Interview with Malte Weidemann

Ice-cold energy

The energy concept for the TUP extension was developed by the Weidemann planning office in Bad Sassendorf. Owner Malte Weidemann has been planning heat pumps for over ten years, most of which are powered by renewable energy. In particular, he has made a name for himself as a specialist in ice energy storage technology. This is also increasingly being used in district heating networks with heating loads of up to 4.5 megawatts.

As in the first construction phase, ice energy storage technology is also used in the new TUP campus building in conjunction with the ClimaLevel Multiboden. Have you also examined alternative concepts?

Weidemann:
The client is very satisfied with the energy concept of the existing building, both in terms of energy consumption and comfort. We have oriented ourselves on this. As an alternative to the ice energy storage system, we examined the use of a ground collector under the building. However, since we also have a relatively high cooling load in the new building, as in the existing building, the ice energy storage system was the more efficient solution, as it supplies the cooling energy practically free of charge.

The ClimaLevel Multiboden was chosen because of the positive experiences in the existing building. I am absolutely convinced by the system and have been working with ClimaLevel GmbH for over ten years. The multi-floor air conditions the rooms optimally and particularly efficiently. The system is perfectly suited to heating and cooling buildings with low-temperature systems such as heat pumps and ice energy storage systems, as it uses the screed mass as an additional heat exchanger. In this way, the incoming air is always close to room temperature. The high air volume flow at the outlets also ensures very good cooling distribution in the room. In the existing building, the meeting rooms are additional air conditioning split units installed. We were able to do without these in the new building.

They have been planning all types of heat pumps for years and largely avoid the use of fossil fuels. What role does ice energy storage play in your concepts?

Weidemann:
We only use fossil fuels to cover peak loads in combination with heat pumps. The ice energy storage system is the key element for harnessing and temporarily storing renewable energy. Compared to other storage systems such as water heat storage tanks, it can store around 80 times as much energy. It always shows its strengths when cooling energy is required in addition to heating. But ice energy storage technology is also an efficient solution for heating only.

However, the investment for this technology is considerable. When will this pay for itself?

Weidemann:
The high investment is a deterrent at first, but on average the additional costs can be amortized after ten years. If the proportion of cooling energy required is particularly high, as is the case at the TUP campus – in some cases cooling is also required from February/March – this value is significantly lower.

What projects with ice energy storage technology are you currently planning?

Weidemann:
We are currently planning three warehouses with an adjoining office for a logistics company with an ice energy storage system that is based on is designed for an output of just under 500 kW. The technology is also gaining ground in the development of local heating networks. We are preparing feasibility studies for BEW applications with ice energy storage technology in districts throughout Germany. We have just submitted a BEW application for an efficient heating network with an ice energy storage tank that is regenerated by a waste water heat exchanger. For another supplier, we are developing a district solution based on three ice energy storage units with a total output of 4.5 megawatts, which does not use any fossil fuels at all.