My strange equipment room

[Mesozoic]

Getting closer to finishing my garage build - I have an office that is adjacent to a sound isolated 6'x9' equipment room. The air compressor, dryer, and related filtration equipment will be installed in the equipment room on one side. I would like to place network equipment on the other side. This includes a couple of rackmounted computers and a server, UPS system, as well as a cable modem, router, and some other network devices. As all of this equipment generates a fair bit of heat, a 110 cfm exhaust fan has been spec'd out to facilitate fresh air flow through the room.

One question I've been pondering is whether a single 110 cfm exhaust fan is sufficient for my equipment room. The other question is whether computer equipment and a 5 hp air compressor, being co-located in the same enclosure, are going to co-exist nicely. Thoughts?

 

[cvairwerks]

No and no... Ever look at a circuit board that has been in any kind of a shop atmosphere?. We consider the computers out in our hangars as expendable items.

 

[nadogail]

If it is noise insulated, it is also thermo insulated, IMHO it will get hot and your equipment will suffer from the heat.

 

[sberry]

I would say it depends on the heat, the equipment doesnt have feelings and normally doesnt mind other stuff if hi freq isnt next to it. You are already in AZ, how hot is it anyway? If the shop is conditioned pull the air from it thru the room.

 

[wyliesdiesels]

Technology is what i do for a living.

Your equipment wont be happy in there without some air conditioning.

Can you get a mini split?

 

[Mesozoic]

The shop is equipped with a 3-ton HVAC. The garage has R19 exterior walls, but one of the walls is R35 as it is shared with the main residence. The ceiling is all R38. I've got a couple of garage doors with R9 ratings and some insulated glass on one door. The room has the 110cfm fan spec'd as well... the heat should hopefully not be the worst of the issues... it's more the vibration from the compressor I was concerned about, but don't really know!

 

[wyliesdiesels]

The shop is equipped with a 3-ton HVAC. The garage has R19 exterior walls, but one of the walls is R35 as it is shared with the main residence. The ceiling is all R38. I've got a couple of garage doors with R9 ratings and some insulated glass on one door. The room has the 110cfm fan spec'd as well... the heat should hopefully not be the worst of the issues... it's more the vibration from the compressor I was concerned about, but don't really know!

I would still get some AC flowing in there.

as to the compressor, will it be in the same room and will the vibration transfer to the rack?

 

[Mesozoic]

I figure when the exhaust fan is running it will pull cool air through the ventilated door.

As for the compressor, yes it will be in the same room as the server rack. The slab is about 8" thick or more (reinforced w/#3 rebar at 18" centers both ways). I have some rubber isolators for the compressor feet, so hoping there won't be significant vibration, but not really sure yet since I haven't fired it up yet.

 

[couch67]

If there isn't any yet, I'd have some kind of filtration for the incoming air - maybe add a filter to the inside of the door, in front of the louvers? This will impact the flow rating of the exhaust fan, how much will depend on the filter, but I wouldnt want to pull unfiltered shop air through a server room.

 

[Kaizen]

Make the room smaller and locate equipment on shop side of soundproof wall. Isolated would be better.


Sent from my iPhone using Tapatalk

 

[matt_i]

How hard are you running this compressor? Running a blast cabinet is a lot different than just airing up a tire and triggering a 1 time tank fill....

All you're really trying to do is cool the room with the existing shop's AC. More flow is good, I can't comment on the 110CFM but you'll know soon if its working or needs more.

 

[Mesozoic]

Thanks for all the feedback and suggestions.

Today, I had a chance to run my concerns past my HVAC sub and the owner of the business, who is a mechanical engineer, helped me out. First off, the 110cfm fan is apparently total overkill for the 6'x9' closet - it exhausts to a 7" T-top duct at the roof. He's going to add a Y section near the ceiling so I can run an auxiliary server HVAC system that exhausts into the same duct. The sizing of the exhaust fan and exhaust ducting was done using a tool that performs the Manual J calculation. Anyhow, I think we're good on the cooling air situation at this point.

 

[Mesozoic]

I am in need of a computer controlled 2-speed switch. This is to control the exhaust fan in the equipment room. If the compressor turns on, I'd like to detect the activation using any viable method (analog digital conversion, etc.) and run the exhaust fan for the duration of the compressor activation, followed by a 5-minute period of running after the compressor turns off. I'd also like to automatically turn the fan on if the server equipment is active and the inlet temperature measurement to the enclosure exceeds 80F.

