Air to air heat exchanger using cardboard
Cardboard is not the best heat conductor but it is cheap and plenty-full and easy to work with.
This unit consists of alternate layers of cardboard, laid out to cause the fresh and stale air to flow in channels in opposite directions so that the heat is exchanged gradually, this results in high efficiency.
The bulk of the exchanger is sheets of cardboard glued together with cardboard strips to create channels for the air to flow through.
This unit consists of alternate layers of cardboard, laid out to cause the fresh and stale air to flow in channels in opposite directions so that the heat is exchanged gradually, this results in high efficiency.
The bulk of the exchanger is sheets of cardboard glued together with cardboard strips to create channels for the air to flow through.
The ends of the stack are cut at an angle to facilitate construction of the manifolds. As the lower picture demonstrates fresh air flows through the corrugations and the stale air flows between the sheets of cardboard in the space made by the spacer strips.
Manifolds are made by bending cardboard into "U" shapes and gluing them on the ends of the stack. build the stack and manifolds to match the size of your fans.