November 7, 2017
As part of SAV’s low carbon education programme, consulting engineers from the UK visited the factories of SAV’s manufacturing partners Danfoss, EC Power and AirMaster. The highlight of the trip was the Fredericia district heating scheme.
Founded in 1954, the Fredericia district heating scheme is a private consumer-owned district heating company that supplies heat and hot water to the connected properties. Around 99% of the heat load for the connected properties is met by a combination of waste heat, CHP and the surplus heat from the local Shell oil-refinery.
Fredericia district heating scheme is one of the eight local district heating companies that are connected to the regional heat transmission system TVIS. Located in the middle of Denmark, this multi-city district heating system serves 83,000 homes in the cities of Vejle, Fredericia, Middelfart and Kolding, where its 183,000 consumers benefit from the large amounts of surplus heat generated in the area.
TVIS is an independent general partnership company established in 1983. Its main principle is to be a non-profit company and is owned by the four municipalities it serves (Fredericia, Kolding, Middelfart, Vejle).
Currently the distribution network comprises 82 km of main pipe, from Kolding in the south to Vejle in the north. Pipe diameters range from 200mm to 660mm with a 2-3% heat loss across the main distribution network.
The fact that all district heating (DH) companies in the area are interconnected through one system, enables efficient use of the surplus heat which would otherwise have gone to waste. Local operation of directly fired oil or gas boilers in the former district heating stations has ceased, thus almost eliminating the direct consumption of fossil fuels for district heating. Once the recent conversion of the Skærbæk power station to wood chip (biomass) CHP is fully implemented, the district heating in the so-called Triangle Region will become 95% CO2 neutral.
This is economical for the DH customers as the heating production price from the biomass plant will be reduced by 20-25% compared to 2014 prices and it also improves the environmental quality for everyone living in the region by reducing emissions of greenhouse gases.
Future plans for the scheme include the provision for new surplus heat and new renewable energy production, as well as the implementation of a more systematic procedure for determining the flow temperature from the CHP plant. It has been estimated that just a 1°C drop in flow temperature could save approx. 125,000 EUR.
Big savings are also possible from reducing return temperatures. The Fredericia district heating scheme recently launched a campaign to educate consumers on the importance of lowering the return temperatures and advise them on how to achieve this. The campaign resulted in a drop on the scheme’s return temperatures by 1°C, which, in turn, resulted in a reduction in energy costs for the scheme’s consumers.
The trip also included a visit to a multi-residential development connected to the Fredericia district heating scheme, where the consulting engineers were shown how a 60/30 system operates and performs in real life. The conversation continued inside a flat within the development, where particular emphasis was given to the importance of controls of radiators and underfloor heating to obtain low return temperatures.
The benefits of reducing return water temperatures is also a key theme in SAV’s lean heat networks education programme.