Compared to steam turbines based on a water circuit, ORC installations make it possible to recover heat from low-temperature sources available in small-capacity plants. An ORC system can work well in concert with biomass combustion and solar concentrating units. The system was named for its use of an organic fluid characterised by high molecular mass and a liquid-vapour phase change at temperatures below water-steam transformation.
The ORC unit in Brønderslev will come from Italian-based Turboden. Turboden has implemented around 300 ORC units all over Europe in recent years, according to a document by DTU, the Technical University of Denmark (see the document attached).
The parabolic trough field was delivered and installed by Danish-based Aalborg CSP. It came online in spring 2017 and has since been feeding into the town’s district heating network. Once the ORC system is put into operation, as is planned for April 2018, solar energy – collected via thermal oil at around 300 °C – is said to be used for fuelling it. “By the end of this July, the collector field will have produced 6,500 MWh, and we expect 16,000 MWh from year-round operation,” said Thorkil Neergaard, Managing Director of Brønderslev Forsyning. This would translate into a specific yield of 594 kWh/m²a. Both biomass systems are said to start producing heat late this year. Neergaard expects gas to be used only during very cold periods and perhaps the units could be stopped during some years completely.
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