What is Solar Thermal Technology?

Concentrated solar thermal (CST) technology uses the sun’s energy to create power. It converts light into heat using lenses and reflectors, which concentrate sunlight and produce steam that runs a turbine.

How Does Solar Thermal Technology Work?

The major element of solar thermal heating is to use the sun’s energy and transform it into heat, which is then delivered to your home or company via hot water and space heating.

Solar panel-based heating is the most common way to generate heat. A boiler, collector, or immersion heater is used in conjunction with solar panels to produce heat.

The sun’s rays are used to warm a transfer fluid that is generally made up of water and glycol (antifreeze), preventing the water from freezing.

The heated water from the collectors is transferred to a heat exchanger within the water tank of your house.

The heat from the exchanger will be used to warm the water inside the tank.

When the liquid’s thermal energy has been dissipated, the water will flow back to the collectors for reheating. When there is sufficient heat available, a controller will ensure that the fluid circulates to each collector.

Related: The Different Types Of Solar Thermal Panel Collectors

Can solar thermal be used for central heating?

Yes, solar thermal can be used to provide central heating and hot water.

A solar thermal system can usually generate around 60-70% of a household’s hot water needs in summer and 30-40% in winter.

If you are considering using solar thermal for central heating, you should note that it will not work on its own and will require a backup heat source such as air or ground source heat pumps, wood-burning stoves, or a boiler.

Related: Photovoltaic Vs Solar Thermal Technology

What Are The Major Solar Thermal Applications?

The major applications for solar thermal energy are space heating, air conditioning, hot water, industrial process heat, drying, distillation and desalination, and electrical power generation.

Solar thermal space heating

Solar thermal space heating systems use the sun’s energy to heat a fluid, which is then used to heat air or water for space heating.

The most common type of solar thermal space heating system is the solar air heater, which uses the sun’s energy to heat air that is then circulated through a building using fans or natural convection.

Solar air heaters can be used to supplement or replace conventional space-heating systems such as forced-air furnaces and boilers.

Another type of solar thermal space heater is the solar water heater, which uses the sun’s energy to heat water that is then circulated through a building using pumps or gravity.

Solar water heaters can be used to supplement or replace conventional water-heating systems such as electric tankless water heaters, gas-fired demand (instantaneous) water heaters, and storage water heaters.

Solar Thermal Air Conditioning

Solar thermal air conditioning systems use the sun’s energy to cool air. The most common type of solar thermal air conditioning system is the evacuated tube collector, which uses the sun’s energy to heat a working fluid, which then vaporizes and drives a piston compressor.

The compressed refrigerant is then expanded in an evaporator coil, where it absorbs heat from the indoor air.

The cooled indoor air is then circulated through the building using fans or natural convection.

Solar thermal air conditioning systems can be used to supplement or replace conventional air-conditioning systems such as window air conditioners, central air conditioners, and ductless mini-split air conditioners.

Solar thermal hot water

Solar thermal hot water systems use the sun’s energy to heat water. The most common type of solar thermal hot water system is the active solar water heater, which uses the sun’s energy to heat a working fluid, which then transfers its heat to the water in a storage tank.

Passive solar water heaters do not have a working fluid; instead, they rely on natural convection to circulate the water through the system.

Solar thermal hot water systems can be used to supplement or replace conventional water-heating systems such as electric tankless water heaters, gas-fired demand (instantaneous) water heaters, and storage water heaters.

Solar thermal industrial process heat

Solar thermal industrial process heat systems use the sun’s energy to heat a working fluid, which is then used to transfer its heat to an industrial process.

The most common type of solar thermal industrial process heat system is the solar collector, which uses the sun’s energy to heat a working fluid, which then transfers its heat to the process via a Heat exchanger.

Solar collectors can be used to supplement or replace conventional fossil fuel-fired boilers and furnaces.

Solar thermal drying

Solar thermal drying systems use the sun’s energy to evaporate water from a wet product.

The most common type of solar thermal drying system is the solar dryer, which uses the sun’s energy to heat air, which then dries the product.

Solar dryers can be used to supplement or replace conventional dryers such as electric clothes dryers and gas-fired flash dryers.

Solar thermal desalination

Solar thermal desalination systems use the sun’s energy to evaporate water, leaving the salt behind.

The most common type of solar thermal desalination system is the multi-effect distillation (MED) plant, which uses the sun’s energy to heat water in a series of Evaporator/condenser units.

The water vapor is then condensed and collected, while the salt is left behind.

Solar thermal desalination systems can be used to supplement or replace conventional desalination systems such as reverse osmosis (RO) plants and multi-stage flash (MSF) plants.

Solar thermal power

Solar thermal power systems use the sun’s energy to generate electricity. The most common type of solar thermal power system is the parabolic trough collector, which uses the sun’s energy to heat a working fluid, which then drives a steam turbine.

The steam turbine spins a generator, which produces electricity. Solar thermal power systems can be used to supplement or replace conventional fossil fuel-fired power plants such as coal-fired power plants and natural gas-fired power plants.

