Veks utilizes the excess heat from heated lubricating oil

Date: 27 January 2020

A new surplus heat project at the Køge CHP plant provides energy savings, which are equivalent to the heating demand of 250 homes. (The energy in the discharged cooling water corresponds to approximately 4,750 MWh annually).

The focal point of the surplus heat project is the heated lubricating oil used for the turbine on unit 8 at the Køge CHP plant. Veks have now started to remove the heat from the oil.

The heat pump moves in
Previously, the hot oil was cooled in a closed system using water from Køge Bay with a temperature between 25°C and 40°C, but now the sea water cooling system is replaced with a heat pump, where the heat from the turbine lubricating oil and other components are recovered. The heat pump raises the temperature of the cooling water so that it can be used in Køge District heating system without creating noise or vibration.

The project started in May and with the 16.5-tonne heat pump being delivered and fitted in the late summer, trials were already possible during the winter. Now the heat pump is in normal operation and will contribute towards a one percent improvement of the units energy efficiency.

The repayment period for the heat pump project is 6.5 years.

Nothing new
It is unconventional to combine heating and cooling needs in one and the same process, but Veks have not embarked on a pioneering project. This known technology has not compromised on operational security whilst still retaining the seawater system as a backup in case of a breakdown of the heat pump or when the turbine needs to be started.

However, the energy savings do not stop here. The next project will be to establish flue gas condensation – also on unit 8 of the cogeneration plant. This project starts in the spring of 2020 and will significantly reduce the temperature of the flue gas from unit 8, so that large amounts of energy can be recycled into the district heating production.

Block 8 at the Køge CHP plant was built in 1998 and has an estimated service life of 2040.

The heat pump at Veks was installed in late summer
The heat pump at Veks was installed in late summer