Venting Outside Heated Shop

[William C Rogers]

I was initially going to vent inside with twin Wynn Nano filters. The more I think about it I am thinking to just vent outside and forget the filtering. My questions are:
1) is there a "big" loss of heat?
2) venting outside, should it be into a drum?
My heat source is radient hot water in the floor and I will be using a ebay cyclone connected to a Jet 1900 DC. I would then sell my Wynn 1425 filters instead of setting that up and it would save space.

[Peter Aeschliman]

1) you'll get arguments both ways. My experience has been that the heat loss really isn't bad at all. Most of the heat you feel is from the surfaces that retain the heat due to their thermal mass. Especially for you since you have radiant heat.

2) you should only need a drum under your cyclone, not outside. I use the eBay cyclone vented outside and don't even see any dust residue.

One other thing to note is make up air. Your setup will only work well if you have enough fresh air coming in to replace the air you're blowing out. I've read guidance that says you need your make up air inlet to be 2x the size of your dust collection duct, and I've seen some people claim you need even more than that.

[Bill Adamsen]

Suspect everyone that uses cartridge filters wonders about this. It would be so nice to not have any filters to manage. Installing some sort of manifold that gave you the choice by simply throwing a baffle or gate would be nice. I seem to recall someone here that had done just that. Put an elbow with a gate just below the cartridges and aim that through the wall to the outside.

[Keith Outten]

You don't need your cyclone, filters or bags. Build an outside box and connect the DC pump outlet to the box. A 400 gallon box or larger works well.

With the exception of extreame Winter weather you will not notice any affect on your heating conditions. If you have at least one garage door it will provide all the makeup air you need from natural leaks. I have been using an exterior chip box for well over twenty years. The only change I have ever made to my system is a change in my chip box, I got tired of building a new plywood box every few years and was able to purchase a scrap steel tank that will last longer then I will.

Most days either my CNC Router or my Laser Engraver are running for the majority of the day.
.

[John C Bush]

My cyclone is outside the shop in an attached shed and exhaust vents outside the shed. Still use a 55 gal. drum to move chips. I also have in floor radiant hot water heat. I do a lot of rough stock milling and the DC is usually running for long stretches. Heat loss isn't an issue with the warm floor. Hard part is remembering to dump the drum before the shed backfills with chips. My record so far is 2+ft of chips on the floor.

[Lee Schierer]

Just be aware that what ever volume of air your DC system is rated for will be moved out of your shop and turned loose outside. That air will be made up from air coming in from outside, this past week with below zero temperatures around here it wouldn't take long to cool down a small shop. Depending upon how long and how often you run your DC, you shop heating bill may reflect a increase in cost.

[Mark Kornell]

When I built my new.shop, I set it up so that I could change the outlet of the cyclone from venting directly outside to venting through a.filter stack by opening or closing two blast gates. I know I posted that setup here, so maybe I'm the guy Bill was thinking of.

Well, I've gone through my first winter - a warmish Canadian winter although we spent some time around -15° C for a few weeks - and have never bothered to set up the filter stack. The cyclone has been venting outside throughout and it has never made a large impact on the overall shop temp.

I should add that the shop is about 30' x 35' with 12' ceilings. Make up air comes from opening a window. Heating is via a suspended 4500W electrical construction heater, which is effective enough to maintain the shop at a constant 17°C through the winter.

On one of the coldest days, the DC was running for about 2 hours straight and the ambient temp dropped from 17°C to 15°C. This surprised me, as the cyclone should be able to turn over the air in the shop in about 10 minutes. I realized that there were 2 factors that came into play. First, as has been mentioned, the thermal mass of the objects in the shop as well as the shop itself matters. The second factor is that air is not evenly drawn from the room. Subjectively, it feels like there is a current of cold air drawn from the open window through the equipment in use to the cyclone and exhausted outside. The remaining air in the shop is mostly undisturbed, so temperature remains fairly constant. I know.just enough about fluid dynamics to realize there is interference and mixing at the boundary of this air current that means that an equilibrium would eventually be reached wherein the shop temperature would hit a point only slightly above the prevailing exterior temperature. But from a practical experiential outcome, it would take a lot longer than what my working practices require.

