insulating exhaust system?

[bquiggle]

Hi, first question for this site, living at 9000', with winter temps down to -40 or more how do I do an exhaust system for the garage?
Mostly to exhaust welding, and other various fumes when needed but don't want cold air flowing or radiating back into garage when not in use.
Any ideas or suggestions ..........Thanks

 

[Torque1st]

First you must realize that when operating that exhaust fan is pulling that -40 air in through every crack and crevice. Otherwise most people build an insulated box with insulated doors for the fan. Use louvers that open and close on the fan exhaust.

 

[buddyboy]

you should do a search for air to air heat exchangers.

you should try to capture some of that heat as it's leaving your shop in your make up air.

not sure if there is anything out there that has a high enough cfm but worth a shot.

 

[e-tek]

Torque pretty much described the system I have. I built a ridgid foam insulation box that I can pop into the fan hole which covers the fan, to stop cold air from coming into shop through the louvres. When I want to use the fan I just lift the box at the bottom, propping it up with a short stick.
Of course, when the fan is running, the make-up air is coming from the cold outside air. Even with 2- 9x16 foot doors my shop is airtight enough that I HAVE to crack a window when I run the fan. Therefore I only run the fan on low and just long enough to exhaust the smoke/dust/exhaust I want to clear.

 

[jklingel]

HRV would, of course, be great, but if you are exhausting smoke from stick welding, I suspect the HRV would plug up pretty quickly. I think you are going to have to just pump the heat out with the exhaust. If your garage is pretty tight, I would install a make-up air vent so that you are not pulling air back into your shop's walls with the negative pressure. That could be a problem when it is warm enough to have humidity outside. j

 

[bquiggle]

Thanks guys, the insulated box idea is pretty much what I was looking for, but after looking up air exchangers am thinking that might be a possibility worth looking into more,
I am not planning on running it often just when creating fumes, vapor and dust or after a chili dinner ......
jklinhel. I am not too worried about pumping heat out, just not wanting cold air coming in when the system isn't running.
Thanks again