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Research and development

Fire has accompanied mankind for thousands of years. But we see fire not (only) as a cultural-historical heritage, but also as a contribution to a better future. We see our task as combining healthy and comfortable heat with high efficiency and low emissions.That is why we have been carrying out intensive research work for many years in areas such as storage technology, combustion control and filter technology. Together with the partners Kiefel Geräte- und Metallbau GmbH & Co. KG and the Institut für Luft- und Kältetechnik gGmbH and funded by the Central Innovation Program for Medium-Sized Businesses (ZIM), DROOFF has developed a latent heat storage system for stoves in 2020 after 3 years of research and development work.

The DROOFF latent heat accumulator

A latent heat accumulator (also called phase change or PCM accumulator) is a heat accumulator that stores a large part of the energy supplied to it in the form of latent heat. It is the mode of operation of the well-known hand or pocket warmers: When the storage unit is charged, special salts or paraffins are melted as the storage medium, absorbing a great deal of energy (heat of fusion) in the process. A (e.g. mechanical) impulse causes the liquid to solidify again, whereby the storage medium releases the previously absorbed large amount of heat back into the environment as solidification heat.


For a wood-burning stove, this means that containers are filled with a PCM storage material around the combustion chamber. During operation, the thermal energy of the stove liquefies the storage medium. And the energy remains stored there for days. Only "at the push of a button" is the storage tank discharged, as the liquid crystallises again and the molten heat continues to supply the installation room of the stove with cosy warmth for a long time after the last operation (or even the next morning).

We are currently working on the optimisation of individual parameters such as service life, costs or size of the storage elements in order to achieve series production readiness as soon as possible. We will keep you up to date!