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HUBER Heat Exchanger RoWin Modular design and especially to be used with all types of wastewater

Energy recovery from wastewater

  • Modular design
  • Developed especially to be used with all types of wastewater
  • Not easily affected by coarse and floating material
  • Odour-tight
  • Low maintenance requirements
  • Self-cleaning

Right below the ground, in sewers, is a hidden and seldom used source of energy: our wastewater. Generally the temperature of sewage is in the range of 12 to 20 °C. Even during winter the wastewater temperature never drops below 10 °C, or only for a few days. This makes wastewater an excellent heat source for the operation of heat pumps.

As a link between the wastewater and heat pump, a heat exchanger is required to extract the heat energy contained within the wastewater: The HUBER Heat Exchanger RoWin transfers the thermal energy from the wastewater to the heat pump. Up to 80% of the useful heat can be recovered from the wastewater and utilized economically.

Utilisation of wastewater as a heat source is especially suitable to be applied in large buildings, such as nursing homes, hospitals, schools or swimming baths. It is also possible to recover heat from the effluent of sewage treatment plants and use it e.g. for sludge drying.

HUBER Heat Exchanger RoWin
HUBER Heat Exchanger RoWin
HUBER Wastewater Heat Exchanger RoWin installed in boiler room
Partially insulated version of the HUBER Wastewater Heat Exchanger RoWin
Above ground, parallel installation of two HUBER Wastewater Heat Exchangers RoWin
HUBER Heat Exchanger RoWin C tank version being lifted into the concrete tank
A HUBER Wastewater Heat Exchanger RoWin C is lifted into the concrete channel
Eco-friendly heat supply for buildings: HUBER ThermWin process with HUBER Heat Exchanger RoWin
Eco-friendly heat supply for buildings: HUBER ThermWin process with HUBER Heat Exchanger RoWin
Schematic drawing of a HUBER Heat Exchanger RoWin
Schematic drawing of a HUBER Heat Exchanger RoWin

Design and Function

Schematic drawing of a HUBER Heat Exchanger RoWin
Schematic drawing of a HUBER Heat Exchanger RoWin

The HUBER Heat Exchanger RoWin consists of a welded stainless steel construction in which horizontal pipe modules are arranged in parallel. The pipe modules are made of stainless steel to achieve maximum heat transfer efficiency. The pre-screened wastewater flows through the heat exchanger and, via the compactly arranged pipes, gives off its thermal energy to the cooling water. The energy for the heat pump is supplied through the heated cooling medium.

Due to the specific chemical-biological properties of wastewater a biofilm is developed over time on the heat transfer surfaces that significantly impairs heat transfer. Preventive cleaning of the heat transfer surfaces with an innovative, fully automatic cleaning mechanism therefore is applied to ensure the maximum heat transfer capacity is permanently maintained.

Sediments and solids settling on the tank floor are removed by a screw conveyor and returned to the sewer along with the cooled wastewater. Due to the enclosed tank design and return of solids thermal energy is the only emission from wastewater. The HUBER Heat Exchanger RoWin is available, as required, with an outer insulation for particularly exposed sites. Installed above ground, the system offers the benefits of easy maintenance and operation.

Due to its modular design the HUBER Heat Exchanger RoWin can be tailored to suit specific site requirements. In combination with a heat pump up to several hundred kilowatts of thermal output can be generated, depending on the unit size.

With the optimal combination of both systems municipalities or industrial enterprises can cover up to 80 % of the heat required from wastewater as energy source.

HUBER Heat Exchanger RoWin C installed in a concrete tank. The flow streams through the heat exchanger by gravity
HUBER Heat Exchanger RoWin C installed in a concrete tank. The flow streams through the heat exchanger by gravity

Version for Concrete Tank and Channel Installation: HUBER Heat Exchanger RoWin C

HUBER Heat Exchanger RoWin C installed in a concrete tank. The flow streams through the heat exchanger by gravity
HUBER Heat Exchanger RoWin C installed in a concrete tank. The flow streams through the heat exchanger by gravity

The HUBER Heat Exchanger RoWin C can be used for installation in the outlet of the wastewater treatment plant or in buffer tanks. Installed directly in the wastewater flow, the heat exchanger modules are optimally surrounded by the flow.

