Automotive
absorption cooling system
with falling film.
Date 07 février 2014PSA-DRD/DRIA/ACBI/INT/THQA
Emmanuel BOUDARDPSA: Responsable d’unité élémentaire d’innovation
Thermique Habitacle et Qualité de l’Air
+33 1 81 22 24 36
2
Sommaire
Contexte
Technologies
Propositions techniques
Evaluations scientifiques
Résultats sur banc d’essais
Conclusion
Summary
Context
Technologies
Technical proposals
Scientific validations
Test bench results
Conclusion
CONTEXT
Context
Technologies
Technical proposals
Scientific validations
Test bench results
Conclusion
Automotive CO2 regulations:
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
Effort on CO2 emissions:
regulations worldwide
Cylce WLTP:
Worldwide / more representative
Introduction of MAC regulation
Mobile Air-conditionningConsumption
Automotive absorption cooling system:
Expected benefits
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
•Engine load:
•70% compressor work (up to
5kW)
Automotive A/C system
•Engine thermal losses: (50 to
80% of combustion energy)
•85% heat conversion
•2 pumps (50W electrical power)
Absorption A/C system
Automotive absorption cooling system
Constraints
Implementation volumes
Power
Heat sources temperatures
Mass
Reliability (>15years)
Raparability & end of life
Industrialization
Cost…
Absorber: 23L
Desorber: 8L
11L
3.7L
Objectives
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
TECHNOLOGIES
Context
Technologies
Technical proposals
Scientific validations
Test bench results
Conclusion
Falling film for absorption
Water
LiBr solution
Benefits:
• Small packaging
• Vapour displacement with low pressure
drop
• Reproduced plates
• Use of water as liquid calorific flow
• Use of solution as liquid calorific flow
Capillarity is used for vibration response
Capillarity is used for inclination response
Constraints:
• Small
• Water dropplets
• Multi-physics
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
Grids as key point for automotive
Meniscus
LiBr flow 100 L/h
54 % salt mass fraction
Fluid inlet Distribution chamberHole for liquid distribution
Grid glue line
Fluid outletLiquid collector
l =14.4 cm
L=22.3 cm
206µm
388µm
Open ratio: 55%
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
Interest of capillarity for automotive
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
Interest of capillarity for automotive
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014
TECHNICAL PROPOSAL
SCIENTIFIC VALIDATIONS
Context
Technologies
Technical proposals
Scientific validations
Test bench results
Conclusion
Grids limitation
)Y,T(PPP Beq−=∆
The driving force for absorption or “distance to equilibrium” is defined as :
decrease is mainly due to the temperature increaseP∆
0 3 6 9 12 150
3
6
9
12
15
Out
let
driv
ing
forc
e [m
bar]
Inlet driving force [mbar]
Slope=0.7
0 3 6 9 120
0.5
1
1.5
2
2.5
3
3.5x 10
-4
Abs
orpt
ion
rate
per
pla
te [
kg s
-1]
Inlet driving force [mbar]
Absorption rate is roughly equal to one third of the maximal rate that
could be achieved (only valid within the flow rate range of the tests)
R. Goulet. PHD 2011
Development and analysis of an innovative evaporator/absorber for automotive absorption-based air conditioning
systems: investigation on the simultaneous heat and mass transfer
CETHIL, UMR5008 INSA de Lyon - CNRS - UCBL & PSA
Identification of absorption limitations:
meniscus & grids porosity
H. Obame MVE. Ongoing PHD (2011-2014):
Intensification of heat and mass transfer in Lithium Bromide water solution flow confined in grids absorption
[email protected] / +33 1 57 59 70 25 / +33 6 45 57 83 75
CETHIL, UMR5008 INSA de Lyon - CNRS - UCBL & PSA
Identification of absorption limitations:
Stabilization of interface & LiBr flow modification
H. Obame MVE. Ongoing PHD (2011-2014):
Intensification of heat and mass transfer in Lithium Bromide water solution flow confined in grids absorption
