performances of an orc power unit for waste heat recovery ... · performances of an orc power unit...

PERFORMANCES OF AN ORC POWER

UNIT FOR WASTE HEAT RECOVERY

ON HEAVY DUTY ENGINE

Roberto Cipollone, Davide Di Battista

Department of Industrial and Information Engineering and

Economics – University of L’Aquila - Italy

Federica Bettoja

FIAT Research Center – Turin, Italy

SAE INTERNATIONAL

• Waste Heat Recovery opportunity for emission savings

• Experimental test bench development

• Fluid choice

• Hot thermal source characterization (Heavy Duty ICE)

• Heat recovery vapor generator

• Turbine characterization

• Pump

• Condenser

• Overall plant performances

• Energetic and exergetic analyses

• Conclusions

Summary

ORC Conference 2017 2 D. Di Battista

SAE INTERNATIONAL

Cultural Motivation


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Fluid choice


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Hot source characterization


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Heat Recovery Vapor Generator characterization

ORC Conference 2017 7

- Effectiveness close to 0.8

- Low gas side pressure drop

Steel finned coil heat exchanger

min , ,( )h i c i

Q

C T T

D. Di Battista

SAE INTERNATIONAL

Condenser characterization


- Cooling water is at 50°C

- R245fa at 5 bar and 90°C inlet temperature

Plate heat exchanger

D. Di Battista

mwater

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Turbine characterization


Axial turbine

- Oil circuit for gear

lubrication

- Syncronous electric

generator

- 24 V DC current rectifier

D. Di Battista

SAE INTERNATIONAL

Pump characterization


Internal gear pump

- Oil free

- DC brushless motor

- Magnetic clutch

D. Di Battista

-High volumetric effficiency

-Low electric absorption

- 100 – 300 g/s mass flow rate

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Test bench description


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Test bench description


1100 mm

700 mm

700 mm

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Selected tests – Entropy diagrams


A B

C D

D. Di Battista

- High distance from

hot source

- High condenser

undercooling

- Low superheating

value in lower loads

conditions

- Higher

desuperheating

Regeneration

opportunity

PICE=53 kW

PICE=110 kW

PICE=72 kW

PICE=93 kW

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A B

D. Di Battista

PICE=53 kW PICE=72 kW

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C D

D. Di Battista

PICE=110 kW PICE=93 kW

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Plant energy balance


- Thermal power recovered up

to 55 kW

- Max turbine thermodynamical

power = 6 kW @ full engine

load (110 kW)

- Negiglible pump power

D. Di Battista

SAE INTERNATIONAL

Efficiencies analysis


, ,

3 2

, . , .

1( )

el turb el pump

plant

hs

T pump

th

HRVG turb cond pump

ex

hs hs in hs out ref hs in hs out

P P

Q

h h

h h

I I I I

m h h T s s

D. Di Battista

- Thermodynamic efficiency around 10 %

- Overall plant efficiency only 3%

- Exergetic efficiency is 30 % in lower loads and under 20% in higher load cases

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Exergy analysis


3 2 , ,

2 1 2 1

3 4 3 4

4 1 4 1

( ) ( )

( ) ( )

[( ) ( )]

( ) ( )

HRVG WF hs hs in hs outref

pump pump WF ref

turb WF ref turb

cond WF ref

I T m s s m s s

I P m h h T s s

I m h h T s s P

I m h h T s s

D. Di Battista

- Higher irreversibilities related to HRVG temperatures distance

(in particular in higher load cases)

- Neglibile irreversibilities on turbine and pump

- Condenser ones also high

- Exergetic efficiency from 30 % to 20 %

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Conclusions


• ORC based plant for Waste Heat Recovery from Internal

Combustion Engine

• R245fa as actual fluid choice road to R1233zd

• Heat recovery vapor generator finned coil heat exchanger

• Axial turbine (smaller and lightweight, high efficiency)

• Internal gear pump

• Overall plant performances

• Compactness

• Maximum heat recovered about 55 kW

• Up to 10 % thermodynamic efficiency (maximum ICE load)

• 3 % of global efficiency (24 V electrical power)

D. Di Battista

SAE INTERNATIONAL

Conclusions


• Axial turbine conversion efficiency

• 80% of isentropic efficiency 6 kW thermodynamical power

• 2,5 kW as maximum rated electrical power

• Very low 24 V DC electrical conversion efficiency (40-50%)

• Lubrication oil management

• Turbine start-up difficulties due to the fluid thermal regimation

(need of a turbine bypass branch)

D. Di Battista

SAE INTERNATIONAL

Regeneration stage study


Reduction of condenser heat rejected

Smaller condenser

•Up to 16-18 % of thermodynamic efficiency improvement

•Heat recovery reduction of the same amplitude

PERFORMANCES OF AN ORC POWER

UNIT FOR WASTE HEAT RECOVERY

ON HEAVY DUTY ENGINE

Roberto Cipollone, Davide Di Battista

Department of Industrial and Information Engineering and

Economics – University of L’Aquila - Italy

Federica Bettoja

FIAT Research Center – Turin, Italy

performances of an orc power unit for waste heat recovery ... · performances of an orc power unit...

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