1.The complete unit adopts skid design, easily installed and maintenanced, the assembly period of the whole unit is less than 3 days. 2.The noise level could be lowered within 60 db,quite user-friendly ; 3.The new refrigerant R404A is more environmental friendly and has been accepted by the developed countries; 4.R744 works as the secondary refrigerant wihtout the compression, always working at the evaporation temperature so that the system could be working in a low pressure. 5.R744 flooded-liquid supply, which the efficiency is 30% higher than the conventional direct expansion system, and the COP is higher . 6.Factory assembly, factory commissioning, quality more stable. 7.Skid design, No specific plant room design needed.