DA-13-015 -- Development of an Outdoor Air Cooling-Type Air-Cooled Package Air Conditioner for Data Centers PDF

The authors have developed a high-efficiency air-cooled package air conditioner for the purpose of reducing energy consumption in air-conditioning facilities at data centers. Improvements in the compressor efficiency in mid-to-low outdoor air temperature conditions and an expansion of the low-pressure ratio operating area, which takes into consideration year-round cooling, can be listed as its features. The air conditioner, which also serves as a pump cycle in addition to the original compression cycle, was developed with the target of additional reduction of energy consumption. Specifically, the pump cycle is the system of taking the low-temperature outdoor air into a coolant cycle from the heat exchanger in the outdoor unit (indirect outdoor-air cooling method), and transporting cold into the room with a pump. By also using a pump cycle, cooling can be performed without operating the compressor during periods of low outdoor air temperature, resulting in a reduction in energy consumption. Compared to the conventional computer-room air conditioner, the new air conditioner developed uses about 54% less energy in Sapporo in Japan and about 50% less in New York.