Electric indoor brewers: What size (CFM) bathroom fan? (pics)

[bakins]

I don't use a hood at all. All electric, 5 gallon batches. 800 square foot finished basement - all very open. Just run a fan to disperse the steam and always have a dehumidifier. Been doing this for over a year. Never have condensation on anything or "clouds of steam." Maybe because I have a relatively large space? FWIW, before I finished it, it was 80-90% humidity in the basement - that's just part of living in Georgia. I keep it at 40% now.

 

[kal]

One thing you could do to enlarge the holes. Lay out the bigger holes with a piece of cardboard. Once you go over it in your mind about 10 times, rent/borrow a 1/2" hammer drill and 1/4" & 3/8" bits. You should be able to rent/buy long enough drill bits to get through. Even if it won't quite go all the way through, you can make it work with 2 passes. Then, drill around the perimeter of the circle with the small bit making the holes 1/2" apart. Go back around with the big bit and enlarge the perimeter holes. Take a chisel and 4lb. shop hammer and connect the dots. Remember, you are going to slick down the outside with mortar or something stronger so even if the hole is ugly, you can fix it. That's such a nice room that it would be a shame not to have it as "perfect" as possible. Luck - Dwain

Good idea Dwain. I actually have a hammer drill (not sure if it's 1/2" - probably not) and bits of all sizes with a 12" extension rod. I'll try with the holes that are there now and if there's too much CFM drop I'll go with making one of the holes bigger (to 6" probably).

I've been thinking about the condensate hood. I have no need for anything too huge (I don't think). I'm thinking about having a shop make up stainless box something like this commercial unit:

Commercial stainless condensate hoods are crazy expensive ($700 to the sky's the limit) and most are too big anyway.

I'd exhaust out the side like this instead:

(Excuse the quality of the image... an artist I am not!)

Is exhausting out the side of this custom hood a problem? I only ask because every commercial unit vents out the middle top. It's a pretty small unit so I'm hoping it would be ok. I could see going out the side problematic if it was, say, 4 feet long.

It's basically a box without a bottom, but with a small 1" or so lip all around the inside bottom to catch condensation and a drain in the corner. Total distance from the custom hood to the outside is about 4-5 feet.

Does this make sense? I would simply drill 4 holes inside the "roof" near the corners and bolt it directly to the ceiling and then silicon caulk over the bolts to ensure no leakage.

Hopefully that would provide enough airflow. Unlike regular range hood fans the Vertex inline fans are supposed to be very good with static pressure meaning that smaller diameter duct and turns isn't going to severely reduce the CFM output.

If the airflow's not enough I could increase the wall hole diameter from 4" to 6" or exhaust out the other 4" hole too. I really hope neither is needed.

The other thing is that the hood doesn't even need to be stainless. Any sort of non-organic material will work for a hood (acrylic, formica, etc),
since you don't need to be concerned about flame/heat/grease from a grill top. I could build something temporary myself to see how it performs first.

Kal

 

[user 29649]

Something like this would make a good hood.

Tamco® Heavy Duty Polyethylene Tanks with An Internal Flange - US Plastic Corporation

 

[kal]

An update...

After much tinkering and thought I decided I don't really have room to vent out the hole on the right (same side of the room as the sink and kettles) because of the sink goose-neck arm. So the Vortex 400CFM fan has been installed to vent out the left side hole and the right side is a fresh air intake now (plugged up in the picture below):

With the tiny size of the room I thought that maybe just running the fan like this would be enough to keep moisture out of the room so I boiled up 10 gallons but after 20 minutes the walls were already completely dripping in and around the boil kettle so some sort of condensate hood over the boil kettle is needed.

My plan now is to get a custom stainless hood built from a local shop. It'll have a drip lip too with a drain into the sink. Before doing that I wanted to test out the size/shape to make sure it vented properly. So I built a temporary one for $20 out of pink foam:

The test hood worked extremely well. It's 5' long x 1' high x 2' wide. Walls stay completely dry. 99% of steam goes where it's supposed to go. The control panel eventually goes on the wall out of the way of course...

The only issue is condensation build-up in the exhaust vent and the Vortex fan. With a screw removed from the bottom of the fan it drips every second or so so there's a lot of condensation. The little black compartment on the side of the fan where the power cord goes in also had water in the bottom of it (it seeps in from the inside of the fan). Not good I would imagine since it houses all of the electrical connections and a capacitor. I thinking I'll need to seal it up nicely and let condensation drip out the bottom of the fan into a bucket of some sort.

