Solar Thermal Systems

Solution advantages

  • Carbon-neutral, important way to reduce CO2 and other emissions
  • Integrates renewable energy within any heating/hot water system both in existing and new buildings
  • One time investment, low maintenance costs and a long lifespan
  • Ease of installation and ease of use
  • Solar heat is available & free to everybody


Solar collectors convert sunlight into heat and produce hot water, and, in larger systems, assist the space heating system. Solar thermal systems can save significant quantities of energy and reduce CO2 emissions. Most systems work in combination with another heat generator (running on oil, gas, electricity, wood) which only operates when heat demand is too high to be met by the solar system alone.

System components

In a solar water heating system, the solar collectors are usually installed on the roof of the building. The circulating fluid in the system, which delivers the solar heat from the collectors to the storage tank, must be both frost and heat-resistant. Flat-plate collectors are the most frequently used type of collector. Vacuum tube collectors – a heat pipe in an evacuated glass tube (vacuum) – can achieve high yields and temperatures. Because of their higher efficiencies, they require less surface area than flat-plate collectors.

The heat is transferred to the water in the storage tank via a heat-exchanger. Solar energy can also be used to top up the central heating system, when the size of the collector surfaces is increased by a factor of about 2 to 2.5. The saving on fuel is somewhere between 10 % and 30 %, depending on the insulation levels of the building. With low energy buildings, savings of up to 50 % are achievable. Where solar heat is used to assist a heating system, either a second storage tank (buffer store) or a combination storage can be used. Stratified tanks or cylinders are also available.

Solar heat opportunities

Solar thermal systems for hot water production and space heating are suitable for a great variety of residential and commercial buildings, in both retrofitting and new-build projects. Moreover, solar collectors can provide hot water for both open-air and indoor swimming pools. In southern countries, there are systems that operate on the thermo-siphon principle with a heat-insulated storage tank above the collector. Solar assisted industrial process heating is still in its early stages but the potential is enormous.

Solar cooling

Solar thermally driven cooling systems – so-called solar air-conditioning – have a great potential, as the highest need for cooling goes hand-in-hand with the sun’s presence. Moreover, the widespread use of solar cooling could make an essential contribution to lowering the electricity demand peaks caused by traditional air-conditioning systems.


Solar thermal - vacuum tube collector
Solar thermal - vacuum tube collector
Solar thermal - flat plate collector ©
Solar thermal - flat plate collector ©
Solar thermal - flat plate collector ©
Solar thermal - flat plate collector ©