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District energy

District heating


Private households test new heat battery

14. November 2017

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If we are to succeed with the transition from fossil fuels to renewable energy, there is a need for more flexibility in the energy system. In the project ”Storage of electricity and heat in salt hydrate”, we demonstrate and test the prototype of a new heat battery that is able to store solar energy and excess heat from heat pumps for up to 24 hours.

Heat battery and heat pump

The project will install the heat battery and a heat pump in a number of private households to gather data, and to analyse how the installations should be controlled and monitored to be a part of the intelligent energy system of the future. The expectation is that the battery can improve the performance of the heat pumps with up to 30% without increasing the price.

Salt hydrate dissolved in plant oil

The new heat battery has been developed by the company Suntherm, and it is based on salt hydrate dissolved in plant oil. The way the battery works is by storing solar heat and excess heat from air/water heat pumps for up to 24 hours, so it can be used flexibly at other times of the day. The battery can contain excess heat equivalent to 1,500 litres of hot water, which is enough to heat up a normal single-family home for 12 hours in the winter.

Live tests

The homeowners that are part of the project play an important role in testing how you store the heat in the best possible way in order to save it for when the price of electricity for the heat pumps is high and the electricity production is low. The reason for involving real consumers in the project is that the maturation of new technologies does not happen behind the desktop, but in the real world where new technologies and business models interact with the society around us.

"By testing the product with real users, we get their unreserved opinions and feedback from the start. That helps us develop the most optimal solution that not only produces heat when it is cheapest, but also meets the users’ requirements for comfort," Says Morten Veis Donnerup, CEO at Suntherm and project owner.

Insero’s role

During the project, Insero handles project management as well as dissemination and reporting of the measurement results from the tests. Furthermore, we are responsible for settling the participants' heat consumption during the project.

Facts about the project

  • Budget: DKK 5.6 million and supported by ForskEL
  • Project periode: 2016-2018
  • Partnere: Neogrid Technologies, Suntherm and Insero