Temperature Control - Intake Vs. Exhaust

[2k1Toaster]

Hello all,

I have a bit of a different setup than most here, I am not growing anything. I have electronics inside a tent but they make a bunch of heat and I'm struggling to keep them cool when the ambient outside is 80F or higher basically.

The setup: A 60x60x80 tent. There are 2 intakes being driven by 12in ~2000cfm fans. Then there are 2 exhausts being driven by the same style of 12in ~2000cfm fans through 25ft of ducting then 2 10in boosters (~1200 cfm) right before being blown outside via 10in ducts.

I basically have x12 1600W heaters in there, like a 12 lamp setup I guess. I'd like to keep temps inside the tent closer to 100F or below. Right now they're running about 120F to 130F which is on the hot side. In the winter, they run about 80F with 40F air intake. There is currently no AC and it is not really feasible to add.

My question is what do you all usually do when you have excess heat? Do you blow more intake in? Or do you pull more out with more exhaust? I realize this is a deceptively simple question, but in general.

 

[1diesel1]

Hello all,

I have a bit of a different setup than most here, I am not growing anything. I have electronics inside a tent but they make a bunch of heat and I'm struggling to keep them cool when the ambient outside is 80F or higher basically.

The setup: A 60x60x80 tent. There are 2 intakes being driven by 12in ~2000cfm fans. Then there are 2 exhausts being driven by the same style of 12in ~2000cfm fans through 25ft of ducting then 2 10in boosters (~1200 cfm) right before being blown outside via 10in ducts.

I basically have x12 1600W heaters in there, like a 12 lamp setup I guess. I'd like to keep temps inside the tent closer to 100F or below. Right now they're running about 120F to 130F which is on the hot side. In the winter, they run about 80F with 40F air intake. There is currently no AC and it is not really feasible to add.

My question is what do you all usually do when you have excess heat? Do you blow more intake in? Or do you pull more out with more exhaust? I realize this is a deceptively simple question, but in general.

Basically what you have is a computer room in a tent. A sizable one at that. Best to install a mini split system. You’ll have a condensing unit out side and a wall unit inside with a line set for supply. A lot of calculations need to be taken into account. Or you can put a package unit outside and duct supply and return to cool the tent.

 

[1diesel1]

Or put a vent on one side and a fan on the other to push hot air out.

 

[GT21]

Does the tent have flaps on the bottom

 

[2k1Toaster]

Basically what you have is a computer room in a tent. A sizable one at that.

Correct.

Best to install a mini split system. You’ll have a condensing unit out side and a wall unit inside with a line set for supply. A lot of calculations need to be taken into account. Or you can put a package unit outside and duct supply and return to cool the tent.

I don't think that's feasible. Rule of thumb is 1KW of heat needs 1KW of cooling. I'm making about 54000 BTU of heat. That's a 4.5ton system just to replace to keep it ambient. A 5 ton system could keep up if run 24/7/365 which would consume an additional 17.5KW running 24/7 which in my area is over $1500/month to cool the tent. I've already got x3 5 ton units cooling the house and my electrical is basically maxed out until the utilities trench a new line to a new transformer for the area. Then I have to trench and upgrade my utility at my expense once they finish that.

Or put a vent on one side and a fan on the other to push hot air out.

That's what I've got. 2 intake vents at the bottom at the front. 2 exhaust vents at the top. About 4000cfm intake and exhaust. When I shut it down tonight to do some cable maintenance, I timed it took 3 minutes to go from 45C (113F) in the tent to 27C (80F) in the tent which was ambient.

Does the tent have flaps on the bottom

It does. Right now I actually am running with the main door opened to keep in in the 42C to 48C range. I get over temperature warnings higher than that.

Two intakes, one on the left, one on the right, both on the bottom:

Then two exhaust vents on the top in the back:

I am thinking I need another exhaust. I currently have negative pressure since I mounted the exhaust fans directly above the tent and the intake fans on the end of the intake ducting. But more negative pressure may be needed. I just didn't know if the wisdom here on the forum had a general rule of thumb. But I guess it is not really possible to run 12 high power lights in a 5ft x 5ft tent, so this is somewhat unique.

 

[heisen]

You need at least 3500 btu for every 1kw of heat generated.you didnt say how many watts your running.your 1kw math is off for 1kw cooling.im running almost 5000 watts of lights and chillers and no way in hell my ac is running at 5kw on a 20 amp breaker.its pulling around 1100 watts on 220 at full blast.
I hope your not an accountant.

