Heat recovery from sewers for low temperature DH supply

Heat recovery from sewers for low temperature DH supply Case study of an eco-district Marta Golisowicz, Lynne Bouchy, Gilles Bideux Energy4PowerLive 15 November 2016

Wastewater Unlimited decentralised source of heat Compared with other traditional solutions, energy recovered from sewers is : Renewable: recovery, avoiding GHG emissions Locally available: in all built areas Stable: supply throughout the year Heat pump Heat transfer network Reliable availability Capable of base load provision Low carbon Heat exchanger Average annual waste water temperature is about 12-15 C 2 I Degrés Bleus - Heat recovery from sewers

Heat exchanger features 1 meters long Half-shell shape Small cross section Adaptable to different sewer shapes Module system that can be extended All components installed in the sewer are made of stainless steel Generates approx. 2 5 kw of useful heat per m² of heat exchanger Service life of at least 30 years 3 I Degrés Bleus - Heat recovery from sewers

Installation of in-sewer heat exchangers Quick and easy installation. Civil works kept to a minimum (heat exchangers modules can be inserted via a manhole). Installation of in-sewer heat exchangers via a manhole Source: UHRIG Kanaltechnik GmbH 4 I Degrés Bleus - Heat recovery from sewers

Connection between building and heat exchangers Circuit connecting boiler room with in-sewer heat exchangers Source: UHRIG Kanaltechnik GmbH 5 I Degrés Bleus - Heat recovery from sewers

Technical requirements (Indicative) Average waste water flow min 12 L/s Sewage pipe min Ø 400 mm (new) Sewage pipe min Ø 800 mm (existing) Length of heat exchanger Min 9 m Max 200 m Sewer Building Distance between heat exchanger and a HP maximum 300 m. Minimum heating requirement 80 kw Minimum heat demand 800-1000 MWh/y Maximum heating feed temperature 60 C 6 I Degrés Bleus - Heat recovery from sewers

Degrés Bleus Applications Applications Space Heating & Cooling Domestic hot water Process heat, e.g. swimming pools and Multi residential dwellings Local amenities (swimming pools, schools, offices, leisure centres) Central heating District heating New sewers Existing sewers water parks. End-users and stakeholders Property developers Local authorities Housing associations Water utility companies 7 I Degrés Bleus - Heat recovery from sewers

Case study Eco-district, France

Eco-district Transformation Before Location Industrial area hosting ECAC Fulmen batteries factory (3.5ha) Land contaminated with heavy metals (factory site + surroundings) Dense urban area between old Nanterre centre and residential areas In close proximity to transportation hub Close to the city centre Factories were closed in 2005 Create a centre of urban, architectural and environmental excellence Low temperature district heating network, sourcing heat from renewable sources including wastewater) Create new roads and pedestrian pathways Harmonious integration of new buildings into existing architectural context Provide mix of affordable, and open market dwellings All buildings must have high thermal performance Preserve the tranquillity of the place 10 I Degrés Bleus - Heat recovery from sewers

Eco-district Eco-district in 2017 Area : 5 ha Last buildings (C lots) to be commissioned in 2017 More than 700 new homes- a mix of affordable and open-market dwellings of high thermal performance. Source: SEMNA 2015 http://www.construction21.org/france/data/so urces/users/5441/presentation-generale.pdf 2 No. of new Lots Commissioning Floor area in m homes A2 2011 14,300 166 B3 2012 20,221 246 A1 (school) 2013 5,063 0 B1-B2 2015 11,687 157 C1-C2,C3 2017 11,178 143 Total 62,449 712 A sustainable nursery & school able to accommodate 15 classes, together with a recreation centre and canteen. School building made of renewable, bio-based materials (mainly wood), equipped with PV panels, cooled in the summer by groundwater. More than 1000m 2 of commercial floor space, retail units, cafes/bars Degrés Bleus - Heat recovery from sewers 11 I

Eco-district Today New Roads Very high energy performance buildings Lots B1 and B2, (low energy buildings) Source:http://www.construction21.org/france/data/sources/user s/5441/presentation-generale.pdf Abdelmalek Sayad School Source: http://www.nfa.fr/nanterre 12 I Degrés Bleus - Heat recovery from sewers

References Eco-district Sainte-Geneviève in Nanterre, France 2007: Energy strategy 2008: Technical, economic and legal feasibility study First two developers sign expression of interest for two lots 2009 (3 rd quarter): Preliminary drafts, legal consultation, fine tuning, submission of the grant application. Start up of the tender for public service concession (Dec 2009 June 2010) 2010: 25-year concession contract won by Engie (formerly Cofely) and SUEZ s subsidiary (July) Site preparation prior to construction of the boiler room (September) 2011: Installation of heat network Installation of heat exchangers in the sewer (March) Installation and commissioning of gas boilers (April) Network commissioning June: First occupants mowing in (lots A2 & B3) (June) 13 I Degrés Bleus - Heat recovery from sewers

Eco-district District heating system 14 I Degrés Bleus - Heat recovery from sewers

