Panels photovoltaic solar energy

Solar panels for the production of heat and electricity

Solar panels for the production of heat and electricity

A solar panel (or solar panel) is a device that captures the sun's radiant energy and converts it into another form of usable energy. There are two main types of solar panels: photovoltaic and thermal.

A photovoltaic solar panel is made up of photovoltaic solar cells that contain semiconductor materials capable of converting sunlight into electricity. These cells absorb photons of sunlight and release electrons, thus generating a direct current (DC) electrical current. Photovoltaic panels are used to produce electricity and can be found in residential, commercial and industrial systems.

On the other hand, a thermal solar panel is designed to harness the sun 's thermal energy and heat water or other fluids. These thermal panels are made up of solar collectors that absorb solar energy and transfer the heat to the water or circulating fluid. Solar thermal panels are primarily used to heat water in residential, commercial and industrial applications, and can significantly contribute to the reduction of conventional energy consumption for water heating.

Photovoltaic panels: electricity generation

Photovoltaic panels are designed for the production of electricity. This type of panels is made up of small solar cells that convert the Sun 's radiation into electrical energy thanks to the photovoltaic effect.

Photovoltaic panels

This type of solar panel is made up of semiconductor materials that are normally derived from silicon. The panels are built by interposing two layers of silicon in which each one is treated in a special way to generate an electric field.

When a photon of light hits these layers, it makes an electron jump from a silicon atom. The loose electrons flow in the same direction generating an electric current due to the electric field created.

Photovoltaic solar panels generate electricity in the form of direct current and are usually accompanied by current converters to obtain alternating current.

Used materials

In general, solar cells are made of crystalline silicon or gallium arsenide. Gallium arsenide crystals are created for these uses, while silicon crystals are also produced for consumption by the microelectronics industry. 

Depending on the configuration of the silicon of the solar cells, photovoltaic panels are classified as polycrystalline, monocrystalline and thin film solar panels. The main differences between them are cost and efficiency.

Construction technique

A 6 cm silicon cell exposed to 1 AU direct light can produce a current of 0.5 amperes at 0.5 volts. Gallium arsenide is even more efficient than silicon.

The glass is cut into small discs and polished to eliminate the danger of cutting. Dopants are then inserted into the disks and metal drivers are deposited on each surface: a small connector on the sun -facing surface and a connector on the other side.

Solar panels are built with these cells cut into appropriate shapes. Additionally, they are protected from radiation and other damage by applying a layer of glass and cemented onto a substrate (either a rigid or flexible panel).

Electrical connections are made in series-parallel to determine the total output voltage and must have a protective layer that must be a thermal conductor.

Photovoltaic cells that make up a solar panel

Although each photovoltaic cell provides a small amount of energy, a set of solar cells can generate enough energy to be useful.

The most common configurations of solar cells are the following

  • 36-cell solar panels: this type of panel is the most compact on the market and the most recommended option in small isolated installations. The 36 solar cells generate an output voltage of 12 volts.

  • 60 cell solar panels. It uses 60 solar cells to obtain an output voltage greater than 24V.

  • 72 cell solar panels. This type of photovoltaic module connects 72 solar cells to obtain a voltage greater than 24V and is mainly used in installations connected to the electrical grid.

Solar collectors: heat generation

Solar collectors are part of solar thermal energy installations. 

Rooftop solar collectorsIts function is to harness the heat energy of the sun to heat a liquid.

This type of solar panel works by circulating a fluid inside it. The panel captures the sun's heat energy. This fluid heats up as it circulates inside the collector.

Types of solar collectors

There are different types of solar collectors. Its use depends on the application where it is going to be used:

Examples of uses and applications

Installing solar panels offers the ability to generate electricity or heat, expanding their possibilities for use in a variety of applications.

Solar panels for the production of heat and electricityBelow we present examples of applications of photovoltaic solar panels:

  1. Portable Electronics: Solar panels are used to supply electricity and recharge batteries in consumer electronics such as calculators and portable devices.

  2. Electric vehicle charging: Electric cars can charge their batteries with solar energy. This can be achieved through solar panels built into the vehicle or at charging stations.

  3. Energy for buildings: In tropical and subtropical regions with abundant sunlight, large solar panels, such as solar collectors, are used to power buildings and homes.

  4. Space applications: Spacecraft use solar batteries as the main source of electrical generation. These batteries are highly efficient and sustainable, in contrast to nuclear and radioisotope energy sources.

The main applications of solar collectors are:

  1. Domestic hot water: Solar collectors are used to heat water used in homes and buildings, thus reducing the need for conventional heating systems.

  2. Heating systems: Provide heat for heating systems in homes and buildings, reducing dependence on traditional heat sources.

  3. Large-scale electricity production: In thermal steam power plants, solar collectors are used to generate electricity on a large scale, taking advantage of solar radiation as a heat source.

Publication Date: July 16, 2015
Last Revision: October 25, 2023