 

[kj_mustang]

I think you would just need a thermostat controlled exhaust fan. Set it at the turn on and turn off temps.

 

[sberry]

Agree, simple thermostat. You don't got to put every gadget they ever invented on it.

 

[Mesozoic]

Agree, simple thermostat. You don't got to put every gadget they ever invented on it.

LOL fair enough

 

[APEowner]

Where does that fan exhaust to? If it's outside then you may have an issue with not getting enough makeup air from inside the building particularly if it runs for any length of time.

The last place I worked we could never keep our server room cool even after they added a second exhaust fan and blocked the door opened. I changed the hose from the first fan so that it dumped back into the building and turned off the second fan and it cooled right down.

 

[Mesozoic]

Where does that fan exhaust to? If it's outside then you may have an issue with not getting enough makeup air from inside the building particularly if it runs for any length of time.

The last place I worked we could never keep our server room cool even after they added a second exhaust fan and blocked the door opened. I changed the hose from the first fan so that it dumped back into the building and turned off the second fan and it cooled right down.

The fan exhausts to the roof. I had an HVAC mechanical guy design everything, so I'm hoping it's all good. There's actually a 3-ton mini split that cools 2 zones in the shop, one dedicated indoor unit for the office (130 sqft) and another for the entire shop space (over 1500 sqft). I'm kind of assuming that the indoor units have the return air duct integrated within them. I've had the same thoughts, though... where does the fresh air come from if the HVAC is off and the equipment room exhaust fan is active?

 

[kj_mustang]

Pulls from every leak in your building envelope.

 

[Mesozoic]

Pulls from every leak in your building envelope.

I wonder if it would be a smart idea to install a suction flap that is normally closed if there is positive pressure in the building, but opens up to allow something like an exhaust fan or other consumer of indoor air to flow freely from the outside.

 

[sberry]

Negative pressure for orderly flow. Draw on the building, tune it. Normally tuned by limiting the air. For a room limit the air to it while having free flow in to the building.
A clean room is positive, blows everywhere like a baloon.

 

[sberry]

Up a couple posts, they blocked the door open. It doesn't flow right. Too tight it doesn't flow. Hold door shut with light rubber band. Play with the opening to tune it, can feel and hear it.

 

[ericm]

Why not run the exhaust fan outlet into the rest of the shop? Then you'll just be circulating the shop's conditioned air through the server/compressor closet.

 

[Mesozoic]

Up a couple posts, they blocked the door open. It doesn't flow right. Too tight it doesn't flow. Hold door shut with light rubber band. Play with the opening to tune it, can feel and hear it.

Good idea. Once it's all built, I'll conduct a positive/negative pressure test with various systems on/off to see if it's deficient anywhere.

 

[American Locomotive]

IMO, no need for air conditioning for normal consumer grade computers (and servers). Things like routers and modems are typically rated for 100-105°F ambient temperatures. Most desktop computers and servers are perfectly fine at 90°F+ ambient temperatures.

The classic idea of 70-72°F ambient temperature for equipment basically has its roots in the real old days of punch-cards with human operators needing to be right next to the equipment. There's a trend lately of "high ambient" data centers, which have servers running in 80°F+ temperatures. Google has a few facilities that have no conditioning at all and run the servers in 95°F ambient temperature. Dell has a line of servers they guarantee for up to 115°F ambient.

Put a thermostat in the space to turn the fan on if the temperature gets over 80-85°F. You'll be good. You'll likely need more than 110 cfm though. Probably need something more in the 500 CFM range. Make sure the space is vented to the outside as well, so the fan will only draw in outside air, and not conditioned air out of the space.

 

[wyliesdiesels]

The fan exhausts to the roof. I had an HVAC mechanical guy design everything, so I'm hoping it's all good. There's actually a 3-ton mini split that cools 2 zones in the shop, one dedicated indoor unit for the office (130 sqft) and another for the entire shop space (over 1500 sqft). I'm kind of assuming that the indoor units have the return air duct integrated within them. I've had the same thoughts, though... where does the fresh air come from if the HVAC is off and the equipment room exhaust fan is active?

