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AC_Hacker · 06-28-10, 06:05 PM

(NOTE: My original post said 'polyethylene', my error. I should have said 'polypropylene' and have corrected this post.)

Today, I picked up my black plastic sign-board material.

I explained to them that I was going to stack the 12" square pieces and that I wanted to end up with with a 1 foot cubed stack. Since the material is 4mm thick, it turned out that I required about 72 pieces, which worked out to about two and a third 4' x 8' pieces to make one heat exchanger.

I was a bit off on the prices in my previous post, but the Corex charge for black was $15.25 per 4 x 8 sheet, and the cutting charge was $15, so the overall cost to me was $45.50. They had a bit of scrap laying about, so they didn't charge for it.

Since I'm trying to build a $700 Energy Recovery Ventilator for far less, $45.50 cost for the core seems reasonable, but I do think it could be done for less.

When I was stacking the 12" square sheets (alternating the orientation of each layer) , I noticed that most of the sheets had a slight 'cup' to each sheet, so I pit them all 'cup-side' down. My resulting pile had less 'spring' than my original, randomly oriented pile, so that should mean that the sheets are in closer contact.

I have done some searching for polypropylene cement, and it doesn't seem to exist. So, it looks like some kind of pressure arrangement will be the way to go. If anyone has any other ideas, I'm all ears. I suspect that even with fiters, periodic cleaning of the core will be required.

Best Regards,

-AC_Hacker

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06-28-10, 06:05 PM	#52
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	1 Cubic Foot Polypropylene DIY HRV Core... (NOTE: My original post said 'polyethylene', my error. I should have said 'polypropylene' and have corrected this post.) Today, I picked up my black plastic sign-board material. I explained to them that I was going to stack the 12" square pieces and that I wanted to end up with with a 1 foot cubed stack. Since the material is 4mm thick, it turned out that I required about 72 pieces, which worked out to about two and a third 4' x 8' pieces to make one heat exchanger. I was a bit off on the prices in my previous post, but the Corex charge for black was $15.25 per 4 x 8 sheet, and the cutting charge was $15, so the overall cost to me was $45.50. They had a bit of scrap laying about, so they didn't charge for it. Since I'm trying to build a $700 Energy Recovery Ventilator for far less, $45.50 cost for the core seems reasonable, but I do think it could be done for less. When I was stacking the 12" square sheets (alternating the orientation of each layer) , I noticed that most of the sheets had a slight 'cup' to each sheet, so I pit them all 'cup-side' down. My resulting pile had less 'spring' than my original, randomly oriented pile, so that should mean that the sheets are in closer contact. I have done some searching for polypropylene cement, and it doesn't seem to exist. So, it looks like some kind of pressure arrangement will be the way to go. If anyone has any other ideas, I'm all ears. I suspect that even with fiters, periodic cleaning of the core will be required. Best Regards, -AC_Hacker * * * Attached Images Last edited by AC_Hacker; 06-28-10 at 07:16 PM..