Helsinki’s public energy company, Helsingin Energia's, has built a new eco-friendly data centre in a cave under Uspenski Cathedral. The data centre is cooled by district cooling and the heat generated is piped out as district heating. The capacity of the data centre is two megawatts, with an extended capacity of five megawatts. When the hall is full of computers, the heat it produces is enough to heat up to 500 family homes.
The aim of the joint project between Academica and Helsingin Energia is to produce the world’s most eco-efficient data centre. The district cooling is produced from the thermal energy from heat pumps, cold seawater or energy generation that would otherwise be wasted. The heat produced is piped via a heat pump into the district heating network to heat Helsinki buildings and the residents' domestic hot water.
In its press release the company points out that the efficiency factor (which I assume means PUE) of ordinary data centres is between 1.5 and 2. The efficiency factor of Academica's and Helsingin Energia's hall is around one, and ‘it is possible to get even below this figure’. (I’m not sure how that’s done).
But it’s a reminder that taking individual facilities in isolation, particularly data centres) may well not be the best way to demonstrate energy efficiency. It’s possible to use the heat generated within a data centre for another use, saving energy elsewhere.