A small town on the coast of the North Sea

A small town on the coast of the North Sea – a world concept of a sustainable way of heating

The Danish town of Esbjerg on the coast of the North Sea has become a world concept of a sustainable way of heating, thanks to a heat pump that converts the temperature of the sea into energy.

Instead of the decommissioned thermal power plant, a large heat pump has been put into operation that will turn the temperature of the sea into 280,000 megawatt hours of energy, enough to heat 25,000 households, writes Deutsche Welle.

Residents of the southern seas may be surprised by this, but Tobias Hirsch from MAN Energy Solutions explains how this heat pump works perfectly “even at the lowest temperatures, when the North Sea is four degrees or even lower”.

“And then we can still get enough energy from seawater and make water heated to over 90 degrees available to the city and its population,” says Hirsch.

This heat pump has two sources of energy: in the first stage, a large amount of 4000 liters of seawater per second is “taken” by a heat exchanger of approximately 3 degrees Celsius. That heat is transferred to the cooling agent – carbon dioxide. Like in a home refrigerator – but in the opposite direction, then that gas is compressed to 120 bar and thus its temperature rises.

Of course, a lot of electricity is needed for the pump and for the compressor, and it is obtained from the wind farm of that heat pump industrial plant.

For Harmut Spliethoff of the Technical University of Munich, it is an extremely efficient system.

Ecologically meaningful, economically attractive

“Such a heat pump generates three to five units of heat energy from one unit of electricity. Such a plant is first of all reasonable when electricity from renewable sources is also available.

The German expert explains that as a rule, the water temperature is higher than the air temperature, and this is not the case only with the sea, but also with rivers and lakes, which are on average 8 to 10 degrees warmer.

Such industrial heat pumps “make ecological sense, just as they are economically attractive options”, points out Martin Pehnt from the Institute for Energy and Environmental Research (IFEU) in Heidelberg.

Of course, this primarily applies to places where there is already a heating system, but also in cities where it is not possible to install “home” heat pumps.

The Bavarian Rosenheim is actually the first city in Germany that has already turned to heating using water, in this case it is the river Mühlbach. It is actually just a part of the whole system that includes both an electric boiler and gas engines.

Advantages of the heat exchanger

Getz Bruhl from the utility company Rosenheim explains that this way you can react quickly to changes in the price and supply of electricity: “When there is too little electricity, additional electricity can be produced with the heat exchanger, and if there is too much electricity, then we use the heat pump for heating “.

With this plant, around a third of the forty thousand households in Rosenheim can be optimally heated ecologically and economically.

However, the new facility in Denmark has gone one step further – a heat tank has been installed that can be filled when it is not so cold.

For now, this method of energy production is used by only a few German cities. One of them is Mannheim, located at the confluence of the Neckar River with the Rhine. That city built a heat pump for 3,500 households for 15 million euros.

Energy concern RheinEnergie has ordered a heat pump with a capacity of 150 megawatts. From 2027, it should supply about 50,000 households in the city of Cologne with heat from the Rhine.

Environmentalists are not entirely sure whether such heat pumps on rivers and seas are really ecological. If heat is “taken” from the waters, it inevitably means that they will become colder.

Source: DW

Photo: Pixabay, screenshot