Solar collectors are categorized into three main types: flat-plate collectors, evacuated tube collectors, and concentrating collectors. Flat-plate collectors are the most common type, suitable for low-temperature applications such as swimming pool heating and domestic hot water. Evacuated tube collectors are more efficient and suitable for higher temperature applications such as space heating and cooling. Concentrating collectors use mirrors or lenses to focus sunlight onto a receiver, achieving high temperatures and used in industrial processes and power generation.