"Do as I say, not as I do." -- Michael Moore
April 22nd, 2004
Penn State University, in cooperation with Unilever and Ben & Jerry's, demonstrated an environmentally-friendly thermoacoustic chiller today that uses helium gas and acoustic pressure waves instead of fluorocarbon refrigerants. The system also, apparently, has no moving mechanical parts such as valves or compressors, which should mean increased reliability.
There is a floor HVAC register behind my chair in the space that serves as our office. Since the register was thin sheetmetal (one might say "shitmetal") and was collapsing to the extent that we were afraid a chair caster or someone's foot was going to go through it, I made a new register consisting of a 7" x 12" steel plate about .100" thick, drilled with a hexagonal array of fifty-three 0.5" holes on 1" centers. (It works great, far superior to the original register. All holes are fully deburred and chamfered on both sides, of course.)
One of the kids just dropped half of a plastic Easter egg on the new register, where it landed open-end down. The register is smooth enough that the half egg acts as a plenum, and it is now merrily drifting around the register on its own little bottom-fed air cushion, bouncing off the wall of stationary air around the register every time it gets close to the edge. (Yay Bernoulli!)