| 摘要 |
<p>Adjacent plastic twin-wall boards 11 of a stack of such boards are separated by foam spacers/seals 12. In use stale air is passed through the flutes of the twin-wall boards and is in heat exchange with fresh air flowing through cavities defined between adjacent boards spaced apart by the seals/spacers. The seals/spacers are preferably made of double sided, self adhesive, compressible plastic foam strips. The stack of twin-wall boards is in use assembled into a ventilation unit which comprises boxes housing fans 33 for forced flow of stale and fresh air through respective flow paths in the stack.</p> |
