Draft-free enclosure with pre-heater
I'm thinking of building the enclosure for my first 3D printer (the MK3) with an air intake that is impervious to drafts. To achieve that I'm thinking of using a coiled 1-inch pvc tube several feet long, with something like a "hat" on the end of it like what I see on air flues on the roof of a house. As it enters the enclosure I want to "cap" it with a short piece of tubing that has a bunch of small holes in it. The idea is to "sprinkle" the air into the inclosure so that it doesn't come in like water out of a fire hose.
Because I want to be sure cold air doesn't enter through this tube to "shock" the build and cause imperfections in the print, I'm thinking of mixing some of the exhaust warm air with the air intake -- sort of a "pre-heater" for the incoming air. I'm thinking some valves in the tubes, one fan, and some thermometers to monitor the situation. Possibly some thermostatic valves so I don't have to sit there and watch it.
I'm going to make a sketch and add it to this thread.
Any thoughts, comments, dirty remarks ?
Re: Draft-free enclosure with pre-heater
Id make a small air exchanger. Here is a link to a dyi page on making one http://handmadematt.blogspot.ca/2015/01/heat-recovery-ventilation-heat.html?m=1 You can scale it to your enclosure, I would have it the size of the back or side of the enclosure so you could have it thiner and still have maximum heat transfer.
Re: Draft-free enclosure with pre-heater
Here is a early work in Progress i started for a heat exchanger for the back or side of an enclosure It still needs exhaust fan mounts\piping and a Intake filter .
15"x15" Corrugated Plastic Cardboard 0.157" thick will be placed in the heat exchanger 4 for the Intake placed vertical and 4 for the exhaust placed horizontal.
Example:
Back Plate: Currently i have the Intake going into the bottom of the enclosure to get extra heating from the heat bed (piping for that will be made later)
Front Plate:
If you have any comments for suggestions please feel free and let me know as i continue work on this little project.
Re: Draft-free enclosure with pre-heater
Could either of you please clarify where the exchanger would go and how exhaust heat from the enclosure would be returned to ....what goes where? Thanks so much. It seems that using an exchanger would eliminate the possibility of a cold draft. Very nice idea.
Re: Draft-free enclosure with pre-heater
Hey robert i will be doing more work on the design today and make more detailed notes on how it will work.
Re: Draft-free enclosure with pre-heater
The main part of the heat exchanger is the main block that we will make with corrugated plastic cardboard, they have channels that run the length of the board where we will have air flow through them. We will stack the boards so the channels will alternate directions for each layer (see EX: 1 & 2 below).
The cold air will enter from one side of the block and exit the other side. The warm air will be going through the opposite layers of the block. The cold and warm air will be going through the alternating layers and do not mix, but because the layers are touching and the warm air warms the block, it will warm the cool air that way (see EX: 3).
Once I have the case for the exchanger design completed, I will post it here.
(EX: 1)
(EX: 2)
(EX: 3)
