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Indoor swimming pool heated with the local sewer

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Indoor swimming pool heated with the local sewer

3 min read 27 Mar Download text

The Blinkerd in Scheveningen is bidding farewell to natural gas. The new heat source will soon be sewage water, which, through a heat exchanger and heat pumps, will sustainably warm the swimming pool and sports hall.

Wesley Verschoof is the manager of Sportcentrum De Blinkerd and Patrick Wagemans is the project leader. They are both responsible for this project. The building currently uses 170,000 cubic meters of natural gas per year. "After the summer, we'll heat the swimming water differently," says Wesley Verschoof. 

"We're the first swimming pool in The Hague to move away from natural gas. That's very special. In the rest of the Netherlands, there are only a few swimming pools that have done so. We're lucky to have a large sewage pumping station just 50 meters away for wastewater."

Wesley Verschoof, manager Sportcentrum De Blinkerd

The Blinkerd will utilise sewage thermal energy, also known as aquathermy. Project leader Patrick Wagemans explains how it works: "Sewage water has a temperature of about 18°C in the summer and 12°C in the winter. It's a stable and reliable heat source. You can extract heat from it using a heat exchanger: Two pipes are placed against each other in the ground. One pipe carries warm sewage water, while the other carries coolant. The sewage water transfers heat to the coolant, which then transfers it to heat pumps in the swimming pool's engine room. There, it's further heated to warm the building. The cooled sewage water then flows back to the pumping station."


Storing heat and cold in the ground

In the summer, the sewage provides more heat than the swimming pool needs. In the winter, extra heat is required. To prevent heat loss, it's stored in groundwater at a depth of 200 meters. Two wells are drilled: one for storing heat in the summer and retrieving it in the winter, and the other for returning cooled water to the ground. This system is called aquifer thermal energy storage (ATES) and is already used to heat and cool The Hague's city hall.

The explanation of Riothermal energy by Aquafin

Covers over the pool

The Blinkerd has already implemented other sustainable measures. All lights have been replaced with LED lighting, and the many windows have HR++ glass. Wesley provides another example: "For ventilation, we now have equipment that extracts heat from the air blown outside. We can use it to warm up the cold air coming from outside. Additionally, we cover the pools with blankets when the pool is closed. The less heat loss, the less energy needed."

Work schedule

The work will begin in May 2024. By September, visitors can swim in a sustainably heated pool. The old gas boilers will remain for another year in case of any initial issues. 

Making all swimming pools sustainable

The municipality aims to make all swimming pools in the city sustainable.

"Every building is different. For example, you can't install solar panels on the Blinkerd's round roof, but it's often possible at other swimming pools. You have to investigate the opportunities and find the best solution for each location, but that applies to the entire energy transition."

Patrick Wagenmans, project leader for the Blinkerd energy transition
Rioolgemaal Scheveningen - Source Hofmeijer MP
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Learn more about the work of the serwer system of Scheveningen The Hague, Location Haringkade.

About Swimming Pool The Blinkerd

Read more about swimming at The Blinkerd

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