Tall Homemade Cabinet Style Incubator Heat/Fan Question

[SED]

I have a pretty large pan (12"x15") of water and the highest I can get my humidity is 45%. What can I do to increase it?

 

[shelleyd2008]

Put a sponge in the pan that sticks up out of the top of the water. This will increase your surface area and should help.

 

[_Randall_]

Quote:
I have a question about this if you don't mind. Most designs show the fan blowing across the water source for humidity. Where would you put the water in an incubator with a false back like this?

Use the same concept as GQF. I'm in the midst of building a cabinet bator, and I will have a false back (~5" in from the main back all the way from the top of the bator inside to 7" from the bottom. (Bator is 24" deep x 22" wide x 32" tall). My water shelf will come out from the false back 12" deep. My fans will be mounted to the false back (between the false back and main back....blowing out across the water pan). My heating element is the one GQF uses, and will be mounted on the activity side of the false back. I plan to post some pics soon. My philosophy of going almost to the bottom with the false back is when the fans are blowing across the heating element and water, that warm damp air will have to travel "downward" acoss all the eggs (no matter how many racks you have as long as the opening is below you bottom rack) before it "returns backward and then back upward for a continious flow. The fan and element in the pic below is mounted to a "very short" false back. It stops at the water shelf. Now, picture that false back going "almost" to the bottom. The moving air is circulating, and will have to go almost to the bottom to make the trip back up between the false back and main back to make the trip again, thus creating circular flow, thus even temp.

https://www.backyardchickens.com/forum/uploads/43975_24137_ppba_poultry_show_009.jpg

Where'd the pic go?

 

[rebelcowboysnb]

Quote:
I think i would reverse the air flow from what you have drawn. I also suspect that with two fans the one in the path of the air off of the heat source might get a little to hot. Really, all you need is one fan, I circulate my cabinet air with a 60cfm fan. The objective is to keep the air moving inside the cabinet, not create a breeze. I also agree with Rebel, take out one of the water trays and add another egg tray

Why would you reverse it? Heat is trying to go up. Its easier to force it down on the small side than it would be if you were trying to get it to go down on the big side.

 

[rebelcowboysnb]

Quote:
12X15 is huge.. Are you over ventilating?

 

[SED]

I don't think so. I even have a sponge in it.

 

[muddstopper]

Quote:
I think i would reverse the air flow from what you have drawn. I also suspect that with two fans the one in the path of the air off of the heat source might get a little to hot. Really, all you need is one fan, I circulate my cabinet air with a 60cfm fan. The objective is to keep the air moving inside the cabinet, not create a breeze. I also agree with Rebel, take out one of the water trays and add another egg tray

Why would you reverse it? Heat is trying to go up. Its easier to force it down on the small side than it would be if you were trying to get it to go down on the big side.

My way of thinking, and feel free to correct me if you think I am wrong, is this. Forceing the air from the bottom up in the tray area will create a hot spot at the top of the tray area. Like you said, warm air will rise. In fact, blowing the air upwards will cause warm air pockets any place near the top of the tray area that there isnt an opening. A incubator cabinet and air flow isnt like it is in a house with a ceiling fan. In a house, you would want to move the air upwards to cause the warm air that gathers at the top of the room to move back down along the wall towards the floor, only to rise again, thus keeping the room temp more stable. In a incubator, its a little different in that the air you are moving around isnt staying in the same room, instead it is being pushed or pulled out of the room (tray area) to be reheated and then moved back into the room, (tray area). The moving air is always being effected by the variation in temperature between the outside of the cabinet walls and the warm air inside the cabinet. As the air moves along the walls, it is being cooled down. I dont want air that has already been cooled down to touch my eggs first. Instead I would much rather have the air right after it has been heated by my heating element to enter my egg tray area. This air is much easier to regulate the temperature of and will result in a more stable temperature inside the cabinet, than trying to regulate the air that is being cooled at varying degrees due to outside enviromental conditions. ex., air conditioner kicks on, someone opens a door or window to the room, someone decides to cut down the thermostat settings on the entire house. etc.

I think everybody needs to stop thinking of forceing the air and instead think of just moving the air. You dont need massive air movement to control temps in an incubator. A gentle constant movement is all that is needed to mix the cold air off the side of the incubator cabinet, and the warm air being generated by the heat strip and fan.

 

[muddstopper]

Quote:
12X15 is huge.. Are you over ventilating?

I only have one 1/4inch hole for ventilation in my cabinet. My humidity pan is only about 12x6 and maybe 5 inches deep, and I have over half of the top covered to keep the humdity levels down. The float valve is set to maintain the water level about 1inch from the top of the pan. Is the water level in your 12x15 pan at or near the top of the pan, and is the heated air blowing directly across the pan. If I had something that big in my incubator, it would fog the windows. Post a pic and show us how it is set up.

 

[rebelcowboysnb]

The way I see it is the air in the incubator is always trying to create layers with the hotest air in the top an the coldest in the bottom.

If you pull cold air from the bottom an heat it an reintroducing it in to the incubator at the top the hottest air will always be at the top an the coldest air will always be at the bottom.

If you pull the hot air from the very top an put it back in at the bottom you are mixing the hottest air with the coldest which destroys the thermal layers.

Ether way will probably work if you move enough air but the second way would still work well even with very little air speed.


By the way, mine has a vent at the top an one at the bottom that are both the size of a quarter.

 

[SED]

Here is what I have now. Two fans, one on top and one toward the bottom blowing on the heat source (which is at the bottom, right over the water). The thermostat is right below the turner (I have planned on more than one turner so it would be in the middle of the two turners). It has a 3/4" vent hole at the top and a small hole where the egg turner cord exits the back of the bator. Here is a drawing. It is not working out as I had hoped. I really think I am "over thinking" this set up. I am trying to make it too complicated.
I am showing 102.8 deg on the left side front and 99.3 on the right side rear.