EVE, Energy Via Exhaust: Waste heat recovery through ...turbo-moteurs.cnam.fr/publications/pdf/conference3_2014.pdf · EVE, Energy Via Exhaust: Waste heat recovery 15 e cycle de conférences:

EVE, Energy Via Exhaust:

Waste heat recovery

15e cycle de conférences:

Utilisation rationnelle de

l’énergie et environnement

www.exoes.com

Waste heat recovery

through Rankine Cycle

on heavy duty vehicle

24-Mar-14 1

Date of creation 2009, May 20th

President Mr A. Desrentes

Exoès company

Employees 12 (10 engineers)

7Test benches

www.exoes.com 224-Mar-14

Web site www.exoes.com

@ [email protected]

Patents

7

Strategic committee with 3 former

top managers of international Tier 1 suppliers.

Test benches

8

Table of contents

• Context

• WHR state of the art

• Reminders

• RC design: key choices

www.exoes.com


• RC state of the art

• Modeling

• Exoès technology, tests and results

• Conclusion

24-Mar-14 3

Table of contents

• Context• WHR state of the art

• Reminders


www.exoes.com



• Modeling


• Conclusion

24-Mar-14 4

Key values on heavy duty market

• Heavy trucks account for around 11% of global oil consumption. (source OECD)

• 1990-2006 : +27% on GHG emissions from road transportation

but +77% from MD and HD truck sector. (source DoT 2010)

Context

www.exoes.com

• Fuel costs account for >30% of freight operator’s costs!

• Strong regulations are coming (EPA)

• Global commercial vehicles sales

forecast :

24-Mar-14 5

Context

Medium and heavy-duty

commercial vehicle CO2

emission forecasts

900

650

540

-25 to

-30%

-35 to

-40%

950

800

620

Average CO2 emissions for new vehicle fleet

Average CO emissions for vehicle stock

www.exoes.com

Average CO2 emissions for vehicle stock

0%

5%

10%

15%

20%

25%

30%

35%

1980 1990 2000 2010 2020 2030

Engine and vehicle improvements Aerodynamic

Telematics Waste heat recovery

Impact of HCVs(1) fuel consumption reduction

levers in the past 30 years

HCV manufacturers will

have to adopt new emission

saving technologies to meet

these targets ICE

aero

telematics

whr

24-Mar-14 6

�SCR, EGR, DPF, Heat management

�Tough reduction in emission limits

�New cycles with cold start

�Extensive OBD requirements

�Durability: 700,000km or 7 years

Synergies with existing solutions for HCV

Pollutant

regulation

Euro 6 in

June 2013

�Generalized EGR (high T source for

recovery)

�EGR and exhaust can be used as combined

hot sources

�Faster warm up of the ICE with a Rankine

system

Constraints

Technical solutions

Opportunity for exhaust heat recovery

Context

www.exoes.com

EPA

program to

reduce

greenhouse

gas

emissions

�42% is the best efficiency

of a modern Diesel engine

�EHR is identified as a

compulsory technology to

meet up with regulations

�Hybrid drivetrain will

appear for the inter urban

fleets, offering a new

opportunity market for EHR Source: Renault Trucks

Opportunity for EHR

7724-Mar-14

Example: Daimler Supertruck program

Context


Table of contents

• Context

• WHR state of the art• Reminders


www.exoes.com



• Modeling


• Conclusion

24-Mar-14 9

WHR technology

• What power flows exist in an ICE’s exhaust

– Kinetic power flow

– Thermal power flow

– Chemical power flow

WHR state of the art

BIG

BIG

SMALL

www.exoes.com

– Chemical power flow

– Latent heat power flow

24-Mar-14 10

SMALL

SMALL

Kinetic power flow

• The turbine, regenerating kinetic but also thermal energy, is

the basic element that serves in a variety of applications:

– Turbocharger (widely used)

– Mechanical turbocompound (Cummins-Scania, Volvo)


www.exoes.com

– Electrical turbocompound (John Deere, Caterpillar)

– Exhaust turbine generator (Visteon TIGERS)

24-Mar-14 11


Turbocharger Mech. turbocompound

www.exoes.com 24-Mar-14 12

Fuel economy

by downsizing

– Power density

– Good fuel economy

in loaded application.

