OPTEMUS Project: How to create a micro- climate around the passengers to dispense with climatizing the entire cabin Felix Weidmann, Fraunhofer LBF
OPTEMUS Project: How to create a micro-
climate around the passengers to dispense with
climatizing the entire cabin
Felix Weidmann, Fraunhofer LBF
OPTEMUS 2
Agenda
• OPTEMUS energy reduction ambition
• Fiat 500e vs. OPTEMUS Fiat 500e
• OPTEMUS technologies
• Evaluation of thermal comfort
• Creation of localized climates
• Macro climate vs. Micro climate
• OPTEMUS micro climate technologies
• Summary
Figure: CRF
OPTEMUS 3
OPTEMUS Ambition
• Absolute driving range 160km (NEDC)
• High range variation dependent on ambient climate
Most critical: extreme cold
• Reasons
• Temperature dependency of battery pack
• Climate comfort technologies cannot harvest dissipated heat from ICE
• Optemus ambition:
Reduction of driving range variation due
to ambient climate
How to do that?
SotA Fiat 500e OPTEMUS Fiat 500e
<1%
<1% -36%
-18%
OPTEMUS 4
OPTEMUS Ambition
Extreme ambient temperatures mostly affect energy consumption of
comfort technologies
Reduction of energy consumption of interior climate comfort to reduce
range variation
0
50
100
150
200
250
Stota Optemus
traction
comfort
componentheating/cooling
0
50
100
150
200
250
Stota Optemus
traction
comfort
componentheating/cooling
Hot ambient climate Cold ambient climate
-60%
-15%
-78%
-15%
Ene
rgy C
on
sum
ption [W
h/k
m]
Ene
rgy C
on
sum
ption [W
h/k
m]
OPTEMUS 7
OPTEMUS Comfort Technologies
Weather
Data
Preconditioning
strategy
Eco routing/
driver profile
OPTEMUS 8
OPTEMUS Comfort Technologies
Weather
Data
Preconditioning
strategy
Eco routing/
driver profile
Preconditioned climate Localized climate Thermal Comfort
OPTEMUS 9
OPTEMUS Comfort Technologies
Weather
Data
Preconditioning
strategy
Eco routing/
driver profile
Preconditioned climate Localized climate Thermal Comfort
OPTEMUS 10
OPTEMUS Evaluation of Thermal Comfort
Evaluation of Thermal Comfort
Predicted Mean Vote PMV (Fanger, 1972)
• Developed for thermal evaluation of buildings
• Adaption for inhomogenities in vehicle interiors
• Separation of passenger body in segments
• Solar insolation included
PMV index Description
-3 cold
-2 cool
-1 slightly cool
0 neutral
+1 slightly warm
+2 warm
+3 hot
0
10
20
30
40
50
60
70
80
90
100
-3 -2 -1 0 1 2 3
Pre
dic
ted
Perc
en
tag
e o
f D
issati
sfi
ed
(P
PD
) / %
Predicted Mean Vote (PMV) / -
OPTEMUS 11
OPTEMUS Evaluation of Thermal Comfort
Evaluation of Thermal Comfort
Predicted Mean Vote PMV (Fanger, 1972)
• Calculation om comfort based on quantitative measurements
Enables use of thermal manikins
𝑄 𝑟𝑎𝑑𝑖𝑎𝑡𝑖𝑜𝑛
𝑄 𝑐𝑜𝑛𝑣𝑒𝑐𝑡𝑖𝑜𝑛
𝑄 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑖𝑜𝑛
𝑄 𝑚𝑒𝑡𝑎𝑏𝑜𝑙𝑖𝑐
𝑃𝑀𝑉 = 0,303 ∙ 𝑒−0,03∙𝑞 𝑚𝑒𝑡 + 0,028 ∙ 𝑞 𝑚𝑒𝑡 − 𝑞 𝑖
𝑛
𝑖=1
𝑞 𝑖𝑛𝑖=1 = 𝑞 𝑟𝑎𝑑 + 𝑞 𝑐𝑜𝑛𝑣 + 𝑞 𝑐𝑜𝑛𝑑
OPTEMUS 12
OPTEMUS Localized Climate
Weather
Data
Preconditioning
strategy
Eco routing/
driver profile
Preconditioned climate Localized climate Thermal Comfort
OPTEMUS 13
OPTEMUS Localized Climate
Stota Fiat 500e
• Passenger comfort systems
based on convective heat
transfer
Climatizing whole interior
• Targeted comfort systems as
contribution • Smart Seat
• Smart dashboard
Climatizing specific locations
OPTEMUS Fiat 500e
Energy consumption reduction with micro climates at equal comfort
OPTEMUS 14
OPTEMUS Localized Climate
Weather
Data
Preconditioning
strategy
Eco routing/
driver profile
Preconditioned climate Localized climate Thermal Comfort
OPTEMUS 15
OPTEMUS Localized Climate
Smart seat • Heating and cooling function
• Peltier elements at bottom and back
• Heating and/or cooling of different body parts
• Direct contact with body
• Material requirements • Thermal conductive polymer based materials
• Flexibility in order to adapt to passenger body
• Energy consumption • less than 100 W (per seat)
• Heat dissipation • Liquid cooling by integration into thermal layout
Contact pressure Heat transfer
[Source:Karimi, 2004]
OPTEMUS 16
OPTEMUS Localized Climate
Weather
Data
Preconditioning
strategy
Eco routing/
driver profile
Preconditioned climate Localized climate Thermal Comfort
OPTEMUS 18
OPTEMUS Localized Climate
Smart Dashboard – Targeted radiation Heating
• Cold ambient climate: targeted radiation heating
Targeted radiation heating
OPTEMUS 19
Smart Dashboard – Targeted radiation Heating
• Heating concepts
resistive heating concepts (A & B):
• Joule Principle
and thermoelectric concept (C):
• Peltier Principle
• Variation of parameters:
heating concept
panel thickness
panel material
effect on temperature homogenity
BA C
2 mm1 mm 4 mm
