Ceiling fan vs through-wall-mount fans

[thoraxe]

I'm progressing with my shop build and will end up with a building that's longer than it is wide, but not by much (38x48). So that's ~1800sqft on the ground but it's a farmhouse style building with a high gable in the middle (3:12 gabled roof). 14' wall height. This is outside Atlanta, Georgia where it can regularly get up to 90F+

There will be 2 large roll-up doors (10x10) at one of the 38' ends, and right now no other openings other than a people door. Metal building, insulated walls.

I'm trying to figure out what to do for airflow, since there will only be the 2 rollup doors. I was thinking about doing the industrial-style wall mounted fans with the gravity louvers. The building builder uses these:

https://www.designcomponents.com/wp-content/uploads/2018/01/In-Stock-Wall-Fans.pdf

A ceiling fan isn't really going to promote flow through the building very well, and, much like a cross-breeze in a house, this is why I'm thinking wall fan.

38x48x14 is 25536 cubic feet, and each of those 36" fans moves 10,000CFM. It seems like moving the entire air volume of the building every two minutes (1 fan, 10,000CFM, 25,536 CF of space) is excessive, but I don't know what kind of formulas should be used.

I did a quick search of the forum for "fan" and "wall fan" but mostly got HVAC or ceiling fan results.

Would love your thoughts.

 

[thoraxe]

Quick internet search lead me to https://www.engineeringtoolbox.com/air-change-rate-room-d_867.html

That site also has https://www.engineeringtoolbox.com/garage-ventilation-d_1017.html

Air change out rate for a warehouse is listed as anywhere from 6-30 times per hour, but, on the garage specific page, they say 4-6 for "storage garage" and 20-30 for "repair garage". While I do intend to work on the vehicles, I don't expect to be driving them in and out all that often, or running them inside.

For a storage garage with a recycle factor of 6:
Their "fresh air supply" formula says I would need 153,216 ft3 of air flow per *hour*. So, if a fan moved 10,000CF per *minute*, that's 600,000CF per *hour*, right? So isn't just one of these 36" fan units oversized by 390%?

For a repair garage with a recycle factor of 20:
The formula says I would need 510,720 of air flow per hour. So, the 10,000 CFM fan would move 600,000 CFM per hour, so it's still bigger than required.

But having only one fan, even if it hits the flow required, seems like it wouldn't provide much comfort? Would two 5,000CFM fans be "better"?

Would just putting some mechanical louvers on the far wall and using large portable fans blowing out the door be "better"?

 

[thoraxe]

Replying to my own thread because that's how I do. I looked at Big *** Fans and other ceiling fan threads and saw the price of even the smaller BAF. I also saw a comment about just moving around hot air.

I then looked at mini split pricing, not that I would specifically buy this unit, but:
https://hvacdirect.com/perfect-aire...plit-heat-pump-w-wifi-230v-2pamshqc36-16.html

Granted with my super high ceilings this may not be enough BTUs to cool the space. But this is 1/2 the price of a BAF and is not significantly more than the through-wall-louver van.

Now, that being said, I might still go with a through-wall fan, but I think that I would do a mini split before I spent a ton on adding electrical and other work for many ceiling fans....

 

[Jackfre]

Check this out
https://www.tjernlund.com/cool_breeze_garage_cooling_fan.htm
I know these folks well. They are an old line American manuf. Nice people, nice products

I don't like ceiling fans. I'm always sticking a board or a piece of pipe in them.

 

[thoraxe]

Check this out
https://www.tjernlund.com/cool_breeze_garage_cooling_fan.htm
I know these folks well. They are an old line American manuf. Nice people, nice products

I don't like ceiling fans. I'm always sticking a board or a piece of pipe in them.

This is a metal building without an interior ceiling. There's no attic to blow anything into. If it just went out the roof, it's no different at that point than a through wall fan.

 

[Mike Folks]

One or more of the passive roof "Turbine' vents? Or a Solar powered one?

 

[Sureshot]

I worked in a shop in Oklahoma with those fans and found them near useless. I think the issue is that the slab gets so warm during the day that it can't dump the heat during the night running the fans and was therefore hot all the time. The job entailed working all odd hours and I found the big floor fan the best. If I were to build a shop in this area I would put heat lines in the slab and circulate the water year round underground. Cooling in the summer and warming in the winter.

Edit: Our shop was around 40x60x16 with a 14x14 door in each end.