Long time no update... some words on glue...

A project log for Entropy Wheel Heat Recovery Ventilator

Rotating perforated disk counter-flow heat exchanger maintains indoor temperature while exchanging fresh outdoor air.

bryan-williamsBryan Williams 01/26/2015 at 05:470 Comments

The clips are definitely the way to go here... I have finally completed the original glued wheel (just the wheel, not the whole prototype) and it's quite the chunk of plastic, 10" cylinder x 14" long, almost two full 4x8ft sheets. The glue is messy (3M High Strength #90) and slow owing to the tack time between layers. Took 3 cans and that means $40-45 just for adhesive. Not to mention the special cyanocrylate I bought that was even more expensive, and have yet to use. Disadvantages beyond cost is that it leaves "boogers" blocking some tubes owing to the squeeze-out, and layers vary in length a bit, which is bad for air sealing. I need to cut off a tenth of an inch or so from either end to clean the boogers & even it up. HOW to do that is going to be a trick as it needs to be neat and perpendicular and my bandsaw doesn't have a 10" capacity. The belt sander might work to even things up, but I know it will friction-melt and perhaps clog openings more. The there's the issue of mounting it in a balanced fashion so it spins easily with a small motor.

I'm still trying to work out the best type of motor. Stepper-sized BLDC's I have seen run very expensive, like $80. I might initially use a stepper but I expect that to be much too loud. Not sure a hobby BLDC would be much better as they "cog" also and typically use non-sinusoidal coil excitation, unlike brushless servo motors that run with sinewave drive instead. If you have sourcing suggestions, please message me!