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PCM-STOVE - Innovative PCM‐based heat storage integrated in woodstoves

With typical thermal efficiency of 70-80 % at nominal load, modern wood stoves often produce more heat than actually required, especially in well-insulated, low-energy buildings and passive houses. At the end of the combustion, the heat release rapidly decreases, while the need for heating remains.

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Photo: Jøtul
Photo: Jøtul

The underlying idea of PCM-STOVE is therefore to extend the heat release from the stove by developing a compact heat storage using phase change materials (PCMs) to store excess heat and release this heat gradually to the room.

PCMs are materials that, during melting and solidification, respectively store and release large amounts of heat at a nearly constant temperature. PCMs with a melting temperature of 100-150 °C, will store excess heat from the wood combustion and release it to the room over an extended time-period after combustion ends. Compared to current sensible heat storage solutions using e.g. soapstone, PCMs offer higher heat storage capacity and more stable heat release. Such systems may be retrofitted to existing wood stoves or included as an add-on to new products.

The challenge of PCM-STOVE is, therefore, to develop a lightweight and compact heat storage solution for integration in the lightweight cast-iron stoves produced by JØTUL AS. This includes finding and characterising a suitable PCM, designing a prototype with optimal heat exchange properties and experimentally testing the prototype.

Increased use of heat storage solutions for wood stoves is expected to result in a reduction in the overall wood consumption required to sustain a given level of thermal comfort and reduce the need for part load operation of wood stoves. These, in turn, will also lead to a reduction in particle emissions and other pollutant gases, benefiting society at large through increased air quality and health benefits thereof, and reduced environmental impact.


This is an Innovation Projects for the Industrial Sector financed by the Research Council of Norway.


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Project duration

2021 - 2023

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