Solar Thermal
Technology that uses solar heat for hot water preparation and space heating support via solar collectors.
Also known as: Solar Heat, Thermal Solar System
What Is Solar Thermal?
Solar thermal technology uses solar energy to generate heat. Unlike photovoltaics, which produces electricity, solar thermal converts sunlight into thermal energy — typically for hot water and space heating support.
How It Works
Solar collectors on the roof absorb solar radiation and heat a heat transfer fluid (water-glycol mixture). This heat is transferred via a heat exchanger to the hot water storage tank in the building.
Collector Types
| Type | Efficiency | Application |
|---|---|---|
| Flat-plate collector | 60—75% | Hot water, heating |
| Evacuated tube collector | 75—90% | Heating, process heat |
| Pool absorber | 50—60% | Pool heating |
Solar Thermal vs. Photovoltaics
| Criterion | Solar Thermal | Photovoltaics |
|---|---|---|
| Produces | Heat | Electricity |
| Efficiency | 60—90% | 20—24% |
| Flexibility | Heat only | Electricity for everything |
| Storage | Hot water tank | Battery or grid |
| Trend | Declining | Strongly growing |
Practical Tip
The trend is clearly towards photovoltaics combined with a heat pump, as this solution is more flexible than solar thermal. A PV system can simultaneously serve electricity, heating (via heat pump), and mobility (EV).