 

[GT21]

Sweet!!! Flux capacitors to get us to 1.28 gigafucks!!!

Close off the round holes... Open the rectangle ones. Put 2 blowers up top. Close doors... pull air through the rectangle and blow it out the top of the tent.

 

[MIMedGrower]

An intake fan will help the exhaust fans work better. My room cooled a few degrees going from passive to active intake. But I still need ac in summer to cool far less heat than you are creating.

Maybe lose the tent? Easier to keep bigger spaces cooler.

 

[oldskol4evr]

Correct.



I don't think that's feasible. Rule of thumb is 1KW of heat needs 1KW of cooling. I'm making about 54000 BTU of heat. That's a 4.5ton system just to replace to keep it ambient. A 5 ton system could keep up if run 24/7/365 which would consume an additional 17.5KW running 24/7 which in my area is over $1500/month to cool the tent. I've already got x3 5 ton units cooling the house and my electrical is basically maxed out until the utilities trench a new line to a new transformer for the area. Then I have to trench and upgrade my utility at my expense once they finish that.



That's what I've got. 2 intake vents at the bottom at the front. 2 exhaust vents at the top. About 4000cfm intake and exhaust. When I shut it down tonight to do some cable maintenance, I timed it took 3 minutes to go from 45C (113F) in the tent to 27C (80F) in the tent which was ambient.



It does. Right now I actually am running with the main door opened to keep in in the 42C to 48C range. I get over temperature warnings higher than that.

Two intakes, one on the left, one on the right, both on the bottom:

View attachment 805869

View attachment 805870

Then two exhaust vents on the top in the back:

View attachment 805871

I am thinking I need another exhaust. I currently have negative pressure since I mounted the exhaust fans directly above the tent and the intake fans on the end of the intake ducting. But more negative pressure may be needed. I just didn't know if the wisdom here on the forum had a general rule of thumb. But I guess it is not really possible to run 12 high power lights in a 5ft x 5ft tent, so this is somewhat unique.

this might be stupid,but just found out recently,by putting the exhaust fan inside the tent instead of outside,its a direct suction going out and not restricted by vent hose.
i was using my exhaust fan and filter on top a platform to mount them too,pushing hot air out and threw filter,when i moved it back in the tent to draw instead of push,my temps went way down,i also leave the back and side intake windows open and wall surrounds them to keep light out,just a shot

 

[bicky studs]

imo more exhaust!!
all pulling hot air from the top. be sure to have enough cool intake too. just crank em up n watch the tent walls....blown up more exhaust...sucked in more intake....etc

this might be stupid,but just found out recently,by putting the exhaust fan inside the tent instead of outside,its a direct suction going out and not restricted by vent hose.
i was using my exhaust fan and filter on top a platform to mount them too,pushing hot air out and threw filter,when i moved it back in the tent to draw instead of push,my temps went way down,i also leave the back and side intake windows open and wall surrounds them to keep light out,just a shot

im pulling the air direct from top ventholes with fan mounted outside tent.... u dont need the fan inside, but agreed its way better pulling it out, my fan is quieter like that too... i just made the assumption its straining less n therefore using less power.... nfi if it is true. i never measured it pushing....

 

[heisen]

this might be stupid,but just found out recently,by putting the exhaust fan inside the tent instead of outside,its a direct suction going out and not restricted by vent hose.
i was using my exhaust fan and filter on top a platform to mount them too,pushing hot air out and threw filter,when i moved it back in the tent to draw instead of push,my temps went way down,i also leave the back and side intake windows open and wall surrounds them to keep light out,just a shot

Because your not just pulling air from the intake b every crack an air leak including the zippers.

 

[2k1Toaster]

You need at least 3500 btu for every 1kw of heat generated.

Correct. A BTU is 3412KW.

you didnt say how many watts your running.your 1kw math is off for 1kw cooling.im running almost 5000 watts of lights and chillers and no way in hell my ac is running at 5kw on a 20 amp breaker.its pulling around 1100 watts on 220 at full blast.
I hope your not an accountant.

Also correct, had a brain fart. In the past rule of thumb calculations, you size the equipment though so that it doesn't have to run 100% duty cycle. You want some good overhead. Hence the 1:1. Brain farted into 100% duty. When it is 40C outside you still want the inside to be 18C or cooler, that's a lot of BTUs. In this case

For you it seems a 17000BTUh/1100W = 15 SEER unit.

