SUNTHERM – storage of excess heat

The need for flexibility of renewable energy in the energy system is increasing. For that reason, the entrepreneurial company SUNTHERM has developed a prototype of a heat battery based on salt hydrate dissolved in vegetable oil.


The heat battery can store solar heat and excess heat from air/water heat pump installations for up to a day. Furthermore, the heat battery can hold excess heat equivalent to approximately 1,500 liters of hot water corresponding to approximately 12 hours of energy consumption for heating of a conventional single family house in the winter. The heat battery requires the same physical space as a standard kitchen cabinet of 60x60x200 cm.


Insero is participating in a demonstration project that focuses on testing and documenting SUNTHERM’s technology and prototype in practice. In this project, which will continue until January 2018, the prototype will be fully developed to a 0-series that will be installed in 5-10 private households along with a heat pump. As part of the project, analyses will be made on how this installation is to be controlled and monitored in order for it to be included in the Smart Grid and intelligent energy system of the future.


In the households, the project will test and demonstrate how best to store heat when the price of electricity for the heat pumps is high. In addition, the project will provide the partners with operating experiences, thus making it realistic to strive for a performance that is up to 30% better than a standard air/water heat pump.


During the project, Insero will handle the project management as well as dissemination and reporting of the results from the tests. SUNTHERM will deliver the prototype and the technology for the project, and Neogrid Technologies provides the aggregator to be used for controlling the consumption of the private consumers.


  • The project is funded by ForskEL
  • The project will continue until January 2018
  • The project partners are Neogrid Technologies, SUNTHERM and Insero


Claus Weber

Project Specialist

Insero Energy

+45 41 77 01 57

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