Large Tank IN a Basement-Ventilation Suggestoin Please oh brethern of the mamoth tank

[capncapo]

Drawing air from the house is not necessarily a bad thing but not necessarily the best thing. CO2 levels in the home can influence your pH in a negative way.

In order to exhaust any given amount of air you must intake the very same given amount of air from somewhere otherwise you would be living in a vacuum.

Negative pressure results from blowing air out of the house that is not replenished by air leaking through cracks and crevices, open windows or doors or other types of "leakage" to the outside. When that happens, air is brought into the house via the "path of least resistance" which is typically DOWN your flue in homes with furnaces that are NOT electric or rated as being 90% efficient OR homes with a gas water heater ( unless power vented). If your gas furnace or hot water heater happens to be running then potentially dangerous exhaust gases are brought back into the house instead of being harmlessly exhausted up your flue. Not a desirable situation, I'm sure you'll agree.

If you have an electric furnace and water heater then flue gases are not a problem. Gas furnaces that are rated as 90% efficient typically have a "flue" made of PVC ard are power vented to the outside and the chance of a negative pressure situation bringing the exhaust gases back into your home are practically non-existent.

If your home can't leak 100 cfm of air then you can't vent 100 cfm of air without some kind of a fresh air intake. If it happens to be very cold or very hot then you are working against your furnace or air conditioner by allowing air to "leak" into your home. It's best to let the air "leak" into the room where it is desired and will do the most good thus keeping the rest of your home more comfortable.

There is NO single solution to keeping humidity at bay unless you never have rain, excessive heat or cold. The solutions are dependent upon the climate in your area, the seasons of the year and even the weather on any given day. What works in one area of the country WILL NOT work in another area of the country unless the climates are identical.

Venting light hoods that are part of a "closed system" may keep your lights cooler but does NOTHING as far as removing humidity from your home except for possibly keeping temperatures down in your room. The cooler the temp of the air in your room, the less moisture it is capable of holding...i.e. the moisture content of the air in a room with 80% humidity at 70 degrees is less than the moisture content of the air in a room with 80% humidity at 90 degrees.

[bguile]

Now that entire explanation makes sense to me. Thanks for chiming in. I believe I do have the 90% efficient utilities you spoke of.
This is a pic of the water heater. The vent goes through pvc to the outside of the house on the side.


This is the furnace and the vent outside the house.



So on your point of replacing exhausted air. Seeing that the wall to the left and just above the tank is to the outside, I was thinking of creating some type of opening that I can open in the winter time to help cool the room and close in the summer to pull more of the cool air from the house. Not quite a window, but an opening that would be a "least resistant path". I was thinking of a screened opening attached to vent shaft with a closeable register or something of sorts. Will this work? Do you have any low cost suggestions?

[siropa]

I was thinking of doing an opening similar to bguile. I was going to use one of the standard air intake pieces found at a home improvement store for the outside and put a duct baffle on the inside to close it off.

capncapo, my question is: would it be better to put this intake right into the fish room as is, or run that duct into the cold air return for the whole house?

[capncapo]

Anything that is weatherproof and can be closed or capped off will work fine. That can include PVC, aluminum, galvanized metal or anything else you might think of.

I think you'll find more air exhaust items at your local hardware store than you will intake items. Most will have some sort of flapper that requires air blowing out in order for the flapper to open. You can always remove the flapper but try to insure that animals and bugs don't have a path into your home if you do.

Personally, I would have the fresh air intake in your fish room if you have a fish room. I would also run it down close to the floor.

If you will be venting the hot air out through the same wall I would place the intake and exhaust as far apart as possible. You don't want to exhaust hot, moist air and then turn around and suck it right back in.

[siropa]

Thanks a lot for the info capncapo.

[capncapo]

NO problem siropa.....that's what I live for.

[jnarowe]

I did a 6" exhaust and a 12" x 14" open attic vent. The vent goes through the tank room wall and is exposed to the outside air under my deck. This affords me cooler air during the Summer, and the exhaust fan is cycled by tank room temperature. I can't use teh humidistat because sometimes it's very humid outside here.

