Heating with ice: This is what the municipality of Tutzing is planning for its middle school, which is currently being completely renovated. The indoor swimming pool, which is no longer used, becomes an ice storage facility. The new heating system could become a flagship project, says Mayor Ludwig Horn.
Tutzing
– The community of Tutzing, which is currently in the middle of renovating its middle school, is launching a remarkable project. She solves the question of future heating for the school and the adjacent buildings with the help of an ice storage system. The pool for this already exists: it is the old swimming pool under the school gymnasium.
“We have agreed on an ice storage system for the heating concept for the middle school,” announced Tutzing’s mayor Ludwig Horn at the meeting of the main, finance and works committee. The swimming pool is used for this.
“We wanted sustainable heating,” added Horn when asked. An interim solution was also discussed, and the local council has now agreed on the ice storage facility. “This could be a flagship project,” he said.
The principle: The energy for heating or cooling the school buildings is obtained from the water in the ice storage. “Cables will be laid in the swimming pool to serve as heat exchangers,” explained Michael Engelhart, a planner from Weißenhorn who was responsible for the heating/ventilation/sanitary system for the school renovation. “A frost-proof liquid flows through this, which removes the heat from the water in the storage tank. Even if the water temperature drops below freezing point, the system can continue to generate energy.” Because: During the freezing process, in which the water temperature is constantly at zero degrees, the so-called crystallization energy is released. “The energy that the water releases in this phase is enormous,” said the expert and gave a comparison in the conversation: “With the heat that the water releases during the freezing process until it solidifies completely, you could use the same amount of water from zero Heat to 80 degrees.”
The heat reservoir of the ice storage is constantly recharged by so-called absorbers installed on the roof, Engelhart explained. “In addition to heating and year-round hot water preparation, the system is particularly suitable for cooling buildings in the summer.” The middle school therefore also receives cooling, which is almost free thanks to the ice storage.
It is planned to switch on gas heating for peak periods during a particularly cold winter. “The old elementary school is a listed building, so you can’t simply replace the windows or insulate the building,” said Engelhart. “The middle school, on the other hand, will operate without fossil fuels.”
The local council also examined alternatives. An air heat pump, for example, but it was far too loud in the middle of town, said Horn. “If we burn biomass, we would have the emission problem of particulate matter,” he said. The ice storage, on the other hand, is noiseless and the necessary cistern is already in place. The costs for the initial investment are significantly higher than with other heating systems, but the follow-up costs are significantly lower, as Horn says. There are also subsidies that almost put the additional costs into perspective, says Engelhart.
As an expert, Engelhart is fully behind the Tutzinger ice storage facility. “With a water volume of 1,300 cubic meters, the ice storage is really a showcase project and very innovative for a school campus.” He was there when Horn and the planning team looked at the Weilheimer Stadtwerke ice storage. It has been around since 2015, but at 50 cubic meters it is significantly smaller.
The Tutzinger swimming pool has not been in operation since 2010. At the time, the local council considered the renovation effort to be too high. The bathroom and hall had previously been closed due to the risk of collapse. The hall was then renovated, but the bathroom, which was already a subsidized operation, was no longer renovated. The swimming pool dates back to 1969, it was renovated in 1989 - and when the renovation was due in 2010, there was no money.