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Time to design HHVAC for chamber... help?

SYNOPSIS: I am gearing up to design an "environmental" system for my chamber (Heating, Humidification, Ventilation and Air Conditioning... so I guess it's "HHVAC").
-I'd love to hear some of your suggestions, and descriptions of your setups. I would rather not charge blindly into this while I can prolly get some decent advice right on this forum.

BACKGROUND:
I have a 48" long x 16" high x 15" deep custom acrylic chamber. I never designed a lid for the thing, so I build a wood frame and made a temporary lid with plastic wrap recently. I will be designing a better lid soon which will totally enclose the chamber.
In the mean time, I need to design an environmental system! My priorities are
A: Ventilation
B: Humidification
I suppose I could incorporate a heater and such, but that is not the main purpose of my little system (a seed bed under the chamber may work, all I am using currently is a big water bottle and an aquarium heater -takes up too much space).

The "virtual design" so far consists of several elements. The specifics have not yet been determined (power of air pump, humidifier and fans). I don't know if I'll have to worry about a specific cfm (cubic feet/min) for airflow, or if I'll just 'wing that mother'.
One Ultrasonic Fogger (mainlandmart.com)
One aquarium air pump
Three or four CPU fans
Humidistat
Thermostat?
Seed heating blanket? Or other type of heater? I'm more of a fan of heating the aquarium by radiation or conduction, not convection (ie. heater in ventilation system)
Cooling is not really an issue. The 2x2 48" shoplights do not generate much heat. However, if any of you have good ideas for cooling, bring em on!

LAYOUT:

Three ventilation fans in chamber (I may do away with the Vent IN fan because it may not be necessary with the air pump... but it still seems like a good idea):
One medium-flow fan mounted high at left side of chamber for ventilation IN to the chamber, two low-flow fans mounted high and low at right side of chamber for ventilation OUT.

There will be a flex-tube or some other wide vent tube connected to the Vent IN fan. This tube will lead to a Y junction. The Y Junction is connected to a fogger and an air pump or fan or something.
HUMIDITY:
The fogger will be an Ultrasonic fogger or some sort (mainlandmart.com). There will be a resevoir in which the disc is placed (duh). This resevoir is connected to fan, connected to a hose that leads to the Y juntion. There will be a valve on the foggers side of the junction -that way the air pump may ventilate without humidifying.
The fogger will be connected to a humidistat (70% min).

That just about does it for the humidifier.
VENTILATION
On the other end is an aquarium air pump -at least that's what I'm thinking I might use right now-. This air pump is also wired to the humidistat so the fogger has a means of getting it's fog into the chamber. Otherwise if the humidistat activated the fogger while the air pump was off, it would have little force behind it.

Ahead of the humidistat, there will be a timer to control the air pump (approximatley "whenever I feel like it").

-exhaust
As I previously mentioned, there will be two smaller fans at the other end of the chamber, mounted high and low. These fans will expel air from in the chamber at set intervals (don't know what those invervals are, tho). I thought about having them operate when the Vent IN fan operated, but it seems like that may just push the fresh intake air right out the other side -that would make the whole ventilation system moot if that happened. So I may try
"expel old air"
"intake fresh air"
-humidity is independent (of the exhaust).

That's just about all I can think of at the moment. I wish I had a drawing to show, but I have no web space.

Questions? Comments? Please let me know what you think, and what your experiences have been!
Does something work well for you? Obviously this is not a perfect system yet. I know there are some things that don't add up, but I've only been working on this for a day or two now.

Obviously I'm trying to have an un-obtrusive system. I don't want any unsightly apparatus laying around my living room, and more importantly I don't want to have glasses of water and stones and several different apparatus cluttering up my chamber. Two small fans in one side. One medium fan (couple inches) at the other side connected to a hose which leads to the "air/fog farm" stored nearby.

Much thanks!
-Trevor
 
humidifier.jpg


This is a diagram of my frog tank environ system, which all hides behind the back of the tank. Keep in mind that this drawing is not to scale and is laid out like an electrical drawing (spacial relevance is not correct) this controls the venilation, humidity and cooling for this tank (although A/C is just high flow ventilation with water in it to evaporate. let me break it down for you (in case you missed the previous post on this setup)

starting at the water resivoir containing a ultrasonic water fogger, it is a sealed tank (ie big tupperware bucket with a lid ) that has a PC fan blowing INTO the tank. This is also on a rheostat controller that can modulate the fan speed thus controling the airflow through the tank. the fog that is generated is pushed (not sucked, as the water would kill the electric components of the fan) into the tank through a 2" PVC pipe. because this is an enclosed system the pipe directly across the tank from it creates suction that pulls it out again. the fog rolls slowly through the tank gently misting the inhabitants as well as raising the humidity almost instantly. the exaust then passes through the only open air part of the system. This is just a simple rig made by drilling a lot of holes in a 2" PVC pipe and then sliding a 2.5" pipe over it. you can control how much "fresh" air the system will accept. just slide the bigger pipe to expose more holes for more air and reverse for less air. the new air mixes with the old air and passes through a chamber that has 3 hepa air filters in it to pull out any dust or contaminants that are an inevitable part of life. lastly the air passes back into the water tank to push the fog all back into the tank.

