There are many low-cost options to keep your energy bill low and to make homes, even industries as energy-efficient. One of the major option is to go for most abundant solar energy source to power up homes and industries. Over the past few years usage of solar power utilization is increased significantly and is expected to grow rapidly in the coming years. As cleanest and more sustainable energy, solar energy system is familiar with a wide variety of applications like solar power plants, spacecraft, home appliances, handheld calculator and so on.
How Solar Energy Works?
Solar energy is the cleanest renewable energy source and it can be used to meet the electricity requirements such as lighting systems, water heating for domestic, commercial and industrial applications, etc. The essential component in solar energy system is photovoltaic or solar cell, by which sunlight energy is converted into electric current upon the principle of the photoelectric effect.
A Solar PV cell has a P-type silicon layer placed in contact with a N-type silicon layer.The P-type material consists of holes to accept the electrons and the n-type material has ample electrons, thus forms the P-N junction as like diode component. Under the influence of the solar energy, electrons passes from an N- type material combines with holes. This creates an electric charge on either side of the p-n junction to create an electric field. This field develops a potential difference across the junction. If an external load is connected to the solar panel, this charge difference drives the load current. As a long as the sunlight is present on the panel, current will drive the load.
Usually the output voltage of a solar panel when it is open circuited is higher than rated voltage. Suppose if the solar panel is rated at 12V, it gives approximately 20V in an open circuit condition,but if it is connected to battery then it will give 14-15V. The output of the solar panel is measured in terms of watts or kilowatts, some of these ratings are 5 watts, 10 watts, 20 watts, 100 watts, etc. Hence it is necessary to find out the power requirement of the load before selecting the solar panel. The main consideration of solar panel is the generation of output power when it is installed in optimal position. Some of the Factors to be considered for getting high power from solar panels are panel orientation, panel pitch, roof, shade, etc.
The above figure demonstrates how the solar energy conversion takes place. As we discussed above the solar panel produces the electrical energy. This electrical energy is stored in the battery using a charge controller circuit. The charge controller directs the voltage and currents from solar panel and also protects the battery from over and under charging conditions. The DC power from battery is converted to AC using an inverter to power the loads. By this way solar system is installed in homes and industries to power up the loads.
Advantages Of Solar Energy
- It is a renewable and a large inexhaustible source of energy
Power generation using generators or turbines and other conventional methods causes noise pollution but solar panels cause no noise.
- As compared with non renewable energy sources based power generation, solar power generation does not cause much pollution.
- It can be used to generate and utilize the electricity in remote areas where transmission of electricity is more expensive.
- Since the solar panels don’t have any moving parts and thus requires a little maintenance.
- Solar energy is free of cost and In long term usage, the solar power installation investment can be regained at maximum levels.
Solar Energy Disadvantages
- The initial investment of solar panels installation cost is very expensive, and its payback period could be after several multiple years.
Depends on the sunlight, the solar power energy generation, therefore in cloudy days the solar power generation is very less.
- The batteries used for storing the solar power are very costly. These huge sized batteries need maintenance and to be replaced from time to time.
- The efficiency of solar energy based power generation is around 22%. To improve this further, large space is required to capture more Sun light.
- Solar panels manufacturing results more pollution than is saved by solar usage.
Application of Solar Energy System to Power-up the Street Lights
This prototype project is designed to demonstrate the solar energy system to power up the street lights. The below figure shows the circuit diagram of auto intensity control of solar LED street light system which uses components as solar panel, battery, charge control circuit, microcontroller and a set of LEDs.
The working operation of this solar energy system is easily be understood by below block diagram. Here in this circuit, microcontroller is used as a main controlling device which directs the power to the LED street lights. In microcontroller program, PWM technique is implemented such that MOSFET is triggered at particular intervals.
During the daytime, solar panel gets the sunlight and converts it into electricity. Charge control circuit charges the battery with the solar panel power and also protect it from under and overcharging conditions. During the night times the stored energy is used for supplying the power to the set of LED lights.
The intensity of the lights is reduced gradually as the traffic on the roads tends to decrease by varying the voltage applied to the lights. This reduction of intensity is progressed till morning and completely shutdown in the morning. Therefore the streetlights are switched ON at dusk and switches OFF at the dawn automatically.
This is about the solar energy system working with advantages and disadvantages. Hope you have understood this concept well with practical application. If you have any doubt regarding installation of solar energy systems for home or practical implementation of this project you can comment below.