[tinmanny]

skippyreef here are some ideas and sugestions from a licensed sheet metal worker who also happins to run the apprentice training program in the state of RI

negative air is caused by removing more than replaced it genraly takes a very strong fan to do this

I would not ever run air from your fish room to your furnace because it will cause rust and corrosion in the unit and that can be very expensive and dangerous you will rust the heat exchanger and let carbon monoxide into the house

I would guess that the pipe I saw in one of the pictures going to the furnace area is a freash air or possible combustion air because some units consume a lot of air and can starve and do a poor job of heating when that happens

all you have to do to lower the humidity in your fish room is steel heated or cooled air from other areas and the you will acomplish two things
#1 figure what size the room is in sq ft length x width that is the amount of air you want to move
once you know that figure get a 2 speed fan high being the one you shoot for in fan capicity example 10 x10 room = 100cfm fan on high should do just over 100cfms low being the seasons when the water evap is lower
#2 use a basement window to vent the fan with a dryer vent they come in all sizes lows may have them but any heating supply store will carry them use the size on the fan
then get 2 of the same registers to accomidate the cfms you calculated and install them in the wall across from the exaust fan and the air will exchange with house air that is low in humidity and at the same temp as the house
by doing this you have exausted the air with all the water in it and you replace it with good dryer air at a rate equil to the size of the room at a medium to high rate depending on the speed you choose and your house will thank you for it and your furnace will suffer no ill affects

Good luck
Manny

[FishTruck]

OK. Strap on your jocks and see if you can follow me through this one!

Review issues with a "closed" system vented in and out from the outside. I am answering my own questions here, but, I am not sure if I am correct. This is Chicago land with all extremes of temp and humidity.

I am planning a sealed headspace above the tank and above my sump. Both exhausting outside and aspirating outside air. Both as close to "air tight" as possible. I will keep the skimmer outside of the sealed area, so that the water will be aereated by skimmer action with constant house air.




Ideal spring and fall. Cool air with reasonably low humidity will ventillate the system, keeping it cool, but not too cool, and venting humidity out of the canopy and the equipment room. Could be controlled to keep the air above the tank below 80 degrees.

1. Extreme Winter. Cold dry air will be coming in which will cool the tank nicely. But, because the cold air cannot hold much water, and there will be a limit to how much I can vent in before the tank starts to get cold. So, the potential problem is a 100% humidity situation above the tank and in the equipment room. Is this a problem?

Also, if it is really cold, there will possibly be very little ventillation.
This could cause CO2 accumulation if the system is really sealed from the house. Could this be counteracted by keeping the skimmer outside of the sealed area?

And... in the winter I could set the above canopy temp to a lower setting to encourage more ventillation. Using heaters to keep the water temp constant.

2. Summer. Hot humid air will be coming in. If it is 90 degrees outside with high humidity, the fan will run constantly, and might not be able to keep the tank temperature down. Hello chiller. I guess as long as the lights don't overheat, this would be o.k., just sucking up lots of electricity.

For a 300 gallon tank, and 180 gallon sump, I am planning a single 120 cfm fan. Maybe I should have two of them with independant temp control? One for the sump, one for the tank? I can start with one and upgrade as needed.

Thanks for any comments.

My tank arrives friday.

[tinmanny]

what happins when it rains for two days

[tinmanny]

what happins when it rains for two days

[tinmanny]

just use house air for supply it is already the best for the situation and when you get it too damp it is out

[FishTruck]

Well, if it rains for two days straight, I will be venting the tank with humid air. This will keep the lights cool and fresh air over the water, it will just be high humidity. I guess the tank lights can handle that without corrosion problems? It will be isolated from the house anyway.

As backup, I do have the system set up to vent with inside air if I need to from time to time. I could even automate this with another fan and some louvers.

Regarding venting with house air and exhausting outside...
My water heater and furnace have open flus... so I have to avoid negative pressure in the basement.

[Whaledriver]

FishTruck
The winter air can be your friend because it is so dry. The key is letting the lights warm the air to the point it can carry away a lot more humidity than in the summer. Another benefit is that in the winter you can use the heat for your house if you set things up right with a heat exchanger. In the summer your last resort is to turn off some lights if temps get to high.

The ideal system would have intake/exhaust fans that can be slowed down depending on the needs of the seasons. My best cheap way would be a pair of 3 speed fans and a 3 speed controller. This would allow you to control the exhaust temp in the winter to keep it from going to low in he winter. In the summer you should be able to cool the tank to the point. Beyond this point you could then have some of the lights go off to lower the heat input. At a certain point when the temps over 95 or 100 you might have to open the tank to your inside air to keep things alive. This could be a simple servo to open the ducting system to the inside air and close it off to the outside air.

This is easier to plan and blog about than to actually do. If I ever get to the point of remodeling my basement I will find out if it works. Hopefully by then a controller computer will be cheap and helpful enough to monitor and control the parameters in all the sasons

[Nanook]

HRV for winter months may be necessary if you lose too much heat, or simply using exhaust fan with fresh air intake if losing heat is not an issue.

Air conditioning the room via a window unit or split AC would be better for humidity removal and temperature control in the summer months.

[FishTruck]

Thanks guys! This helps. I think this is going to work!

I will have an AC3 controller programmed to to cut the lights in heat emergencies. This will also control the ventillation fan.

I have a 100 pint per day dehumidifier in the basement for backup. Will look into an HRV unit.

The good thing, is that I have the winter to just run the plumbing and cure some rock and see how the temp control and humidity work out.

