Well, I can quantify this¡ a couple of houses ago, I had a 25x35 shop with 8¡¯ ceilings, built out of Integra block (very hollow block with poly foam sprayed in the cavities), then insulated with 1 1/2¡± more foam ?as I furred out before the drywall. I had the 1.5hp Oneida DC set in the adjacent garage and originally had the exhaust empty into the garage. I found that in the summer with the A/C set to 80?, I could turn on the DC and suck all the cool air out of the shop in about 5 minutes, the temp would rise to about 90? and 3 tons of AC couldn¡¯t cool it down.?
So, I had to revise the plan and poke a hole in the wall and re-route the exhaust back into the shop. Even with that, the time the air spent in the warmer garage caused the AC unit to labor much more than the times when the DC wasn¡¯t running. AC unit was on a 40 amp breaker¡ doesn¡¯t take long to burn through a lot of $$$$ running that kind of amperage.
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On May 23, 2020, at 10:22 AM, mark thomas <
murkyd@...> wrote:
On Sat, May 23, 2020 at 09:22 AM, Brian Lamb wrote:
In AZ where we have massive heat loads in the summer, exhausting air outside is a foolish endeavor
Maybe, but foolish is relative.? My point is that it might be worth quantifying, since everything is a tradeoff.
For exampling, using my previous estimate of costing $2.50/hr to make up for lost DC exhaust cooling, that might be a very "foolish" loss rate for 24x7 operation like a house ($18k/year), but less foolish for a DC running an hour per day ($900/yr)
One could say it's foolish to have a 2400 sq ft shop.? Or maybe 2400 ft the sweet spot, and 5,000 ft is foolish.? Or foolish to set themostat at 68 instead of 75.? ?Or foolish to spend $200k on hobby equipment.?? Some people think it's foolish that humans inhabited Arizona.??
I'm just saying, without some attempt to quantify and put it into one's personal context, just declaring it infeasible or foolish seems not very well grounded.
