A rooftop air conditioning unit (AC unit) is a self-contained cooling system that is installed on the roof of a building. It is designed to provide cooling to the interior of the building, and it is typically powered by electricity. The AC unit is composed of several components, including an evaporator coil, condenser coil, compressor, and expansion valve. The evaporator coil absorbs heat from the air inside the building, while the condenser coil releases the heat outside. The compressor then pumps the refrigerant through the coils, and the expansion valve regulates the flow of the refrigerant. The AC unit is connected to the building’s ductwork, allowing the cooled air to be distributed throughout the building. Rooftop AC units are an efficient and cost-effective way to cool a building, and they are often used in commercial and industrial applications.