A little different ventilation system that has worked well

[big medicine]

With all the question about heating coops, and or heating vs ventilation discussions, let me share what I have done, with good results. First off, my coop is a classic 12' by 32' shed roof coop probably built from some Dept. of Agriculture bulletin 50 years ago. It was in pretty rough shape, after several years of neglect, when we bought. After getting it back in shape, and putting birds in it for the first time in many years, every thing seemed to be going well. As we approached winter here in Ohio, and kept the coop windows closed more I started seeing signs of too much moisture in the coop. Ended up having to keep windows cracked open all winter long. Read as much I could find on the subject of ventilation that winter, and came up with this.

First thing I did was cut a hole in the peak of the roof and mount a whirlygig type turbine vent. Directly below the vent I built a plywood "duct" inside the coop that reached from roof to about 10" off the coop floor.

I put a openable flap on the duct as high as possible, which when open would draw the hot summer air near the roof out. When closed would draw the colder winter air near the floor, while allowing any accumilating body heat to remain in the coop. This worked well on windy days but did not move enough air on most days, so I gave it a boost by mounting a removable fan right below the turbine vent for warm weather. I lucked onto a attic fan at a garage sale and mounted it down near the bottom (with the top fan removed and upper flap closed) for winter.

This improved things considerably. Allows good air exchange while keeping it noticably warmer than outside temp. in winter.

For fresh air intake I mounted modified dryer vents high along the back wall, being carefull not to put them above the roosts.

 

[mgw]

Hey that's a great idea, looks like it would work good.

 

[patandchickens]

That's a good design for commercial-type heated chicken barns, because it helps remove ammonia which can otherwise be a bit of a problem with high stocking densities and not wanting drafts down at chicken level (ammonia fumes are heavier than air so tend to pool near the floor).

However, if it's working for you that's great, but in general it is not such an appropriate design for a more lightly-stocked (esp. if unheated) backyard coop, because it leaves a disproportionate amount of humidity in the coop and can make it difficult to avoid excessive humidity.

As I say, if you haven't had any problems to date, that's great and certainly it may be quite adequate in some situations; I am just posting this as a comment to others who may think about installing a system like that, because it is not so appropriate for most backyard peoples' needs.

Good luck, have fun,

Pat

 

[big medicine]

Quote:
I'm a little confussed here. The only source of heat during winter months are cookie tin water heaters, and a few 100 watt bulbs in the brooders during the spring. Since putting in the fans humidity has not been an issue. So what what do you see as the weakness of this system, and suggest as improvements.

 

[patandchickens]

If it's working well in your coop then that is great

All's I'm saying is that the system (an old-timey traditional one) is designed for, and best suited to, situations where the highest priority is to remove ammonia (because of high stocking density and/or old-timey deep litter mgmt methods) rather than humidity (either because one is taking an Oh Well approach to humidity-related problems or because the coop is well enough heated that frostbite is not an issue).

The weakness of this design for typical backyard coops is that by venting the *coldest* air in the house, it also minimizes how much water vapor (humidity) you're getting rid of and can create/perpetuate humidity problems.

Evidently in your particular coop your stocking density is low enough and/or hygeine vigilant enough and/or ventilation high enough that you are not seeing humidity problems, and that's great

But IMO in a typical backyard coop, humidity is a much more common problem than ammonia. So since this setup addresses ammonia a lot better than humidity, it is not necessarily the most useful way to rig most backyard coops. You know?

It is nice to see that some of the traditional ways have not been forgotten though

Pat

 

[big medicine]

I do use a modified deep litter method, and have pea combed birds. There is no frost on the windows, or on the tin roof like there was before I installed the fan. Would you suggest opening the upper flap, or possibly drilling holes in the upper part of the "duct" to allow more mixing of the warmer upper stratified air ?

 

[knjinnm]

Quote:
What is missing is the number of birds in you 12'X32' building and just how air tight is your 1930's coop.

Joe

 

[Mac in Wisco]

Quote:
If it's working for you and you are satisfied with what it's doing, then don't fix it.

By pulling air from higher up you remove more moisture, but also heat. Pulling air from floor level takes out cooler air with less moisture. There is a balance involved there that depends upon the number of birds (hence the amount of moisture) and the actual ventilation rate. Depending upon how well the air is mixing and how much air the system is moving, you may have found a nice balance for your barn, a balance that may tip the other way and remove too much heat if you pull the air from further up in an effort to fix a humidity "problem" that doesn't seem to exist.

Many of the power roof ventilators found in commercial barns have a duct that extends down from the ceiling to keep from removing all of the heat that has accumulated there, but they also move enough air to create a significant pressure drop that brings air in through the intakes at a high velocity which provides good mixing of air and pushes that warm air back down from the ceiling.

While others may point out that your system is somewhat less efficient at removing moisture than it could be, you may be overcoming that by providing a higher ventilation rate.

 

[big medicine]

It's pretty tight, tongue and groove pine siding, built around 1960. The first six feet or so of the building is walled off in the same tongue and groove pine as a feed/tool room. I am currently carrying more birds than ussual till some of these Brahmas grow out and I can decide who gets added to the breeders. Without counting I would say about40- 50 large fowl Brahma, THey have the run off the yard during the day.

 

[big medicine]

Quote:
If it's working for you and you are satisfied with what it's doing, then don't fix it.

By pulling air from higher up you remove more moisture, but also heat. Pulling air from floor level takes out cooler air with less moisture. There is a balance involved there that depends upon the number of birds (hence the amount of moisture) and the actual ventilation rate. Depending upon how well the air is mixing and how much air the system is moving, you may have found a nice balance for your barn, a balance that may tip the other way and remove too much heat if you pull the air from further up in an effort to fix a humidity "problem" that doesn't seem to exist.

Many of the power roof ventilators found in commercial barns have a duct that extends down from the ceiling to keep from removing all of the heat that has accumulated there, but they also move enough air to create a significant pressure drop that brings air in through the intakes at a high velocity which provides good mixing of air and pushes that warm air back down from the ceiling.

While others may point out that your system is somewhat less efficient at removing moisture than it could be, you may be overcoming that by providing a higher ventilation rate.

The upper summer fan is just something I took out of an older window fan, but spins the turbine pretty good asit is mounted right below it. The lower winter fan is much larger and moves the turbine a good bit faster,. Watching the spider webs on the ceiling, the air coming in the inlets is moving a good ways across the width of the coop before dropping lower. I suspect I am getting pretty good rotation in the upper air column.