The Recirculating Air Conditioning Unit is designed to demonstrate key air-conditioning and refrigeration processes, including heating, cooling, humidification, de-humidification, mixing, and air recirculation. The system features a stainless-steel air tunnel equipped with sight windows, multiple hygrometers, temperature and pressure sensors, flow meters, a variable-speed axial fan, and electric pre-heater and re-heater elements. It allows complete study of the refrigeration cycle using R134a, including evaporator and condenser performance. All components—air cooler, heaters, humidifier, and fan—can be operated independently for detailed experiments. operating conditions.