Low hanging fruit in decarbonisation of buildings? Wastewater Heat Recovery (WWHR) systems Robert PintĂŠr, European Copper Institute, Green and Healthy Buildings Team Leonardo ENERGY Webinar, 26 November 2020, 13:00 CET
Content
1.
INTRODUCTION
2.
HOW WASTEWATER HEAT RECOVERY (WWHR) WORKS
3.
a) PRINCIPLE b) EFFICIENCY CURRENT MARKET SITUATION
4.
EVALUATION OF WWHR POTENTIAL FOR DECARBONISATION a)
5.
HOUSEHOLD LEVEL: A SAMPLE CALCULATION OF ANNUAL ENERGY CONSUMPTION AND EMISSIONS OF A CHOSEN SHOWER SYSTEM WITH AND WITHOUT WWHR b) EU-28 LEVEL: ENERGY CONSUMPTION AND CO2 EMISSIONS OF SHOWERS, SAVINGS WITH WWHR c) 2030 WWHR SCENARIO – ENERGY SAVING POTENTIAL IN 2030 (Renovation Wave) ADDITIONAL BENEFITS OF WWHR SYSTEM
6.
POLICY RECOGNITION NEEDED FOR WWHR
2
| Wastewater Heat Recovery (WWHR) systems
Introduction
• EC: buildings are responsible for approximately 40 percent of energy consumption and 36 percent of CO2 emissions in the EU • New built sector: growing share of energy to produce hot water, dramatic fall in energy needed for space heating • Daily 22 million m3 hot water used in EU homes • 80 percent of the heat ends up in sewers • Up to 70% of energy wasted in shower drains can be cost effectively and simply recovered 3
| Wastewater Heat Recovery (WWHR) systems
Growing share of energy for hot water production (Switzerland)
Source: https://joulia.com/ 4
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How WWHR works?
• No moving parts, no electricity required (mostly) • A heat exchanger transfers heat energy of wastewater to incoming fresh water supply and warming it from around 10 up to 30°C • Why showers? • Highest consumption of hot water (≈ 80%) • Hot water demand and drain water available simultaneously
• Easy heat exchange • Relatively unpolluted wastewater, ideal for heat exchange • A wastewater heat recovery system could effectively recapture and reuse instantly up to 70 percent of waste energy, reducing energy consumption in a cost-effective manner. 5
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Basic Principle
For more schemes (individual and multi-dwelling solutions) see the White paper
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Fresh water incoming at 10°C preheated to 30°C arriving at the mixing valve, reducing the need for hot water from the boiler.
Product examples Horizontal type heat exchangers
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Product examples Vertical type heat exchangers
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Installation
Plumber connects: • potable water in- and outlets (preheated) • Drainage out- and inlet (vertical) For manufacturers, product specifications visit: WWHR Europe
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Product safety
In WWHR systems double-walled heat exchangers are required by EN 1717 “Protection against pollution of potable water in water installations and general requirements of devices to prevent pollution by backflow�.
Double-walled tubes ensure that domestic hot water and grey water are reliably separated. Moreover, the standard-compliant leakage gap makes it possible to detect leakages.
10 | Wastewater Heat Recovery (WWHR) systems
Efficiency
• The lower the flow rate, the higher the efficiency – the higher the flow rate – the higher the performance. • Efficiency, as a percentage of energy gained from drain water varies by systems used, up to the value of around 70 percent.
Vertical type heat exchanger with over 60% efficiency.
11 | Wastewater Heat Recovery (WWHR) systems
Efficiency
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Where to use WWHR systems? Residential
• single family houses • multifamily houses Non-residential with higher hot water consumption • sport facilities, hairdressers, hotels, swimming pools…
Due to ease of installation ideal for also for renovation.
13 | Wastewater Heat Recovery (WWHR) systems
Current market situation
• Europe has the greatest technological lead in the world on this subject, with 326 patent applications since 2010, which is 70 percent of all patent applications in the world.
