The Caldameg heating system was used to replace the gas boilers at the Anne Frank Montessori school in Doesburg. This system consists of a CO2 heat pump of 34kW in combination with three PCM buffer tanks of 500 litres. The application of PCM balls in the buffer vessels increases the capacity to approximately 4500 litres. Because this CO2 heat pump can heat up to 80 degrees Celsius, it was not necessary to replace the existing installation/radiators.
This makes the 1970 school building in the Doesburg district of Ooi the first existing school building that can be heated without gas. The gas boilers are still stuck so they can be used in case of calamities. The Doesburg city council has also used the renovation of the building to make it more sustainable with the installation of PV panels. In this way, the building will be made gas-free and thus reduce greenhouse gas emissions.