Jyman wrote:Thanks Canoe, but doesn't the irrigated pad always have to be the intake on the unit, and the fan has to always be the cooled output?
I thought it's just a matter of:
Outside: Fan is against outside wall of shelter
Inside: Irrigated pad is up a against inside wall of shelter
I think FIGJAM said all his designs are in this configuration whether inside or outside the shelter: Pad= Intake>Fan= Cooled Output.
It seems necessary to have the fan be on the same side of the unit that the human is on, and directing air out of the box regardless of placing the unit in or outside. You suggest having the fan direction towards the inside of the cooler?
Canoe, "The opening with the fan is always the opening that is sealed against (or ducted through) the opening in the shelter, only moving air from outside to inside"
I can't see how this is correct - In the case of the Unicooler, the Pad intake side is sealed against the opening in the shelter and the fan is closest to the human (as a cooled output).
So I'm thinking that if I want to increase intake area and make a unit with 3 sides of Pad intake (like FIGJAM's Box Cooler) with a "Fan-Side Cooled Output" then the cooler must be outside the shelter. Thoughts?
WARNING: what follows are technical details that are totally unnecessary to successfully building and successfully using one of FIGJAM's designs
as he designed and tested them.
If you simply want to build and use one of his proven designs, or you're in a rush, or get confused by details, skip this.
I jumped the gun in stating absolutes. The hot dry air has to move through the irrigated filter - the filter and the cooling evaporation doesn't care which way the air flows. However
, FIGJAM configures his designs to pull
air through both the filter and box. Why? This creates a negative pressure inside the container/box between the irrigated pads and the fan, which (for reasons we won't confuse the issue by discussing) results in more efficient air flow than if the fan pushes hot dry air into a box to have it exit through the irrigated filter. Any of the three can be run with negative pressure inside or positive pressure inside, but you're much much better off if you run it with negative pressure - as FIGJAM's recommended configurations are. To be setup for negative pressure, this means that, except for the unicooler (with intake on only one side of the box, which makes it unique in that it doesn't matter if it's installed inside or outside, you get to run it with the efficient negative internal pressure), they have to be installed outside (or, to be technically correct, installed inside but have a shrouding outer containment box built around the entire cooler - not recommended
, especially for such little benefit and potential problems from additional failure points).
So if you take your idea of FIGJAM's outside box cooler with three sides open to the irrigated filter and install the box inside with one intake sucking air from outside - it will not work properly, and for the reason you identified, that the inside air would be sucked through the other two sides. This completely destroys the dynamics of why these coolers work so well on-playa for various shelters.
If you HAD to install the three-sided box cooler inside, then you have to rotate it 180 degrees to have the fan side on the outside wall with its hole, and reverse the direction of the air flow. With everything appropriately sealed, this will cool, but as it's now running a positive pressure configuration it will not work as well as FIGJAM's recommended and tested configurations
. Same for the bucket cooler, with the duct sucking hot air from outside, and the cooled air spilling out through all the bucket holes. Works, but not as well (and you have a hot-air heated duct running inside to the cooler).
If you deviate from FIGJAM's recommendations in a manner that you don't run it with the fan pulling air through the box, you won't have the same air flow which means reduced cooling capacity, therefore it has to run longer to get the same cooling, which may mean it doesn't have enough cooling capacity for your shelter, and it will also mean you'll be using more power/electricity for the cooling you get.
If you're going to deviate from FIGJAM's designs and recommendations, you have to understand how and why they work, and the consequences of your deviations.