• Together, WWHR systems have already recovered 300 GWh corresponding to the annual domestic hot water consumption of 17,000 households.
14 | Wastewater Heat Recovery (WWHR) systems
Acknowledgement of WWHR technology in national building codes and standards • France: RT2012 and forthcoming RE2020 where WWHR can contribute to targets for heat from renewables. • The Netherlands: WWHR systems are included in the calculation software for new construction projects as they have a positive bearing on the energy performance of a building. This is the case for the existing EPC (energy performance certificate) regulation. It will also be the case with the BENG (nearly energy neutral buildings) regulation that will be used from 01 January 2021. • UK: In October 2019, the Ministry of Housing, Communities and Local Government (MHCLG) published a consultation on the Future Homes Standard, regarding changes to Part L of the Building Regulations for new dwellings. WWHRS is widely recognised as one of the most costeffective SAP-listed energy efficiency technologies available, and proposed changes to Part L in 2020 suggest WWHRS will have an even bigger impact under the new regulations. 15 | Wastewater Heat Recovery (WWHR) systems
Energy and CO2 emissions calculation of a sample household Energy consumption and emissions of shower systems depend on many variables, e.g. temperature of incoming cold, hot water and shower water used, shower time, fuel used to heat water (electricity, gas…) size/design of shower enclosure and flow rate. In our example: Shower time: Cold water temperature: Hot water temperature from the boiler: Mixed shower water temperature: Flow rate: Number of days: Number of residents per home:
9 min./shower 10°C 60°C 38°C 9.2 l/min 365 2.30
CO2 emission coefficient (based on Dutch standard NTA8800, “Energy performance of buildings - Determination method): Electricity: Gas:
0.34 kg/kWh 0.183 kg/kWh
WWHR unit efficiency: 56% (market average) 16 | Wastewater Heat Recovery (WWHR) systems
Energy and CO2 emissions calculation of a sample household
Household Without WWHR
Hot water preparation
Household With WWHR
Energy demand
CO2 emissions
Energy demand
CO2 emissions
per year
per year
per year
per year
Household Saving with WWHR CO2 Energy saving emissions saving per year per year
Electricity
2,264 kWh
770 kg
1,430 kWh
486 kg
833 kWh
283 kg
Gas
231 m3/year
414 kg
144 m3/year
262 kg
85 m3/year
153 kg
In this sample household, with deployment of an average efficiency (56%) WWHR system, 833 kWh electrical energy and related 283 kg of CO2 emissions can be saved, or consumption of 85 m3 natural gas, equivalent to 153 kg CO2 can be avoided.
37% of energy consumption and CO2 emissions avoided 17 | Wastewater Heat Recovery (WWHR) systems
RETURN ON INVESTMENT
• Electricity and natural gas prices vary across Member States and there is a wide range of WWHR systems available on the market, so the exact return on investment needs to be calculated specifically for each project. • An average family can save around €50-150 annually on their hot water bill after deployment of a WWHR unit and this justifies the investment into this safe, energy efficient, environmentally friendly, simple, and easy to install, operate and maintain system with a long lifespan.
