Both hot and cold air containment can significantly improve the predictability and efficiency of data center cooling systems. While both approaches eliminate the mixing of hot and cold air there are practical differences in implementation that have significant consequences. Although traditional cooling approaches (such a perimeter cooling through a raised floor plenum) are still quite prevalent, a new approach such as hot and cold aisle containment are making significant inroads.
Containment in both hot & cold aisle offers the following benefits:
- Cooling systems can be set to a higher temperature (thereby saving energy) and still supply the load with safe operating temperatures
- Reduction of humidification/dehumidification costs
- Better overall physical infrastructure utilization which enables rightsizing which results in equipment running at higher efficiencies
Cole Aisle Containment is traditionally deployed in a traditional perimeter based cooling environment. Traditional cooling environments use the entire room as a hot air return plenum and use delivery cold air via the raised floor plenum to the cold aisles. The CACS encloses the cold aisle allowing the rest of the data center to become a large hot air return plenum. By containing the cold aisle, the hot/cold air streams within the data center are separated.
Although CAC offers efficiency improvements over traditional cooling it does have some draw backs when deployed in a room based, perimeter cooling environment.
- Inefficiencies resulting from distances and pressures required for adequate air distribution
- Density limitations of using cold air distribution though a raised floor
- Predictability of the raised floor
CACA limitations when deployed in a row based cooling approach
- Availability of cold air during a loss of power/cooling
- All of the cold aisles in the entire data center must be contained in order to realize benefits
- Overall perception and operation of a hot data center
Hot Aisle Containment encloses a hot isle to collect IT equipments hot exhaust air and cools it to make available for IT equipment air intakes. This create a self contained system capable of supporting high density IT loads.
Mixing of hot and cold air streams in the data center allows lower availability of IT equipment. Returning the warmest possible air to the computer room air conditioners increases the efficiency and capability of the system. The HACS ensures proper air distribution by completely separating supply and return air paths.
The design of HACS assimilates many of the advantages of the CACS and avoids many of the pitfalls. When upgrading a data center to be more effecient and less costly to operate, any move away from the traditional perimeter cooling approach is a step in the right direction. Which CACS is a better scenario compared to the traditional approach, the “best” scenario is embodied in a HACS system.
