Transcript www.DLR.de • Chart 1 High Temperature Thermochemical Heat Storage: Operation Modes of a 10kW Pilot Reactor based on CaO/Ca(OH)2 Matthias Schmidt, Christian Roßkopf, Marc.

www.DLR.de • Chart 1
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
www.DLR.de • Chart 2
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
www.DLR.de • Chart 3
Thermochemical Heat Storage
reaction system CaO/Ca(OH)2
Temperature [°C]
10
exotherm
endotherm
636
560
496
441
394
352
315
Ca(OH)2(s)
H2O(g)
1
pgas [bar]
CaO(s) + H2O(g) ⇌ Ca(OH)2(s) + ΔH
727
H2O(g)
0.1
CaO(s)
0.01
0.001
1.0
1.1
1.2
1.3
1.4
1.5
Temperatur 1000 / T [1/K]
- Loss free storage of chemical potential
- Adjustable storage temperature
- Possibility of heat transformation
1.6
1.7
www.DLR.de • Chart 4
From a reaction system to a heat storage system
operation principle
Process integration:
Reaction
Material
Properties
Gashandling
Reactor Design
www.DLR.de • Chart 5
Material Properties - CaO/Ca(OH)2
Chemical properties:
 Reversible reaction (400-600°C)
 Sufficiently fast rates of reaction
 No chemical degradation observed
F. Schaube et al., Thermochimica Acta, 2012
Thermophysical properties:
- Fine powder (d50 ~ 5 µm)
- low permeability
- Low thermal conductivity
(0.1 – 0.4 W/mK)
commerical available Ca(OH)2
Ca(OH)2 (4 Cycl)
www.DLR.de • Chart 6
Pilot Reactor Design (10kW; 25 kg Ca(OH)2)
indirectly operated fixed bed
Source: DEG Eingineering
www.DLR.de • Chart 7
Reaction Gas Handling
vapor pressure holder(10mbar – 3bar)
www.DLR.de • Chart 8
Multifunctional Pilot Plant
overall experimental set up for CaO/Ca(OH)2 reactor
www.DLR.de • Chart 9
Multifunctional Pilot Plant
overall experimental set up for CaO/Ca(OH)2 reactor
www.DLR.de • Chart 10
Multifunctional Pilot Plant
overall experimental set up for CaO/Ca(OH)2 reactor
www.DLR.de • Chart 11
Multifunctional Pilot Plant
overall experimental set up for CaO/Ca(OH)2 reactor
M. Schmidt et al., Applied Thermal Energy 62 (2014)
www.DLR.de • Chart 12
Multifunctional Pilot Plant
overall experimental set up for CaO/ Ca(OH)2 reactor
M. Schmidt et al., Applied Thermal Energy 62 (2014)
www.DLR.de • Chart 13
Charging Mode
dehydration of Ca(OH)2 at ph2O = 100mbar
600
1.00
0.90
550
0.80
0.70
0.60
450
0.50
400
0.40
Conversion
Temperature [°C]
500
T_air_outlet
T_air_inlet
Conversion
0.30
350
0.20
300
0.10
250
0.00
50.00
100.00
150.00
200.00 250.00
Time [min]
300.00
350.00
0.00
400.00
www.DLR.de • Chart 14
Buffer Storage Mode
droping inlet temperature, hydration of CaO at 1 bar vapor
550
Temperature [°C]
500
Tequilibrium = 490°C
@ (ph2O ~ 1bar)
450
T_air_inlet
T_R_01
T_R_05
400
T_R_11
T_R_13
350
300
0.00
20.00
40.00
60.00
80.00
100.00 120.00 140.00 160.00 180.00 200.00
time [min]
www.DLR.de • Chart 15
Heat Generation Mode
Hydration of CaO, starting temperature of 350°C
1.00
490
0.90
0.80
450
0.70
430
0.60
0.50
410
0.40
390
0.30
370
0.20
350
330
0.00
0.10
50.00
100.00
150.00
time [min]
200.00
0.00
250.00
Conversion
Temperature [°C]
470
T_air_inlet
T_air_outlet
Conversion
www.DLR.de • Chart 16
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
www.DLR.de • Chart 17
Thank you!
Matthias Schmidt
German Aerospace Center (DLR)
Institute of Technical Thermodynamics
[email protected]
www.DLR.de