimum of expensive semiconductor material while increasing efficiency with more solar energy doubling of the cell surface. But because the lens must be directed to the sun, the use of collectors limited by location or region that get the most sunlight. Almost the same as flat plate solar panels, this technology can also be mounted on sun tracking devices are simple, but most use a sophisticated device. As a result, the use of solar cell technology is still limited to the power company, industry and large buildings.
Solar Cell Performance
Solar cell performance can be measured by looking at its efficiency in turning sunlight into electricity. Only a certain energy range from the sun which can efficiently converted to electricity, and most of it is reflected or absorbed by the material forming solar cells.
Because some of these, then the efficiency of commercial solar cells is only 15%, or about one-sixth of the sunlight that produce electricity. The lower efficiency, the more wide solar panels needed, and that is, the more expensive price to be paid. Increasing efficiency solar cells while maintaining low prices is a challenge that must be
solved. Until now, little by little these challenges can be overcome, as evidenced by the efficiency of the current 15% which in the 1950s, the efficiency is still less than 4%.
Solar Water Heaters
Shallow water in a pond or lake tend to hotter than the water in the deeper places. This occurs because the sun can heat the bottom of a pond or lake in the more shallow areas, and that means water that was on it become hot too.
With the same principle, the sunlight can be used as a water heater in the building and swimming pool. Most of the water heating system that uses the sun as a source of heat, consists of two main parts: the sun collector and storage tank. Collector commonly used are flat plate collectors. Collector consists of a thin flat box with a transparent top cover and facing toward the sun. Small pipes in the box with liquid, which can be water or other liquid, to be heated. The pipes are attached to a black plate that serves to absorb heat from the sun. After the heat formed in the collector, the fluid inside the pipes get hot.
Hot liquid is then flow to the storage tank which usually larger and thermally insulated better than conventional water heater storage tank. Systems that use a liquid instead of water, usually using the liquid to heat the water through the pipes like loops formed in the tank.
The system used can be active or passive systems, but the most commonly used is the active system. Active system works depends on the pump to move fluid from the collector to the storage tank. While passive systems rely on gravity to work with and the nature of water to circulate when heated.
The system used for the swimming pool is much simpler. Pool filter pump is used to drain water through a collector of sunlight, which is usually made of plastic or rubber, black, and hot water then flows back to the pool.
Solar Thermal
Most of currently existing power plants use fossil fuels as a source of heat to boil water. The resulting water vapor then turn turbines, which in turn drive generators to produce electricity. But now came into power generation using solar concentrator system, using the sun as a source of heat. There are three main types of solar concentrator systems: parabolic, dish / engine, generator tower.
Parabolic system concentrate energy from sunlight by using a U-shaped length mirror. The mirrors are arranged toward the sun and focus sunlight into a pipe containing oil that extends in the midst of such a parabolic focal point. Hot oil is used to boil water in a conventional steam generator and produce electricity.
Dish/engine system using the mirror disk to collect sunlight on a receiver that receive the sunlight and transfer heat to the fluid inside the machine. Heat result in fluid to expand and push the piston or a turbine and produce mechanical energy. Mechanical energy is then used to turn a generator or alternator to produce electricity.
Meanwhile, the generator tower using a mirror in a large number and placed in a large location to collect the sun rays and centralize it to the top of a tower where a receiver is placed. Generated heat melt salt which then flows to heat the water. The steam generated from hot water used to turn conventional steam generator. Molten salt can store heat for a long time. That means electricity can be generated at the sunset or when the sky is very cloudy.