22 September 2011

DISTRICT HEAT DRIVEN ABSORPTION COOLING OF DISTRICT COOLING PLANTS IN TRONDHEIM, NORWAY


In 2003, Trondheim Energi Fjernvarme AS started to deliver district cooling at St. Olavs Hospital, which is a new University hospital in Mid Norway. Stage one of the district cooling plant consists of one 3 MW absorption chiller and two compressor chillers. The total cooling capacity is 7 MW.

In 2007, the new hospital buildings covered 100 000 m2 floor area. The annual cooling load was 6 600 MWh, where 67% was covered by “free cooling” from river water, and 30% was
covered by the absorption chiller. During this summer, the compressor chillers covered only 3% of the cooling demand. Hence, this is a cooling system with little environmental impact.

In 2009, the new hospital buildings approached 200 000 m2 floor area, and during the warmest summer days the chiller plant operated at 100% capacity. The annual cooling load had increased to 10 000 MWh. About 70% of the cooling was covered by “free cooling”, while the absorption chiller covered about 20% and the compressor chillers 10% of the cooling demand.

In order to reduce the use of the electrically driven compressor chillers, a new 3 MW absorption chiller will be installed prior to the 2011 summer cooling season.