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Component development for a liquid sorption thermal energy storage system
• Activities in the IEA SHC Task 58 “Material and Component Development for Thermal Energy Storage” - Subtask 4T: Component Design for Thermo Chemical Materials
• Practical application in liquid sorption heat storage with aqueous sodium hydroxide
Webinar, Nov 27, 2019 14:00 - 15:30 GMT
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Motivation
• There are many different demonstrator and lab scale systems under design, construction and testing.
• These vary highly in reported process, power, capacity and application. • In addition to heat transport, components for thermo chemical storage
systems have to provide an optimised heat and mass transport. • The actual heat/mass exchanger design is crucial for the achievable storage
capacity and power output. • The possibilities in designing such a reactor are multiple, and so are the
testing methods.
A common basis is required
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
• four performance criteria: • gross temperature lift
(temperature effectiveness)• volumetric energy density• volumetric power• round trip efficiency
• four evaluation scales:• material (mg)• bulk (g) • component (kg)• system (Mg)
• varying system process types• many different testing profiles
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
• four performance criteria: • gross temperature lift
(temperature effectiveness)• volumetric energy density• volumetric power• round trip efficiency
• four material levels:• material (mg)• bulk (g) • component (kg)• system (Mg)
Realistic temperatures
• varying system process types• many different testing profiles
Nov 27, 2019 14:00 - 15:30 GMT
AmbientCharging
95 °C
92 °C
30 °C
35 °C38 °C
92 °C
54 KSource
In
Out Out
Sink
In
Sorbent Sorbate
Realistic operating temperatures for building application
25 °C
27 KSorbate
AmbientSpace heating
35 °C
7 °C(6 °C)
4 °C1 °C38 °C
37 K
28 °C
Sink
In
Out Out
Source
In
Sorbent
Guideline from EN 14511-2
Fumey B, et al. Building application specific temperatures for the testing of phase change and thermo chemical materials, components and systems, Publication submitted.
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
• four performance criteria: • gross temperature lift
(temperature effectivness)• volumetric energy density• volumetric power• round trip efficiency
• four material levels:• material (mg)• bulk (g) • component (kg)• system (Mg)
Pros and Cons
• varying system process types• many different testing profiles
Nov 27, 2019 14:00 - 15:30 GMT
Basic sorption heat storage processesSystem sketch open transported
Charged absorbent
Discharger absorbent Absorbate
Heat and mass exchanger
high temperature heat source / sink
STORAGE TANK / AMBIENT
CONNECTION PUMPS AND VALVES
HEAT CONVERTER
System sketch open fixed
Adsorbate
Heat and mass exchanger
high temperature heat source / sink
AMBIENT
CONNECTION PUMPS AND VALVES
HEAT CONVERTER / ADSORBENT STORAGE TANK
Adsorbent
System sketch closed transported
Charged absorbent
Discharger absorbent Absorbate
Low temperature heat sink / source
Heat and mass exchanger
high temperature heat source / sink
STORAGE TANK
CONNECTION PUMPS AND VALVES
HEAT CONVERTER
System sketch closed fixed
Adsorbate
Low temperature heat sink / source
Heat and mass exchanger
high temperature heat source / sink
STORAGE TANK
CONNECTION PUMPS AND VALVES
HEAT CONVERTER / ADSORBENT STORAGE TANK
Adsorbent
Open Closed
Fixed
Transported
Fumey B, Weber R, Baldini L. Sorption based long-term thermal energy storage – Process classification and analysis of performance limitations: A review. Renewable and Sustainable Energy Reviews 2019;111:57–74
Nov 27, 2019 14:00 - 15:30 GMT
System sketch closed transported
STORAGE TANK
CONNECTION PUMPS AND VALVES
HEAT CONVERTER
Sorbate
Low temperature heat sink / source
Heat and mass exchanger
high temperature heat source / sink
Charged Sorbent
Discharged Sorbent
Advantages Disadvantages
- increased vapour pressure and density
- no external fouling- steady state process- continuous charging
and discharging - capable of single
pass and counter flow
- maximum GTL- discharge to
minimum input temperature
- operates at sub atmospheric pressure
- requires condenser and evaporator
- sensitive to non-condensing gases
- requires sorbate storage
- Increase in complexity, storage vessels and means of transport
Fumey B, Weber R, Baldini L. Sorption based long-term thermal energy storage – Process classification and analysis of performance limitations: A review. Renewable and Sustainable Energy Reviews 2019;111:57–74
Closed and transported process
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
• four performance criteria: • gross temperature lift
(temperature effectiveness)• volumetric energy density• volumetric power• round trip efficiency
• four material levels:• material (mg)• bulk (g) • component (kg)• system (Mg)
Theoretical evaluation
• varying system process types• many different testing profiles
Nov 27, 2019 14:00 - 15:30 GMT
NaOH
Pres
sure
[kPa
]
0.1
1.0
10.0
Temperature [°C]0 10 20 30 40 50 60 70 80 90
55wt% NaOH
50wt% NaOH
45wt% NaOH
40tw% NaOH
35wt% NaOH
30wt% NaOH
25wt% NaOH
20wt% NaOH
15wt% NaOH
10wt% NaOH
0wt% NaOH
5wt% NaOH
Temperature of aqueous NaOH [°C]
Wat
er v
apou
r pre
ssur
e [k
Pa]
Concentration of NaOH in solution
381
Charging
Discharging SH
28
Aqueous sodium hydroxide
Olsson J, Jernqvist Å, Aly G. Thermophysical properties of aqueous NaOH H2O solutions at high concentrations. Int J Thermophys 1997;18:779–93.
