Feolite is a type of iron oxide sintered into building blocks, which are then used for heat storage.[1][2]

Feolite was developed in Great Britain.[1]


Feolite, one of many materials used for heat storage, being a solid, does not have any volumetric or pressure containment issues, but correspondingly does require the use of a transfer medium to then get the stored heat to the desired location.[3]

The specific heat of feolite is 920.0 J·kg−1·°C−1,[4] its density is 3,900 kg·m−3, and its thermal conductivity is 2.1 W·m−1·°C−1.[5]

Feolite may be used at temperatures up to 1000 °C (1832 F).[1]


Feolite was invented in 1969 by Electricity Association Technology, then called Electricity Council Research Centre.[6]

Feolite was a registered trademark[a] in Australia for all iron oxides for use in the manufacture of thermal storage units which has now lapsed, by Electricity Association Technology of the United Kingdom.[7]

Heating systems with a storage component now widely use feolite as the storage core.[8]


Blocks of feolite enclosing sheathed electric heating elements to form a heat storage core, surrounded by thermal insulation, are used in storage heaters and storage radiators.[9][10] Because feolite blocks will conduct electricity, electric heating elements must be electrically insulated when used with feolite storage.[11]

The typical heat exchange medium for feolite storage is air.[10][12][13]

Feolite has been considered for use as a component for braking systems in railway rolling stock.[14]


  1. ^ 21 May 1973 - TM: 268578[7]


  1. ^ a b c Wettermark, Gunnar (1989). "High Temperature Thermal Storage". High Temperature Storage. Springer International Publishing AG. pp. 539–549. doi:10.1007/978-94-009-2350-8_24. ISBN 978-94-010-7558-9.
  2. ^ "Night Storage Heaters" (PDF). Bavarian State Office for the Environment. Retrieved 28 June 2016.[dead link]
  3. ^ Hausz, W.; Berkowitz, B.J.; Hare, R.C. (October 1978). "CONCEPTUAL DESIGN OF THERMAL ENERGY STORAGE SYSTEMS FOR NEAR TERM ELECTRIC UTILITY APPLICATIONS" (PDF). National Aeronautics and Space Administration. Retrieved 27 June 2016.
  4. ^ Willmott, John A. (2002). Dynamics of Regenerative Heat Transfer. Taylor & Francis. ISBN 9781560323693. Retrieved 27 June 2016.
  5. ^ L´opez, Juan Pablo Arzamendia (2013). "Materials Design Methodology Architectures for the Latent Storage in the Field of Building" (PDF). INSA de Lyon. Retrieved 28 June 2016.
  6. ^ "Our History". Electricity Association Technology. Retrieved 28 June 2016.
  7. ^ a b "FEOLITE - 268578". Intellectual Property of Australia. Retrieved 28 June 2016.
  8. ^ A sample of commercial systems from around the world:
    • "Olsberg - State-of-the-art Astral Static Storage Heating with European-designed Technology" (PDF). Energy Efficient Products. Retrieved 27 June 2016.
    • "ASTRAL - Static Storage Heaters". Opus Electrical Technologies. Retrieved 28 June 2016.
    • "Nightstor Boilers Selby". KW Grant. Retrieved 28 June 2016.
    • "ELECTRIC ACCUMULATION HEATING". Atlantic. Retrieved 26 June 2016.
    • Coote, Nathan; MacLeman, David (2012). "Low Carbon Networks Fund Tier 1 Project Close-Down Report – Trial evaluation of domestic demand side management" (PDF). Scottish and Southern Energy Power Distribution. Retrieved 28 June 2016.
    • "Storage heating with Technotherm" (PDF). Devi Heating Systems. 2015. Retrieved 28 June 2016.
    • "Nightstor Boilers". Hyndburn Engineering Services. Retrieved 28 June 2016.
  9. ^ Frazer, Stephen. "Electrical Heaters". Building Services Engineering. Retrieved 27 June 2016.
  10. ^ a b Wright, Andrew J (1997). "ELECTRIC STORAGE HEATERS IN BUILDING SIMULATION" (PDF). Electricity Association Technology. Retrieved 28 June 2016.
  11. ^ Hegbom, Thor (1997). Integrating Electrical Heating Elements in Product Design. Marcel Dekker. ISBN 9780824798406. Retrieved 27 June 2016.
  12. ^ "PIONEER OF ELECTRIC HEATING ACCUMULATION - Design and manufacture Belgian since 1961". ACEC HEATING. Retrieved 28 June 2016.
  13. ^ "The TECHNOTHERM electro storage heater" (PDF). Technotherm International. Retrieved 28 June 2016.
  14. ^ McGuire, M. (1973). "Some further investigations into the use of feolite as a friction material". SPARK - Rail Safety and Standards Board. Retrieved 28 June 2016.[permanent dead link]