Data centers: Cooling them down

The process of establishing data centres is a tedious job, mainly because of two major challenges involved. These are, firstly, how to cool down the servers, and secondly, how to handle the heat influx from those servers. This article will address both of these issues and highlight a few innovative ways in which these problems have been addressed by data centres in Norway.

Water-cooling

Power consumption in data centres is significantly high, which translates into large amounts of wasted heat. As a result, it becomes imperative that efficient cooling methods are employed to keep the servers within the data centres running at maximum efficiency. In Norway, mean temperatures are generally low, which makes air-cooling a suitable approach in order to maintain the right atmosphere for the data centres. However, water-cooling is another option that data centres can and should start adopting. This is because water has a much larger heat capacity than air. Data centres need a very huge amount of air, as compared to water when it comes to the same cooling requirements. This makes water a better cooling solution than air. Norway has two prime examples of data centres that have utilized water from nearby natural water sources rather than using the traditional cooling air compressors:

Green Mountain

green mountain

The Green Mountain data centre at Rennesøy, called DC1-Stavanger, is built deep within a Norwegian mountain, right next to a cold fjord, which provides a constant supply of cooling water. At levels below 75 m depth, the fjord supplies the water at a substantially constant temperature of 8 degrees Celsius all year round. This is the ideal temperature for the data centre, which makes this the perfect location for the data centre. The cooling system at DC1-Stavanger uses gravity to bring the water to the data centre cooling station from a depth of 100 m., without using any energy in the process. The smart use of resources by DC1-Stavanger helps cut down the energy costs for the center, while keeping servers cool.

Lefdal Mine Datacenter

The Lefdal Mine Datacenter in Nordfjord is another example of a data centre that uses water to cool its servers. Similarly to the Green Mountain DC1-Stavanger data centre, it is also located next to a fjord. Taken right from the depth, the water stays at the desired temperature throughout the year, keeping servers cool.

Lefdal and Green Mountain have found an innovative way to keep the servers of the data centre cool, while simultaneously minimizing energy costs.

Heat recovery solutions for data centres

The proximity of natural water sources makes it easier for Green Mountain and Lefdal to keep the systems from overheating.  However, a question arises as to what the other data centres in Norway can do about the huge amount of energy that their servers are producing. Such high levels of heat production in data centres are inevitable, which is why it is important to work on potential heat recovery technologies so that the data centres can continue to work efficiently.

Heat recovery has become one of the top ideas when it comes to handling the heat from data centres. Rather than rejecting the heat out into the atmosphere, where it will just warm up the area, data centres are working on using that heat for a better purpose. For this purpose, engineers and technicians have come up with innovative ideas on how to aid data centres in terms of heat recovery and utilization.

Utilizing heat for other purposes is not a new idea and has been used for quite a while now. However, using heat from data centres offers some obstacles to this approach:

  1. The temperature of the heat is relatively low.
  2. The data centre is usually at a distance from other facilities that could utilize the waste heat.

We will address these two issues later in the article, but before we get to that, we provide an approach on how the heat can be reused to benefit the data centre. This approach essentially entails the recovery and reuse of the heat influx that a data centre produces, for use by its own facility.

Heating and cooling cycle

heating and cooling cycle

In a cycle that benefits data centres from both ends, the heat influx servers can be used to cool down the servers themselves. How does this work? The heat generated from the servers and elsewhere in the data centre can be used to power a chiller, or a refrigeration device, that uses heat as its power source. The heat from the data centre powers the refrigerator, which in turn cools the water that runs in the pipes that lower the temperatures of the computers and servers. If there is no need for the heat to power a chiller, it can be utilized in various other ways. Data centres have used their waste heat to warm up nearby swimming pools, in addition to being rerouted to residences and other buildings nearby.

Back to where it came from

There is another efficient heat recovery solution for data centres, which is the possibility of combining the heat power from data centres with power plants. Data centres that are already close to current power plants will benefit from the arrangement in several ways. Approximately 8-10% of the power is lost across transmission lines and via the power grid. However, for data centres that are located close to power plants, this power loss would be greatly reduced and so would the cost of power. These data centres situated close to power plants can transfer their heat/ thermal energy back towards the power plants, which can then use this heat to power the water heaters or the turbines that run on low-pressure. This creates a closed loop system in which the data centres, as well as the power plants, benefit from each other, in terms of energy and costs.

Heat pumps

One of the problems with heat recovery solutions that we mentioned earlier was that of low temperature of the heat produced by the data centre servers. While data centres do produce a lot of heat, the heat is at relatively low temperatures between 80 and 95 degrees Fahrenheit. For the heat to power up a machine or help heat up a building or a swimming pool, the temperature needs to be higher. One of the ways to go about solving this issue is by magnifying the temperature of the heat output with a heat pump. A heat pump works by using the heat produced by the data centre to help raise the temperature of another heat producing unit that can reach the high temperatures more efficiently.

Another problem that we mentioned above was that of physical distances between facilities. The simple solution to this is to transport heat to whichever facility is nearby since data centres are not normally located in isolation. Your data centre can help provide effective heating solutions to homes and offices nearby or to swimming pools and greenhouses located in the vicinity.

Conclusively, it is safe to say that there are several ways to utilize the heat produced by data centres. Even with Norway’s cooler temperatures, this is a problem that needs to be addressed by both smaller and larger data centres. The aforementioned innovative solutions to heat recovery will surely help you utilize the heat wastage in a more efficient manner.