Thermal Energy Storage Application Perspectives

SCCER Heat and Electricity Stroage HaE

7th Symposium HSR Rapperswil, November 6, 2018

Paul Gantenbein, Xavier Daguenet-Frick, Mihaela Dudita, Lukas Omlin,

Mattia Battaglia, Michel Haller, Daniel Philippen, Daniel Carbonell, Andreas

Häberle

Institute for Solar Technology SPF – HSR University of Applied Sciences

Rapperswil

Thermal Energy Storage Application Perspectives

Technical Challenges in the Component Development

http://www.solarenergy.ch/index.php?id=44

http://www.solarenergy.ch/index.php?id=44

SCCER HaE 7th Symposium

Content

2

Sensible Heat StorageStratification / heat and mass transfer

Fluid inlet design though CFD

Latent Heat StoragePhase change: water Ice / heat transfer

Heat exchanger design & Simulation model

Sorption / Thermochemical Heat Storage

Closed – internal heat and mass transfer

Heat and mass exchanger design

0.0E+00

5.0E+06

1.0E+07

1.5E+07

2.0E+07

2.5E+07

3.0E+07

3.5E+07

4.0E+07

0 2 4 6 8 10

Nu

*Pr4

.226

[-]

Re [-]

Desorber

0.3

-0.3

ref

1

4

2


Heat Storage Types & Examples of Materials

3

solid - gas

Sensible heat Latent heat Chemical energy

Materials

gas - liquid

solid - solidsolid - liquid

inorganicsorganics

Mixtures

Temperature

interval

Eutetics

Single

temperature

Mixtures

Temperature

interval

Eutetics

Single

temperature

Fatty acidsParaffins

(alkanes mixtures)Hydrated salts

Source: A. Abhat: Solar Energy 30 p. 313 (1983)


Temperature Distribution in a Sensible Storage

4

Thermal stratification of sensible storage tanks

fulfilling application temperature conditions

Temperature T

Height H

Thermocline

T high

T low

Diameter D

temperature stratification

D

H

Cylindrical tank shapes

H=height, D=diameter

𝒍𝒔 =( 𝑴𝟎 𝝆)

𝟑𝟒

(𝑭𝟎 𝝆)𝟏𝟐

=( 𝑽𝟎𝒗𝟎)

𝟑𝟒

𝑽𝟎𝒈∆𝝆𝝆

𝟏/𝟐𝛘 = 𝒍𝒔/𝒅𝒇

Dimensionless number

- deflection relation

- geometry A & v0, r(T), g

IN

OUT


Sensible Storage Type

5

Feed Inlet / Volume Flow / Stratification

recommendation v< 0.1 m/s

900 l/h

2’’, 30°C

1800 l/h

2’’, 30°C


Sensible Type

6

Temperature stratification

Battaglia, M.; Haller, M. Y. Stratification in large thermal storage tanks. Eurosun 2018, September 10 – 13, Rapperswil, Switzerland


Sensible Storage Type

7

Fluid feed inlet design

fluid velocity v0

horizontal inletinlet bent

towards the

top/bottom

of the

storage

Battaglia, M.; Haller, M. Y. Stratification in large thermal storage tanks. Eurosun 2018, September 10 – 13, Rapperswil, Switzerland


Content

8








0.0E+00

5.0E+06

1.0E+07

1.5E+07

2.0E+07

2.5E+07

3.0E+07

3.5E+07

4.0E+07

0 2 4 6 8 10

Nu

*Pr4

.226

[-]

Re [-]

Desorber

0.3

-0.3

ref

1

4

2


Latent Heat Storage Using Ice Storage

9

Ice Storage

Heat Source or Sink

Eisspeicher

Ambient air Bore hole Ice storage

solar collector field

A) B) C)

Heat

Pump


Ice Storage Modul

10

Cylindrical storage shape

Plate heat exchanger (hex)

Mainly stainless steel

Diameter of storage mm 1200

Height of storage mm 1950

Water content m3 2.0

Parallel pairs of hex-plates # 4

Distance between plates mm 120

Active surface of hex m2 22

Latent heat (max.) kWh 129

Maximum icing fraction of mass 70 %

Philippen, D.; Battaglia M.; Carbonell D.; Thissen B.; Kunath L.; Validation of an ice storage model and its integration into a solar-ice system. Eurosun 2018,

September 10 – 13, Rapperswil, Switzerland


Mathematical Model: Ice Storage and Heat Exchanger

11

UAtot = 1

𝑈𝐴𝑖𝑛+

1

𝑈𝐴𝑤𝑎𝑙𝑙+

1

𝑈𝐴𝑖𝑐𝑒+

1

𝑈𝐴𝑜𝑢𝑡 −1

Model based on a more detailed

TRNSYS-model (transcription)

Mathematical model implemented

into the Polysun simulation software

One-node (1) ice storage

Multi-node (12) heat exchanger

(4 elements in parallel)

Physical model (versus old model

which is empirical)

Ice storage can be coupled:

a) with ground or

b) with a room temperature

121 2

1

Tamb

Tice

2 plates in series (12 knots)


Validation of the Ice Storage Model

12

Example: Freezing over 30 hours (steady state growing of ice)


