New HVAC Technologies Can Help Save Energy in Data Centers
April 2, 2012
This is Casey Laughman, managing editor of Building Operating Management
magazine. Today's tip is that taking advantage of new HVAC technologies can help manage power usage in data centers.
Leading companies are coming around to the use of new HVAC technologies and operating procedures such as air-side economization, evaporative cooling, and operating the data center under a wider range of temperatures.
An air-side economizer intakes outside air into the building when it is easier to cool than the air being returned from the conditioned space and distributes it to the space; exhaust air from the servers is vented outside. Under certain weather conditions, the economizer may mix intake and exhaust air to meet the temperature and humidity requirements of the computer equipment.
Evaporative cooling uses non-refrigerated water to reduce indoor air temperature to the desirable range. Commonly referred to as swamp coolers, evaporative coolers utilize water in direct contact with the air being conditioned. Either the water is sprayed as a fine mist or a wetted medium is used to increase the rate of water evaporation into the air. As the water evaporates, it absorbs heat energy from the air, lowering the temperature of the air as the relative humidity of the air increases.
These systems are very energy efficient, as no mechanical cooling is employed. However, the systems do require dry air to work effectively, which limits full application to specific climates. Even the most conservative organizations, such as financial institutions, are beginning to use these types of systems, especially because ASHRAE has broadened the operating-temperature recommendations for data centers.
Airside economizers and evaporative cooling systems are difficult to implement in existing data centers because they typically require large HVAC ductwork and a location close to the exterior of the building. In new facilities, these systems increase the capital cost of the facility, HVAC equipment and ductwork. However, over the course of the lifetime of the facility, these systems significantly reduce operating costs when used in the appropriate climate.