Evacuated tube collectors are devices used to harness solar energy for heating purposes. They consist of a series of glass tubes, each containing a vacuum that minimizes heat loss. Inside these tubes, a dark absorber material captures sunlight and converts it into heat, which is then transferred to a fluid, typically water or antifreeze, circulating through the system. These collectors are efficient in various weather conditions, including cloudy days, due to their insulation properties. They are commonly used in residential and commercial applications for heating water, supporting systems like solar water heaters and solar heating systems.