Energy Savings in Geothermal District Heating Pumping at Veitur

Abstract

Most of the Geothermal District heating in the Reykjavik area and surroundings dates back to the 1960s and 1970s, when distribution networks, transmission pipelines, pumping stations and reservoir tanks were built in large quantities. Pumping of geothermal water was originally done with pumps running at fixed speed and all flow and pressure controls were implemented with throttling control valves. Furthermore, pumping between tanks has been the norm since the beginning. Since electricity costs are a significant figure in the district heating operation of Veitur, there are numerous opportunities for energy savings. In the last 20 years, frequency controlled pumps have been installed in new pumping stations and more recently, the use of control valves for throttling has been minimized. Electrical installations are being upgraded, as older cabinets have poor efficiency and have long since surpassed their operational life. The overall strategy of large transmission pipelines and pumping/throttling between tanks is also being re-evaluated, where the role of the largest pumps is being reduced, resulting in significant electricity savings. Veitur are currently implementing strict measures in design of new installations and performing refurbishments of older pumping stations with this goal in mind.