Recovering Thermal Energy from Urban Wastewater Sewers and Using It for Heating and Cooling

Recovering thermal energy from urban wastewater sewers and using it for heating and cooling purposes in buildings (FAIRHEAT)

1-Need

In the EU-28, households accounted for 19 % of greenhouse gas emissions (GHG) in 2016. This percentage jumps to 29 % in Belgium where the building sector in urban areas is mostly composed of low-energy buildings. In the Netherlands the percentage is stable at 19%. Around 15 % (up to 30 % in low energy buildings) of the thermal energy delivered to buildings is lost through the drain and ends up warming wastewater in the sewer system, making this a large source of heat leakage in buildings.

The project will recover heat from wastewater flowing through the sewers to improve the general efficiency of heat pumps-based heating and cooling systems in urban buildings. The use of a heat pump will allow us to reduce buildings’ GHG by up to 76 % in wintertime and up to 70.7% in summertime, compared to traditional fuels (gas, heating oil, electricity).

2-Rationale

-Large-scale technology testing:

The in-sewer heat exchange system which will be implemented is the result of two previous project pilots launched in Brussels: the first project ran from 2007 to 2009 in a water screening-building, while the second one has been in operation since 2009, in a connection between a sewer and a 3.200 m³ water basin. The technology is patented (patent obtained in Belgium and patent is pending in Europe: no°WO 2016/023867 A1) but has not been tested in occupied buildings yet.

The technology is classified as:

• Heating: Technology Readiness Level 7 (System prototype demonstration in operational environment)
• Cooling: Technology Readiness Level 3 (Experimental proof of concept)

Interreg gives us the opportunity to implement this technology in several cities (Brussels, Rotterdam and future partners) in order to test it in occupied buildings: In Brussels: a 15.000 m³ office building, occupied 5 days per week and 16 hours per day. The opportunity to test the technology in various cities enables us to analyze its functioning and to further improve it.

-The launch of several pilot projects in urban areas :

As highlighted above, the main sources of greenhouse gas emissions are the heating and cooling of the building sector which represents 39 % of emissions in Brussels and 20 % in Rotterdam. In the Brussels-Capital Region, the energy performance certificate of half of the dwellings is E or F (very energy intensive). The implementation of this technology on a large scale will contribute to reduce the GHG in urban areas.

-Offering a new market to final costumers:

The development of this new technology will allow customers to choose between different and financially competitive energies. VIVAQUA carried out a study for the chosen pilots to compare the cost of heating and cooling from sewers against the cost of other energy carriers (gas, electricity and heating oil), both for household consumers and commercial/industrial consumers. Results underline that, in Belgium, prices per kWh are competitive for households and commercial/industrial consumers:

Heating cost during a renovation / Average price kWh Gas / Elec. system / Average price kWh heating oil / Elec. system / Average price kWh heating elec. / Elec. system
€ 0,0863 / € 0,089 / € 0,109 / € 0,165

-New technological and financial opportunities for public operators:

The implementation of this technology will bring new technological and financial opportunities for public operators. The heating and cooling system can be managed by the national or regional competent authorities. The links between public operators will be strengthened and local policies will be better coordinated.

3-Objectives

The target of project FAIRHEAT is demonstrating the feasibility, both technical and economical, of the technical solution for recovering thermal energy from urban waste water systems and using it for heating and cooling purposes in buildings.

-Short-term:

- Developing, adapting and validating the technology

- Promoting technology to other public operators

- Preparing and adapting the current legislation thanks to studies conducted during the project

- Defining a clear framework of which public entities are responsible for the management of the technology.

-Mid-term:

- Implementing the technology during renovations

- Starting the commercialization of recovered heating and cooling energy to final consumers

-Long-term :

- Bringing a new market for final consumers throughout the entireurban areas

- Contributing to the reduction of GHG

- Strengthening links between public authorities / operators

4-Results

The main results of the project will be:

• For urban population: reduction of GHG emissions in urban areas which would translate into environmental and health benefits.
• For household consumers: a wider offer of technologies for heating and cooling;
• For wastewater operators: a new technology will be able to reduce the amortization of the investment in case of the need to renovate a sewer
• For public authorities: a clearest legal and juridical framework and a better cooperation between public authorities

5-Search for partners

The partnership is composed so far of a Belgian public utility (Vivaqua, lead partner), a Belgian city and Dutch city.

The partner search is two fold

a)A third pilot project is foreseen and therefore partners are searched among public utilities and cities in other Interreg NWE eligible regions.

b)Higher education or research organisations with the following mission :

In the process in which heat present in sewage systems can be recovered by installing heat exchangers in direct contact with effluents, VIVAQUA uses high-density polyethylene (HDPE) as main material, because it is insensitive to corrosion and rather cheap. The low conductivity of this material would be offset by the number of heat exchangers lined up, knowing that this configuration would be part of sewer rehabilitation.

A first pilot project and related research have revealed a wide range of conductivity coefficients for polyethylene tubes. In order to optimize the process it would be useful to conduct a project to understand and gather information about the manufacturing parameters influencing this conductivity. Polytechnic faculties would be the right places to conduct this kind of university research.

The application is intended for the next Interreg NWE call which will be opened from 17 April till 24th May. Eligible regions can be found here.

Deadline for expression of interest: 24th April 2017

Lead partner contact details:

Mr. Olivier Broers – Vivaqua : Director Studies and Investments

- + 32 (0)2 518 85 89

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