FRANK WET / Water Heat Exchanger

Heating and cooling with the water of lakes and rivers

For the use of renewable energies also surface waters are of great importance. Water is an excellent temperature storage. For building sites near lakes, rivers or on the coast, this free of cost energy can be used to heat or to cool the building. This makes you independent of fossil fuels, protects the environment, saves heating costs and reduces CO₂ emissions.

Project BV Loosdrecht (Netherlands) - FRANK WET system with integrated weekly monitoring

Einsatz WET
Häuser am See

FRANK WET / water heat exchanger

The water heat exchanger is specially designed to extract heat from the surrounding water. The compact, highly efficient heat exchanger extracts the energy required for heating from the water. In conjunction with a heat pump, the extracted energy is converted into thermal heat. Furthermore, the heat exchanger can be used effectively for cooling the building.

The convection openings in the surrounding housing and the optimized pipe routing of the heat exchanger ensure a high level of efficiency.

All components of the water heat exchanger are made of environmentally friendly, high-quality polyethylene: This guarantees a long service life. Low weight and attachment points on the housing allow quick and easy installation.

The principle

The closed circuit enables safe operation regardless of the water quality. No contamination of the filters and no risk of corrosion in the water circuit as with open systems. In combination with a conventional geothermal heat pump, as used in geothermal systems, the energy is extracted from the water and supplied to the building. The heat or cold exchange takes place in the heat pump and the free energy is available for heating or cooling.

FRANK WET Wärmetauscher

Warm up in winter with standard radiators.


Or warm up in winter with underfloor heating.

Extraction capacity

The possible extraction capacity of the WET depends on the ambient temperature of the water. Due to the 3 sizes, a good adaptation to the individual power requirement and the existing water depth is possible. For buildings with higher energy requirements, several WETs are simply connected in parallel and brought together via a FRANK distribution shaft.

FRANK WET Wärmetauscher

Installation locations

All waterfront buildings, whether single or multi-family homes, holiday homes, hotels or restaurants, commercial and harbour buildings can be heated and cooled with this environmentally friendly and innovative solution. The WET water heat exchanger has already proven itself in many properties in combination with heat pumps from various manufacturers. The compact design also allows for large outputs with a small footprint. Even construction sites by the sea can be supplied in an environmentally friendly way. The WET can be installed in fresh and salt water without any problems.

Gebäude am Hafen
Hotel am See

Example for fastening

The low weight and multiple attachment points on the WET's housing allow for easy and quick installation. For easy transport, the upper attachment points can be used as transport lugs. Insertion into the mooring can be done from the shore or jetty or from a boat. Due to the low buoyancy of the WET, it floats on the water surface until it is anchored. Anchoring is done with a counterweight on the bottom of the water or by fastening it to pile structures, jetties or the quay. The connection lines are made of insensitive PE pipes, all connections are welded and offer maximum safety due to the material-locking connection.

Wasserwärmetauscher am Gewässergrund montiert
Wasserwärmetauscher unter Steg

Technical Data:

Extraction capacity                                                  

depending on module size and water temperature

Max. Operating pressure

3,0 bar

Temperature range

-10°C to + 40°C

Connection flow / return (PE spigot)

40 mm

Dimensions (diameter x height)

Type WET 1

Type WET 2

Type WET 3

1220 x 600 mm

1220 x 900 mm

1220 x 1200 mm

We are happy to advise you

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