1 W/m K0.5 W/m K 5 W/m K
Figure 1: Variation of heating concepts
Figure 2: Variation of panel thickness
Figure 3: Variation of thermal conductivity
𝑃 ∝ 𝐼2 ∙ 𝑅
𝑄 = ∏𝐴𝐵𝐼 = ∏𝐴 −∏𝐵 𝐼
OPTEMUS Localized Climate
OPTEMUS 20
Smart Dashboard – Targeted radiation Heating
• Experimental testing:
• Evaluation of energy consumption and heat up time
PMV = 0
0
20
40
60
80
100
rel. h
ea
t up
tim
e &
en
erg
y c
on
su
mp
tio
n /
% -30%
prototypePTC - reference
heat up time
energy consumption
Combined use of PTC convective and radiation heating systems
Reduction of energy consumption of ~30% at equal PMV
OPTEMUS Localized Climate
OPTEMUS 21
OPTEMUS Localized Climate
Smart Dashboard – Heat transfer device
• Hot ambient climate: anisotropic heat transfer de Anisotropic heat transfer
OPTEMUS 22
OPTEMUS Localized Climate
Smart Dashboard – Heat transfer device
• Heat-up of interior due to solar insolation 𝑸 < 𝟏𝟎𝟎𝟎 𝑾/𝒎²
• Dashboard temperature can reach ~100°C
• Absorbed heat needs to be reduced by climate comfort technologies
Increase of energy consumption for climate comfort
OPTEMUS 24
OPTEMUS Localized Climate
30% reduction of
absorbed solar energy
while appearing black
Thickness insensitive
spectrally selective (TISS)
Layer
Heat-up due to insolation
Solar Radiation 𝑄
OPTEMUS 25
OPTEMUS Localized Climate
30% reduction of
absorbed solar energy
while appearing black
Thickness insensitive
spectrally selective (TISS)
Layer
Form-stable Phase Change Materials
Deceleration of temperature
increase during phase change
Heat-up due to insolation
Solar Radiation 𝑄
OPTEMUS 26
OPTEMUS Localized Climate
30% reduction of
absorbed solar energy
while appearing black
Thickness insensitive
spectrally selective (TISS)
Layer
Form-stable Phase Change Materials
Deceleration of temperature
increase during phase change
Anisotropic Heat Transfer
Heat-up due to insolation
Solar Radiation 𝑄
Transfer of exzessive heat to
panel backside using TME
OPTEMUS 27
OPTEMUS Summary
Summary
• OPTEMUS target:
Reduction of range variation by reduction of
energy consumption of comfort technologies
• Novel OPTEMUS holistic technologies:
• Smart Seat
• Smart dashboard
Generation of micro climates
• Evaluation of resulting thermal comfort:
PMV based approaches
OPTEMUS 29
Thermal comfort definition
- Which zones are keen to be cooled down for localized cooling?
The Equivalent Homogeneous Temperatures (EHT) temperatures of the Thigh, Pelvis, and
Back are significantly impacted by the seat cooling discharge and are sensitive to the
changes in discharge parameters in terms of the airflow rate and temperature [1].
Heat transfer between body and seat depends on the contact
pressure distribution [2].
[1] M. Wang et al. Localized Cooling for Human Comfort, SAE Int. J. Passeng. Cars - Mech. Syst., Volume 7, Issue 2, 2014.
[2] G. Karimi et al., Thermal Modeling of Driver/Seat Interfaces in Automotive Applications, SAE Technical Paper, 2004.
[3] S.Paulke and E. Kreppold, The Application of Thermal Simulation Techniques for Seat Comfort Optimizations, 2008.
Contact pressure
[2] [3]
Heat transfer
OPTEMUS 30
Task 2.1 – Novel Materials
Form-stable phase change materials
• PCM-Polymer-Composites
• Micro-encapsulated PCM-Epoxy-Composite
• Manufacturing of PCM-Epoxy-Composites at varying wt% (30,40,50)
• PCM-Epoxy-Composites provide processability at low temperatures
• PCM-Polymer-Blends
• PCM-HDPE-Blend
• Twin-screw-extrusion of HDPE and liquid paraffin
• Manufacturing of HDPE-Paraffin- Granulate at varying wt% (30,40,60)
• Must be processed above melting point of PCM-HDPE-Blend (~110 °C)
PCM-Epoxy-Composites chosen for integration into battery modules due to processing temperatures
OPTEMUS 31
Bologna - Localized conditioning
Micro Climate
Climate control only of limited areas
Climate technologies targeting specific passengers
OPTEMUS 32
Form-stable phase change materials
• HDPE-Paraffin-Blend
50-60% of PCM latent heat
Little/no leakage (to be tested)
Little change of tensile properties
at phase change
T2.3 Interior: Smart Cover Panel – Heat Transfer
HDPE + Frozen PCM HDPE + Liquid PCM
OPTEMUS 33
Thickness insensitive spectrally selective coating (TISS)
• Materials
• “Cool Leather”
• Differently coloured PP
• Testing of spectral selectivity
• Spectroscopy
Cool leather with very small
absorptance in NIR spectrum
• Testing of heat build-up
• ASTM 4803
• Miniature Interior
T2.3 Interior: Smart Cover Panel – Heat Transfer
scattered directed
Air Temperature
Surface Temperature
1
2
3
Windshield
Panel
Interior Housing
Radiation Source
Solar Spectrum
Wavelength Wavelength