[email protected] / +33 1 57 59 70 25 / +33 6 45 57 83 75
CETHIL, UMR5008 INSA de Lyon - CNRS - UCBL & PSA
Identification of absorption limitationsMass transfer & heat transfer intensification:
• Create more fluid mix in grid spaces
• Increase grids porosoty
• Conserve capillarity effects
H. Obame MVE. Ongoing PHD (2011-2014):
Intensification of heat and mass transfer in Lithium Bromide water solution flow confined in grids absorption
[email protected] / +33 1 57 59 70 25 / +33 6 45 57 83 75
CETHIL, UMR5008 INSA de Lyon - CNRS - UCBL & PSA
Heat flux
W/cm
Robin SCHUCKER, Benjamin BROCHE, Mohamed
SABAH, Jonathan GRANDPERRIN, Shen DENG,Alexandre
BUTTERLIN PSC 2013: Investigation on dropplets,
Laboratoire d'Hydrodynamique (LadHyX), Ecole
Polytechnique, PSA
hL
Droplet %
Affecting absorption
Water dropplets elimination in a water vapor gas flow
Identification of absorption limitations
TEST BENCH RESULTS
Context
Technologies
Technical proposals
Scientific validations
Test bench results
Conclusion
Absorbers: configurations & results
LiBr 3,5kW test bench for absorbers (2005 - Bertin Technologies – stainless steel)
• 8,8L evaporator /absorbers (painted aluminium+plastics – PU+PP distribution + PET grids)
• 5 plates (3 LiBr/2 Water) for 2400cm2 absorption surfaces
• Climatic conditions & heating systems representative in car conditions (+30C / +90C)
• Tests with different plates geometry and same grids
0200400600800
100012001400160018002000220024002600280030003200340036003800400042004400
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Pui
ssan
ce e
n W
T en °C
Puissance en fonction de la température d'eau en so rtie absorbeur
Données banc proto_2Empirique 1,7 W/cm²Empirique 1,3 W/cm²Empirique 2 W/cm²Données banc proto_baseEmpirique 2,6 W/cm²Données banc proto_1Données banc proto_1 non dégazé
Absorption prototype plate # 1
Theorical line of performance for car
Theorical line of poor performance
Theorical line of good performance
Absorption standard plate
Theorical line of very good
performance
Absorption prototype plate #2
Absorption prototype plate #2
(with uncondensable gases)
Test bench power limit
Water outlet temperature (C)
Cooling
power
(W)
Area: Not compatible
with car implementation
Area: Poor performance
Area:
Automotive performance
PSA Peugeot Citroën – Patrick BACH – essais 2013
Proto #2Reference
Proto #1
Absorbers: configurations & results
0200400600800
100012001400160018002000220024002600280030003200340036003800400042004400
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Pui
ssan
ce e
n W
T en °C
Puissance en fonction de la température d'eau en so rtie absorbeur
Données banc proto_2Empirique 1,7 W/cm²Empirique 1,3 W/cm²Empirique 2 W/cm²Données banc proto_baseEmpirique 2,6 W/cm²Données banc proto_1Données banc proto_1 non dégazé
Absorption prototype plate # 1
Theorical line of performance for car
Theorical line of poor performance
Theorical line of good performance
Absorption standard plate
Theorical line of very good
performance
Absorption prototype plate #2
Absorption prototype plate #2
(with uncondensable gases)
Test bench power limit
Water outlet temperature (C)
Cooling
power
(W)
PSA Peugeot Citroën - ADTH– Patrick BACH – essais 2013
Proto #2
Reference
Proto #1
Proto #1 &
uncondensable
gases
CONCLUSION
Context
Technologies
Technical proposals
Scientific validations
Test bench results
Conclusion
Automotive falling film for absorption:
Conclusion
WaterLiBr
solution
Power on 1/3 on absorber is checked.
Improvements for the future are identified.
Still very difficult to make it work:
- Flow equilibrium between grids
- Flow distribution on grids
- Pressure equilibrium
- Uncondensable gases
The key points are known today but the
optimised characteristics are still to identify.
PSA Peugeot Citroën – Emmanuel Boudard – 07 février 2014