– Very good drivebility

– High EGRflow

achievable

– Complexity, cost, weight

– Negative η @ low load

(back-pressure)

– Packaging of EGR and TC

– Reduced efficiency of ATS

3-5% total efficiency


Powt-Powc =

PowelG+L innotec GmbH & AVL

Electrical turbocompound TIGERS


Garrett TC with electrical

assistance

G+L innotec GmbH & AVL

List GmbH

+ : Less space, easier mounting

+ : Can speed up turbo

(No jet lag and better emissions

control)

+ : Power fed into veh. electrical

demand or stored into batteries

- : Gain clearly visible @ rpm

close to the max torque (max gas

p)3-5% on cycle, up to 10% peak fuel cut

• 800°C, 0.05kg/s, 80.000RPM

6kWe from 41kWth (enough for

the car electric system)

• Fuel consumption reduced from 5

to 10%

• Small and low cost for interesting

benefits

Thermal power flow

• Heat to heat converters

• Thermo electric (→electrical power)

• Thermo-dynamics (→mechanical power)

– Rankine cycle (steam or organic)


www.exoes.com

– Rankine cycle (steam or organic)

– Stirling engine

– Ericsson cycle

• Thermo-chemical (→chemical power)

• Thermo-acousOcs (→mechanical power)

24-Mar-14 14

Heat to heat converters

• Faster engine coolant and cabine heating leads to lower

emissions and fuel consumption



Faurecia RTE system on C4

Picasso (gen 1)

EHR system on Toyota Prius

3rd gen.

Faurecia EHRM system on

Ford Cmax hyb.(gen 2)

• Comfort system

•Faster heating of the cabine in cold countries

• Replace a 1000W electric radiator (2000W for

the ICE = 1l/100km)

•Dedicated loop with electric pump

• Depollution system through faster

warming up of the engine coolant

•Dedicated loop with electric pump

•Faster ICE cut off thus better fuel

cut (+30%)

Thermo electric generators

• Based on Seebeck effect : ∆T → proporOonal voltage

• Reversibility possible (Pelletier effect).

• Many projects targetting 3 to 5% fuel reduction with TEG from 300 to 1200W.

• Low maturity for the market. Works on the performance/cost ratio are in progress

on:

– Materials (expensive Bi2Te3 → Mg2Si , Mn2Si , nanomaterials, etc.)


www.exoes.com

– Materials (expensive Bi2Te3 → Mg2Si , Mn2Si , nanomaterials, etc.)

– Better heat repartition with low back pressure

24-Mar-14 16

TEG on BMW X6 prototype

Table of contents

• Context


• Reminders• RC design: key choices

www.exoes.com



• Modeling


• Conclusion

24-Mar-14 17

• A Rankine cycle is a closed loop in which a working fluid (WF)

is evaporated and condensed to produce power during the

vapor expansion: basically, it is a « steam cycle ».

• A Rankine cycle needs a hot source and a cold sink.

Reminders

By-pass LP steam 4

Rankine cycle

www.exoes.com

G

Eva

po

rato

r Co

nd

en

ser

Feed

pump

Expander

By-pass

Fluid tank

HP liquid

HP steam

LP steam

LP liquid

LP: low pressure

HP: high pressure

12

3

Exh

au

st,

EG

R,

etc

.

1824-Mar-14

0

50

100

150

200

250

300

-1,00 0,00 1,00 2,00 3,00

Temperature [°C]

Entropy [kJ/kg/K]

Temperature-entropy diagram

Parameters:

• Working fluid parameters:

– Working fluid: ethanol

– High pressure: 30 BarA

– Over-heat: 30°C

– Sub-cooling : 10°C

Reminders

Rankine cycle : example

www.exoes.com

Entropy [kJ/kg/K]

Saturation curve Working fluid Cycle

0

1

10

100

-500 0 500 1000 1500

Pressure [barA]

Enthalpy [kJ/kg]

Pressure-enthalpy diagram

– Sub-cooling : 10°C

• Condenser parameters:

– Indirect cooling HT

– Cooling fluid temperature:

90°C

• Hot source parameters:

– ESC point: B75

191924-Mar-14

• Pinch phenomenon:

– Energy balances are not sufficient

– The evaporation plateau impedes a complete energy recovery

– It exists a minimal gap (=pinch) where heat fluxes are critically low

• An evaporator design with small pinches would lead to extra sized evaporators.

