International News
DATA CENTRE EXPANSION
CREATES ATTRACTIVE SOURCES OF HEAT
The HVAC industry is warming up to using the heat from data centres . Data centres - the spaces , buildings , and campuses that house computer servers and related data-storage equipment - generate enormous amounts of waste heat , which is often simply released into the atmosphere .
But in an increasingly computerised world , in which billions of devices are connected to the internet and many companies opt to co-locate server functions at shared facilities , the need for more and ever-larger data centres is growing , even as the pressures for greater energy efficiency and decarbonisation mount .
Meta , the parent company of Facebook , for example , has 21 data centres around the world and seven more under development , including one in Mesa , Arizona , that will total 2.5 million square feet when completed .
That kind of growth and several other factors have prompted major HVAC manufacturers to introduce more products to recover the excess heat and put it to good use .
There is keen , industry-wide interest in data centre heat recapture according to leading suppliers that have deployed technology at data centres around the globe .
HEAT CENTRES A typical large data centre can generate 20 to 50 MW of heat , while a data centre campus can generate up to 300 MW — enough to power a mid-sized city .
To capture the heat and reuse it at scale is a unique challenge compared to capturing and repurposing waste heat in residential , commercial , or institutional buildings . The use of data-centre heat is more common in Europe than in the US , but is catching on quickly . The University of Notre Dame warms a local greenhouse with the heat from a campus data centre , and the Department of Energy ’ s Energy Systems Integration Facility , in Golden , Colorado , uses data-centre heat to heat the building and a related research laboratory , for example .
Data centres have several features that make them uniquely attractive for heat recovery , including consistent heat output due to their 24 / 7 operation , consistent load , and backup power systems that provide resiliency for external users of the recovered heat .
Chilled-water cooling systems are optimal for heat recapture , and data centres have been favoring chilled-water systems , over direct-expansion ( DX ) air conditioning , because of their greater efficiency and the lower refrigerant charge that ’ s required . This creates a significant potential for efficient heat reuse .
Taylor Vick | Unsplash
Computer data centres , which generate vast amounts of waste heat , are increasingly attractive sources of heat for vertical farming , space and water heating , and district heating systems .
HIGHER TEMPS , HIGHER VALUE A heat-recovery chiller at a typical data centre may be able to transfer excess heat to warm adjacent offices or heat water for use nearby . But some larger-scale heating needs , like district heating , may require the use of water-source heat pumps to boost temperatures . The higher the temperature it is , the higher value it is for reuse .
In addition to overall growth in the number of data centres , several other trends , experts said , have made using the waste heat from them more attractive .
One is that many data centres are cooled to higher temperatures than in the recent past , when one might have had to don a sweater before entering . ASHRAE now says that centres with A1-class equipment , which require the highest level of environmental control , can be kept at 80.6 ° F , and within an allowable range of between 59 ° F and 89.6 ° F .
In the past data centre managers sought lower temperatures , fearing the overheating and malfunctioning of critical equipment . That same equipment is very tolerant of the 80.6 ° F that most newer facilities are trying to run at . What ’ s important , though , is enough backup cooling to avoid “ thermal runaway ” in the event of a primary cooling system failure .
Another trend is the move toward larger data centres that generate more heat .
A third important trend is the use of new computer chips with higher transistor densities that can no longer be air-cooled . This means the industry must use direct-liquid and -immersion cooling systems to effectively and efficiently handle the heat being generated by this IT equipment .
www . refrigerationandaircon . co . za RACA Journal I November 2022 13