The Future of Low Carbon Heat with Mitsubishi Electric

With data centres more in demand than ever before, they are fast becoming greater users of energy - causing challenging impacts on the environment. Given that the world now relies on them so much, in line with increased investments into AI and cloud-based technologies, data centres are having to find ways to limit global impact.

We hear from Shahid Rahman, EMEA Data Centre Strategic Account Lead (Engineered IT Cooling Solutions) at Mitsubishi Electric, about how data centres can become more energy efficient and minimise environmental impact.

“Data centre users are increasingly concerned with their carbon footprint,” he says. “This has created increasing pressure for data centre developers and operators to provide robust, fault-free services while reducing energy use and emissions – a difficult balancing act.”

How can data centres best reuse their own heat?

As data centres consider new ways to be sustainable, heat reuse could contribute to organisations being more energy efficient as they seek to make good on their sustainability and Net Zero pledges. 

This is more timely than ever, as Rahman cites increased regulations are slowing data centre development, using the example of the Dutch government having banned new hyperscale projects for nine months. Likewise, the government in the Republic of Ireland is also introducing measures to consider new data centre projects more closely.

To mitigate matters, he says that data centres can reduce carbon impact via heat reuse. Whilst there has been increased focus on using cooling technologies within data centres, as they meet energy-reduction targets, Rahman highlights that it may be beneficial to reuse data centre heat instead.

“Shifting the focus onto the reuse of heat energy actually gives data centres the potential to decarbonise further and build a greener future,” he says. “In fact, excess heat from data centres can be used to heat other nearby buildings – including homes – and provide them a more sustainable heating source.”

This is already taking place in Germany, with its Energy Efficiency Act making reuse of waste heat a requirement. Data centres will have to achieve 10% heat reuse from 2026. 

“One heat recovery model is district heating and cooling as a service: a heat pump recycles the water from the district heat network to cool the data centre,” Rahman says. “The waste heat from the cooling activity is then collected by the heat pump and pushed to the city network. The reheated hot water from the data centre mixes with the water in the general heat network, increasing the return temperature. Overall, energy consumption across the whole heat network is reduced, and so are energy costs and carbon footprint.”

Are there any examples of successful heat reuse implementation?

Leading technology companies and data centre developers have already been keen to utilise heat reuse. Rahman cites Amazon’s Tallaght data centre in Dublin as a crucial example.

“It uses a system where heat generated by servers is transferred to an air-handling unit and then recycled to warm water,” he says. “The water is then directed to an energy centre outside the warehouse, where heat pumps further increase the water temperature.

“This innovative approach not only results in an estimated annual reduction of 1500 tons of carbon dioxide emissions but also provides heating for over 505,000 square feet of local public buildings, 32,800 square feet of commercial buildings, and 133 apartments.”

Heat pumps and heat networks have also been cited as solutions to improving data centre energy efficiency, as they are able to efficiently provide heat and hot water, thereby reducing carbon footprint.

Rahman says: “Heat pumps are particularly useful for making the most of waste heat. Data centre output heat is around 30oC to 35oC. Heat pumps can use water at this temperature as a heat source, topping up the temperature to 70oC or even 80oC. This heat energy can be used in the data centre to meet domestic hot water (DHW) demand in washrooms and showers, for example.

“Alternatively, it can be used on a wider scale in heat networks connected to buildings and homes located further from the data centre. Households can then be provided with heat and hot water via a large network of pipes. The Climate Change Committee (CCC) estimates that 18% of UK heat could come from heat networks by 2050 (up from 2% today).”

When it comes to heat reuse options, what should businesses consider?

“When looking at linking the data centre to a new or existing heat network, the first step is to ensure that there is an outlet for the waste heat a reasonable distance from the data centre – or that there is an existing heat network that can use extra capacity – through heat mapping,” Rahman notes.

“It is then vital to understand what the cooling demand of the data centre is across the year, and to size and specify cooling equipment.”

He continues: “The ideal solution is a water-to-water heat pump, or a heat pump chiller. The heat output of the heat pump can then be calculated to establish the annual heat output profile.”

Investing in local communities is also something to bear in mind, as data centres hold great potential to create jobs and improve local infrastructure. 

Rahman suggests that data centres should also be considering their heat output in line with local heating requirements. Buildings close to the data centre, or those that are large sources of heat demand such as hospitals and schools, should also be considered by developers. These types of initiatives hold the potential to enable local communities to reuse excess heat from data centres and further decarbonise

“This kind of process not only enhances energy efficiency in data centres but also contributes to providing neighbourhoods with heat and hot water in a more sustainable way,” Rahman highlights.

“Framing the data centre sector as part of the solution for our decarbonised future, rather than simply an energy user, has clear benefits for future development and growth.”

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