Technologies

State of the art of solar thermal collectors

Today, several solar thermal collector technologies exist: flat-plate collectors, evacuated tube collectors, Fresnel concentrator collectors, etc.

Flat-plate collectors do not reach temperatures high enough to ensure proper operation of absorption chillers.
Evacuated tube collectors, although more efficient, cannot provide the high-temperature output required.
As for Fresnel concentrator collectors, they have major limitations that make them unsuitable for our application:
- By design, about 30% of the collected energy is lost, as the flat mirrors prevent optimal concentration of the solar radiation on the absorber.
- Each mirror requires individual solar tracking, which greatly complicates the system, reduces reliability, and increases maintenance needs

Cylindrical-parabolic concentrator collectors thus represent a much more suitable solution for solar cooling systems.

Today, the most common technologies rely on thick, heat-formed glass mirrors. While they offer high reflectivity and durable surfaces, their very high cost and significant weight make them unsuitable for rooftop integration.

At the same time, some solutions using polished metal sheets are emerging. They are easier to implement, but their already lower reflectivity deteriorates over time.

Until now, there was no collector truly adapted to absorption chillers: installable on rooftops, reliable, and economically competitive. It is precisely to meet this need that we designed, developed, and industrialized our own cylindrical-parabolic concentrator collectors.