for heat i use an aquarium heater in the water tank that the fogger is in. this raises the temp of the fog and the air in the resivoir as it goes into the tank. usually keep that water at about 90F. pretty warm, but it cools quickly. at the present time, this tank is all manual, but i dont have to make too many adjustments once i gain a desireable level of humidity/ventilation running in the tank. the entire system shuts off at night with the lights and gives the plants and frogs time to dry out a bit but it never drops too much as it is an enclosed system. the only thing that i need to add into this set up is a CO2 generator as i think that the plants are a little stunted.
 
Thanks for the description. That provides a decent amount of info


I have to take into consideration the issue of having the humidified air blow through the fans -as you mentioned- which seems like it may lead to Bad Things.
" the fog that is generated is pushed (not sucked, as the water would kill the electric components of the fan) into the tank through a 2" PVC pipe"

One of my ideas was to incorporate the fogger hose into the main air hose at a 45degree angle. Thus, if the air pump was on, the air moving past the fogger would suck the air out of the fogger hose without needing a fan (it would form a venturi). Additionally, using an air pump pumping into the chamber might be enough by itsself without the need for my "medium Vent IN" fan. I'm still comparing the benefits of each setup.. let me know your opinion.
 
That idea would probably work, but my main goal was to make a system that was as small and self contained and simple as possible. i have just added a Co2 device into the water tank last night. so now the heating, Co2 and humidity are all generated in one aux tank and pushed in all together.
 
I like the idea of returning the exhaust air back into the water tank. That provides a good way in which to maintain the humidity, but more importantly it is a good way (the only way) to measure the return air humidity & temp, which is a great way to control your devices.
 
where is the pic of this frog tank
 
right in his post... took a while for me to see it...
 
Hi,
I'm new to this group but have been doing terrariums for a few years and the ultrasonic foggers are great, the idea of using air movement to form a suction of the fog works great as the fog moves easily. Another idea is; on mine I use a coffee filter over the "intake" for air and dabble a little alcohol on now and then or H2O2 that way if you get some mold or whatnot once you kill it and the spores it wont come back in.

Joe
 
[b said:
Quote[/b] (superimposedhope @ Feb. 20 2004,12:30)]Hi,
I'm new to this group but have been doing terrariums for a few years and the ultrasonic foggers are great, the idea of using air movement to form a suction of the fog works great as the fog moves easily. Another idea is; on mine I use a coffee filter over the "intake" for air and dabble a little alcohol on now and then or H2O2 that way if you get some mold or whatnot once you kill it and the spores it wont come back in.

Joe
hey superimposedhope,

can you give a little more description on the coffee filter? what is it?im thinking of making a system like that and i don't really know what air filters are, coffee filters sound common

thanks
 
  • #10
Coffee filers are the filters used to separate the coffee grounds from the liquid coffee during brewing of... coffee.
They come in a few different shapes -cones or round scalloped wafers. They are fairly large ~you could prolly fit an most of an apple in a cone -style filter.

They are basically just paper. You should be able to find them at just about any gas station or supermarket or what have you. There exist a few different "Grades" but just about any grade should do the job. I could be wrong -this is not my system, after all.
I would not imagine a coffee filter to be the best choice for air filtration unless you A: were just looking for a simple, uncomplicated coarse particulate filter
Or B:
You have a much better particulate or organic filter somewhere down the line, and are using the coffee filter as a "precharger" style of air filter to catch the large particulates before they hit the finer filters .

-Trev
 
  • #11
Yeah, like Trev said it is'nt the best for good filtering. The thing is I have 3 dogs and 4 cats when originally constructed I needed something to keep junk out. Well I let it go and a few months passed and it never did begin to grow anything like mold, etc.. so I have left it on and it still does the job and I began dabbing the alcohol or H2O2(peroxide) to kill anything that might try to pass. On the other hand I should not recomend it because if you absolutely neede to keep out that stuff this setup could not be guaranteed. HEPA filters should be used for control over airborn particles and whatnot. What I got is probably luck.

Joe
 
  • #12
I use humidifiers and vaporizers (H/L). and they work very well.
 
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