Sustainable energy or as an energy input for other uses such as cooling equipment. In many climates, a solar heating system can provide a very high percentage (20 to 80%) of domestic hot water energy. Energy received from the sun by the earth is that of electromagnetic radiation. Light ranges of visible, infrared, ultraviolet, x-rays, and radio waves received by the earth through solar energy. The highest power of radiation comes from visible light. Solar power is complicated due to changes in seasons and from day to night. Cloud cover can also add to complications of solar energy, and not all radiation
Ultraviolet light therapy Ultraviolet light therapy Ultraviolet light therapy or ultraviolet phototherapy is a form of treatment for certain skin disorders including atopic skin disorder and vitiligo when used with psoralen to form the PUVA treatment. It consists of irradiation of the patient with the UVA band of ultraviolet light (fairly closely matching the ultraviolet output from the sun), usually delivered from a fluorescent bulb specially designed to output this frequency of ultraviolet. This treatment is similar to the light from good quality solariums but differs from the mainly UVB ultraviolet band used to treat psoriasis. Tanning beds are used both in dermatology