Nov 27, 2019 14:00 - 15:30 GMT
Gross temperature lift and temperature effectivenessM
ass
fract
ion
NaO
H in
aqu
eous
sol
utio
n [-]
0.30
0.35
0.40
0.45
0.50
0.55
Gross Temperature Lift [K]10 15 20 25 30 35 40 45 50
Vapour pressure 8.1 mbar (4 °C)
Absorption
Desorption
Good performancePoor performance Poor performance
GTLGTL
Mass fraction
GTL in absorptionGTL in desorption
temperature effectiveness=
Loss in GTL
Fumey B, Weber R, Baldini L. Sorption based long-term thermal energy storage – Process classification and analysis of performance limitations: A review. Renewable and Sustainable Energy Reviews 2019;111:57–74
Nov 27, 2019 14:00 - 15:30 GMT
Evaporator temperature 1 °C (6.5 mbar)M
ass
fract
ion
NaO
H in
aqu
eous
sol
utio
n [-]
0.300.320.340.360.380.400.420.440.460.480.500.520.54
Gross Temperature Lift [K]10 15 20 25 30 35 40 45 50
Condenser temperature 38 °C (67 mbar)
Minimum charging GTL
Maximum discharging GTL
Discharging loss due to vapour
pressure decrease
Loss in GTL due to vapour pressure
decrease
Minimum discharging concentration
Absorption
Desorption
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
• four performance criteria: • gross temperature lift
(temperature effectiveness)• volumetric energy density• volumetric power• round trip efficiency
• four material levels:• material (mg)• bulk (g) • component (kg)• system (Mg)
• varying system process types• many different testing profiles
Theoretical evaluation
Nov 27, 2019 14:00 - 15:30 GMT
Volumetric energy densityEn
ergy
dfe
rnsi
ty [k
Wh/
m3]
0
50
100
150
200
250
300
350
400
Final concentration [wt%]30 32 34 36 38 40 42 44 46 48 50
Energy of solutionEnergy of condensationTotal energy
162
190
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
Mass and heat transport
• four performance criteria: • gross temperature lift
(temperature effectiveness)• volumetric energy density• volumetric power• round trip efficiency
• four material levels:• material (mg)• bulk (g) • component (kg)• system (Mg)
• varying system process types• many different testing profiles
Nov 27, 2019 14:00 - 15:30 GMT
Bulk scale power investigation
Absorber / DesorberEvaporator / Condenser
Vapour connection
Nov 27, 2019 14:00 - 15:30 GMT
PPCPso l
Bulk scale power
30 min.