I'm still concerned that the Vortex fans are probably not rated for moving steam like this however...!

I'm also wondering if I'll have enough room to stir and maneuver with a large hood like this over all 3 pots (including the MLT which will need to be stirred during dough-in). Wondering if I should just get a smaller hood made that *only* goes over the brew kettle. Any thoughts are appreciated.

Kal

 

[Hang Glider]

angle the front out somewhat? - for room to stir.
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that's an insane controller!

alternate fan source?

 

[Burgia]

If you're getting a hood made they should calculate all this for you. If the person making this knows what they're doing you can tell them how long and tall your hood needs to be and they can design it so that it works better. It's not all about CFM (quantity of Air), you also need to look at FPM (speed of Air).

The manufacturer of your hood can calculate the speed that they need to move the air to effectively pick up the steam. I used to work in the sheet metal duct industry and have made lots of these kitchen/exhaust hoods. It's all about the opening in the bottom of the hood. Say you need a 10' long hood, well they will basically weld slats in the bottom of the hood and space them evenly (reducing opening size) to move the air at the speed they need. (hope this makes sense)

Also 4" pipe is pretty small to move 400CFM and I don't know how much static that fan will handle, but it could really be choked out and slowing down way to much to move the steam out fast enough to prevent it from turning to water in the duct. You should definitely look up the stats on the fan and give them this info. A duct calculator will give them the static pressure. I may actually have one at home that I could look at for you later. You may need to step up the pipe size.

Insulation will also help the condensation.

 

[Sean]

You might use a filter like in restaurant kitchens. They are meant to catch airborne grease, but the same idea should work for airborne water.

If the back of the hood were lower than the front, with the sides angled, the water could collect on the filters, condensate and run down toward the back into a channel that drains into the sink.

If you search for hood pics, you will see what I mean. Or ask to tour a large restaurant when they are not busy.

 

[kal]

Thanks for the ideas guys!

Insulation will also help the condensation.

Interesting. Never thought of that but it makes sense: Helps keep the water from condensating as soon so more of it should escape the house as steam. Very interesting.

Some comments:

If you're getting a hood made they should calculate all this for you.

Yes, a good place will build/sell you what you need but this fan is reasonably small for this size hood but it seems to work just fine. I will ask them about it however. I didn't want to spend $500-800 on only the exhaust fan however not to mention that I don't really have room for it. The Vortex ~450CFM fan I'm using I'm told is very good with static pressure. It has 6" openings and everything is 6" except for the last foot to the outside (which is 4"). In tests it's able to exhaust the room very nicely during a full 10 gallon boil.

angle the front out somewhat? - for room to stir.

I thought of making it slanted but see the pictures above: I need to evacuate out the front as in the pictures. I can't do it out the back or the top. So slanting would be difficult to do I think.

You might use a filter like in restaurant kitchens.

If I used grease filters as is used in a regular grease hood it would work but they'd have to be installed on the front (closer to the operator) which I'm not sure would fit or work right. But it may - it's interesting thought.

I've been talking to these guys here: FASTKITCHENHOOD Fully Stainless-Steel Kitchen Hoods

I got some quotes on their heat hoods but the possilbly of using one of their grease hood looks interesting actually. Or a combo of the two. Just something to catch some extra condensation.

I'm also considering not making it 2x5' but 2x2' to only cover the brew kettle. 2x5' looks nicer though.

Food for thought. Thanks guys.

Kal

 

[Burgia]

My expertise was mainly in fabrication but I did pick up some knowledge of air and ventilation. We mainly worked in dust and smoke collection and an occasional kitchen hood. Obviously steam only, is a little different but I was thinking.

What if you built a larger box to connect directly to the inlet side of your fan? In the bottom of the box you would need to put a clean out or drain door. My theory behind this would be that the steam would move through your 6" pipe at a fast rate and would slow way down once it hits the larger box. Causing the moisture to fall to the bottom of the box. After cooking you could open your drain door and allow the water to run out.

We did this all the time in dust collection. It was called a cyclone effect. You had to determine how fast you needed to move the air in order to move the dust. The dust would be carried back to another chamber in which the air was moving much slower and fall into a collection bag or barrel.

This may be a crazy idea, I don't know. I haven’t worked with steam much other than kitchen hoods and they mostly had grease filters and the fans were set up to handle grease and moisture.