Sewer

Eco-district Waste heat recovery from sewer The in sewer heat exchangers output capacity equals 370kW assuming the following conditions: Wastewater flow 115m 3 /h Difference between the temperatures of wastewater and heat transfer fluid entering the exchangers:11 C Heat exchangers were installed in 5 sections, each one comprising of 40 modules. Total heat exchange area of the modules equals to 112m 2 Recovered wastewater heat in 2015 = 1,337.2 MWh 16 I Degrés Bleus - Heat recovery from sewers

Eco-district Community Heating Scheme Place Foch 17 I Degrés Bleus - Heat recovery from sewers

Eco-district Heat exchangers inside of the sewer Source: UHRIG Kanaltechnik GmbH 18 I Degrés Bleus - Heat recovery from sewers Note presence of pipes (within sewer) for other utilities. An egg-shaped sewer Sewer height: 2m Typical temp. range (sewage): 15 21 C

Eco-district Installation of sewer heat exchangers, Nanterre Source: Screenshot from a TV programme, FUTUREMAG (ARTE Channel), Heizen mit Wärmerückgewinnung episode. http://sites.arte.tv/futuremag/de/heizen-dank-warmeruckgewinnung-futuremag *to watch it in French google: Se chauffer en récupérant les rejets de chaleur - FUTUREMAG ARTE 19 I Degrés Bleus - Heat recovery from sewers

Eco-district Inspection of sewer with heat exchangers, Nanterre Source: Screenshot from a TV programme, FUTUREMAG (ARTE Channel), Heizen mit Wärmerückgewinnung episode. http://sites.arte.tv/futuremag/de/heizen-dank-warmeruckgewinnung-futuremag *to watch it in French google: Se chauffer en récupérant les rejets de chaleur - FUTUREMAG ARTE 20 I Degrés Bleus - Heat recovery from sewers

Heat Network & Energy Centre

Eco-district District heating network Installation designed to cover the 4,555 MWh of annual heat demand (renewables + gas). 800 meters long heat distribution network, 14 heat substations Innovative 3-pipe heating network (separate supply pipes for DHW and space heating, common return pipe) 22 I Degrés Bleus - Heat recovery from sewers

Eco-district Energy plant in more detail Gas Boilers Heat pump 2 -high outlet temperature (Carrier 30 XW 802) 400 kw DHW circuit flow (constant temp. 63 C) Buffer tank 1500 L Space heating circuit flow (regulated temp. 35-65 C) Plate heat exchanger (geothermal) Plate heat exchanger (wastewater) Heat pump 1- medium outlet temperature (Carrier 30 HXC 130) 400 kw Buffer tank 1500 L Return DHW + space heating (temp. 35-40 C) F1&F3 Reinjection wells F2 Abstraction well, flow rate :25m 3 /h 200 kw 23 I Degrés Bleus - Heat recovery from sewers Twin-head pump, heat recovery flow rate: 80m 3 /h 370 kw In-sewer heat exchanger along the Georges Clévenceau Avenue 5 x 40 heat exchanger modules Surface area of exchangers: 112m 2

MWh Eco-district Heating loads vs. heat pumps output in 2015, MWh 800 700 Extra energy supplied by gas boilers 600 500 400 300 200 100 HP1* is off HP2** is off 0 Jan-15 Feb-15 Mar-15 Apr-15 May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15 Nov-15 Dec-15 Network losses DHW load Space heating load Heat pumps -output *23.05.15-08.10.15 **10.07.15 24.09.15 24 I Degrés Bleus - Heat recovery from sewers

Temperature Eco-district Space heating and DHW circuits temperatures 70 C Temperatures vs. time 60 C 50 C 40 C DHW Space heating Return 30 C 20 C 10 C 0 C 17/12/14 11/02/15 08/04/15 03/06/15 29/07/15 23/09/15 18/11/15 13/01/16 Date Départ DHW ECS Space Départ heating CHG Retour Common commun return Température Outdoor temp. extérieure 25 I Degrés Bleus - Heat recovery from sewers

Eco-district Waste heat recovery from sewer In 2015, 54% of heat produced (2,074.5 MWh) originated from renewable resources (19% groundwater & 35% wastewater). The heat pump system (geothermal + wastewater heat recovery + compressors) covered more than 84% of heat demand. Heat Production in 2015 30% 16% 19% 35% GHG emission reduction by 55% (488.2 tco 2 eq) when compared to heat production based solely on gas boilers*. Gas boilers Groundwater Wastewater Compressors *Assumptions for gas boilers: Boiler s net efficiency: 102%, and emission factor for natural gas (France): 234g CO2eq/ kwh (NCV) 26 I Degrés Bleus - Heat recovery from sewers

Thank you for your attention! Special thanks to Gilles Bideux and Arnaud Heinrich for providing the information. 27 I Degrés Bleus - Heat recovery from sewers

SUEZ Advanced Solutions UK Ltd. 290 Aztec West BS32 4SY Bristol Tel. 01454 804040 Marta Golisowicz Email: Marta.Golisowicz@aqualogyuk.com 28 I Degrés Bleus - Heat recovery from sewers