Exhaust evaporator area on ESC B100

Reminders

Evaporator thermodynamics: pinch

www.exoes.com

0

100

200

300

400

0 50 100 150

Tem

pe

ratu

re [°C

]

Exchanged power [kW]

Working fluidExhaust gases

PINCH POINT

PREHEAT

EVAPORATION

OVERHEAT

Exhaust evaporator area on ESC B100

0

20

40

60

80

100

120

140

0

5

10

15

20

25

30

0 20 40 60

Po

we

r [k

W]

Are

a [

m²]

Pinch [°C]

Area [ m² ]

Power [ kW]

2024-Mar-14

• There are huge variations in the heat transfer coefficients while evaporating:

10

100

1000

10000

100000

200

300

400

500

600

700

He

at

tra

nsf

ert

co

eff

ice

int

[W/m

²/k

]

Tem

pé

ratu

re °

C

Working fluid temperature [°C]

Gases temperature [°C]

Wall Temperature [°C]

WF heat transfert coefficient

Reminders

Evaporator thermodynamics: heat transfer

www.exoes.com

• Exhaust gases have the lowest heat transfer coefficients: this will directly size the

exchange area.

• The highest evaporator wall temperatures will be in the superheating region (when in

counterflow)

� It impacts the evaporator design when trying to avoid the fluid and lubricant

breakdown

1

10

-

100

200

0% 50% 100% He

at

tra

nsf

ert

co

eff

ice

int

[W/m

²/k

]

Tem

pé

ratu

re

Exchanged power [%]

WF heat transfert coefficient

[W/m²/K]Gases heat transfert coefficient

[W/m²/K]

2124-Mar-14

• A = nlo + 0.25(nhi - nlo)

B = nlo + 0.50(nhi - nlo)

C = nlo + 0.75(nhi - nlo)

• nhi: highest engine speed where

the power equals 70% of the

Reminders

ESC cycle for HCV

www.exoes.com

hi


maximum net power.

• nlo: lowest engine speed where


maximum net power.

2224-Mar-14

Table of contents

• Context


• Reminders


www.exoes.com

• RC design: key choices• RC state of the art

• Modeling


• Conclusion

24-Mar-14 23

What are the key choices when desinging a RC?

• Hot source

• Cold sink

• Working fluid

• Expander and transmission

RC design: key choices

www.exoes.com

• Expander and transmission

24-Mar-14 24

Hot source

• Exhaust waste heat as favorite heat source (high T)

– Exhaust: evaporator after the ATS (no emissions penalty)

– EGR:

• Adopted by a majority of truck makers to face EURO6


www.exoes.com

• Adopted by a majority of truck makers to face EURO6

• EGR must already be cooled down

• A combination of EGR and exhaust evaporators will boost the

fuel economy but increase weight, integration issues and

control complexity

24-Mar-14 25

Hot source: examples


Main radiator

ICE ATSCondenser & subcooler

EGR Boiler

Exhaust

counter

flow


Expander

PumpTank

EGR Boiler

Hot source: examples


Exhaust

counter

flow

EGR

co flow


→16 arrangement possibiliOes when considering coflow or counter flow!

Exhaust

+ EGR in

parallel

EGR +

exhaust

in series

Exhaust counter flow EGR coflow


Hot source: pinch

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200

Tem

pera

ture

[°C]

Working fluid

EGR gases

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200

Tem

pera

ture

[°C

]

Enthalpy [kJk /g]

Working fluid

Exhaust gases

www.exoes.com

EGR coflow + Exhaust counter flow in parallel

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200

Tem

pera

ture

[°C

]

Enthalpy [kJ/kg]

Working fluidExhaust gasesEGR gases

EGR coflow + Exhaust counter flow in series

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200

Tem

pera

ture

[°C

]

Enthalpy [kJ/kg]

Working fluidEGR gasesExhaust gases

Enthalpy [kJ/kg]Enthalpy [kJk /g]

2824-Mar-14

• Example for ethanol, ESC point B75

First criteria: EGR gas T ≈ 100°C to fulfill with depollution and performance targets

→ only 6 configuraOons remaining on 16 possibiliOes.

Second criteria: Max Twall to prevent from breaking down WF and lubricant

Third criteria: Trade-off cost / packaging / performance


Which evaporator configuration choice?

www.exoes.com

0

20

40

60

80

100

120

140

160

Exhaust & EGR

parallel

EGR & Exhaust

series

Exhaust co flow

& EGR parallel

EGR & Exhaust

co-flow series

Exhaust only EGR only

[%]

Recovered power / Gases power [%] Exchange Area / max exchange Area [%]

Exhaust recovered power / Gases power [%] Twall/ max Twall [%]

29

123

24-Mar-14


Which configuration choice?

