Background/Motivation

Every day, buildings produce warm wastewater - from showers or kitchens, for example - which has previously been discharged unused into the sewer system. This wastewater has considerable energy potential, especially in in-house areas where higher temperatures (20-30°C) are available and technical implementation is easier due to the proximity to heat consumption points.

At the same time, the heat supply in the building sector must be decarbonized - however, the available heat sources are often limited, especially in the renovation of existing buildings in densely populated areas. Therefore, the use of wastewater heat as a renewable energy source, especially in combination with other renewable energy sources such as geothermal, air, or solar energy, can make an important contribution to the phase-out of fossil fuels for heat supply.

The new heat exchanger was developed specifically for in-house use, i.e., the use of the building's own wastewater, and is now to be implemented as a prototype as part of the research project.

Objectives and innovation content

The objective of the Drain2Energy project is to implement and demonstrate a prototype of the innovative in-house wastewater heat exchanger in two selected existing buildings. 

This compact heat exchanger technology with a very high heat exchange surface has been specially developed for in-house use to offer a low-maintenance and space-saving solution that can be used primarily in existing buildings. In existing buildings, there is no separation of grey water (showers, washing machines, etc.) and black water (toilets) without total renovation, which is why solutions for grey water use alone can not be used very often.

The retrofittable wastewater heat exchanger can also use black water in combination with the pre-separator (removal of coarse materials such as wipes, etc.) and is therefore particularly suitable for use in existing buildings and renovations.

In both implementations, the heat from the wastewater will be extracted by the innovative self-cleaning heat exchanger and brought to the required temperature level by means of a heat pump. The systems will then be monitored in order to collect comprehensive data from their operation.

Expected results

In the course of the project, important findings from the operation of the heat exchanger system will be collected (amount of energy gained, wastewater volumes, efficiency, etc.). The findings in particular will provide information on the respective available wastewater volumes and, accordingly, on the heat potential from wastewater.

The findings will serve as a basis for the dissemination of the wastewater heat exchanger technology and make an important contribution to the decarbonization of heat supply in existing buildings as well as in new buildings.

Project management

Schöberl & Pöll GmbH

Project or cooperation partners

• rabmer Bau & Umwelttechnik GmbH
• BPS Engineering GmbH

Schöberl & Pöll GmbH
Lassallestrasse 2/6-8
A-1020 Vienna
E-mail: office@schoeberlpoell.at
Web: www.schoeberlpoell.at