Experimental Investigation of Waste Heat Recovery Using an...

4th Engine ORC Consortium WorkshopNovember 15 - 17, Detroit, Michigan

Experimental Investigation of Waste Heat Recovery Using an

ORC for Heavy Duty TrucksM. Hombscha, K. Shariatmadara,

D. Maesb, P. Garsouxc

a Dana Belgium NV, b Flanders Make VZW,c Bosal Emissions Control Systems NV

4th EORCC Workshop, Detroit 2017

Experimental ORC - WHR for Heavy Duty TrucksDesign methodology and system optimization tool – Flanders Make

ORC design challenges

Working fluids• Water • Ethanol

• Butane • Refrigerant


Fuel

En

ergy

BrakePower

Friction / Misc. Losses

HeatTransfer

ExhaustEnergy

42%

8%

24%

26%

10

0%

Engine Cooling

Charge Air Cooling

80-100°C

20-60°C

EGR Cooling

Tailpipe

200-750°C

200-600°C

Was

teH

eat

Qu

alit

y Lo

w

Was

teH

eat

Qu

alit

y H

igh

2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander

Engine heat sources

Experimental ORC - WHR for Heavy Duty TrucksDesign methodology and system optimization tool

Use case specification

Heat sources (averaged)

• Exhaust 0.204 kg/s, 354 °C

• EGR 0.081 kg/s, 520 °C

Heat sink (averaged)

• Cooling water 1.5 kg/s, 60°C

Topological variations

• Six evaporator configurations

• Recuperator not useful

• EGR replacement(cost saving from

existing cooler)


Exhaust onlyEGR only

Exhaust first

EGR first

ParallelEGR split

403 days* . 225 days*. .

Optimization• Changes components size and thermal cycle

• Constrained nonlinear programming

• Exhaustive search over fluids and topologies

Maximize expander power Minimize cost / net power


4th EORCC Workshop, Detroit 2017*assuming 11 hour driving per day

Dynamic model in Amesim



2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander

2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander

2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander



2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander

Control Design



Control Design- Control of evaporator pressure

PI + feedforward + decoupling Model based control

simplest to implement better constraint handling32

31

30

29

28

500 1000 1500 2000 2500

Time in seconds

27

26

25

32

31

30

29

28

500 1000 1500 2500

Time in seconds

27

26

2520002000

Experimental ORC - WHR for Heavy Duty TrucksHeat exchanger development – Bosal

Non-dimensional evaporator sizing• NTU method (Number of Tranfer Units)

• Non dimensional numbers, 𝑁𝑇𝑈 = 𝑓 𝑟𝑐𝑝, 𝐶𝑟 , 𝑆𝑡, 𝐽𝑎−1,

Δ𝑇𝑠ℎ∞

−Δ𝑇𝑠𝑐, …

– Heat capacity ratio 𝑟𝑐𝑝, heat cap. rate ratio 𝐶𝑟, Stanton number 𝑆𝑡

– Inverse Jacob number 𝐽𝑎−1 (phase change)

– Ratio of superheating to subcoolingΔ𝑇𝑠ℎ

∞

−Δ𝑇𝑠𝑐

• No working fluid “hard coded” in calculations



Evaporator size optimization for HD trucks• Target: minimum pay-back for total WHR system• Inputs

– Tool developed by Flanders Make– Bosal evaporator model– Bosal cost model– European operating conditions

• Assumptions– Exhaust & EGR evaporators– Working fluid: Alcohol based– Volumetric expander– ...

Evaporator size minimizing €/W



Stability of evaporation process• Slope of -2 (-20dB/decade), indicating higher frequency massflow

oscillations do not affect the outlet temperature significantly


Time [s]

Tem

per

atu

re

Raw signal, Temperature oscillation

Frequency [Hz]

Air Massflow oscillation dmair

Po

wer

Frequency [Hz]

Water Massflow oscillation dmair

Po

wer

Frequency [Hz]

Transfer function

Am

plif

icat

ion


Heat exchanger performance• More than 50 sensors (T, p,ṁ)

• Heat transfer validation in 2-phase flow


Set of operating points Sequenced perturbations

Experimental ORC - WHR for Heavy Duty TrucksFlow validation – Voxdale

CFD validation• Pipe bundle replaced with porous blocks

• Heat exchange inside blocks

• Nonlinear pressure drop in X and Y direction

• Wall temperature given as boundary condition

Results• Flow uniformity

• Bypass duct optimization

www.voxdale.be [email protected]