• EGR counter flow & Exhaust co-flow in series configuration is the simplest way to design quickly an evaporator but also the least efficient in this final group of solutions.

1

www.exoes.com

• & are more efficient than the previous configuration but need a special flow arrangement on the exhaust and/or the EGR evaporator to limit the wall temperature.

30

2 3

24-Mar-14

Cold sink

• The majority of the tailpipe exhaust heat may be rejected under hood!

• Trade-off to be found between weight, packaging, fan on time and aero complexities.

– Aerodynamic drag = 19% of truck losses


www.exoes.com

– Aerodynamic drag = 19% of truck losses

– Extra-weight = fuel penalty

• The cold sink can be:

– the existing LT (for the CAC) cooling loop,

– the existing HT (for the ICE) cooling loop,

– a dedicated very LT cooling loop with an additional front radiator.

• Direct link with working fluid choice

24-Mar-14 31

Cold sink

Dedicate

d cooling

(direct)

Existing

cooling


Condenser& subcooler

Condenser & subcooler


Mix :

additional

subcooler

Subcooler

Condenser

Working fluid: which one?

• Selection example (source IVECO)




• No fluid fulfilling all the requirements

• Focus on 3 fluids: ethanol, R245fa and

water

• Mass flow:

Working fluid

www.exoes.com

• Mass flow:

• Area : amount of energy that can be

transferred to 1kg fluid

• If small, high mass flow for a given

amount of energy

• QR245fa > Qeth > Qwater [L/h]

• Same for the pipes and pumps

3424-Mar-14

• The impact of the cooling temperature is huge.

• To have the lowest cooling temperature a direct cooling with an additional

front radiator is the best solution.

• Using the existing loops implies to accept their temperatures.

• Hereafter are plotted some results extracted from an Exoès paper, on a serial

assembly of the evaporators (EGR first):


Cold sink and working fluid interaction

www.exoes.com

assembly of the evaporators (EGR first):

Cooling temp.: 80°C Cooling temp.: 100°C

35

2,2

3,74,1

Fuel cuts [%]

3,4

4,74,1

Fuel cuts [%]

R245fa Ethanol Water (1 bar)

24-Mar-14

Impulse turbine Manufacturers: Barber Nichols (US), Bosch (DE)

+ : compact, efficient, oil-free

- : erosion with droplets, costly, high speed

Piston expander Manufacturers: Amovis & Voith (DE), Exoès (FR)

+ : robustness, cost, low rotary speed

- : Poor compactness, lubrication issues


Expander and transmission

• No consensus on expander

www.exoes.com

- : Poor compactness, lubrication issues

Screw expander Manufacturers: Eaton [US]

+ : compact, robustness

- : cost, efficiency

Scroll expander Manufacturer: Sanden [JP]

+ : robustness, low cost, low rotary speed

- : poor compactness, lubricated, efficiency

Transmission:

• Mechanical transmission (Classic HCV, fixed speed ratio).

• Electrical production for hybrid trucks.

3624-Mar-14

Table of contents

• Context


• Reminders


www.exoes.com


• RC state of the art• Modeling


• Conclusion

24-Mar-14 37

• AVL claims more than 1,000h of running of a RC. They seems the most advanced

company on this topic and they work already with several OEMs.

• Layout suggested by AVL:

– parallel evaporators

– indirect cooling on existing HT loop plus an additional MT loop.

RC state of the art

Example 1: AVL


• Cummins has benefited from the

DOE Supertruck program to develop

a complete on-board Rankine cycle.

