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calif123

parabolic
Dealing with heat from parabolic

25 posts in this topic

First, thanks to all who posted information on this forum. Very helpful. I have just started doing environmental testing for my setup and I am currently fighting heat issues, wondering if anyone can spot any mistakes. My setup is:

 

  • Dr120 in a smallish room (with 1 window left ajar and 1 door closed with gaps frame in the allow some air flow through room)
  • 600W magnetic ballast (placed outside of room)
  • 1m parabolic reflector (raised to the ceiling as much as possible).
  • 6 inch CAN fan (470m3) for an exhaust. Exhaust vented through approx 3 meter ducting to a discreet window adapter (6inch circle to rectangle converted which ive taped to the bottom of the window sill. Its not perfect, but I put a blind down the close it off as much as possible in the vertical direction, and also have a curtain behind the blind which I can pull across to close off the horizontal, so that the only gaps are just around the rectangular exhaust, and also small gaps around blinds. This is to maintain some room airflow.
  • 4 inch CAN fan (270m3) for an intake as well as opening some passive vents to regulate pressure to just about maintain negative pressure to ease fan stress. The 4 inch active intake is routed up through the attic (via about 15 meters ducting - its ridiculous it even works at all with this poor fan) and out to fresh air. My outside duct is fixed at 4 inch, otherwise I may have considered going from 6inch exhaust-4inch intake to 8inch exhaust-6inch intake.
  • SMS fan controller hooked up to both the intake/exhaust fan.
  • little clip on fan in the tent.

 

For example today I started with 19 degrees room temp /55 RH with nothing on. I then fired everything up and the temp started rising and the humidity started falling. Nothing I do seems to be able to get the temps down from around 32-33 deg C in the tent, with about 23 deg C in the room. I hung some wet teatowels in there and this only bumped the RH levels up a few percent before the teatowels dried. Now one meter reads "--" and the other 21%.

 

 

  • What is the consensus on parabolic reflectors? It seems most people think they are cooler than horizontals, but I have also read that they restrict heat flow (which I can feel with my hand).
  • Are paras used mainly in bigger spaces with more space around the shade to suck away the heat? If they can be used in smaller tents, is the heat flow issue not an issue - How does one get around this? - Ive seem people blowing air at the reflector, which I tried, but no luck.
  • If the solution to this is more extraction, then how can I limit the reduction in humidity, as I am already struggling with humidity. I suppose any output of the humidifier will just get sucked up by the exhaust fan. Whilst my teatowel idea worked a bit, i fear it is not sustainable :) Would the tent get much more naturally humid from having plants in there when the time comes? 
  • What kind of temp differential would you expect as normal in the above setup between the tent and the room the ten is in? 9-10 degC difference with intake and exhaust running flat out seems high.

 

Thanks for any suggestions info in advance guys. This forum has been really helpful so far, just reading everyones comments. I'm trying to avoid an AC, as then I will be heating up the world with my slightly ajar window and recently modified door frame with air gaps (for the exhaust, I have no other option to vent out window as there is no outlet in the roof for a 6 inch, and I don't want to blow it directly into the loft, possibly blowing air back into the house).

 

 

It doesn't strike me that with 600W in a 1.2m tent with outside temps of 19degC/54 % RH I should be having problems, but alas, I am! I am pretty sure it is because I am effectively double wrapping the light with a tent in a room, but its all I can do for now.

Cheers

 

 

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8 inch extractor fan or drop to 400w might help

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1 minute ago, sidders said:

8 inch extractor fan or drop to 400w might help

 

Do you have any idea on what kind of temperature drop is achievable with that wattage drop? I assume it would be significant?

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Posted (edited)

It's not the parabolics fault it's been hot recently, it would still be hot with most reflectors. Just run your lights at night and leave the window open a bit, that usually works for me.

 

If you still want lower temps, then get LED or CMH lighting over HPS.

Edited by cypher79
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8 minutes ago, calif123 said:

 

Do you have any idea on what kind of temperature drop is achievable with that wattage drop? I assume it would be significant?

sorry mate bit stoned .. running lights thru the night should sort your temps as cypher has said

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Posted (edited)

I think you need to upgrade your extraction fan/filter  to at least a 6 inch one, to be honest.

ohh scrub that I see youre using a 6 inch one. in which case, is it possible to draw yourintake from a colder source, like under the floorboards?

Edited by badbillybob

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43 minutes ago, cypher79 said:

It's not the parabolics fault it's been hot recently, it would still be hot with most reflectors. Just run your lights at night and leave the window open a bit, that usually works for me.