Will start a post to log my trials and errors with this.

Ryan.

[bguile]

Originally posted by capncapo
Anything that is weatherproof and can be closed or capped off will work fine. That can include PVC, aluminum, galvanized metal or anything else you might think of.

I think you'll find more air exhaust items at your local hardware store than you will intake items. Most will have some sort of flapper that requires air blowing out in order for the flapper to open. You can always remove the flapper but try to insure that animals and bugs don't have a path into your home if you do.

Personally, I would have the fresh air intake in your fish room if you have a fish room. I would also run it down close to the floor.

If you will be venting the hot air out through the same wall I would place the intake and exhaust as far apart as possible. You don't want to exhaust hot, moist air and then turn around and suck it right back in.

I'd like to say thanks also. I thought it could be implemented but wanted to put it past an expert for critique.

[jnarowe]

And the bugs can be a problem. My inbound vent gets covered with them and I have to shop-vac them off. I guess they are attracted to 1000W 20K lamps!!

[bbrantley]

It sounds like you are on the right path.

I use a pair of fans plus a humidity and temperature controller to trigger them for air exchange in my fish room. I happen to live in a place where the outside air is always cooler and drier than my tank's water temp (80F), which means passive cooling and air exchange are both viable.

During the daytime in the winter, the tank lights and solar flux keep the tank room above 80F with no active heating, which means the tank water stays warm without any extra heating, too. A few times during the day the fans will kick on and bring in cool, dry air while purging the wet stuff. At night the room drops as low as 65F and the heaters kick in. I set the controller to keep the room humidity at 70% or better.

In the summer, the room can get considerably warmer, so the fans will stay on much longer, and I must allow the room humidity to get higher, too. There is plenty of cool night-time interval, though, to let things stabilize and "dry back out" in time for the next day's round of warming up.

Since you have a nice chunk of time to "practice" with environmentals, try the passive routes first. They are cheaper, more energy efficient, and there are less things to "break." If your controller permits it, put an extra sensor in the room to measure the ambient temp and collect some data. You can use this to "tune" your choice of equipment. Do recognize, though, that the real challenge will probably be in the summertime unless you live in a cold climate.

Good luck!

Ben

[wmilas]

I'm the the process of planing out an inwall 7x3(or 4)x2.5 tank for the basement. Some particulars:

* I bought a new builders spec house on the cheap. The HVAC system was ripped out and redone.
* I live in Chicago so its both humid in the summer and cold/dry in the winter.
* I have a 90+ variable speed lenox in the basement that services basement and first floor.
* I have an 80 variable in the attic that services the second floor. the reason its not a power vent is because its in an uninsulated part of the attic.
* Both condensors outside are variable speed, and the controlers can lower them to draw more humidity out of the air in the summer basd on the humidistats and the outside temperature sensors.
* The system monitors the dew point and kicks on the humidifier in the winter to keep humidity just under where the windows dew up based on outside humidity. Furnaces circulate air wheter burner is on or not to spread humidity if humidifier is running.
* HRV runs during the winter and most of the summer (I turn it off spring and fall when the windows open)
* Both systems have large canister hepa filters. Furnaces are the 4 inch media filters. Hepas run 24x7.
* Waterheater is a powervent, and its next to the furnace in the basement.

As you can see I take my HVAC seriously Its the best system I could put together energy effeciency wise that still made "sense" It helps that my cousin-in-law is a HVAC contractor

I'm REALLY happy with it.. the variable speed means its always comfortable, its always the right humidity, its always, well nice. I don't want to completely screw this up with the tank going in

So this was what I was thinking after reading as much as I can:

* Seal off the fish room.
* Install a HRV fishroom only.
* Install a dehumidifier. I have a lil portable jobbie put I'll probably look for something maybe a bit larger and more efficient.
* Install a small dedicated AC system with a condenser outside.

How it would work
Summer:

Run the dehumidfier on a controller over 60%. Run the ac system keep room at 78ish. Temp sensor and humidi sensor installed outside. If at night temp falls below say 74, HRV kicks on and runs. Obviously the settings need to be tweaked but you get the general idea. Keep it as energy efficient as possible. I'm toying with the idea of adding a simple non HRV vent with a outside return to capitalize on the cool summer air.

Question: any way possible to hook a chiller into the outside condenser to make this even more efficient?

Winter:

Air return in fish room opened up so that humidity can be circulated in house. Manual system or humidity control actuater. If it screws up with the dewpoint calculations of the whole house system I'll just leave it closed. Will need to plumb in a fresh air vent to the rest of the basement for pressure to equalize so the return works. this is midly complicated and I have reservations about it. All I gain out of it is "free" humid air, and the current system actually does a good job of that. I also risk taking in nano-sized salt crystals and rusting the hell out of the HVAC gear.