The real math: I am running 19200W. I'd need 65513 BTU to keep it cool. A 5 ton system is 60000BTU. 60000BTUh at 15 SEER would be 4000W, $350 a month at $0.12/KWh.

Sweet!!! Flux capacitors to get us to 1.28 gigafucks!!!

Close off the round holes... Open the rectangle ones. Put 2 blowers up top. Close doors... pull air through the rectangle and blow it out the top of the tent.

Already doing that. But can't keep the door closed as the heat generated overwhelms the exhaust. Room temps rise, boards shut off to thermal warnings.

An intake fan will help the exhaust fans work better. My room cooled a few degrees going from passive to active intake. But I still need ac in summer to cool far less heat than you are creating.

Maybe lose the tent? Easier to keep bigger spaces cooler.

Unfortunately in a bigger space the house heats up to 80F to 85F. Manageable but really annoying. That room is directly underneath most of the main level flooring, so the heat transfers straight through. Without the tent, the 3 other AC units get overwhelmed trying to cool the house. Too many stupid windows.

I think I'll go for a third exhaust. Keep the 2 intakes, make more negative pressure. 2 active intakes plus the passive. Build a cold/hot wall in the middle maybe with some mylar fabric. Or maybe just get a tent that is divided and cut holes into it.... Hmm...

 

[heisen]

Correct. A BTU is 3412KW.



Also correct, had a brain fart. In the past rule of thumb calculations, you size the equipment though so that it doesn't have to run 100% duty cycle. You want some good overhead. Hence the 1:1. Brain farted into 100% duty. When it is 40C outside you still want the inside to be 18C or cooler, that's a lot of BTUs. In this case

For you it seems a 17000BTUh/1100W = 15 SEER unit.

The real math: I am running 19200W. I'd need 65513 BTU to keep it cool. A 5 ton system is 60000BTU. 60000BTUh at 15 SEER would be 4000W, $350 a month at $0.12/KWh.



Already doing that. But can't keep the door closed as the heat generated overwhelms the exhaust. Room temps rise, boards shut off to thermal warnings.



Unfortunately in a bigger space the house heats up to 80F to 85F. Manageable but really annoying. That room is directly underneath most of the main level flooring, so the heat transfers straight through. Without the tent, the 3 other AC units get overwhelmed trying to cool the house. Too many stupid windows.

I think I'll go for a third exhaust. Keep the 2 intakes, make more negative pressure. 2 active intakes plus the passive. Build a cold/hot wall in the middle maybe with some mylar fabric. Or maybe just get a tent that is divided and cut holes into it.... Hmm...

2 24k 21.5 seer mini splits on each wall would cool that thing no sweat and would not be that bad on the electric bill.

 

[MIMedGrower]

Correct. A BTU is 3412KW.



Also correct, had a brain fart. In the past rule of thumb calculations, you size the equipment though so that it doesn't have to run 100% duty cycle. You want some good overhead. Hence the 1:1. Brain farted into 100% duty. When it is 40C outside you still want the inside to be 18C or cooler, that's a lot of BTUs. In this case

For you it seems a 17000BTUh/1100W = 15 SEER unit.

The real math: I am running 19200W. I'd need 65513 BTU to keep it cool. A 5 ton system is 60000BTU. 60000BTUh at 15 SEER would be 4000W, $350 a month at $0.12/KWh.



Already doing that. But can't keep the door closed as the heat generated overwhelms the exhaust. Room temps rise, boards shut off to thermal warnings.



Unfortunately in a bigger space the house heats up to 80F to 85F. Manageable but really annoying. That room is directly underneath most of the main level flooring, so the heat transfers straight through. Without the tent, the 3 other AC units get overwhelmed trying to cool the house. Too many stupid windows.

I think I'll go for a third exhaust. Keep the 2 intakes, make more negative pressure. 2 active intakes plus the passive. Build a cold/hot wall in the middle maybe with some mylar fabric. Or maybe just get a tent that is divided and cut holes into it.... Hmm...

Sounds like you will get it under control.

One thing. I had to close off my passive intake that was left when I installed the fan. It was messing up the airflow and leaking room air back through.

I run a lung/veg room with a window ac and the intake fan goes through the spare bedroom wall and into the flower room next door about 10” above floor level. I wanted the intake as close to the floor as possible for coolest air.

I use an 8000btu window unit. I also have a 10k in my living room that still plugs into a regular 110v wall outlet.

Hope any of this info helps. Good luck cooling. I feel I spend an awful lot of time worrying about it. Lol.

You could get a portable in the room ac. But it has to vent somewhere too.