Heat re-use

The supercomputer systems at PDC generate an enormous amount of heat, so PDC and Akademiska hus (the company that is the owner of most of the university buildings in Sweden) have developed an environmentally-sound method of re-using that heat, rather than wasting it.

The KTH main campus has a hydronic (water-based) heating and cooling system, so the buildings are linked by networks of pipes carrying hot and cold water. Akademiska hus produces heating and cooling from its own plant, but the network of pipes is also connected to the Stockholm city district cooling and heating systems in case extra cooling or heating is needed.

The heat from the PDC supercomputers is captured (by heating water) and transferred, together with heat produced in other KTH buildings, to the central heating and cooling facility through the network of water-filled pipes. This heated water is not quite hot enough (17 ºC) for heating purposes, so heat pumps increase the temperature enough that the water can be used for taps and for the hydronic radiators in the buildings at KTH. PDC’s supercomputers are the single largest sources of heat for the KTH heat pump.

This environmentally friendly approach saves PDC from having to purchase large amounts of cooling from the Stockholm district system in order to cool the supercomputers, and it also cuts down on the amount of extra heating that KTH needs.