Ways to deal with heat from halides

[FishWife]

When we hung the lights for our 175g bowfront (a 4 250w halide fixture that came with our tank) last night, we realized that things are going to heat up quickly in our tank (and that ballasts are LOUD and HEAVY monsters!). We have the luxury of having most of our equipment behind a wall in our mudroom, that backs to our display room.

 

The display room is small: picture the front office of a typical newer colonial home in MD. The room is about 10' X 10' with one AC/Heat vent in the room. We think that once those halides are on for hours/day, that room (especially in summer) will heat up pretty quickly. The mud room is even smaller, and opens to our garage. Solutions we're considering:

 

1. Put an inexpensive window AC unit into the mudroom, mounted in the wall above the door to the garage and venting to the garage. Cool that room way down, and as water comes through the mudroom, it will be chilled and filtered at the same time.

 

2. Buy a chiller. (Power usage? Expensive? Plumbing?)

 

3. Install small fans behind the tank to vent into the mudroom (noisy?) and then another, larger fan to vent from the mudroom to the garage.

 

4. Other ideas/concerns we haven't thought of?

 

Thanks in advance, as always!

Edited January 7, 2008 by FishWife

[dhoch]

1. Put an inexpensive window AC unit into the mudroom, mounted in the wall above the door to the garage and venting to the garage. Cool that room way down, and as water comes through the mudroom, it will be chilled and filtered at the same time.

 

Without cooling down the room the tank is in or cooling the mud room down a LOT this is not going to be the best (in my mind)

 

2. Buy a chiller. (Power usage? Expensive? Plumbing?)

 

This is a good option

 

3. Install small fans behind the tank to vent into the mudroom (noisy?) and then another, larger fan to vent from the mudroom to the garage.

 

Sounds like a lot of work and you may need the chiller anyway

 

4. Other ideas/concerns we haven't thought of?

 

Is there sump? If so where? Where is the thermostat for the house (is there a room specific one?).

 

You are going to have to: Either Vent that air or cool the air or cool the water down.

 

You can put fans on a sump or tank, but that will cause more water into the air... may work better in the garage if the sump is there.

 

More details.

 

Dave

[ctenophore]

Typically the most efficient thing to do is cool/heat water directly. If you cool the room, you gain heat through the walls, floor, and roof in addition to the tank. So you might require X BTUs to cool your tank, but when you cool your room, you need to remove X+Y BTUs (the amount needed for the tank, plus the room itself). This might be offset somewhat by a more efficient A/C unit compared to a chiller, but even a really nice A/C (high SEER, expensive) is going to cost more to run than a small chiller. I believe window units are approx. the same efficiency as water chillers.

 

The heat gain from halides is from irradiance not convection. So venting the hot air above your lights isn't going to do much. Halides give off a lot of infrared light (IR) which is basically just heat for our purposes. That, plus the high PAR, equates to increased water temp.

 

If you are feeling DIY/clever, you might experiment with a short polyethylene water loop run outside your house during the colder months, you could get the effect of a chiller probably 4-5 months out of the year. Run it with a little pump (MJ1200?) and put it on your temp controller (Ranco? AC3?), and plumb it so that it gravity drains when not powered, to prevent freezing in winter nights. Sort of a cheapo reverse solar collector.

 

Hope this helps

Justin

 

Oh, forgot to mention, it's best to keep your chiller outside. Otherwise, the heat it removes just goes right back into the room, adding to the load on your house A/C. It's worth plumbing through the wall if possible.

[FishWife]

Without cooling down the room the tank is in or cooling the mud room down a LOT this is not going to be the best (in my mind)

This is a good option

Sounds like a lot of work and you may need the chiller anyway

Is there sump? If so where? Where is the thermostat for the house (is there a room specific one?).

 

You are going to have to: Either Vent that air or cool the air or cool the water down.

 

You can put fans on a sump or tank, but that will cause more water into the air... may work better in the garage if the sump is there.

 

More details.

 

Dave

 

Yes; large (50+) g sump in mud room, along with a frag tank and a separate refugium (same water supply; fuge dumps into display, frag tank dumps into sump) plus a planned (future) 75g in kitchen on OTHER side of mud room.

