Solar energy has become a popular alternative energy source as a renewable energy source. It is the energy that comes as natural resource from the sun. Nowadays, there are many home appliances and devices that are based on solar power like solar-powered vehicles, solar-powered buildings, street lightings, and even solar lighting kits for small applications.
Solar-based projects or devices convert light energy of the sun into electricity that is used to operate the device. For converting process, photovoltaic cells are used that are available in different sizes and ratings based on the application used.
According to the way in which solar energy is utilized, solar energy is classified into two types:
- Active Solar Energy
- Passive Solar Energy
1. Passive Solar Energy
The passive solar energy is used directly from the Sun for various applications without using any intermediate devices or converters. By using the solar energy passively, we can heat water, water in swimming pools and can even heat houses or buildings. The best example of passive solar energy is drying up clothes in bright daylight.
Applications of passive solar energy include the following:
- Solar heating and cooling
- Day lighting
- Drying up cloths, food products and other materials
2. Active solar energy
Active solar energy reduces a building’s fossil fuel energy requirements for loads operation. An active solar energy source has two major applications. With this energy system, the solar energy from the sun is converted into electricity by using an intermediate circuit (Photo voltaic cells), as shown in the figure.
Usually the solar panels are placed on the roof of a building or house that absorb the sun energy, and then transfer the electricity to the point of usage. A solar heating system can provide a high percentage of domestic energy requirements for heating purpose.
Applications of active solar energy include the following:
- Active solar space heating
- Active solar water heating
- Active solar pool heating
Conversion of Solar Energy into Electricity Using Solar Panel
The solar panels are made of solar cells composed of semiconductor materials. Solar panels convert solar energy into DC electricity usually of 12V, which is further utilized for the rest of the circuit. The number of cells required and their size depend on the load rating. An array of solar cells can produce maximum electricity if the solar panel is placed exactly at right angle to the sun rays.
A charge controller is the heart of any solar-power system. The charge controller is used to maintain proper charging voltages of the batteries. The charge controller regulates voltage and current from the solar panel and charges the battery. It also prevents the battery from overcharging and undercharging conditions.
The function of the battery is to store current produced from the solar panels and deliver this stored power to the corresponding loads. The battery rating and the number of batteries required depend on the load requirement.
An inverter converts the available battery’s DC voltage to the main AC voltage in order to operate the loads. Therefore, the inverter helps us to run home appliances, computers or other electronic devices. Different types of inverters are available today; typical inverters have the characteristics like high conversion efficiency, less harmonic content, high switching frequency, and so on.
Advantages of Solar Energy
- Clean and Renewable Energy
- Pollution free
- Produces zero emissions during operation
- Requires little maintenance
Disadvantages of Solar Energy
- Requires Large Surface Area
- Offers no night-time functionality
- Generation of electricity depends on country’s climate
- Requires Expensive Solar Panels
Applications of solar energy
Solar energy is used for the following purposes:
- Public transportation vehicles like buses, trolleys and light rails use solar energy.
- Solar heating system uses solar energy to heat up water in pools during cold seasons.
- Industrial and residential sectors use solar energy for different purposes.
- Remote areas like island require solar energy for power generation due to unavailability of power transmission lines.
As a pragmatic approach to demonstrate the solar energy conversion system, the following project demonstrates how solar energy is used to drive the overall circuit. This project deals with the solar powered led street light with auto intensity control, 6V 3W solar panel that converts the sun light energy into DC electricity. The block diagram of this circuit is shown in the following figure.
In this proposed project, the power from a solar panel is directed to a charge controller that charges the battery as well as protects the battery from low and high voltage conditions. This power drives a set of LEDs placed as street lights. A microcontroller is used in this project to achieve the auto intensity of lights depending on the density of traffic on roads.
The microcontroller sends control signals to a MOSFET switch to have a better control of the power supplied to the LED lights. As the traffic on the roads tends to decrease slowly during the late night hours, the intensity can be reduced progressively until morning to save energy.
Thus, with this project, the street lights are switched on at the dusk, and then switched off at the dawn automatically by a PWM technique, and the process repeats every day. This system uses the entire power source as solar energy.
This is all about the solar energy conversion system using solar panels. You might have gained some valuable insights out of this article, after thoroughly reading it. However, for further details, suggestions, and comments, you can comment in the comment section below.