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 Ped
Relax
Registered: 05/31/13
Posts: 62
Last seen: 11 years, 3 months
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 Recapturing HID Heat? 
#673894 - 06/08/13 04:15 PM (11 years, 6 months ago) |
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Hey all,
I'm curious about cooling my HID, and potentially capturing the bulb's heat and dumping it into my home's ventilation system, which will help save on energy costs during the winter. I did some digging, but couldn't find any posts or articles which pertained to these specific circumstances.
The hypothetical setup is as follows:
- 42" x 48" x 84" space, (14 square feet, 98 cubic feet).
- 600 watt digital ballast, dimmable, running a 600 watt bulb.
- 300 CFM fan exchanging air in the garden.
- 170 CFM fan to cool the bulb through a typical air-cooled reflector. This will be a completely separate airstream.
The idea is to dump the heat from the bulb into the house's ventilation system during the winter time. This is to capture the heat and save on heating costs.
I am not referring to an HVAC system, as this house is not heated with a forced-air furnace.
The in-house ventilation system is a Fantech SHR-1504. Its function is to mix and to circulate dehumidified fresh air into the house, creating a fresh and mold-free internal environment.
The Fantech system operates at 150 CFM (max 170 CFM). I want to modify this system to accept heat from my 600 watt HID bulb. My wish is to dump this heat into the airstream coming from the Fantech and into the rest of the house. I will attempt match the unit's native CFM as closely as possible so as not to generate back pressure against its fans, but the CFM from my bulb will be about 20 CFM higher.
My questions are:
- Is 170 CFM enough to cool a 600 watt HID bulb in this space?
- By dumping this additional air flow into the system, will I be increasing its static pressure in a detrimental manner?
- Is this idea liable to cause the smell of marijuana to fill the entire house? (HID-cooling and tent intake/exhaust will be two separate, self-contained systems, but not necessarily sealed)
- Is this modification likely to damage the existing ventilation system, or compromise its effectiveness in any way I haven't considered?
- Is there anything I need to know before making this modification?
Here is a graphical representation of what I want to do:
I appreciate any insights. Thanks!
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Edited by Ped (06/08/13 06:30 PM)
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TomCollins
Registered: 10/06/09
Posts: 2,943
Last seen: 1 year, 9 days
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Re: Recapturing HID Heat? [Re: Ped] 1
#673929 - 06/09/13 07:51 AM (11 years, 6 months ago) |
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In regards to the adequacy of your HID cooling:
HID lights can run without any cooling - it's not like they'll blow up. The cooling is for the plants - that said, from your diagram, it looks as though you're venting air into the HID enclosure from outside the tent. So the fact that you're not pulling air from inside the tent (which will be slightly warmer than outside the tent), thereby pulling cooler and less humid air over the bulb, would compensate for lack of airflow.
It also depends on the size of your grow space; that is, how powerful the fan should be. From your setup, it should not be an issue at all, since you essentially have two cooling systems running inside of the tent - your plants will not get too hot with that combined cooling.
The best way is to test the system, and see how warm temperatures get inside the tent in maybe a 6 hour period. If you're not going above 27C then it's completely adequate.
In regards to heating your house:
I read about your ventilation system. It works by capturing heat from the exhaust being pulled out of your house, and then using that heat to heat air coming into the house. So you would need to hook up the HID exhaust to the air being fed into the air exchanger.
Like so:
But think about it: hooking the exhaust to your air system, would no doubt "help" to heat your house. The amount of heat contributed by your HID to the overal heating of your house would be so marginal, I don't think it would cover the cost of the construction work you would have to do. You can't really heat a house with an HID bulb, even if it's 600watt.
In addition to that, the system works by capturing the heat of the aggregate air exhaust going out of your house - your HID heat exhaust will be apart of the aggregate exhaust no matter what you do.
Hope this helps.
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andyistic said:
Ok so let me bring you idiots up to speed.
The admins are tired of this shitfest being made the joke of the weed community on the Internet.
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Ped
Relax
Registered: 05/31/13
Posts: 62
Last seen: 11 years, 3 months
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Re: Recapturing HID Heat? [Re: TomCollins]
#673937 - 06/09/13 11:16 AM (11 years, 6 months ago) |
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That is helpful, thank you.
This entire setup would be in the basement. There are no intakes for the exchanger in the basement. The exchanger forces air into the basement, which escapes through small vents on two of the opposing walls. This is because the basement tends to be much more humid in the summer time, and much dryer in the winter time. Because of this, venting the bulb directly into the basement would mean most of the heat from the bulb is ejected outside.
The house is quite small, but being newer it's quite well insulated. We're talking about 1800 square feet altogether. I have no direct experience with HID bulbs, but understand that they are hot enough to cause serious burns if they are touched. Even if the heat contribution from the bulb is negligible, if there is no harm in directing it throughout the house then I can't see why I wouldn't.
The duct work I'd be tapping into runs directly above the tent. It would involve replacing a single curved joint with a "Y" joint, just a few minutes in total. If there is no harm, I will pursue this course.
