'The Pool Stays Warm Even in Winter'... Attracted 340 Billion Won Investment, Heated by Computer [Tech Talk]

Big Tech's Headache: Server Waste Heat Issues
Research on Uses Like Swimming Pools and Tomato Cultivation
Essential to Alleviate Power Consumption Problems

Computers are electronic devices that are hotter than they appear. When enjoying high-performance games, you can feel the heat radiating from the main unit, and the indoor temperature of an office filled with computer equipment is higher than other rooms. Therefore, data centers surrounded by hundreds or thousands of high-performance computer chips emit enormous amounts of heat. This is called 'waste heat.'

[Image source=Pixabay]

Today’s data centers use all kinds of cooling equipment such as air conditioners and large fans to maintain server room temperatures at 26 to 28 degrees Celsius. However, with various global variables such as war, climate change, and soaring oil prices overlapping, the cost of managing waste heat is increasing. Now, server management companies are researching ways not just to cool the heat but to transfer it elsewhere to generate additional revenue.

Abundant but Difficult-to-Use Waste Heat from Server Rooms

How much heat do data centers emit? Let’s look at NVIDIA’s AI GPU 'A100,' which is currently selling like hotcakes. Its thermal design power (TDP?the amount of heat emitted when all circuits are operating, expressed in watts) is 400 watts (W) per unit.

Typically, AI data centers are equipped with at least hundreds to over 10,000 A100 units. Even small data centers generate a minimum of 10 megawatts (MW) of waste heat. A domestic data center of about 500 square meters reportedly produces 430 MW of waste heat. That amount of heat could provide heating for approximately 72,000 households.

Naver Data Center. Not related to specific expressions in the article [Image source=Naver Cloud] [Image source=Yonhap News]

Although this is an enormous amount of heat, data center waste heat is not very practical. The biggest problem is that the waste heat is deadly enough to damage servers but not hot enough to heat homes or buildings.

When the heat from data centers is transferred through pipes, the temperature drops sharply, and by the time it reaches residential or industrial radiators, it is practically useless. This is why data centers have wasted hundreds of MW of waste heat until now.

Data Centers Heating Swimming Pools Appear

Because of this, some data center companies have devised creative solutions. 'Deep Green,' a UK startup that recently raised ?200 million (about 340 billion KRW) in investment, heats swimming pools using data centers.

Deep Green's technology extracts heat from cooling solutions that cool servers to warm public swimming pools [Image source=Deep Green]

This company applies 'immersion cooling' technology, which has recently gained attention for cooling computer chips. Immersion cooling involves submerging servers in a special non-conductive liquid to manage heat. Deep Green cools the servers, then passes the heated special liquid through a heat exchanger to warm nearby public and private swimming pools. The cooled liquid is then recycled to cool other servers.

Swimming pool water must always be kept at a constant temperature, so it requires a considerable amount of heat. Although it is awkward for heating purposes, it is the most suitable space to utilize the still-hot waste heat from data centers.

Big Tech Accelerates Research on Waste Heat Utilization

Another method is to heat the building where the server room is located. This solution is mainly seen in massive data centers in Northern Hemisphere countries that are chilly year-round. For example, Meta, the big tech company operating Facebook and Instagram, reportedly uses waste heat from its Northern European data centers not by venting it outside but by circulating it inside the building as auxiliary heating.

Meta Sweden's Data Center
[Image Source=Meta]

As mentioned earlier, the hot air emitted by data centers is inefficient for actual heating. Therefore, cases of using waste heat for hot water supply are more common. For instance, Meta heats metal coils with waste heat to boil water, and Amazon data centers use air handling units to capture heat and produce warm water.

Using Server Room Heat to Grow Tomatoes and Produce Firewood

Dutch 'Block Heating' Edge Computer Supplying Hot Air to Tomato Greenhouses
[Image Source=Block Heating]

Some startups are conducting unique experiments. 'Blockheating' in the Netherlands is experimenting with creating greenhouses near data centers and using waste heat to warm the interiors. They claim that tomatoes can be grown year-round in these greenhouses.

There are also attempts to produce firewood using waste heat. Pellet fuel made from wood requires processing and drying, and data center waste heat is used to evaporate moisture from the pellets.

Struggling to Avoid Criticism as 'Electricity-Guzzling Beasts'

The reason data centers have started to pay attention to waste heat reuse ultimately comes down to energy issues. Data centers have long been notorious as electricity guzzlers, and the current AI boom, which has led to a flood of more powerful chips, has worsened the situation. Maintaining massive server rooms requires enormous power, and cooling those server rooms also demands huge amounts of air conditioning.

Above all, local communities coexisting with data centers are increasingly dissatisfied. In Western and Northern European countries, where big tech companies mainly choose to build data centers, opposition to data centers has already grown strong.

Data centers are very expensive assets, but aside from the construction phase, they create almost no employment. From the community’s perspective, these buildings are hard to see as beneficial. Therefore, they must prove their utility by developing ways to utilize waste heat.