Low power
Not reached maximum
mass uptake
Nov 27, 2019 14:00 - 15:30 GMT
Subtask 4T: Component Design for Thermo Chemical Materials
Component design
• four performance criteria: • gross temperature lift
(temperature effectiveness)• volumetric energy density• volumetric power• round trip efficiency
• four material levels:• material (mg)• bulk (g) • component (kg)• system (Mg)
• varying system process types• many different testing profiles
Nov 27, 2019 14:00 - 15:30 GMT
Absorption cooling machine
Source (chiller)
Desorption
Absorption
Source
Sink
In
Out
In
Out
Out
Sink
In
In
Out
Sorbent Sorbate
Absorption heat transformer
Source
Desorption
Absorption
Source
Sink (heater)
In
Out
In
Out
Out
Sink
In
In
Out
Sorbent Sorbate
Absorption heat storage
Desorption
Source
In
Out Out
Sink
In
Source
Absorption
Sink (heater)
In
Out
In
Out
Sorbent SorbateStorage Sorbent
Absorption heat storage
Desorption / Absorptiop
In
Out Out
In
Storage
Source / Sink Sink / Source
Sorbent charged
SorbateSorbent discharged
1 2
3 4
Absorption machine comparison
Nov 27, 2019 14:00 - 15:30 GMT
Figure 3
Heat transport fluid ṁAhtf / ṁDhtf [g/min]
Absorbent solution ṁAsol / ṁDsol[g/min]
25 mm
1.5 mm
12.5 mm
0.4 mm1000 m
m
960 mm
5 mm
Material: stainless steel grad 1.4571
Heat and mass changer design for sorption heat storage
Fumey B, Weber R, Baldini L. Liquid sorption heat storage – a proof of concept based on lab measurements with a novel spiral finned heat and mass exchanger design. Appl Energy 2017;200:215–25.
Nov 27, 2019 14:00 - 15:30 GMT
Figure 4
Figure 4a
ϑ2
Absorber / Desorber Evaporator / Condenser
ϑ4
ϑ5
ϑ6 ϑ10
ϑ7
ϑ8 ϑ11
ϑ9
ϑ1 ϑ3
Pr2
Hea
t tra
nspo
rt flu
id
Hea
t tra
nspo
rt flu
id
Vacuum lock
Vacuum lock
Absorbate source / drain
Absorbent drain
Absorbent source
Px4
Px1 Px2
Px3
HMX
Thermo and cryostat machine
Thermo and cryostat machine
Scale
Figure 4bComponent Description
Px1 Absorber / desorber heat transfer fluid pumpPx2 Evaporator / condenser heat transfer fluid pumpPx3 Absorbate circulation pumpPx4 Absorbent solution supply pumpϑ1 Temperature of heat transfer fluid to absorber / desorberϑ2 Temperature of heat transfer fluid from absorber / desorberϑ3 Temperature of heat transfer fluid to evaporator / condenserϑ4 Temperature of heat transfer fluid from evaporator / condenserϑ5 Temperature of absorbent solution entering heat and mass exchangerϑ6 Temperature of absorbent solution after preheating sectionϑ7 Temperature of absorbent solution on heat and mass exchangerϑ8 Temperature of absorbent solution on heat and mass exchangerϑ9 Temperature of absorbent solution after heat and mass exchangerϑ10 Temperature of absorate on heat and masse exchangerϑ11 Temperature of absorate on heat and masse exchangerPr2 Pressure in heat and mass exchanger chamber
Absorber / Desorber
Evaporator / Condenser
Absorbent supply
Absorbate supply
Vacuum lock
Monitoring equipment
Lab scale HMX
Fumey B, Weber R, Baldini L. Liquid sorption heat storage – a proof of concept based on lab measurements with a novel spiral finned heat and mass exchanger design. Appl Energy 2017;200:215–25.
Nov 27, 2019 14:00 - 15:30 GMT
Figure 7
Mas
s fra
ctio
n Na
OH
in a
queo
us s
olut
ion
[-]
0.20
0.30
0.40
0.50
0.60
Gross Temperature Lift [K]0 10 20 30 40 50 60
Evaporator temperature 20 °C (23.3 mbar)
Increase in mass flow Increase
in GTL Increase in mass flow
Increase in GTL
GTL
2.3 g/min, 118 W
11 g/min, 221 W
4.1 g/min, 117 W
11.8 g/min, 258 W
Performance evaluation
Limited mass flux
Fumey B, Weber R, Baldini L. Liquid sorption heat storage – a proof of concept based on lab measurements with a novel spiral finned heat and mass exchanger design. Appl Energy 2017;200:215–25.
Nov 27, 2019 14:00 - 15:30 GMT
Conclusion
• Choice of process affects performance.
• To compare sorption systems, uniform testing temperatures are essential.
• Sorption storage requires operation close to the vapour pressure, temperature and concentration equilibrium.