German energy supplier switches on 20 MW ‘river’ heat pump


MVV Energie AG has switched on an industrial heat pump at a coal-fired power plant operated by Grosskraftwerk Mannheim AG (GKM) in Mannheim-Neckarau, Germany.

The German energy supplier said the new system is integrated into a district heating network and is one of the largest such systems in Europe. The heat pump uses water from the Rhine River and has a thermal output of 20 MW. It will provide heating for 3,500 households. Siemens Energy supplied the heat pump technology and GKM integrated it into the infrastructure of the large power plant for MVV Energie.

MVV Energie said that the water of the Rhine River in Mannheim is up to 25 C in summer and only around 5 C in the winter. This thermal energy is sufficient to evaporate the refrigerant in the heat pump and reduce the temperature of the Rhine River water by around 2 C to 5 C.

The refrigerant vapor is then compressed using an electrically powered compressor to increase the pressure and temperature. The heat generated by the refrigerant vapor is transferred to the district heating water through condensation in a heat exchanger, producing hot water at temperatures ranging from 83 C to 99 C.

The refrigerant liquefies and expands again in the heat exchanger. It then cools down and absorbs thermal energy from the river water at a low temperature to restart a new cycle.

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“The heat pump works on the same principle as the home refrigerator,” MVV Energie said in a statement. “While the heat energy of the refrigerator is released from the inside to the outside, the heat pump uses the heat to heat the district heating water.”

The project is part of the “Large heat pumps in district heating networks” initiative, which is funded by the Germany Ministry for Economic Affairs and Climate Protection (BMWK),

“The MVV project shows that heat pump technology also works in XXL format to provide climate-neutral supply to entire city districts,” said Thekla Walker, the minister of energy for the German state of Baden-Württemberg.The river heat pump is an important building block for our country in reducing its dependence on fossil fuels step by step.”

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