Solar thermal process heat

Solar thermal process heat systems use the sun’s energy to heat a working fluid, which is then used to transfer its heat to an industrial process.

The most common type of solar thermal process heat system is the solar collector, which uses the sun’s energy to heat a working fluid, which then transfers its heat to the process via a Heat exchanger.

Solar collectors can be used to supplement or replace conventional fossil fuel-fired boilers and furnaces.

The Advantages and Disadvantages of Solar Thermal Technology

There are a few key advantages and disadvantages of solar thermal technology to consider.

The advantages of solar thermal technology

  • Can be used to supplement or replace conventional fossil fuel-fired power plants
  • The sun is a free and renewable resource
  • Solar thermal power plants have low emissions of greenhouse gases and air pollutants
  • Solar thermal power plants can be built on a smaller footprint than traditional power plants
  • No CO2 emissions during operation.
  • Cost savings: up to 60% less energy to heat water, up to 35% less energy for space heating.
  • Reduced consumption of fossil fuels.
  • Solar thermal systems can be integrated into existing systems.

The disadvantages of solar thermal technology

  • Solar thermal power plants require a large amount of land
  • Solar thermal technology is still in the development stage and costs more than traditional fossil fuel-fired power plants
  • Solar thermal power plants require a reliable source of water for cooling
  • The output of a solar thermal power plant is dependent on weather conditions
  • Cannot Be Used During the Night.
  • Hot Water Cannot Be Stored for Long.
  • Solar Thermal Is Less Efficient in Winter.
  • Limited Availability of Installers.

Solar Thermal Technology Vs Photovoltaic

If you compare solar thermal technology with photovoltaic, there are some important differences to consider.

Solar thermal technology uses the sun’s energy to heat a working fluid, which is then used to generate electricity or transfer its heat to an industrial process.

Photovoltaic technology uses the sun’s energy to generate electricity directly. Solar thermal power plants have low emissions of greenhouse gases and air pollutants, while photovoltaic power plants have no emissions.

Solar thermal power plants can be built on a smaller footprint than traditional power plants, while photovoltaic power plants require a larger footprint.

Solar thermal power plants require a reliable source of water for cooling, while photovoltaic power plants do not.

The output of a solar thermal power plant is dependent on weather conditions, while the output of a photovoltaic power plant is not.

Solar thermal technology is still in the development stage and costs more than traditional fossil fuel-fired power plants, while photovoltaic technology is more mature and costs less.

Which is better?

This will depend on each individual application. If you are looking for a technology to generate electricity with low emissions, then solar thermal is a good option.

If you are looking for a technology that is more mature and costs less, then photovoltaic is a better option.

The Future of Solar Thermal Technology

Solar thermal usage will continue for the sake of direct heating and drying, as well as water desalination.

However, photovoltaic generators are more suited to producing electricity from solar energy, and they’re already in use to construct gigawatt photovoltaic power stations.

The parabolic trough solar thermal power plants are the most common type of solar thermal power plants.

These power plants have a large field of mirrors that focus the sun’s energy on a receiver that is suspended above the mirrors.

The receiver contains a working fluid, which is heated by the sun’s energy and used to generate electricity or transfer its heat to an industrial process.

Solar towers are another type of solar thermal power plant. These power plants use a field of tracking mirrors to focus the sun’s energy on a receiver that is located at the top of a tower.

The receiver contains a working fluid, which is heated by the sun’s energy and used to generate electricity or transfer its heat to an industrial process.

Solar dish/engine systems are the most efficient type of solar thermal power plant.

These power plants use a dish-shaped mirror to focus the sun’s energy on a receiver that is located at the focal point of the dish.

The receiver contains a working fluid, which is heated by the sun’s energy and used to generate electricity or transfer its heat to an industrial process.

The future of solar thermal technology is bright. With advances in technology, solar thermal power plants will become more efficient and cost-effective.

Solar thermal power will become an important part of our energy mix, providing clean, renewable energy to help meet our growing demand for electricity.

FAQs

Does solar thermal work in the winter?

Yes, a solar thermal heating system works in the winter. However, it will be less efficient than during the summer months.

What solar thermal technologies are useful for industrial processes?

Solar air collectors, solar water systems, and solar concentrators are three types of solar thermal technology that may be utilized in industrial processes.

Why it is beneficial to use a solar water heater instead of an electric geyser?

Solar water heating systems are far more desirable in a neighborhood where units aren’t continuously occupied but rather in regular homes.
They are less expensive to run over time and are environmentally beneficial.
Solar water heaters are better than electric geysers in many ways. They don’t experience the same power outages that electric geysers do, and they give an uninterrupted flow of hot water as opposed to electrical geysers, which might be affected by power cuts.
Furthermore, solar water heaters take up less space than electric geysers. Finally, solar water heater payback periods are much shorter than those for electric geysers.

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Passionate about helping households transition to sustainable energy with helpful information and resources.

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