What is Solar Thermal Power?

Solar Thermal Power

Sun is the ultimate source of energy for life on earth. Solar Thermal Power is the heat energy from the Sun. We get heat in the form of energy from the sun, so the name solar thermal energy. There is a long history of the sun being regarded as a deity. Therefore, the method to use solar radiation directly has a deep appeal to scientists and engineers. 

solar thermal energy

There are few techniques to collect the Solar Thermal Power or heat energy depends upon the type of heating, whether it is low-temperature heating or high-temperature heating. For low-temperature solar heating, We preferred glazing because of its ability to transmit visible light but block infrared radiation. High-temperature Solar collection uses mirrors to concentrate solar radiation. Practically the collection of solar energy can adopt various methods.

It can be categorized into four types:

  1. Active solar heating
  2. Passive solar heating
  3. Daylighting
  4. Solar thermal engine

Active solar heating

It involves the collection of solar heat at low temperatures. the Solar collector mounted on the roof of a building or house to collect the energy from the sun used for domestic purposes. Low-temperature solar energy has varied applications in conventional power plants, small-scale combined heat, and power generation plants and in heat pumps. Domestic water heating is swimming pool heating are another practical application of active solar heating. 

The solar collectors used for low-temperature heating are unglazed panels, flat plate air collectors, and glazed flat water collectors. solar collectors are generally roof-mounted and once installed, It is not easily reachable. They can withstand all-natural difficulties like rain, hail, and storm and can sustain for more than twenty years.

Passive solar heating

This system uses air to circulate the collected energy for high-temperature heating. The Solar collector does not use any pump or fan but an integral part of the building or house. A large contribution of heat in winter plays a significant role to save the conventional sources of energy and minimizes fuel consumption at low cost. 

A direct gain building and Passivhaus design act as a solar Collector in passive heating. The direct gain building has a large area of glazing to capture sunlight and thermally heavyweight construction.

solar thermal power

Thick insulation on the outside of the structure to retain heat and store the thermal energy throughout the day. The Passivhaus design has a 200 mm thickness of foam insulation on the roof and in the walls. Triple glazed window and mechanical Ventilation with heat recovery and low emissivity coating use heat recovered from outgoing air to preheat incoming fresh air. Passive heating should be thermally massive to avoid overheating in summer. Direct gain design is used in conservatories, Trombe wall, greenhouse, and Atria.


Sun provides natural daylight. it requires detailed knowledge and understanding of the climate of that very particular place. Houses are always well designed to make the best use of natural daylight. Daylighting is a combination of energy combinations and passive solar designs. It aims to make the best use of Sunlight in the daytime.

Daylighting is used in day to day household activities like drying clothes, food grains, etc. Daylighting is also used in the steerable mirror and direct light into light Wells and the use of Optical Fibers.

Solar thermal engine

The solar thermal engine is an extension of active solar heating and requires a little more complex ( complex than simple solar collectors)  solar collectors to drive steam turbines to produce electric power. Solar thermal converts Solar energy into heat energy-absorbing it.

If the sun’s rays are concentrated using a mirror, high temperatures can be achieved which can produce mechanical work for water pumping for driving and electrical generator. This solar thermal electric generation is called solar power.