Same setup above with summer although obviously the AC should never run unless something goes horribly wrong. The HRV and the dehumidifier should be able to hand the load. I assume I do want a HRV... being in Chicago when its -10F I'm thinking humidity and not heat are going to be the issue.

Am I missing anything here?

Thanks for your time

[Oldtimer]

wmilas

I've been following this thread because I'm also in he process of planning in a large basement tank. I live in more or less the same climate as you (suburb of Detroit) and have similar plans. My current HVAC system is far from being as up to date as yours. It's a 25+ yr old system in a 1937 home. Suffice to say that it's in need for an upgrade, so I'm trying to plan my new HVAC system in conjunction with the tank.

My install shares one significant difference in that the tank will be an open top braceless design (~225gal) located in the living area of the basement ~10 feet from the equipment room. So, my approach is to focus on conditioning the air not only in the equipment room, but also the living space of the basement. I'll probably install registers above the tank in the ceiling to extract the air away from the tank either into the equipment room or directly through an HRV installed in the equipment room window. My basic idea is to suck humid air out of the area around the tank and the equipment room and process it through an HRV (geared towards the cooler/dry months). I'd also ike to maintain flow through the equipment room in order to avoid pH swings. Managing all this seems like quite a task, but I'm fortunate enough that my next door neighbor is a Sr. HVAC Tech at York. It's a good thing he appreciates beer!

I'm also thinking about installing a second A/C unit to focus purely on the equipment room. Although, it would likely only be needed during the June-Aug months when outside temp/humidity peaks. I'd prefer to go this route only in lieu of a chiller. I like the idea of dumping the chiller's heat outside though. Perhaps that would eliminate the need for a dedicated A/C unit. I'll have to dig into this option.

I also share your concerns with rusting out the HVAC system. At least using a dedicated system (HRV, second A/C unit, blowers, etc) offers some piece of mind for your main HVAC equipment.

It seems that there's about a million different ways to setup a system like this. So far, I've been seriously researching this for a few weeks and have learned more about residential HVAC than I ever would have dreamed to know. This thread has been very helpful in pulling together a lot of good info.

One other item I've come across is an ERV (Energy Recovery Ventilator). It's basically an HRV with a built in dessicant wheel or other form of removing moisture from one air stream and transferring it elsewhere. It's mainly targeted for warm/humid climates, but I think it has it's value in our hobby. Here's a quote from the following link...

"The most popular design of ERVs utilizes a desiccant
wheel to remove both heat and a significant amount
of moisture from the incoming air, which reduces the load
on the air-conditioning system."

http://www.advancedenergy.org/buildi...lation/erv.pdf

I'm not sure how effective these units are, but they caught my eye. If they reduce the overall burden on an A/C system, that should translate into lower energy bills.

[wmilas]

Oltimer:

From the research I have done it seems that the dessicant wheel in the ERV saturates pretty fast and is not suitable for the amount of liquid generated by a tank. The thing is I know of no one who actually has one so its hard to tell. Since we are in the northern climates none of the contractors up here have any experience with them so I can't get a straight answer out of anyone.

As far as a chiller vs an airconditioner I'm just as stuck. If I install a chiller and a dehumidifier, and then make sure the tank has a closed hood on it in the fish room, along with sealing up the sumps as much as possible, I may not actually need a AC unit. My gut tells me I will though in the summer, then we are back to do I use the house airconditioner and risk the salt damage, or put in a smaller dedicated unit that I can blow up

I was initially toying with an opentop design but having that much humidity in my basement scares me

[jnarowe]

What about using a ground loop to keep your tank cool and save some energy?

[steve the plumb]

I have a dehumidifier but at this time of the month it doesn't go on.It did go on two weeks ago(just bought it recently) and it does heat up the room.I still think an a/c unit is better to dry the room and cool it.I have 2 portable a/c units I think I will install one in the garage and the other in my basement.My tank is covered for now but I also haven't installed my lighting.Once the lights go on the heat will rise.I do see this being a problem in the summer.I also see it as a waste to cool my garage with an a/c unit in the summer(sump is in the garage)I was wondering if I installed a fan to push the hot air out(garage) would that be enough,and left an a/c unit in my basement where the tank is.

[steve the plumb]

wmilas you have pretty much a similar climate as we do.It may get more humid here(75%-95%) in summer and it does get hot.My old 150 was in my basement as well but my sump was underneath the stand.I had most of the top opened and I had to have my portable A/C unit on all summer or the tank would get to hot on those warm humid days.The problem with a chiller is if the room is to hot its not as efficient.I think the dehumidifier will drive the temp to high.I have seen my room temp go up to 25 celcius when the thing is on.Unless you can vent the heat outside you will be heating the room to get it dry you are better off with an A/C unit European models are nice I regret not getting one for my basement instead I have to install my portable one in the summer.