Due to the biological processes taking place, the temperature of effluents from sewage treatment plants is on average by 1 K higher than the inlet temperature. Furthermore, higher amounts of thermal energy can be extracted from WWTP effluents than with heat recovery plants installed in sewer systems.

The biological processes in the sewage treatment plant are not impaired and the introduction of the cool WWTP effluent outlet is beneficial for the flowing water biology. In addition, temperature and oxygen conditions in the waters are significantly improved.

If installed in the channel, no additional pumps are required as the wastewater flow normally runs off by gravity. This avoids costs and significantly improves the economic efficiency of such plants. Especially with regard to the energetic rehabilitation of wastewater treatment plants, the HUBER Heat Exchanger RoWin can make a decisive contribution.

Due to its compact design and installation in a channel or tank, no additional installation space is required and the available space utilised at an optimum. But biofilm growing on the heat exchanger surfaces cannot completely be ruled out with the use of the WWTP effluent. Integrated cleaning of the heat transfer surfaces therefore is of great importance to continuously maintain the maximum heat transfer capacity.

Several HUBER Heat Exchanger RoWin C units can be installed in parallel or in series for perfect adjustment to specific site conditions and customer requirements. Combined with load-bearing covers the units can also be installed under parking areas for example.

The Benefits of the HUBER Heat Exchanger RoWin and RoWin C

  • Compact, enclosed tank design
  • Continuous maximum heat transfer capacity
  • Stable hydraulic conditions
  • Fully automatic operation, minimum maintenance requirements
  • Unsusceptible to grease, floating and coarse material
  • Automatic removal of sediments
  • Modular design for tailored solutions that meet the customer’s specific requirements
  • Various possible applications in both the municipal and industrial field


Videos and Animations


Frequently Asked Questions

If the wastewater quantities are very small but the temperature is very high, the wastewater heat exchanger can be operated discontinuously (batch mode).

When recovering heat from wastewater or sewage, heat pumps have a coefficient of performance between 4 and 6, i.e. for every 1 kWh of electricity they supply 4 to 6 kWh of heat. The higher the temperature of the wastewater and the lower the temperature of the heat supplied, i.e. the smaller the temperature difference to be overcome, the higher the coefficient of performance

The ratio of heat output to electricity used is between 4 and 6 (depending on the application).

Often, this value is also indicated as "SPF" (seasonal performance factor).

Heat extraction from process water or wastewater from the food industry, breweries, beverage industry, chemical industry, paper manufacturing, textile industry, commercial laundries, hospitals. Heating or cooling of building complexes, feeding recovered heat into heating networks, cooling of wastewater to comply with official effluent discharge requirements.

Heating or cooling of building complexes, feeding recovered heat into heating networks for example in industrial areas/parks, cooling of wastewater to comply with official effluent discharge requirements.

A wastewater heat exchanger is a heat exchanger that is suitable for operation with wastewater.

The wastewater heat exchanger must be designed in such a way that the solids contained in the wastewater do not cause any operating faults.

In addition, deposits (biofilm) form very quickly on the heat exchanger surfaces when operating with wastewater, so that regular cleaning of the heat exchanger surfaces is necessary, otherwise performance will be reduced. The HUBER Heat Exchanger RoWin is specially designed for operation with wastewater.

Basically, a certain temperature level is necessary. Municipal wastewater typically has temperatures of 10 - 25 °C, which allow ideal operation of a wastewater heat exchanger. To avoid excessive fouling of the heat exchanger, pre-screening of coarse solids (> 6 mm) is recommended.

Almost any type of water can be used for heat recovery if pre-screened properly. This includes, for example, water from surface waters, wastewater from industrial processes, grey water or black water in the municipal sector or already purified water from the sewage treatment plant outlet.

Case Studies

HUBER Solutions in Operation


Reducing the discharge temperatures of industrial wastewater treatment plants – utilisation concepts for excess heat

In industrial production, products are typically manufactured from raw materials using water and external energy. In...

