Energy from the lake heats rental apartments

Hällvadsholm is a small town in the Bohuslän province — so small that you would be surprised to find a neighbourhood with rental apartments there. But such a neighbourhood does indeed exist, with tall, two-storey wooden houses that have their own garden plots.

Not only is the location idyllic, the proximity to the nearby Kolstorpevattnet lake provides another benefit: Access to free energy.

This area consists of three two-storey buildings with a total of 36 apartments. Vässjebostäder owns the buildings. Rune Falck is the property owner:

"The area was established in 1990. A year and a half ago, we decided to replace the heating system consisting of heat pumps from Thermia that had become outdated," says Rune Falck.

After a few years of operation, the experiences have only been positive.

"Honestly, you don't need to go into the boiler room often. I can't recall a single alarm since the installation. However, the pump for lake water malfunctioned because it was undersized. It has been replaced and now everything works perfectly," says Rune Falck.

Jörgen Hagberg from the HVAC company Hagbergs VVS installed the water source heating system from CTC.

"The lake is ideal for water source heating. It contains around 3000 metres of piping at various depths, from 3 to 12 metres. The temperature never goes below +4 degrees in the winter."

The common boiler room contains three CTC EcoPart heat pumps, two CTC EcoLogic controllers and two CTC EcoZenith 510 buffer tanks. One control unit controls one heat pump that processes recovered air from the apartments.

Want to know more about heat pumps? Read our guide on heating systems and heat pumps.