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Solar thermal heating

Solar energy is available to almost everyone. It's carbon neutral and has low running costs, making it one of the best approaches to water heating possible. Most modern heating systems can even be combined with solar panels, making solar systems available for hot water generation.

How does solar thermal energy work?

The basic principles of solar thermal technology are fairly straightforward, but in practice, designing a system that efficiently captures the sun's energy and turns it into hot water, requires advanced technology. Solar panel installations are the first step in this process, whereby solar energy is captured and transferred into a usable resource.

Solar thermal domestic hot water systems work by collectors on the roof, absorbing the radiated energy from the sun. This energy heats the fluid which is pumped around a sealed circuit, through the collectors and into a coil within a specially designed hot water cylinder. The hot water is then stored in the cylinder until it's needed.

The benefits of solar heating

  • Endless amounts of energy with low running costs
  • No CO² emissions during operation
  • Cost savings from using up to 60% less energy to heat water
  • Reduced consumption of fossil fuels
  • Solar thermal systems can be integrated into many existing systems
  • Modern systems work efficiently all year round
  • At less risk of price fluctuations in the energy commodity markets due to portion of energy budget generated by solar

What you'll need to use solar thermal in your home:

  • Suitable surfaces for solar collectors - south-facing where possible

In order to have solar panels installed, you will need a suitable location for the panels themselves, as well as somewhere to have a dedicated solar cylinder, which includes the necessary technology to transfer the solar energy collected into usable heating energy for your hot water.

  • An area that's free of shade throughout the day

To ensure consistent performance, it’s important that the solar system receives enough sun. Although many believe that solar only works during summer months, solar energy can be collected all year; shade from trees and buildings will heavily impact the efficiency of a solar collector, however, and should be avoided to ensure consistent performance.

  • An expandable heating system that supports solar thermal collection

Solar collectors

There are two types of solar thermal collectors used in solar heating systems: Flat-plate and evacuated tube collectors.

Flat-plate collectors

The main feature of the flat-plate collector is the black absorber surface which is positioned towards the sun. The absorber surface coating has been designed so that it absorbs maximum radiation and reflects a low amount of energy. The absorbed energy is then transferred to the heat carrier fluid circulating in the pipes, below the absorber surface.

The advantages of flat plate collectors

  • Lower purchase price
  • Lower maintenance and repair costs
  • Aesthetically pleasing

To be able to offer you high quality collectors, operating efficiency and a favourable price, Vaillant has developed flat-plate collectors. They achieve high efficiencies with optimum solar yields thanks to their innovative technology.

Evacuated tube collectors

The principle of the evacuated tube collector is the same as the flat-plate collectors. They absorb the solar radiation via absorbers and then transfer it in the form of thermal energy to a fluid.

However, in contrast to flat-plate collectors, the evacuated tube collector utilises the insulation capacity of a vacuum, meaning heat losses are almost completely avoided. In addition, a mirror is mounted below the individual tubes to focus the sunlight towards the absorber pipe. All in all, the evacuated tube collectors are significantly more efficient than flat-plate collectors. They are less aesthetically-pleasing than flat panel collectors, however, so some homes may opt for the lower efficiency as a result. For the best performance in various weather conditions and in limited space, however, an evacuated tube collector solution is the absolute best way to go.

The advantages of evacuated tube collectors

  • Greater energy efficiency, good yields even with less sunlight and diffuse light
  • Require less roof area for the same output
  • Produces higher temperatures