 

No thermostat in room; it's centrally heated/cooled w/house: one vent.

 

THANKS for answers!

[Rascal]

I understand what Justin is saying about irradiance vs convection, but in my experience (I have 3 x 250 MH in an open-backed canopy + a remote sump in the basement) a couple of 4" computer fans in the canopy that run when the MHs do helps considerably.

 

Other things I do:

 

Fans blowing across sump. I am partial to the "turbo" style AC fans you can get at Target/Walmart usually. This is by far the most economical and easiest solution if it works. If nothing else it will save electricity costs by decreasing the amount which you have to rely on your chiller. Since this speeds up the rate of cooling via evaporation, you need to make sure you can deal with the extra humidity. I use a dehumidifier which drains into the house's waterproofing system.

 

Chiller - as others have mentioned needs to be placed outside or (what I do) vented to the outside using ductwork. Otherwise all of the heat removed from the water will just heat up the air in your mudroom, and all you'll be doing is wasting electricity. I did some sloppy ductwork and cut a hole in the crawl space next to the drier vent. I also installed a small 4" inline duct fan that comes on whenever the Chiller does. Other than noise and space, the biggest drawback here is that they are electricity hogs.

[dhoch]

I understand what Justin is saying about irradiance vs convection, but in my experience (I have 3 x 250 MH in an open-backed canopy + a remote sump in the basement) a couple of 4" computer fans in the canopy that run when the MHs do helps considerably.

 

I bet your getting that cooling from evaporation, not pulling the hot air away from the bulbs.

 

Dave

[Rascal]

I bet your getting that cooling from evaporation, not pulling the hot air away from the bulbs.

 

Dave

 

Maybe. They don't push a lot of air though, probably around 45-60 cfm total. I can barely feel it if I put my hand more than 12" or so from the fans. It's just enough to circulate the air. If I remember right, before I got a chiller there was about a 2 deg temp difference if the MHs were on without the canopy fans, which seems like a pretty large effect for such small fans if the only cooling is due to evaporation. This may be partly due to the way I set up my canopy though. I have a large aluminum reflector that runs across the top of the canopy, as kind of a back-up to the individual reflectors on each MH. Without the canopy fans turned on this reflector gets hot to the touch - so much so that I put some insulating tape around the cords where they contacted it because I was worried they would melt. With the fans on it is just warm. It is possible that I get some additional radiated heat from this reflector. Kind of like I created an oven. Oh well, seemed like a good idea at the time.

[Almon]

I also have two fans in my canopy, one blowing in and one blowing out, and I have glass between the canopy and the water. I believe this prevents a substantial rise in water temperature and I don't believe it's from evaporation.

 

A tremendous amount of heat is vented from the canopy. Heat that is not heating the water. It does vent into the surrounding environment adding heat to the house which the Central AC will have to deal with.

 

Because of the canopy and the glass, I have not needed a chiller.

[FishWife]

I also have two fans in my canopy, one blowing in and one blowing out, and I have glass between the canopy and the water. I believe this prevents a substantial rise in water temperature and I don't believe it's from evaporation.

 

A tremendous amount of heat is vented from the canopy. Heat that is not heating the water. It does vent into the surrounding environment adding heat to the house which the Central AC will have to deal with.

 

Because of the canopy and the glass, I have not needed a chiller.

 

 

That's interesting. Now, we have a plastic shield, that's not a true canopy. On, it looks like this:

 

Here it is top down view, and you can see our light fixture:

 

And here is how we're planning to mount it to the wall:

 

In our current scheme, we've mounted two shelf brackets on the wall, too, and the halides hang under that PVC superstructure and about 6" to 8" off the surface of the water in the tank.

 

 

Do you all think we need fans with this canopy arrangement?

Edited January 8, 2008 by FishWife

[jason the filter freak]

Put some of those kids in your house to work and run a ground loop a few feet down to cool your tank

 

 

 

is it possible to exhaust warm air into the space between walls?

Edited January 9, 2008 by jason the filter freak

[Brian Ward]

 

Do you all think we need fans with this canopy arrangement?

 

 

 

You might be OK - esp since it's winter now. I'd plan to mount a few fans to blow across the surface of the water in case you need it. I don't think you'll know for sure until summer.