 

[cyberbackpacker]

Earlier this year I asked about using a "chimney" on your bk like major breweries do in order to evacuate the steam. That link is here: https://www.homebrewtalk.com/f11/cone-chimney-bk-112972/

It is relevant because I think you can solve your condensate problem with a condensate trap. ClaudiusB shows his setup here:


https://www.homebrewtalk.com/f11/cone-chimney-bk-112972/#post1246241

Later in the thread there are some crude drawings/etc and discussion about condensate traps. This was in regards to a chimney, but I believe just as pertinent for hoods.

Just my .02




...

 

[Burgia]

Looks good Cyber. You may be able to get away with a "T" but I think with the velocity you have it would pass over and not fall out. I think you could put a 12" X 10" box in your 6" duct line and put the condensate drain out of the bottom of the box. This would allow most of the moisture to fall into this box and out the drain. I also like the cone, don't think it would work in this setup because you would need more than one, but I like it. Easy to fabricate too.

 

[BrewBeemer]

That 10" x 3" (30 sq/in) box ducting has a sectional area match of one 6" duct (28.27 sq/in), then your really hurting yourself reducing it to one 4" thru the wall, your down to down 12.56 sq/in). Add the ducting CFM resistance with a few bends your really hurting your system. If I were you I would rent a 8" diamond concrete hole saw, make a plywood guide to center the concrete hole saw to start the first 3/8" then punch out both of those existing 4" holes to 8" diameter. One for the cold air inlet ducted to the very back of the room and near the floor the other to your exhaust hood. That 746 cfm in line duct fan sure looks like winner to me if it were my brewing room as those high cfm numbers are without any ducting added. Even 10' of straight 8" ducting added to that 746 cfm fan will add backpressure and reduce the final cfm numbers of that fans ratings before you start adding any bends plus screens at the outlets preventing critters from entering from the outside. You already stated your having sweating walls from a short boil time wait until you have a 90 minute boil. I would be more worried about the heat buildup on your wine bottles stored in your brewing room also. The 8" duct with 50.26 sq/in of cross sectional area, you take this with the additional flow resistance of the ducting plus a few bends, bends kill your CFM's faster than about using any step down in duct sizing. Your system is clean and top notch in design plus equipment I would hate to see it ending up with a bad venting flaw. As mentioned by another members reply to have a flaired out hood vs straight sided plus all the other good features like the condensation drain gutter with line off the hood. Build it once right is far cheaper than twice I recall was also posted above. A Milwaukee Hole Hog would be a great powerhead to turn that hole saw, use tape and duct seal to direct the slurry when adding water to cool and flush away the cement as this would be a rather quick coring process. Two people, a hand square for a straight hole plus plan on getting a little dirty and wet. With the first class brewing system you have why go cheap at the very end here as your comfort will be a big factor with future brewing with a good vent system.
I'm thinking it would be great idea to have a inline duct fan on the fresh air side also for a constant and even air pressure in the brewing room as outside the door to it. I can spend your money rather easy, it's fun also. JMO's as I was taking classes to become a "Tin Knocker" many years ago and we had to figure out the correct CFM's, fan sizes to match the duct length runs.

 

[psyber]

An update...

Kal

I wish I had some sort of erudite response to help ya out but I got nothing.

However, your control box looks incredible. Did you get it from NASA?

 

[ftlstrings]

You might want to check out your original post again. In that third photo I'm pretty sure that it's only two feet...

~M~

 

[shan196]

What if you built steps down from that patio and hid the fan in there? you could make it have a water tight enclosure so it wouldn't be exposed to the elements and then you could vent out the side thats closest to your kettle.

BJ

 

[kal]

Fast forward ~ 2 months....

I've now got a custom vent hood installed and brewed my first batch 2 days ago. The hood and fan works great!

Kal

 

[CodeRage]

Beautiful job mate! Where'd you have the vent hood made?

 

[kal]

A place about 2 hours from me in Montreal Canada: FASTKITCHENHOOD Fully Stainless-Steel Kitchen Hoods
I solicited half a dozen places with my drawings. They were about 1/2 the price and responded first. Fantastic service. If anyone does call, tell Sandro (the guy who runs the place) that Kal from Ottawa sent you!

Kal

 

[kal]

Fast forward more than 1 year....

I've finally gotten around to documenting the ventilation system used in my brewery.
Take a look here: http://www.theelectricbrewery.com/ventilation

Some pictures:

Testing with a prototype hood:

The final hood installed:

Kal

 

[klyph]

Looks great, I'm working on a conical hood for my kettle right now, thanks for the inspiration!