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2023-06-12 Central Hesse, Germany

Energy input to the heating instead of sewage: a university in Hesse uses HUBER ThermWin for heating and cooling with wastewater

Mittelhessen University of Technology (THM) university of applied science intends to exploit a previously quite unknown...

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2022-11-30 Schallstadt,

Heating without fuel with HUBER ThermWin: cold local heating network in Schallstadt (Baden-Württemberg)

In Schallstadt in Baden-Württemberg, the developer and operator of the local heating network found ideal conditions to...

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2021-07-17 Toronto, Canada

World's largest project for energy recovery from wastewater

Noventa Energy Partners and Huber SE have been working together for three years to develop customised solutions around...

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2020-03-23 Arosa, Swiss

Sustainable heat recovery for wellness oasis

The Swiss Hotel Valsana sets new standards in sustainability combined with the highest level of lifestyle partly by...

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2017-04-05 Regensburg, Germany

HUBER SE supplies ThermWin® system for heating and cooling with wastewater at a museum

The HUBER ThermWin® System is part an innovative concept for the use of the energetic potential of renewable energy...

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2016-05-02 Munich, Germany

Wastewater heat utilisation and reuse of process heat at Munich university hospital "Klinikum rechts der Isar"

"Klinikum rechts der Isar" is the university hospital of TU Munich (TUM). There is an intensive cooperation between the...

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2015-05-12 Basel, Switzerland

Use of heat from locally generated sewer wastewater: case study old-age home Hofmatt, Switzerland

Wastewater as a heat source for heat pump systems represents a highly efficient energy source and energy sink. Its use...

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RoWin for a win-win: Various application possibilities for heat recovery

Examples of projects that use wastewater and process water heat show how energy recovery can successfully be realised in...

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2012-10-18 Munich, Germany

Thermal heat from sewers: Bavarian Energy Award 2012 in the category Energy Concepts and Initiatives goes to HUBER SE!

On 18th October, Bavarian Economics Minister Zeil handed over the Bavarian Energy Awards 2012. HUBER SE received an...

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2012-10-15 Witzenhausen, Germany

Energy from wastewater - the HUBER RoWin Heat Exchanger is becoming increasingly popular

A sewage treatment plant in Witzenhausen, a retirement home in Switzerland, and an office building in France – What do...

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2012-03-21 Leukerbad, Switzerland

Leukerbad in Switzerland uses HUBER Heat Exchanger for heat recovery from thermal spa wastewater

Leukerbad is one of the largest spa & holiday resorts in the Alps. HUBER SE has developed the RoWin Heat Exchanger...

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2011-10-24 Winterthur, Switzerland

Three HUBER projects for wastewater heat recovery in Switzerland

Wastewater heat recovery is getting well-established in Switzerland. The innovative projects point out, how our...

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2010-08-30 Berching, Germany

Heat recovery from raw sewage

Environmental disasters, such as the oil disaster in the Gulf of Mexico, the global economic crisis and ever decreasing...

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2010-07-21 Winterthur, Switzerland

First HUBER ThermWin plant for wastewater heat recovery in Switzerland

Due to the owner’s sustainable thinking the Wintower shines in its old splendour after extensive renovation. The HUBER...

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2010-06-01 Berching, Germany

Energy recovery from filtrate water on WWTPs

The HUBER wastewater heat exchanger RoWin extracts and utilises thermal energy from the filtrate water to provide...

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"Tank version" of HUBER Heat Exchanger RoWin

For optimal utilisation of the potential energy contained within the wastewater flow the best position where to install...

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2023-07-25 Regensburg, Germany

Energy from Wastewater: Presentation of HUBER ThermWin System with Bavaria's Minister of Finance at the House of Bavarian History Regensburg

Bavaria's Minister of Finance and Home Affairs Albert Füracker visited the Museum of Bavarian History in Regensburg...

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2012-08-01 Dresden,

Cramer-Klett Price 2012 goes to HUBER employee Christian Frommann

The renowned Cramer Klett Price by the Association of German Engineers is awarded to Christian Frommann, head of...

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