DIY Heat Recovery Ventilator ?

[bassman]

Originally Posted by rdnicolas

There are two general ways to remove mosture from air.
1) Use a dessicant dehumidifier
This uses a mosture absorbant silica gel to trap moisture from air
2) A (direct Expansion) DX Dehumidifier.
This has a refrigeration cycle that cools a heat exchanger below the dewpoint temperature of the air passing through it. The mosture will condense on the surface (like water condesning on a cold pint of beer) and drop out of the air.

Using a dehumidifier is probably the best way to reduce humidity without having to worry about heating transfered air from the outside. If you wanted to build something from scratch, you can build a glycol run around loop to run during the cooler days, however it wouldn't be effective during the summer (but your air transfer from outside idea might work in in its place)

I am not as concerned about removing the moisture from the air as I am in removing the moist air all together, moving it outside. I have thought about a coil, still might do something like that too.

[mark]

Little cost/benefit needs to be done also to guide your solution.

Pushing out a little air with a low wattage fan and the energy cost to heat makeup air compared to the cost of a HRV unit or running a dehumidifier etc.

When my MH are on, I use a muffin fan to blow air up from the basement through my canopy (upstairs) then it just vents to the room (no worries about moisture and have a system volume of ~200g). Figure it probably costs something less than 10 bucks a year.

Electrical cost calculator.

[rdnicolas]

Originally Posted by mark

Little cost/benefit needs to be done also to guide your solution.

Pushing out a little air with a low wattage fan and the energy cost to heat makeup air compared to the cost of a HRV unit or running a dehumidifier etc.

When my MH are on, I use a muffin fan to blow air up from the basement through my canopy (upstairs) then it just vents to the room (no worries about moisture and have a system volume of ~200g). Figure it probably costs something less than 10 bucks a year.

Electrical cost calculator.

Exactly right. Turn down your furnace humidifer and distribute throughout your house during winter.

[ElGuappo]

Originally Posted by bassman

Yes that is pretty much how I envisioned it, it won't need much movement at all.

If you are refering to my pvc pipe thougt there would be no need to run your furnace period. you said this would be an air tight system right? the fans from your lights might even be enough to move the air out!!!!!!!

[bassman]

Originally Posted by ElGuappo

If you are refering to my pvc pipe thougt there would be no need to run your furnace period. you said this would be an air tight system right? the fans from your lights might even be enough to move the air out!!!!!!!

Well I don't have any fans on my lights. I prefer to deal with the heat in my sump in the basement, seems easier to me. So all I would have in there is just lights, no ballast or anything. That is another reason I would like a little air movement in there, that and I am strong believer in keeping fresh air circulating over the surface of the water at all times.

I was picturing some sort of pipe, either a pce of PVC with a little 12 volt computer fan built in line or a inline duct fan but I think that would over kill. One computer fan should do it. I don't think it will take much but that is the reason for this post, I really don't know for sure.

[ElGuappo]

i cant see it needing more power than that. also not sure but angleing the pipe may help warmer humid air "UP AND OUT?"

[KrazyKuch]

It is impossible to make your hood completely sealed because you would always need an access to feed and add corals etc. so you will have air venting into your canopy and going out side so it would seem pointless to even try and seal the canopy at all!!!

[bassman]

The canopy I have now is sealed off, when it's closed. I anticipate air flow through when it's open. I can shut the fan off if it became an issue.

[Doug]

IMO,
If you live in a cold climate and not on the coast, save yourself a headache and install an HRV. If you search them on here, you will find a couple of dandy threads on them and all the happy aquarists that installed one.

Of course if one lives in an older leaky house then its another story but if the house is well sealed, it requires ventilation.

I,m not sure, how running a dehimidifier is cost effective, esp. when compared with an HRV. They must be one of the most non cost effective ways of removing humidity, although, yes, they work good.

I do know of several aquarists who vent their hoods outside. Some in colder climates have dampers on them to redirect heat into the house on cold days but not sure how that removes the moisture, unless its not a problem. I think if vented out as you described, just some form of air replacement into the room that can be dampered is fine.

Still say in the long run, a HRV is the best way to remove humid stale air and bring fresh air back, {in a cost efficient manner} into a house, in the cold season. With central air, no problems in the hot season.

[bassman]

Originally Posted by Doug

IMO,
If you live in a cold climate and not on the coast, save yourself a headache and install an HRV. If you search them on here, you will find a couple of dandy threads on them and all the happy aquarists that installed one.

Of course if one lives in an older leaky house then its another story but if the house is well sealed, it requires ventilation.

I,m not sure, how running a dehimidifier is cost effective, esp. when compared with an HRV. They must be one of the most non cost effective ways of removing humidity, although, yes, they work good.

I do know of several aquarists who vent their hoods outside. Some in colder climates have dampers on them to redirect heat into the house on cold days but not sure how that removes the moisture, unless its not a problem. I think if vented out as you described, just some form of air replacement into the room that can be dampered is fine.

Still say in the long run, a HRV is the best way to remove humid stale air and bring fresh air back, {in a cost efficient manner} into a house, in the cold season. With central air, no problems in the hot season.

You are probably right. I do live in a older home that is far from sealed but I intend to remedy that soon.

It will be a little while before I get to the HRV step so I still have lots of questions to ask and things to learn.

If I know me I will just bite the bullet and buy one when the times comes, I like sleeping at night. LOL I am just poking around to see if any one has come up with a cheaper solution.