Data centers have heat. Many places outside of data centers need heat. And unfortunately, most of the excess heat from data centers never reaches those places.
That raises the question: What can data centers do with their excess heat? Are there practical approaches to reusing heat, rather than releasing it into the ambient environment?
Let's explore by discussing strategies for making the most of excess data center heat.
What Usually Happens with Data Center Heat
In most data centers, the fate of excess heat generated by servers and other equipment is pretty simple: The heat ends up being dissipated by some type of cooling system — such as chilled air or liquid cooling — and, ultimately, distributed into the surrounding environment.
After all, if you pump cool air or water into a data center, you're not making heat disappear. You're just moving it outside — a fact that is obvious to anyone who feels the heat output from an outdoor air conditioning compressor.
The fact that data center heat is typically just pumped into the environment is a shame, of course, because it means that all of the excess heat from data centers is wasted. Capturing and reusing that heat could significantly improve data center sustainability by allowing the energy that generated the heat to live a second life, so to speak.
It could be used, for example, to heat buildings — something that data center operators have been doing in Nordic countries for some time.
Challenges in Data Center Heat Reuse
Pumping heat from data centers into other buildings, however, is the exception, not the rule. In general, reusing data center heat is typically not easy. Data centers are often (but not always) located in remote areas with sparse populations, which means that there is often little demand for heat in nearby buildings. And moving heat over long distances so that it can reach population centers is expensive and inefficient.
If infrastructure for shared heat distribution to buildings already exists — as it does in many Nordic cities — reusing data center heat for other buildings may make sense. But building new distribution infrastructure from scratch is just not a practical prospect in most other regions.
Creative Ways to Reuse Data Center Heat
But there are other ways to repurpose excess data center heat. Here's a look at some approaches that are creative but still within the realm of feasibility.
Agriculture
There may not be many people living around the typical data center, but there is often plenty of open land. By pumping excess heat from data centers to that land, it could be possible to put the land to agricultural use, including in seasons where the ambient temperature would not be warm enough to support crops or livestock.
For example, heat from data centers could warm greenhouses that grow produce during the winter in cool climates. Or it could heat ponds where farmers raise fish.
Factories
Factories are another setting where heat may be valuable. If heat from data centers can be concentrated in sufficient quantities in nearby manufacturing facilities, it could help power kilns and furnaces that would otherwise have to source their heat directly from fuels — which would in many cases take the form of non-renewable energy.
Drying
Removing moisture from materials is another type of manufacturing activity where heat is very useful. In this context, heat from data centers could serve purposes like drying lumber or reducing the moisture content of processed foods to increase their shelf lives.
Generating electricity
Heat from data centers could power thermoelectric generators, which convert heat into electricity.
The challenge here is that more than negligible amounts of energy are lost in the conversion process, so not all of the heat would be effectively reused. But the big advantage is that once you generate electricity, you can move it very efficiently over long distances using wires — so electricity generation via excess data center heat is one way to make the energy from heat available in places far from data centers. Or you could reuse it to help power data centers themselves, which are always hungry for electricity.
Conclusion: A Creative Approach to Data Center Heating
To date, little experimentation with the types of data center heat reuse applications described above has taken place. But it's not especially difficult to imagine these strategies being possible. Nor do they require any special or prohibitively costly technologies.
All this really boils down to is thinking creatively about how to make better use of the heat that comes out of data centers — a goal that more data center operators should prioritize if they want to reduce the carbon footprints of their facilities.
