Flat-Plate Collectors are devices used to capture solar energy for heating purposes. They consist of a flat, insulated box with a transparent cover that allows sunlight to enter while minimizing heat loss. Inside, a dark absorber plate absorbs the sunlight and converts it into heat, which is then transferred to a fluid, usually water or air, circulating through the collector. These collectors are commonly used in solar water heating systems, where they provide hot water for residential or commercial use. They are efficient and cost-effective, making them a popular choice for harnessing renewable energy from the sun.