More efficiency through bulk movement
Chemical heat storage with Calziumoxid is being tested by Scientists
of the DLR in the project BERTI. As a special feature, the laboratory
unit of Stuttgart researchers has a wandering reaction bed. As a result
the heat capacity of the storage and its heat output can be designed
independently of one another.
|Project status||Model of particle movement|
|Temperature type||High temperature|
|Storage/Charging||Direct or indirect|
|Charging temperature||400-600 °C|
|Discharge temperature||400-600 °C|
|Energy storage density||250 kWh/m³, 370 kWh/t|
|Project duration||Ocotber 2013 until December 2017|
The possibility to store energy, especially the storage of thermal energy, plays a key role for a cost- as well as resource-efficient future energy supply. However, the realisation of economic solutions for thermal energy storage mainly depend on the storage density and the storage material. Thermochemical storages, where the heat of a reversible chemical reaction is used, presents a promising technology especially due to their high storage density, which can also be implemented with cost-effective materials, e.g like hydrated quick lime.
In the context of the project "BERTI - Reaction Bed with moving Thermochemical Storage Material" a lead concept for thermochemical heat storage with moving thermochemical storage material is developed and subsequently demonstrated in laboratory scale. The movement of the reaction bed allows the combination of a very high storage density - which represents a distinct advantage of chemical reactions - with the separation of storage capacity from storage performance (thermal power).
Wärmeleistung von der Speichergröße entkoppeln
BERTI tries to demonstrate two main advantages of thermochemical storage by use of gas-solid reactions:
- separated reactants and thereby lossless storage possibilty
- the detachment of storage capacity from thermal perfomance can be realised by a separate storage of the solid material and a controlled supply to the reactor as needed.
However, a key role play the possibilty to move the solid bulk material.
In order to enable efficient operation of a thermochemical storage with moving bulk material, a close collaboration between materials and engineering science is necessary. In the beginning of the project a reactor design is specified, which provides the basis for the subsequent course of the project. Hereafter, the three main issues concerning a moving reaction bed for thermochemical heat storage are addressed simultaneously: material development, movement of the bulk material and reaction control. The final goal of the project is a verification of the general functionality in lab-scale.
Storing without losses
Contrary to alternative technologies, thermochemical heat storage offers the possibility to store thermal energy in principle without losses. The stored thermal energy can even be upgraded thermally by variation of reaction conditions. Both points provide additional degrees of freedom especially for efficiency enhancement. The main focus of the project lies on the movement of a storage material for thermochemical heat storages in combinatino with an efficient reaction control. Both parts present novel issues scientifically as well as technologically.
Storage opens up new fields of application
BERTI addresses the core of development of innovative thermal energy storage and opens up new fields of application from heat storage with integrated heat transformation via concentration of waste heat flows and their concentrated discharge through to lossless transport of thermal energy. However, a key role play the possibilty to move the solid bulk material. In this this project engineering and materials science are combinded with the objective to develop an advanced solution for thermochemical heat storage.