 

If you still want lower temps, then get LED or CMH lighting over HPS.

 

This is the kind of verification I'm looking for. I've not used other reflectors before (1st timer) and so struggling for my own reference. Cheers. More and more I'm thinking night shift may be best.

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Open the door, Get an inlet fan, and tap into air from a cool place. Get rid of the shade, the tent is a reflector anyway, and heat dissipates a lot easier without. I am running 1200w in a 1.5m2 at the moment with no shades, temps are spot on.

 

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12 minutes ago, badbillybob said:

I think you need to upgrade your extraction fan/filter  to at least a 6 inch one, to be honest.

ohh scrub that I see youre using a 6 inch one. in which case, is it possible to draw yourintake from a colder source, like under the floorboards?

 

Its on the second floor so I cant really go under. I've got a compartment for attic intake access nicely tucked in to a room cupboard. My next move is either to seal window and move exhaust through attic to another room in the house. But i'd rather not cut through another hole if the window being open is not the cause of the issue. Do you chaps find the need for AC? If so, how ineffective is it with the window open and a mild breeze coming in and out of the room. Obviously this will depend on a lot of factors, the BTU of the cooler, size of room etc, just looking for any indications. Cheers.

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For my self in currently in a lift with Tempsford occasionally topping 31 ( using 400hps)   with 22 outside. For my self it's a issue of extraction as my 4 inch rvk is only pumping out 220 cubic meters per hour. My plan.is to use the 4 inch r be as the intake with cool air from a outside source then up grade to a better extraction (looking at a 8 inch rvk) if ya can get the air flow and extraction right the rest will follow all though my girls are still looking good with 3 weeks left before the flush. Once they're done i.will up grade the equipment 

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26 minutes ago, mad elf said:

Open the door, Get an inlet fan, and tap into air from a cool place. Get rid of the shade, the tent is a reflector anyway, and heat dissipates a lot easier without. I am running 1200w in a 1.5m2 at the moment with no shades, temps are spot on.

 

Wow, 1200w in 1.5m2. From where I am, that seems like a lot of heat to manage in this current weather. You sound like you have some experience removing the reflector. I will try that on my next cycle to see what happens. What is your air setup and how do you manage the heat? 

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Posted (edited)

I just had a thought, but I'm surprised I could not find something like this after a quick search. Do parabolic reflectors exist with a vertical bulb mount that also includes an air attachment directly above the vertical bulb? (with no glass anywhere). If I had ones of those I could hook it up to my filter and then extraction fan, and get the best of both worlds. I assume that this thing does not exist for a reason? Cheers

Edited by calif123

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An extraction of at least 700m3 would be better this time of year. Make sure the filters extraction rate is at least equal to the fans rate,but pref higher. I have 600w in a 1.2m tent,760m3 fan (canfan as well) and a 900m3 filter,Ive had temps as high as 30c,but generally cope ok.

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Posted (edited)

I checked temps through the night, and they were better, but not great. (30-31). This morning I removed the parabolic and the temps started to rise, but by less than with the reflector. I think the room must be accumulating heat. I've put a fan under the window, so that I have the exhaust and the fan blowing air out the window. Might stimulate air flow in the room. 

 

@ursus1000 For the increase in extraction, how do you manage humidity at that extraction rate? With the 6 inch setup I have at the moment, even at 80% power my humidity drops like a stone once its running?

Cheers

 

Edited by calif123

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Ok, I have gave up on the parabolic reflector with my current extraction rate and the season. Even with a fan, no change in temps, hovering around 29-30. I'm a bit limited with the exhaust as it has to be discreetly output to a window, so I have a round to rectangle type adapter that sits just under the frame, but allows enough space ahead of it to exhaust out. I'm struggling to find these things for 8 inch though.

 

I figure the next best thing to do is an air cooled hood running through the current extraction fan. I may struggle with that as it is not a powerful 6 inch fan (470m3) but I will give it a go because its the path of least resistance. If that doesn't work, my next step would probably be to upgrade my low powered exhaust fan to a high powered version 760m3 and use that for the existing 6 inch exhaust ducting. I would then need to upgrade my current filter as it is the little one, rated to only to 600m3. Darn this hobby is getting expensive! 

 

Then I think I could use the low powered 6 inch fan as a dedicated exhaust fan for the light - would this work:   TENT->FILTER->FAN->LIGHT->WINDOW. I guess this would also help the main fan with exhausting more air out of the tent?

 

Thats way getting too many fans for my liking.... 

Bring on winter!

Cheers

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