Cooling a 150w Hps?

SHONOFF98

Well-Known Member
I have a 2x2x4 tent with a 150w HPS and the tent is in a closet so the temps get pretty high up there especially now that its spring/summer. I do have the HTG 4in Fan with carbon filter and I also have another 6" fan blowing air into the tent. With the closet open it is at about 82-83ish when the house temp is 74-75ish. So I was wondering if there was an easier way than a cooltube for the light. I did check out DIY cooltubes but I'm exactly sure how it would work with my light it is a SunSystem 150w HPS and it already comes in the hood/fixture. Would a piece of plexiglass taped over the light cause and problems and reduce the heat?
 

billy4479

Moderator
i wouldnt mess with the fiber glass ...id try to see if you cant find colder air for your intake .......
 

billy4479

Moderator
"Would a piece of plexiglass taped over the light cause and problems and reduce the heat?" last sentence of your post
 

SHONOFF98

Well-Known Member
Let me try to get a pic up here....I have a 6" fan like an oscillating one but it doesnt move and I have the big 4" 170 cfm HTG fan exhausting out the top. I'm experimenting right now with how I should position the 6" fan....should it be exhausting or used for intake and should it be inside or out
 

billy4479

Moderator
well the problem with putting that 6 as an exhuast is your carbon filters is on that 4 that would make the carbon filter wortless right id maybe invest in a inline 6 inch fan and some flexable air ducting probley run you 40 or 50 at home depot ... Or try putting that 6 in fan you got pointing strait up in your box like grabing air from the floor and blowing it to your ceiling
 

goten

Well-Known Member
well 1 thing is you got a 6" fan blowing in but no exhaust though

Exhaust helps more then intake

you need more air going out then what you have going in

once you start exhausting more air out then what is going in your temps will start to drop

Here are a few examples

COMPARISON OF CABINET DESIGNS

1. Simple Cab - one chamber, no scrubbers or restrictions to airflow.



CFM = 3.16*Watts/deltaT
where deltaT = 10 *F

Intake Area = 2 x Exhaust Area
Fans - Axial/Computer Fans due to minimal pressure loss

Example: A 400 W HPS in a 3 x 3 x 4 cabinet needs 126 CFM of cooling for a 10*F temp rise above room temperature.
The 36 cu ft cabinet is ventilated at over 3 Air Changes Per Minute.

Pro:
Easy to build
Fans - axial

Con:
plants stink up the place
plants are stressed by too much airflow at 3 ACpM.
The plants only need 5 Minutes per Air Changes (MpAC). That's 0.2 Air Changes per Minute (ACpM).

For you hydro guys, this means more rez changes and nute swings because the plants will be drinking alot to keep
up with the dehydration caused by living in a wind tunnel.

2. Simple Cab with Scrubber



CFM = 3.16*(Total Watts)/deltaT
where deltaT = 10 *F

Intake Area = 2 x Exhaust Area
Fans - Blower or Inline for high pressure drop across scrubber

Example: A 400 W HPS in a 3 x 3 x 4 cabinet needs 126 CFM of cooling for a 10*F temp rise above room temperature.
The 36 cuft cabinet is ventilated at over 3 ACpM. The hard part is to match an oversized fan/scrubber combination to get the right airflow.

This design and the simple growbox have cooling requirements that exceed the ventilation requirements of the growchamber by at least 15x. Way too much stress on the plants by living in a wind tunnel.

Pros:
single fan design less equipment to purchase

Cons:
Fan operates at 50% or less airflow due to large pressure drop across scrubber
High SP requires a Centrifugal Blower, won't work with Axial fans
Fan/Filter Curves are needed to determine working airflow
Scrubber is many times larger than Ventilation specs to get light cooling airflow
many restrictions in multi chamber designs require special attention to intakes and intrachamber airflow
high airflow for to cool lights creates stress on plants
high airflow through scrubber reduces effectiveness
Centrifugal Blower and Inline Fans are very noisy 60-70 db

3. Simple Cab with CoolTube/Ventilated Hood and Inline Scrubber



CFM = 3.16*(Total Watts)/deltaT
where deltaT = 20 to 30 for cooltube

Intake Area = 2 x Exhaust Area
Fans - Blower or Inline for high pressure drop across scrubber

Example: A 400 W HPS in a 3 x 3 x 4 cabinet needs 63 - 42 CFM of cooling for a 20-30*F temp rise in the exhaust temps with a 1-2 *F rise in the growbox.

