Generally, the collector panel is even a simple or flat plate of solar panel or one keeping solar evacuated pipes/tubes. The solar panel is either connected to a south facing roof or situated on a free standing support. These types of panel work by effectively collecting direct sunlight that they use to effectively heat any type of fluid (sometimes it can be simple water or more frequently an antifreeze combination containing propylene glycol) which is disseminated in pipes beneath the glass surface of panel.