Answer:
The term "solar collector" commonly refers to a device for solar hot water heating, but may refer to large power generating installations such as solar parabolic troughs and solar towers or non water heating devices such as solar air heaters. radiant energy is the energy of electromagnetic and gravitational radiation.Active solar heating systems use solar energy to heat a fluid;either liquid or air; and then transfer the solar heat directly to the interior space or to a storage system for later use. If the solar system cannot provide adequate space heating, an auxiliary or back-up system provides the additional heat.