So my filters sit. I will likely remove the blast gate setup and have the DC permanently exhatst outside. The blast gates allow leakage of dust-laden air back Into the shop, and the transition at the exhist outlet is inefficient for high-volume air flow.

[William C Rogers]

Regarding make up air. My shop has the insulation in the roof rafters. The shop is 30 x50'withn12' ceiling. I have gable vents down each side and at the ends to the peak. I do have a drop ceiling below the vents, but there are 2" gaps at each end and some holes throughout for stuff hanging. There is no insulation on the drop ceiling. I am thinking the gable vents would make up air loss. Is there a fault in my assumption?

What at happens if you don't make up air? ( how would I know? )

[Lee Schierer]

What at happens if you don't make up air? ( how would I know? )

If you room were air tight (not likely), then you DC system would be trying to create a vacuum in the room. Most likely there will be enough air coming in from around the doors, windows and crack s in the walls and ceiling that you won't nee a separate vent. If the door is hard to close when the DC is running you probably need a separate air inlet.

[Jim Andrew]

Do you have an overhead garage door on your shop? If you do, the door is on the inside of the building, so the air will come in around the door even if you have it weatherstripped.

[William C Rogers]

Jim, I have two overhead doors. One 16 x 10 and one 8 x7.

I have decided that I will vent outside. This will be a much simpler setup and I won't have to worry about cleaning filters. I will install my cyclone as I save the maple shavings from my jointer/planer for the grandkids pet cages. I will list my filters in the classified section later.

What at type of outside vent are you using, standard dryer type?

[Peter Aeschliman]

On the heat loss issue, one of the things I'm considering in my new shop is plumbing in make-up air vents close to my main machines. My TS, jointer/planer, router table, and drum dander are the machines I tend to run for the longest continuous stretches, and the layout of the shop will be such that they are all clustered together. So I will run a large duct close to that area. This way the cold outside air will be pulled straight into my DC ducting rather than drawing cold air from across the room and cooling everything in its path.

Something to consider!

[julian abram]

I vent mine outside and glad I installed it that way. Very little noticeable heat loss although I'm in a warm climate zone than you. Actually most days working in the shop seems like the DC runs very little, guess it depends a lot on your projects.

[Mark Kornell]

What at type of outside vent are you using, standard dryer type?

Well, HVAC type. 12" diameter opening. I plan to modify it a bit to beef up the hinge points and open the hood up some to allow better flow. The standard household vents aren't designed for 1500+ cfm, but you can oversize the piece and make it work.

[Stuart Welsh]

Regarding make up air. My shop has the insulation in the roof rafters. The shop is 30 x50'withn12' ceiling. I have gable vents down each side and at the ends to the peak. I do have a drop ceiling below the vents, but there are 2" gaps at each end and some holes throughout for stuff hanging. There is no insulation on the drop ceiling. I am thinking the gable vents would make up air loss. Is there a fault in my assumption?

What at happens if you don't make up air? ( how would I know? )

It sounds to me like you have plenty of penetrations to achieve make up air.

My shop is 20 x 30 with 10' ceilings and since it was just built last year it is quite tight. The garage door is the only penetration in the shop space walls that has air gaps of any significance and even that is fit pretty well. One evening my wife's garage door opener in her car turned my DC and it ran for hours until I noticed. I came into the shop to find that three of the diffuser lenses on my 4' fluorescent fixtures were on the floor. The DC was pulling air from outside through the ridge vent, through the attic and into the shop via the holes in the ceiling sheet rock where the electrical penetrates for the lights. The DC basically sucked the lenses off the lights.

I think I need to create a few adequate vent holes in the ceiling and use the ridge vent for make up. 60 linear feet of ridge vent should allow a 6" DC main line to function fine. (I hope.)