18 | Wastewater Heat Recovery (WWHR) systems
EU 28 Energy Statistics, 2017
Item Energy for domestic hot water preparation Share of hot water used for shower out of total hot water used in households (see table below)
Value 495 TWh
Energy for shower hot water in households
396 TWh
Final energy consumption Household's final energy consumption Share of hot water in households final energy consumption Share of hot water used for shower in final energy consumption Use of hot water in households according to JRC report “MEErP Preparatory Study on Taps and Showers� Bath Shower
80% 12 329 TWh 3 344 TWh 14,8% 3,21% Share 6% 80%
Tap, washbasin
7%
Tap, kitchen - drinking/cooking
0%
Tap, kitchen - dish washing
5%
Tap, indoor - clothes washing
2%
Tap, indoor - other uses
0%
Outdoor
0%
Total hot water demand in taps and showers 19 | Wastewater Heat Recovery (WWHR) systems
100%
Energy demand and carbon footprint of shower hot water in the EU / saving potential Type of fuel
Share (2017) 47% 19% 11% 11% 2% 10%
Gas Electricity Oil and petroleum products Derived heat Solid fuels Renewables and wastes
Share in heating shower hot water
Energy Demand Total (TWh/y)
66%
Saving potential with WWHR (37%)
CO2 emission coefficient (NTA 8800)
(TWh/y)
kg/kWh
CO2 emissions (million tonnes/y)
Saving potential with WWHR (37%) (m. t./y)
Electricity
19%
74.89
27.21
0.34
25.46
9.92
Gas
47%
189.91
70.27
0.183
34.75
12.86
264.81
97.98
60.22
22.28
TOTAL
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2030 WWHR SCENARIO – ENERGY SAVING POTENTIAL IN 2030 By 2030: • Renovation Wave Strategy:
35 million buildings renovated (82% residential)
• New dwellings:
16 million completed
2030 WWHR scenario: annual savings in 2030 if WWHR deployment rate is 50% Number of dwellings by 2030 2030 WWHR Scenario – number of dwellings by 2030 (50 percent of dwellings deploying WWHR) Household annual energy saving (kWh/year) See household level table Total annual energy savings in 2030 (TWh/year)
Grand total energy savings in 2030 (TWh/year) Grand total energy savings in 2030 (Mtoe/year) 21 | Wastewater Heat Recovery (WWHR) systems
Renovated 28 700 000
Newly built 16 000 000
14 350 000
8 000 000
800
800
11.48
6.40
17.88 1.54
Energy and GHG emissions savings by Renovation Wave Communication „The Commission has proposed in the Climate Target Plan 2030 to cut net greenhouse gas emissions in the EU by at least 55% by 2030 compared to 1990.”
„To achieve the 55% emission reduction target, by 2030 the EU should reduce buildings’ greenhouse gas emissions by 60%, their final energy consumption by 14% and energy consumption for heating and cooling by 18%” (compared to 2015) Final Energy Consumption (Mtoe) -14% (2030 vs. 2015) 370 334
GHG (Mton CO2-eq) -60% 2030 vs. 2015) 456 239
2030 Green Deal (REG scenario)
320
180
Savings needed
50
276
GHG and final energy savings in buildings 2015 2030 (BSL scenario)
22 | Wastewater Heat Recovery (WWHR) systems
Contribution to 2030 targets of the Renovation Wave – 2030 WWHR scenario
Share of WWHR in final energy savings target of the RW: 3.07%
WWHR contribution (1,54 Mtoe)
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Share of WWHR in 2030 in GHG emissions savings target of the RW: 1.52%
WWHR contribution (4,20 Mt)
Additional Benefits
• Hot water preparation system can be designed smaller • Reduced capacity of installed renewable systems (photovoltaic, solar thermal or heat pumps) or renewable energy generated on site can be used for other purposes than hot water. • Circular construction: systems have a long lifespan and contain easy to recycle and highly recycled materials (copper, stainless steel). • Real time production: the recovery and generation of energy adapt continuously and in real time with the usage, without over-or underproduction (no storage and control system necessary) • Aesthetics: systems are integrated into showers, in ducts or technical rooms, so they are hidden.
24 | Wastewater Heat Recovery (WWHR) systems
Policy recognition needed for WWHR Foster use of systems
Energy Performance of Buildings Directive
Renewable Energy Directive
➢
EPBD article 2: WWHR to be defined as „energy from renewable sources”.
➢
EPBD to recognise WWHR as energy source generated on-site in primary energy factors used for the determination of the primary energy use expressed in kWh/m2/year with the aim to take contribution of WWHR to energy savings into account. In the definition of NZEB, recognition is needed that WWHR can reduce hot water needs.
