Passive Vents For Canopy

[Baldguy]

I recently changed lighting and now have more heat buildup in the canopy. I do have computer type fans on both ends of the 4' x 2' canopy but they are not keeping up anymore. I'd like to drill holes in the top of the canopy to help passively cool that area. I'm thinking a bunch of 2" or 3" holes covered with brown plastic vent covers. The top of the canopy is hinged at the back and I lift it to feed or do maintenance. I basically lift a front corner and put a prop under it to hold it open. When I lift there is little flex in the 3/4" plywood. The question is how many holes could I drill without compromising the strength of the top? Also, how many holes of what size would I need to make a noticeable difference? 10, 20, 30? Any and all thoughts would be appreciated. Tia.

 

[redfishbluefish]

Canopy fans should always be blowing inward with holes to allow the hot air to escape. Are you fans set up that way?....with holes to allow hot air to escape?

 

[ca1ore]

I used convection to cool a smaller hood (12x30 footprint) and just a single 2” hole proved sufficient.

 

[Baldguy]

Thanks for both replies. I now have both fans bringing air into the canopy. I've only got one hole for air to exit. I'll see how that works then I'll add a few holes on top if needed. Thanks again!

 

[count krunk]

Canopy fans should always be blowing inward with holes to allow the hot air to escape. Are you fans set up that way?....with holes to allow hot air to escape?

Are you sure about this? Computer cases have fans pulling in cooler air and pushing out warmer air.

It would make sense to me to have tanks doing the same. One fan pulling in cool one fan pushing out hot

 

[fattiremike]

I just took the top of my canopy off completely. I've been running that way for years.

 

[redfishbluefish]

Are you sure about this? Computer cases have fans pulling in cooler air and pushing out warmer air.

It would make sense to me to have tanks doing the same. One fan pulling in cool one fan pushing out hot

If you scratch you head and think about this for a minute, you'll eventually realize that XX cfm IN and XX cfm OUT (requiring two fans) produces the same turnover as one fan blowing IN at XX cfm. One fan IN and one fan OUT is a wash. By having both fans blowing IN, you've doubled the turnover in the canopy.

As far as having them blow IN, this extends the life of the fan by not having moist, salt laden air, flowing over and around the fan. They will last longer.

Hope this helps.

 

[Antics]

It also depends on the canopy design. If it's an open bottom static air will be less of an issue. A computer case is fully (besides venting) enclosed so it's more important to balance air in vs air out so that the fans aren't fighting one another basically.

 

[WVNed]

Could you put in a short prop that creates a 1/2 gap along the lid? That would tell you if drilling the holes is going to work.

 

[Baldguy]

Thanks for everybody's thoughts and suggestions. I turned one of the fans around so both are pushing air in and that seems to have helped a lot. It does make sense that having both fans blowing in would double the cooler air inside the canopy. I think I'll also drill a few holes so convection can do it's thing. I did think about taking the top off completely but my wife and I both like the finished look of the enclosed canopy.