There are 15 standard models of RPA Rooftop Air Conditioner. The cooling capacity and heating capacity range from 15KW to 150KW, can provide air volume 3000CMH-26750CMH. The models with large cooling capacity are using two or more independent cooling systems, which is according to change of load to turn on one or multiple systems automatically, to achieve energy saving, stability and reliability. The heat exchanger uses threaded copper pipes with aluminum fins and is connected in the form of mechanical expansion, which has higher heat transfer efficiency. The adjustment method of the expansion valve allows the system to have a larger operating range and ensure efficient operation. Additional high-efficiency motors and fans, overall efficiency is improved.