Strengths and applications
Thermal energy storage – also called heat storage – has the main advantage that it does not involve any chemical conversion; hence it is typically simple, highly efficient and has a high cycle life. Yet, the economics and efficiency depend on the materials used and especially the integration of the storage into the overall system. A whole range of storage technologies and materials exists – with temperatures from 20°C (water) to 1000 °C (metals or rocks), scales from kWh to GWh, and including phase change ("latent heat") or not ("sensible heat").
Thermal energy storage is the storage technology of choice for non-dispatchable heat production (e.g. process waste heat, solar heat), or where thermal energy such as steam is converted to power, (e.g. in a turbine). Instead of first generating the power and then storing it for later use, it is often better to first store the heat and then generate the power when it is actually needed.
More concrete, thermal energy storage can be applied
In concentrating solar power plants to provide dispatchable power, also during the night
In thermal power plants to operate them more flexibly and perform quicker load changes
In combined heat and power plants to provide security of heat supply and to temporally decouple the heat and power generation
In process industries to recover and utilize heat that is otherwise lost
As a component in other energy storage applications such as for example Compressed Air Energy Storage (CAES)
Linde can draw on plenty of know-how on thermal energy systems.
Our Swiss subsidiary Bertrams Heatec carries a broad know-how and reference base for engineering and construction of molten salt based storage systems in a temperature range from 140°C to 560 °C.
Linde Engineering designs and manufactures heat exchangers of various types (coil wound, plate fin) that can be applied advantageously for high temperature thermal energy storage systems
Within Linde Clean Technologies, we utilize and expand our know-how, e.g. into the use of salt for latent heat thermal energy storage.
In this project we collaborate with the German Aerospace Center (DLR), one of the world’s leading research institutes on thermal energy storage. We will develop a latent-sensible heat storage unit based on molten salt and extruded heat exchanger tubes in order to reversibly store the enthalpy of superheated steam. This shall facilitate thermal energy storage in concentrating solar power plants with “direct steam generation” (DSG) in the solar receivers, but also energy recovery in industrial processes or flexibilization of combined heat and power production. The project is funded by the German Federal Ministry for Economic Affairs and Energy.