• Layout suggested by Cummins:

– Parallel evaporators but

common superheater (from

MODINE)

RC state of the art

Example 2: Cummins

www.exoes.com

MODINE)

– Recuperator

– Direct cooling with additional

cooling loop only

– R245fa with a turbine

3924-Mar-14

RC state of the art

Example 2: Cummins


Table of contents

• Context


• Reminders


www.exoes.com



• Modeling• Exoès technology, tests and results

• Conclusion

24-Mar-14 41

4 to1: Intake

1 to 2: Expansion

2 to 3: Exhaust

3 to 4: Compression

OD expander model

• Simple and robust inlet and exhaust

system

• “Symmetrical” valve timing at TDC and

BDC

Modeling

Pressure

Pin

24

1

www.exoes.com

BDC

• Expander characterized by its swept

volume and expansion ratio:

24-Mar-14 42

0 VTDC VIVO = VIVC VEVC =VEVO VBDC

Volume

Pex 3

EVO EVCE C

IVC IVO

V VR R

V V= = =

EVO : exhaust valve opening

IVC : inlet valve closing

TDC

BDC

IVO IVC

EVOEVC

INTAKE

EXHAUST

Modeling strategy

• 0D model set by geometric data and corrected by coefficients calculated from both test bench measurements and more complex 1D models.

– the isentropic efficiency:

Modeling

wfisentropicwf

xpandermechis Flowh

Pow

.,

e,

∆=η

Flow

www.exoes.com

– the filling factor:

• Several phenomena will change these indicators:

– the internal leaks

– the friction losses

– the pressure drops

– the heat exchanges

24-Mar-14 43

Modeled

Neglected

theorywf

realwf

Flow

Flow

,

,=φ

Data and indicatorsPts E.U.

normTice

[Nm]Nice

[rpm]Occurrence

[%]

9: B25 700 1200 20

3: B50 1200 1200 30

4: B75 1500 1200 40

8: B100 2250 1200 10

Modeling

Data (confidential):

Indicators:


2

,

1v / 2

,

1

.

.

i i i

j j j

wf wf evap

iap waste

hf hf evap

j

m hR

m h

=

=

∆=

∆

∑

∑

&

&

.exp/ICE

,

i mecha pp

ICE mecha

W WR

W

η=

−& &

&

Indicators:

wf : working fluid pp : pump hf : hot fluid

• Pure ethanol, 800cc, 3600rpm (drive ratio 3), Pexhaust 1bar

• EGR only

Results

PointsPwf

[Bar]Wi,exp[kW]

mwf[kg/h]

Rvap/waste[%]

Rexp/ICE[%]

B25 28,4 2,8 63,3 40,4 2,8

B50 31,1 4,7 99,5 37,7 2,8

Modeling

www.exoes.com

• Simplicity:

• No air infiltration

• No additional cooling load

B50 31,1 4,7 99,5 37,7 2,8

B75 32,7 5,8 120,3 39 2,7

B100 35,8 8,0 163,4 39,2 2,5

Rexp/ICE average = 2,7%

24-Mar-14 45


• EGR and exhaust in parallel

Results

PointsPwf

[Bar]Wi,exp[kW]

mwf[kg/h]

Rvap/waste[%]

Rexp/ICE[%]

B25 32,9 6,0 123,8 79,4 6,0

B50 41,4 12,1 243,3 92,9 7,1

Modeling

www.exoes.com

• Better solution regarding pure efficiency without any other

considerations

B50 41,4 12,1 243,3 92,9 7,1

B75 44,2 14,2 283,8 92,6 6,7

B100 49,7 18,4 367,7 88,8 5,7


24-Mar-14 46


• EGR and exhaust in series (counter flow)

Results

PointsPwf

[Bar]Wi,exp[kW]

mwf[kg/h]

Rvap/waste[%]

Rexp/ICE[%]

B25 23,8 4,6 104,1 66,1 4,5

B50 28,2 8,4 182,9 69,2 4,9

B75 29,9 9,8 213,0 68,8 4,6

Modeling

www.exoes.com

• Best performance/cost trade-off

• Smaller exhaust evaporator → lower back-pressure and easier integration

• Less heat to dissipate under hood

• Easier control of the system (no 3 ways valve)

B75 29,9 9,8 213,0 68,8 4,6

B100 33,3 12,8 275,3 66,0 4,0


24-Mar-14 47

Cost analysis

• Hypothesis:

– 150,000km/an

– 33L/100km

– 1.1€/L

– 50,000units/y after 4y

Modeling

Maximum speed

EVE for HCV expander datasheet

7,500 RPM

www.exoes.com

– 50,000units/y after 4y

24-Mar-14 48

Maximum speed

Isentropic eff.

Expander length

Expander diam.

