Heat pump and buffer stratification? That’s not just for St. Nicholas!

Dear friends of the Arnsberg practical seminar, On 6 December 2024, we worked with the bbz Arnsberg to prepare the next Arnsberg Practical Seminar 2025 . For the first time, we loaded our tried-and-tested rSTOR buffer storage tank via a newly delivered DUV box 2×3 with a heat pump and recorded the whole process thermographically.

With the DUV box 2×3 (DUV = double switch valve), a buffer tank can be loaded in two zones for hot water and heating operation. The result almost knocked us off our chairs: First, the upper part of the buffer was loaded cleanly in two passes from about 25 °C to about 37 °C and then to 49 °C; then the whole process was repeated in the lower zone without any mixing of the two zones being observed!

We have shortened the thermography video of the test to 34 seconds in fast motion.

We would be happy to discuss in more detail why you need a buffer and what stratification has to do with the efficiency of the heat pump (COP, JAZ) at our next practical seminar in Arnsberg 2025 on Tuesday 11, Wednesday 12 or Thursday 13 February 2025. There, we will demonstrate the new experiment live, together with the already familiar experiments “Condensing boiler efficiency without hydraulic separator” and “Thermostatic balancing of air heater and single-pipe heating circuit”.

To register, visit – there are a maximum of 40 places available per day (minus the 15 master students on Tuesday, 11 February 2025)!

For energy consultants: You can have your participation recognised with 8 DENA points by the HWK Südwestfalen (subject to a fee). Another tip for anyone who wants to come: Wear warm jackets and scarves; the heat pump turns the laboratory rooms into a draughty cold room!