The 36 cuft cabinet is ventilated at 2 ACpM. The hard part is to match an oversized fan/scrubber combination to get the right airflow.

The cooltube design is a big improvement over the Simple and Simple cab with Scrubber designs as the overall airflow is considerably less. However 2 ACpM is still 10x over what the plants need and will stress out the plants from excessive airflow.

Pros:
single fan design means less equipment to purchase
Cooltube/Ventilated Hood improves cooling significantly by trapping most of the heat in the hood
Less airflow through the grow chamber compared to the above designs but still high.

Cons:
Fan operates at 50% or less airflow due to large pressure drop across scrubber
High SP requires a Centrifugal Blower, won't work with Axial fans
Fan/Filter Curves are needed to determine working airflow
Scrubber is many times larger than Ventilation specs to get light cooling airflow
many restrictions in multi chamber designs require special attention to intakes and intrachamber airflow
high airflow for to cool lights creates stress on plants where only 0.2 ACpM is needed
high airflow through scrubber reduces effectiveness
Centrifugal Blower and Inline Fans are very noisy 60-70 db
 

goten

Well-Known Member
well the problem with putting that 6 as an exhuast is your carbon filters is on that 4 that would make the carbon filter wortless right id maybe invest in a inline 6 inch fan and some flexable air ducting probley run you 40 or 50 at home depot ... Or try putting that 6 in fan you got pointing strait up in your box like grabing air from the floor and blowing it to your ceiling
I also have another 6" fan blowing air into the tent.



hes using that 6 " for intake not exhaust my man
 

billy4479

Moderator
Let me try to get a pic up here....I have a 6" fan like an oscillating one but it doesnt move and I have the big 4" 170 cfm HTG fan exhausting out the top. I'm experimenting right now with how I should position the 6" fan....should it be exhausting or used for intake and should it be inside or out
yeah but he has a oscilating style 6 inch fan plus his 4 inch already has a carbon filter if it was as simple as switch your 4 inch with the 6 that be tight
 

goten

Well-Known Member
yeah but he has a oscilating style 6 inch fan plus his 4 inch already has a carbon filter if it was as simple as switch your 4 inch with the 6 that be tight
My bad i did not see that post

but never the less that 6" is more then likely blowing more cfm then the 4"

he should use the 6" for exhaust and the 4" for intake

he still needs more air exhausted out then what is being brought in

but i have not read it all , so i might be over looking something

But he should be able to get an idea of what to do from the diagram i posted above
 

SHONOFF98

Well-Known Member
I think everyone is getting confused. I have this fan mounted at the top by bungee cords with ducting exhausting the air out of the top of the tent. I also have this fan sitting in the bottom of the tent.
 

goten

Well-Known Member
I think everyone is getting confused. I have this fan mounted at the top by bungee cords with ducting exhausting the air out of the top of the tent. I also have this fan sitting in the bottom of the tent.
if your fan is just sitting in the tent then its not really helping cooling its just circulating the hot air

you could put a 6inch clip on fan from walmart in there blowing between canopy and light i bet you'll get down to the 75-78 range just my thoughts and cheap too 10 bux and will make a world of difference lower temps and stronger stemage

Maybe also a DIY Cooltube to combine with fan blowing between lamp and canopy and you could drop that light right on top of em and get some real nugs going

i have a 150 in my cab also

and i just have 3 ac fans

2 for exhaust and 1 for intake and my temps stay right at 80 degrees
 

goten

Well-Known Member
Going by the 2nd pic it looks like your temp is 82 degrees

your good with 82 , i try to aim between 75 and 80

but my temps with my 150 stays around 80 also , sometimes it hits 82 , 83 degrees

turn your fan up more to blow more towards the light and the exhaust

heat rises `es

so instead of blowing the heat around at the bottom

blow it towards the top , then your temps should drop a few more degrees
 

SHONOFF98

Well-Known Member
Yea it is 82 in the pic but that was with the tent open, but I found a 4in axial fan that I think I'm throw in for another exhaust.
 
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