Expander weight

Architecture

Peak shaft power

7,500 RPM

350mm

~15kg

12kW

60%

6 pistons,

SP, optional

generator

200mm

Price of the system for the end customer

€3,500

Annual fuel savings€2,700 / 2,500 l

ROILess than 1.5 year

Fuel consumption reduction

5%

Net margin of fleet owners

Multiplied by 2 to 3

Table of contents

• Context


• Reminders


www.exoes.com



• Modeling

• Exoès technology, tests and results• Conclusion

24-Mar-14 49

Exoes technology

Data Value / Description

Engine architecture Swashplate – 5 cylinders

Capacity 183cm3

Speed range 1000 – 6000rpm

Expansion ratio Adjustable from 5 to 9

Weight 18kg

Size L270mmxD160mm

Working fluid Water or Ethanol

Maximal inlet pressure 45 bar


Maximal inlet pressure 45 bar

Maximal exhaust pressure 2.5 bar

Maximal inlet temperature 300°C

Minimal oil circulating rate 0% - it can run oil-free

Peak shaft power 4kW

Performance test with water• Effective isentropic efficiency:

• 40- 45% @:

• Inlet pressure: 30-32bar

• Outlet pressure: 1bar

PinTin

PexTex

MwfSubcooler

HP pump

Feed pump

Torque

Heat

HeatHeat

Exp

).( ,isexinwf

mechis hhM

W

−=

&

&

η

Exoes technology


• Outlet pressure: 1bar

• Inlet temperature: 290-300degC

• RPM: 2,000-3,500rpm

• Losses repartition:

• Internal leakage (inlet, rings)

• Friction

• Low expansion ratio

• Target for future developments: 65%

Water tank

CondenserHeatHeat

0,5

0,6

0,7

0,8

Isen

trop

ic e

ffici

ency

[-]Isentropic efficiency

as a function of the piston annular radial clearanc eand the expander expansion ratio

δ= 0.00000 mm

δ= 0.01000 mm

Exoes technology

Last test result early 2014

Performance enhancement timing

Intern leaks 0

Intern leaks +

www.exoes.com

0

0,1

0,2

0,3

0,4

2,5 5 7,5 10 12,5 15

Isen

trop

ic e

ffici

ency

[

Expansion Ratio [-]

δ= 0.01500 mm

δ= 0.02000 mm

Tests with ethanol are in progress, better results expected

Assumptions:

Water, 30bar, 330°C

No friction losses

3500RPM

To be tested mid 2014

To be tested end 2014

52

Intern leaks ++

Intern leaks +++

24-Mar-14

• Expander lubrication concept:

• Lubrication in the crankcase only

• Piston rings moves oil-free

• Endurance test bench:

• Test of the piston rings in an oil-free single cylinder

• Rotates at 1200rpm to reach an average linear speed of 3.1 m/s

Exoes technology


• Rotates at 1200rpm to reach an average linear speed of 3.1 m/s

• Pure water steam is sent at 6 bars, 180 degC

Wear rate

[mm3/N.m]

10E-910E-810E-710E-610E-5

Lubricated Oil-free

Achieved in 2013 Target 2015

1,E-08

1,E-07

0 5 000 10 000

We

ar

rate

[mm

3/N

.m]

Sliding distance [km]

Exoes technology


Lubricated

systems

Oil-free

systemsPrototype lifetime:

•

where:

Tw: Worn thickness

Kv: Wear rate =5x10^-8 mm3/N.m

PSaverage=2.3 Mpa.m/s

� To reach the car market lifetime of

15,000h, our goal is to decrease the wear

rate by a factor of 5 which will result in a

worn thickness of 1.2mm

PSaveKv

TwLifetime

.=

Table of contents

• Context


• Reminders


www.exoes.com



• Modeling


• Conclusion

24-Mar-14 55

Exhaust heat recovery on HCVs

• Incentive regulatory context : WHR mandatory on the

medium term

• Still no consensus on expander type and working fluid

• Exoès:

– Calibrated tools for expander design

Conclusion

www.exoes.com

– Calibrated tools for expander design

– Compact expander prototype manufactured

– Possibility of oil-free running demonstrated

– Efficiency improvement by reducing the internal leakage

– 5% fuel economy leading to an ROI of 1.5 year

24-Mar-14 56

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Documents

EVE, Energy Via Exhaust: Waste heat recovery through ...turbo-moteurs.cnam.fr/publications/pdf/conference3_2014.pdf · EVE, Energy Via Exhaust: Waste heat recovery 15 e cycle de conférences: