Waste heat

We send large quantities of energy down the drain with our wastewater. Hot domestic water currently accounts for around 30% of heating costs, with this figure expected to rise to 50% in the none-too-distant future. When hot water goes down the drain, it takes with it a large amount of energy that can be reused.

Finnish households flush 7.1 TWh of energy down the drain each year. This is the equivalent of around a million tonnes of coal, which is more than 25% of the coal used in Finland (sources: Motiva, Statistics Finland).

At present, heat is generally recovered only from treated water that has already been through a wastewater-treatment plant. By that point, a considerable amount of the waste heat has been lost. The most efficient form of heat recovery is processing of the wastewater before it even leaves the property. The Ecowec system recovers heat from all wastewater generated in the building and cycles it back for reuse more efficiently than any other system.

Heated water accounts for a third of buildings’ heating costs, and at the same time more than a third of the energy used by industry goes to waste, adding up to 54 TWh of lost energy.
According to Motiva, up to 4 TWh of this waste heat could be recovered and reused profitably each year. Putting this waste heat to good use would result in annual savings of 200 million euros in industrial energy costs. The greatest potential for savings can be found in the forest industry, which is the single largest consumer of energy in Finland. The metal, food, and chemical industries also generate large quantities of wastewater and water used for cooling, from which heat could be easily recovered with Ecowec hybrid heat exchangers.

In general, each resident of Finland’s flats and terraced houses uses 80–300 litres of water a day. According to the managing director of the Finnish Association of HPAC Technical Contractors Jari Syrjälä, studies have found that in buildings in which the water charge is not based on actual consumption, residents are not motivated to conserve water as they do not believe that their neighbours are taking any measures to curb their water consumption either.

The Ecowec system can reduce the amount of energy lost by a property, creating considerable savings. But first and foremost, buildings whose owners/managers opt for an Ecowec solution contribute to measures to slow down climate change by recovering and reusing heat from wastewater.