WP stands for Warming Pump. Heated water is pumped into a big isolated tank filled with water and PCM. (BufferTank).
PCM stands for Phase Change Material.
Ice Is also a good PCM but too cold to warm your house.
Melting 1 kg ice of zero degrees Celcius into water of zero degrees needs the same amount of energy to heat that same kilo water up form zero degrees C to ca 80 degrees C !!
Now we take something like candlewax. It melts at about 55 degrees and can store much more energy than ice..We put it into the buffertank, the more, the better. With the PCM we can use a much smaller tank with the same energy volume.
Shifting the (hot and cold) water water sleeves into the PVC insulation tube.
Making the Isolation box
In the front part of the attic, the buffertank is planned. With 12cm PIR panels, a insulation box was created. The round tank will be placed into it.