➢
EPBD to introduce a building renovation passport (as proposed in the Renovation Wave) to provide long-term, step-by-step renovation roadmap, explicitly including WWHR systems.
➢
EPBD to introduce minimum energy performance standards for existing buildings (as proposed in the Renovation Wave), to reach a minimum renovation rate, consider WWHR in calculations
➢
EPBD to introduce a ‘deep renovation’ standard (as proposed in the Renovation Wave), explicitly including WWHR.
➢
RED (or/and EPBD) to introduce requirement to use „Minimum levels of renewables in buildings” (as proposed in the Renovation Wave), facilitate use of waste heat at building level, take WWHR contribution into account
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Policy recognition needed for WWHR Foster use of systems Energy Efficiency Directive
➢
Article 14 (Promotion of efficiency in heating and cooling): Member States shall include wastewater heat recovery systems in buildings in their energy efficiency and renovation programs (Long Term Renovation Strategies).
Ecodesign and Energy Labelling
➢
Energy labelling: package label for heating systems: possibility to include WWHR as a subsystem in the label (next to solar collectors, storage tanks, controllers, …)
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Locker room showers : one collective WWHRS or multiple individual WWHRS ?
Case study: Public swiming pool in Cernay, France. Built in 2020
34 showers
Hugo Durou, European Association for WWHR, Nov. 26th 2020
individual WWHR
isometric view
260 mm
Obox
460 mm
450 mm
individual WWHR
mixer
mixer
showers 1 & 2
mixer
mixer
showers 3 & 4
showers ...
water heater
showers 33 & 34
cold water
overflow
WWHR
overflow
cold water
× 17
overflow
cold water drain
Obox
WWHR
WWHR
overflow
cold water
WWHR
cold water drain
collective WWHR grey water
758
Obox C
803 mm
black water
753
grey water
to sewer
Supporting poles Load = 100 kg
147 mm
collective WWHR
mixer
shower room #1
mixer
shower room #2
mixer
mixer
shower room #3
water heater
shower room #4
cold water
overflow
Obox C
WWHR
cold water drain
individual WWHR
collective WWHR
× 17
Energy lost before Obox
Energy lost in pipes before Obox C
27,3 MWh/yr
Energy lost because preheating only water to shower mixer 34,1 MWh/yr
Energy because preheating only water to water heater
30,6 MWh/yr
Energy lost because Obox has not 100% efficiency
15,7 MWh/yr
Energy lost because Obox C has not 100% efficiency
21,3 MWh/yr
-→ Energy recovered
52,4 MWh/yr
-→ Energy recovered
39,8 MWh/yr
Energy lost because énergie preheating only parce water toperdue shower que montage mixer "ballon seul" 29%
Energyénergie lost in pipes before perdue dans les tubes avant Obox Obox C 14%
16,8 MWh/yr
énergie Energy lost perdue parce because Obox que Obox C n'a has not 100% pas 100% efficiency d'efficacité 13%
énergie Energy récupérée par recovered Obox C 44%
Energy lost because énergie preheating only perdue parce waterque tomontage water heater "ballon seul" 26%
Energyénergie lost in pipes before perdue dans les tubes Oboxavant C Obox C 23%
énergie Energy lost perdue parce because Obox C que Obox C n'a has not 100% pas 100% d'efficacité efficiency 18%
énergie Energy récupérée par recovered Obox C 33%
individual WWHR
collective WWHR
× 17
Energy recovered
Hot water energy reduction
52,4 MWh/yr
-44%
Energy recovered
Hot water energy reduction
39,8 MWh/yr
-33%
Cost (WWHRS hardware)
9 846 €
Cost (WWHRS hardware)
8 433 €
Cost (installation)
6 000 €
Cost (installation)
1 200 €
Payback / ROI
4,1 yr
Payback / ROI
3,3 yr
Thank you For more information please contact Robert Pinter, European Copper Institute robert.pinter@copperalliance.org Hugo Durou, European Association for WWHR hugo.durou@ehtech.fr
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