We have finished the heat exchanger at last! It took three days to build, putting layers upon layers of thin plastic film and spacers to create 50 layers of air “ducts”! 25 for each of the two air streams, separated alternatively in the layers. It was quite difficult to get the plastic film to stay straight and not wobble! We are definitely won’t be using this choice of materials again!
Also we have put up the first fan ready to pull the “old” air out of the living quarters and the garden room. The ducting will be along the ceiling in the garden room and pop through the doorway into the living quarters. The ducting will be 75mm high and 300mm wide to create a fairly low profile square shape, painted white. This is only temporary while the temporary living quarters are there!