The sun's energy can be utilised directly in two ways: either actively or passively, which is to say with or without the intervention of mechanical components, respectively.
Active solar power can, in turn, be classed as low temperature, medium temperature or high temperature, depending on whether the sun's energy is captured directly, has a low concentration ratio, or a high concentration ratio.
Low temperature applications, using glazed flat-plate collectors, commonly known as solar panels, are the most widespread commercially. Their main applications are:
On buildings. To produce hot water, heat swimming pools and provide space heating.
In industrial facilities, where they are also used to produce hot water, either for cleaning or for manufacturing processes.
In agricultural, horticultural and stock rearing facilities. To heat greenhouses, to provide hot water for fish farming, etc.
Solar cooling. On sites that need cold water or refrigeration, by utilising heat in an absorption process.
A refrigeration system using solar energy basically consists of an absorption machine which is powered by hot water produced by a solar-thermal system. This produces cold water which may used to cool a space.
It basically comprises the following systems:
Solar capture system
Conventional backup system