Counterflow Air to Air Heat Exchange

thingiverse

This initial design showcases a printable parametric counterflow air-to-air heat exchanger (HX). It typically features two sets of interleaved plates with supply air passing through one set and extract air flowing through the other for efficient heat transfer. The unique aspect of this design involves a component that merges airflows into rectangular channels, guiding them in different directions for heat exchange. However, the printed version only displays three HX parts, making it challenging to understand its functioning. The bottom section features a regular grid with alternating airflow directions for heat transfer; length, width, height, and channel layout are customizable via the openscad module 'HX'. The middle part directs air from separate channels into parallel paths, while the top section carries it to different sides of the HX for supply and extract purposes. Replication of the middle and top bits is required on the bottom end for multiplexing/demultiplexing. Two versions, small and usable, are demonstrated with the HX in place. Outside air enters through the upper triangle's right side, warms up as it passes through the heat exchange, and exits the left side of the lower triangle before entering the building. Conversely, extracted air from the building enters the bottom triangle, ascends through the HX, transfers heat to incoming air, and leaves via the upper triangle's left side. The design is parameterized for flexibility in determining channel numbers within the HX array. Future steps include breaking down components for experimentation with different lengths and materials (printed or extruded) of the HX array, assessing efficiency using a work harness (e.g., muffin fans), an insulated enclosure, and potential microcontroller-based fan control and instrumentation. To operate this heat exchanger, download 'shapes.scad' and generate the desired size from the scad file.