Thanks for your insights!
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TomCollins
Registered: 10/06/09
Posts: 2,943
Last seen: 1 year, 9 days
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Re: Recapturing HID Heat? [Re: Ped]
#674070 - 06/10/13 07:22 AM (11 years, 6 months ago) |
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Quote:
Ped said:
That is helpful, thank you.
This entire setup would be in the basement. There are no intakes for the exchanger in the basement. The exchanger forces air into the basement, which escapes through small vents on two of the opposing walls.
Sorry confused. Two small vents on opposing walls in your basement, pumping air into the basement? Is this correct?
Quote:
Ped said:
Because of this, venting the bulb directly into the basement would mean most of the heat from the bulb is ejected outside.
How is the heat being ejected? Is it passing through some type of ventilation? Through the wall? How does it get ejected outside?
Quote:
Ped said:
The house is quite small, but being newer it's quite well insulated. We're talking about 1800 square feet altogether. I have no direct experience with HID bulbs, but understand that they are hot enough to cause serious burns if they are touched. Even if the heat contribution from the bulb is negligible, if there is no harm in directing it throughout the house then I can't see why I wouldn't.
Imagine turning on a hotplate in your basement indefinitely - if you touch the hot plate you could potentially get very serious burns, yet it will not do much for the ambient temperature of your house.
No doubt there are costs involved and a little time as well - but all for a redundant exhaust? My two cents: just not worth it. To each his own.
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andyistic said:
Ok so let me bring you idiots up to speed.
The admins are tired of this shitfest being made the joke of the weed community on the Internet.
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Ped
Relax
Registered: 05/31/13
Posts: 62
Last seen: 11 years, 3 months
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Re: Recapturing HID Heat? [Re: TomCollins]
#674097 - 06/10/13 12:58 PM (11 years, 6 months ago) |
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>> Sorry confused. Two small vents on opposing walls in your basement, pumping air into the basement? Is this correct?
The basement is kept at positive pressure and has no exhaust intakes for the exchanger. There are two small, screened vents with backdraft dampers which constantly vent air outside. Basement air is not involved with the exchanger.
>> How is the heat being ejected? Is it passing through some type of ventilation? Through the wall? How does it get ejected outside?
Through the exterior vents described above.
>> Imagine turning on a hotplate in your basement indefinitely - if you touch the hot plate you could potentially get very serious burns, yet it will not do much for the ambient temperature of your house.
Yeah, this makes sense. This modification wouldn't be made until November anyway. By then I'll have experience with the bulbs and will be able to decide if it's worth it. It sounds like it won't be, though.
The guy at the hydro store made it sound like if I didn't vent the bulb straight out the window, the entire basement would become a sweltering tropical rainforest. Perhaps he was overstating things.
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TomCollins
Registered: 10/06/09
Posts: 2,943
Last seen: 1 year, 9 days
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Re: Recapturing HID Heat? [Re: Ped]
#674106 - 06/10/13 02:28 PM (11 years, 6 months ago) |
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Theoretically it's not good to do, in practice in the industry it does not make much difference - save the very exceptional situations.
Besides, any heat produced by your exhaust will rise up into the house.
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andyistic said:
Ok so let me bring you idiots up to speed.
The admins are tired of this shitfest being made the joke of the weed community on the Internet.
|
Ped
Relax
Registered: 05/31/13
Posts: 62
Last seen: 11 years, 3 months
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Re: Recapturing HID Heat? [Re: TomCollins]
#674115 - 06/10/13 04:39 PM (11 years, 6 months ago) |
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I must admit I'm a bit confused about the HID heat thing.
On the one hand, I've been told to vent the bulb directly outside, lest I turn the entire basement into a sauna, and I've been told not to use a fan with plastic blades, because they will degrade from heat exposure.
On the other hand, I've been told that the heat isn't very significant at all, and that it's merely good practice to cool the bulb well for the sake of the garden and the garden only.
I suppose I'll just have to set it up and see for myself!
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trichome
THC
Registered: 07/20/08
Posts: 104
Last seen: 10 years, 10 months
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Re: Recapturing HID Heat? [Re: Ped]
#674995 - 06/17/13 02:59 PM (11 years, 6 months ago) |
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Quote:
Ped said:
I must admit I'm a bit confused about the HID heat thing.
On the one hand, I've been told to vent the bulb directly outside, lest I turn the entire basement into a sauna, and I've been told not to use a fan with plastic blades, because they will degrade from heat exposure.
On the other hand, I've been told that the heat isn't very significant at all, and that it's merely good practice to cool the bulb well for the sake of the garden and the garden only.
I suppose I'll just have to set it up and see for myself!
The former is more correct than the latter, but this is relevant to overall wattage. A 150w hps in a cool basement might be fine without ventilation, but more watts = more heat. i.e., ten 1,000w lights in a small room would need LOTS of ventilation and would likely catch fire if not adequately ventilated.
More airflow is better than less, and HID bulbs get really hot.
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