Thermochemical Storage Systems

M. Bakker

This paper was presented at the GERG Storage Workshop, E.ON Ruhrgas, Essen, Ger-many, 27 September 2011

ECN-L--11-114 NOVEMBER 2011

www.ecn.nl

Thermochemical storage systems

Marco Bakker

Heating49%

Electricity20%

Transport31%

European primary energy use in 2008

Why thermal energy storage?

Why thermal energy storage?

Functions of thermal energy storage

Functions:

• Supply‐demand matching

• Peak shaving

• Flexibility

• Comfort enhancement

Functions of thermal energy storage

Function of storage determines 

main parameters:

• quality  [°C]• capacity  [GJ]

• storage density [GJ/m3]

• power  [kW]

T

h

T

h

T

h

Sensible heat

• heat capacity 

• reservoirs, aquifers, ground/soil

Latent heat

• phase change (melting, evaporation)

• water, organic or inorganic PCMs

Chemical heat

• physical or chemical bonds (reaction enthalpy)

• adsorption, absorption, chemical reactions

Heat storage principles

Heat storage principles

10050

10

sensible latent chemical

Example: storage volume in m3 needed for full solar coverage of 

a very energy efficient household

Examples: sensible thermal storage

Examples: latent thermal storage

Examples: chemical storage

How does it work?

How does it work?

How does it work?

Technically, two different mechanisms ‘under the hood’:

• absorption

- chemisorption

- volume

• adsorption

- physisorption- surface

How does it work?

Advantages Disadvantages

high storage density relatively complex technology

no long‐term storage losses early stage of development

suitable for long‐term, high density storage

Application example: Domestic heating

Application example: Domestic heating

Main drivers:

• high energy density

• low losses

• low price

Application example: Automotive

0 500 1000 1500 2000

1st 2 min. after cold start:95% of emissions

Engine temperature during standard test cycle

Main drivers:

• high power

• low weight

• high cyclability

Application example: High temperature

Main drivers:

• high power

• high cyclability

• low payback time

Ongoing research

IEA SHC/ECES Task 42/24:

Thermal Energy Storage: Material Development for System Integration

www.iea‐shc.org/task42

Renewable Heating & CoolingEuropean Technology Platform:

Strategic Research Agenda

www.rhc‐platform.org

Ongoing research: Materials science

• Identification of promising materials

• Development of new materials

- AlPO, SAPO, MOF

- zeolite composites

Ongoing research: Material optimisation

• Development of material composites

• Optimisation of material properties

• Multi‐scale numerical modelling

• Development of characterisation methods

1 mm 1 mm 1 mm

Ongoing research: Reactor development

• Reactor design and optimisation

- power, storage density, stability• Several types of prototypes

- open, closed- separate, integrated

Ongoing research: Reactor development

Ongoing research: System studies

• Conceptual design and feasibility studies

• Techno‐economical analysis

• Life‐cycle analysis

Ongoing research: Gas storage

• EDGaR Flexistore

- decentralized vs. centralized gas storage- technical, economical, societal

Conclusion

• Heat uses as much energy as transport and electricity combined

• Thermal storage is essential part of many (renewable) heating technologies

• Different applications, different drivers

• Thermochemical storage systems: young but promising technology

Thank you for your attention!

Marco BakkerEnergy Research Centre of the NetherlandsP.O. Box 11755 ZG  PettenThe Netherlands

phone +31 224 568966fax +31 224 568079email m.bakker@ecn.nlweb www.ecn.nl