Validation of the Ice Storage Model

13

Example: Freezing over 30 hours (steady state growing of ice)

Philippen, D.; Battaglia M.; Carbonell D.; Thissen B.; Kunath L.; Validation of an ice storage model and its integration into a solar-ice system. Eurosun 2018,

September 10 – 13, Rapperswil, Switzerland

Solar Collectors

Ice Storage

Hydraulic separator

Heat Pump

Hot Water

Room Heating

Combi

Storage

Model

implemented in

the industry


Content

14








0.0E+00

5.0E+06

1.0E+07

1.5E+07

2.0E+07

2.5E+07

3.0E+07

3.5E+07

4.0E+07

0 2 4 6 8 10

Nu

*Pr4

.226

[-]

Re [-]

Desorber

0.3

-0.3

ref

1

4

2


Concept & Design

15

Separation of power and capacity units

- Power unit: combined A-D & E-C heat and

mass exchangers

- Capacity unit: storage tanks

Seasonal charging and discharging processes

Absorption Storage Experiment

Sorbate loop

Sorbent loop


Potential

16

Storage potential of materials

solid (crystallization) – liquid

Polanyi / Dubinin potential adsorption theory

Solubility boundary of aqueous solutions of

lithium chloride.

Eutectic Points

LiCl-H2O

M. Conde Engineering

0.00E+00

2.00E+05

4.00E+05

6.00E+05

8.00E+05

1.00E+06

1.20E+06

1.40E+06

20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

DF

(J/k

g)

c(H2O) (wt.%)

Absorption potential DF in function of load c

LiBr-H2O

NaOH-H2O

LiCl-H2O

“heat of solution” in case of vapour – liquid solution transition.

(ex: at 90 wt.% and more water the Dhv of water vapour will be released.)


Sorption Heat Storage

17

Charging and discharging

- charging: desorption ok

- discharging: absorption not ok

Condenser maximum flow rate:

12 l(H2O)/min @ T=20 °C

0.0E+00

5.0E+06

1.0E+07

1.5E+07

2.0E+07

2.5E+07

3.0E+07

3.5E+07

4.0E+07

0.0 2.0 4.0 6.0 8.0 10.0

Nu

*Pr4

.22

6[-

]

Re [-]

Desorber

30%

-30%

ref

Heat transfer characteristics: Nu=Nu(Pr, Re)

Re (-)

Nu

*Pr4

.22

6(-

)

pre

dic

ted e

xchanges p

ow

er

(W)

Falling film

tube bundle

power unitsE-C

A-D

A-D A-D E-C

Measured exchanges power (W)

Xavier Daguenet-Frick et al. Renewable Energy 110 (2017) 162-173.

http://www.empa.ch/plugin/template/empa/3/*/---/l=1

http://www.empa.ch/plugin/template/empa/3/*/---/l=1



18

Power unit modification

- heat & mass exchange surface wetting

wetting agent TRITON™ QS-1

tube surface structure

tube surface anneling / coating

- lye residence time in sorbate

SiC ceramic foams low wetting

better wetting

Dudita M., Daguenet-Frick X., and Gantenbein P., EuroSun 2016, Palma (Mallorca)



19

Power unit modification

Tube surface geometry

Wetting agent

Hydrophilic ceramic foam:

wetting with concentrated

aqueous sorbent.

increased residence time of

the aqueous sorbent on the

tube

Hydrophilic SiC ceramic foam with pores partially filled by concentrated aqueous sodium hydroxide.

Porosity is ranging from 10 to 30 PPI , where PPI = number of pores per inch.

Excellent wetting

of the SiC ceramic

foam with

concentrated

NaOH and LiBr

10 PPI and NaOH 50 wt.% 20 PPI and NaOH 50 wt.% 30 PPI SiC and LiBr 54 wt.%

Lye OUT

Lye IN

gravity


Experimental Set-up of the 1 kW Unit

20

Power and capacity units

- Combined A-D & E-C heat and mass

exchangers – seasonal separation

- Sorbent and sorbate storage tanks

AB

C D

H2O loop

NaOH/H2O loop

A-D unit E-C unit

water tank

(H2O)

feed pumpfeed pump

lye tanks

(NaOH-H2O)

T 60T 30T 20

A-D E-C

T 20 T 30 T 60

Lab set-up EW 6


Operation with Water

21

set in operation – tests performed with water

024681012141618202224262830323436384042444648

-4000

-3500

-3000

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

2000

2500

3000

3500

4000

13:00:00 13:30:00 14:00:00 14:30:00 15:00:00 15:30:00 16:00:00

Tem

per

atu

r T

(°C

)

Po

wer

P (

Wat

t)

time (hh:mm:ss)

power AD unit power EC unit T inlet AD

T outlet AD T outlet EC T inlet EC

E-C

A-D

Power and temperatures in the A-D and E-C units

Expected power: 1 KW


Conclusion & Outlook

22

Thermal Energy Storage is a Key Component

Multiple Storage Concepts

Particular Solutions for the Application

Scaling

Heat & Mass Transfer

Power & Energy Balance

Thank you very much!

Swiss Federal Office of Energy SFOE

Innosuisse – Schweizerische Agentur

Für Innovationsförderung

Thermal Energy Storage Application Perspectives

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