matthias schmidt , christian roßkopf, marc linder, antje wörner
DESCRIPTION
High Temperature Thermochemical Heat Storage: Operation Modes of a 10kW Pilot Reactor based on CaO / Ca (OH) 2. Matthias Schmidt , Christian Roßkopf, Marc Linder, Antje Wörner. Content. Introduction to thermochemical energy storage based on CaO / Ca (OH) 2 Material properties - PowerPoint PPT PresentationTRANSCRIPT
High Temperature Thermochemical Heat Storage:Operation Modes of a 10kW Pilot Reactor based
on CaO/Ca(OH)2
Matthias Schmidt, Christian Roßkopf, Marc Linder, Antje Wörner
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Content
- Introduction to thermochemical energy storage based on CaO/ Ca(OH)2
- Material properties
- Reactor design and test bench development
- Experimental results of different operation modes
- Summary and outlook
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Thermochemical Heat Storage reaction system CaO/Ca(OH)2
- Loss free storage of chemical potential
- Adjustable storage temperature
- Possibility of heat transformation
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CaO(s) + H2O(g) ⇌ Ca(OH)2(s) + ΔH
endotherm
exotherm
1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.70.001
0.01
0.1
1
10
Temperatur 1000 / T [1/K]
pga
s [b
ar]
Ca(OH)2(s)
CaO(s)
636727 560 496 441 394 352 315
Temperature [°C]
H2O(g)
H2O(g)
From a reaction system to a heat storage systemoperation principle
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Reactor DesignGashandling
Process integration:
ReactionMaterial
Properties
Material Properties - CaO/Ca(OH)2
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Thermophysical properties:
- Fine powder (d50 ~ 5 µm)
- low permeability
- Low thermal conductivity (0.1 – 0.4 W/mK)
F. Schaube et al., Thermochimica Acta, 2012
Ca(OH)2 (4 Cycl) commerical available Ca(OH)2
Chemical properties:
- Reversible reaction (400-600°C)
- Sufficiently fast rates of reaction
- No chemical degradation observed
Pilot Reactor Design (10kW; 25 kg Ca(OH)2)indirectly operated fixed bed
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Source: DEG Eingineering
Reaction Gas Handlingvapor pressure holder(10mbar – 3bar)
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Multifunctional Pilot Plantoverall experimental set up for CaO/Ca(OH)2 reactor
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Multifunctional Pilot Plantoverall experimental set up for CaO/Ca(OH)2 reactor
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Multifunctional Pilot Plantoverall experimental set up for CaO/Ca(OH)2 reactor
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Multifunctional Pilot Plantoverall experimental set up for CaO/Ca(OH)2 reactor
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M. Schmidt et al., Applied Thermal Energy 62 (2014)
Multifunctional Pilot Plantoverall experimental set up for CaO/ Ca(OH)2 reactor
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M. Schmidt et al., Applied Thermal Energy 62 (2014)
0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00250
300
350
400
450
500
550
600
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
T_air_outlet
T_air_inlet
Conversion
Time [min]
Tem
per
atu
re [
°C]
Co
nve
rsio
n
Charging Modedehydration of Ca(OH)2 at ph2O = 100mbar
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0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00300
350
400
450
500
550
T_air_inlet
T_R_01
T_R_05
T_R_11
T_R_13
time [min]
Tem
per
atu
re [
°C]
Buffer Storage Modedroping inlet temperature, hydration of CaO at 1 bar vapor
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Tequilibrium = 490°C@ (ph2O ~ 1bar)
Heat Generation ModeHydration of CaO, starting temperature of 350°C
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0.00 50.00 100.00 150.00 200.00 250.00330
350
370
390
410
430
450
470
490
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
T_air_inlet
T_air_outlet
Conversion
time [min]
Tem
per
atu
re [
°C]
Co
nve
rsio
n
Summary and Outlook
CaO / Ca(OH)2 combines low material costs with high storage density
Reactor for 25kg (10 kWh) and 10 kW in operation
Charging at temperatures >400°C demonstrated
Discharging at adjustable temperatures (400-600°C) and in different operation modes possible
- Development of integration strategies(CSP and other applications)
- Performance evaluation through system modeling
- Material modifications to improve conveyance
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Thank you!
Matthias SchmidtGerman Aerospace Center (DLR)Institute of Technical Thermodynamics
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