BypassHEX core

http://www.voxdale.be/

mailto:[email protected]


Hardware built: Evaporator• Modular design, different working fluids possible

• High Pressure operation (60 bar)

• Proven in-field operation

• To be integrated in Euro VI muffler

• Add-on with bypass


Gas

Fluid

Evaporator

Bypass

Euro VI truck muffler WHR add-on

Experimental ORC - WHR for Heavy Duty TrucksTest bench and experimental results


Coolant tank


Prototypes:

Bosal evaporators Exoès expanderTube & shell heat exchanger double-acting swashplate

piston expander



Experimental results


0 10 20 30 40 50 60

32

132

232

332

432

532

632

732

0

50

100

150

200

250

300

350

400

-36 164 364 564 764 964 1,164 1,364

Power P transferred to the cycle fluid [kW]

Tem

per

atu

re T

[°F

]

Tem

per

atu

re T

[°C

]

Cycle fluid enthalpy h [kJ/kg]

Experiment

2 Evaporator

( heat source)

4 Condenser

( heat sink)

1 Pum p 3 Expander

1

2

3

4


Thermal efficiency Net fuel savings


0

2

4

6

8

10

12

0%

2%

4%

6%

8%

10%

12%

0 50 100 150

Raw

ou

tpu

t p

ow

er [

kW]

Raw

th

erm

al e

ffic

ien

cy

Waste heat exploited [kW]

Engine back pressure,Pump consumption

Maximum Power tested(Conservative assumption)

0%

1%

2%

3%

4%

5%

0 50 100 150 200 250 300

Fuel

sav

ings

Equivalent shaft power [kW]

Includes:- Engine back pressure loss- Pump consumption

ConservativeMaximum Power assumption


Sankey diagram for highway cruise


Fuel:100%

Brakepower:45%

Coolant:29%

EGR: 12%

Exhaust12%

Turbine17%

WHR:17%

2%WHR gain,

11% from WHR input4% from brake power

Brakepower+ WHR:47%

Charge air 5%

Coolant:44% Ambient:

53%

6%

1%

Exhaustmanifold:29%

2%

6%

11%15%

3%


Drive cycle analysis: GEM model• 340 kW (455 hp) model year 2018 engine, 6x4 configuration

• Applied fuel usage weighting to time spent in given power

• Weighted average ofthree drive cycles:– Urban

– 55 mph with slopes

– 65 mph with slopes



Drive cycle analysis: average fuel savings


Mean fuel savings 3.5%


Yearly savings, US sleeper cab

190,200𝑘𝑚

𝑦𝑒𝑎𝑟118,200

𝑚𝑖𝑙𝑒𝑠

𝑦𝑒𝑎𝑟, first three years, sleeper cab*

∗ 33.3𝑙

100𝑘𝑚7.06 𝑚𝑝𝑔, Model Year 2018 GEM simulation

∗ 1.04$

𝑙3.94

$

𝑔𝑎𝑙EIA 2025 retail +10.5% local tax

∗ 3.5% WHR system fuel econemy improvement

-$ 105 € 100 maintenance

= $ 𝟐𝟐𝟎𝟎 Yearly savings

Payback time ca. 2 years


Today2.65 $/gal+28¢ local tax= 2.93 $/gal

20253,56 $/gal + 10.5% local tax= 3.94 $/gal

Experimental ORC - WHR for Heavy Duty TrucksConclusions

• Design methodology tool developed for ORC WHR– Pre-design tool for selection and size of components

– Optimizing total cost of ownership

– Steady-state design with dynamic evaluation

– Introduction of possible control strategies

• Hardware– ORC Test bench running on Diesel exhaust

– Exhaust heat exchanger prototypes from Bosal, sized using TCO analysis

– Expander prototype from Exoès, tailored for HD truck market

• Test results– Amesim model calibrated using static and dynamic tests

– Peak thermal efficiency of 11%, net drivecycle fuel saving 3.5%

– Payback time of 2 years for a WHR system


Experimental ORC - WHR for Heavy Duty TrucksQuestions


Maximilian Hombsch [email protected]

Keivan Shariatmadar [email protected]

Davy Maes [email protected]

Stephan Schlimpert [email protected]

Stefan Pas [email protected]

Filip Dörge [email protected]

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