There is no ducting with mini splits

The indoor unit just ***** the air in thats around it, pulls it through the evaporator coils and then blows it out the front.

So there is no pressurizing of the building since its only sucking in air thats around it.

theyre not like a central system that creates air pressure in the whole building

 

[Ole Slewfoot]

I was called to a grow room...well, more like building than room, there were a lot of fans and fancy controllers, and it wasn't working well. What I discovered was since they all (4 12"s and a 10") pulled from the same place, negative pressure might have one or two fans idling backward, then when it got hot or humid, a controller sent power, and the fan would come up to full speed in reverse

 

[Mesozoic]

Thanks all.

Regarding the 110 cfm fan, I believe that is already on order. For the room size, I was told that it is overkill. Since I have a small 1-ton Tripplite HVAC specifically to cool the computer equipment, a 5" exhaust duct for that was added to the equipment room as well which joins the 7" main duct for the 110cfm fan out the roof. We'll see how well it does once construction is finished and I can setup all the equipment.

 

[American Locomotive]

The exhaust fan you ordered is likely acceptable for an unoccupied room or an attic, not one with equipment in it. Air compressors waste most of the electricity they use as heat. We can estimate that the compressor will generate around 3KW of heat when in use. 3kw of heat is 10,200 BTU/hr, which will result in a 70+ degree temperature rise with 110 CFM of air-flow. Obviously that would require the compressor to run continuously for a long period of time (like an hour) to heat the room up that much, but it certainly is possible if you do any blasting.

Not to continue to rain on your parade, but a 1-Ton Portable AC with a single outlet house (like that Tripplite) will likely actually make your server room or garage hotter in your climate.

Basically, for every cubic foot of cool air an AC blows into the space, it generates a cubic foot of hot air outside. Single -hose Portable ACs take air from inside the space, and then exhaust it outside. That air that they take from inside the building needs to be replaced, and there is only one place that air can come from - outside. So if it's a 95-degree day in Tucson, that means every bit cool air you feel blowing out of that Tripplite has an equal amount of 95-degree hot air being pulled into that room from outside through cracks and gaps in your garage.

 

[wyliesdiesels]

The exhaust fan you ordered is likely acceptable for an unoccupied room or an attic, not one with equipment in it. Air compressors waste most of the electricity they use as heat. We can estimate that the compressor will generate around 3KW of heat when in use. 3kw of heat is 10,200 BTU/hr, which will result in a 70+ degree temperature rise with 110 CFM of air-flow. Obviously that would require the compressor to run continuously for a long period of time (like an hour) to heat the room up that much, but it certainly is possible if you do any blasting.

Not to continue to rain on your parade, but a 1-Ton Portable AC with a single outlet house (like that Tripplite) will likely actually make your server room or garage hotter in your climate.

Basically, for every cubic foot of cool air an AC blows into the space, it generates a cubic foot of hot air outside. Single -hose Portable ACs take air from inside the space, and then exhaust it outside. That air that they take from inside the building needs to be replaced, and there is only one place that air can come from - outside. So if it's a 95-degree day in Tucson, that means every bit cool air you feel blowing out of that Tripplite has an equal amount of 95-degree hot air being pulled into that room from outside through cracks and gaps in your garage.

This is why the dual hose portable AC units are great

 

[Mesozoic]

The exhaust fan you ordered is likely acceptable for an unoccupied room or an attic, not one with equipment in it. Air compressors waste most of the electricity they use as heat. We can estimate that the compressor will generate around 3KW of heat when in use. 3kw of heat is 10,200 BTU/hr, which will result in a 70+ degree temperature rise with 110 CFM of air-flow. Obviously that would require the compressor to run continuously for a long period of time (like an hour) to heat the room up that much, but it certainly is possible if you do any blasting.

Not to continue to rain on your parade, but a 1-Ton Portable AC with a single outlet house (like that Tripplite) will likely actually make your server room or garage hotter in your climate.

Basically, for every cubic foot of cool air an AC blows into the space, it generates a cubic foot of hot air outside. Single -hose Portable ACs take air from inside the space, and then exhaust it outside. That air that they take from inside the building needs to be replaced, and there is only one place that air can come from - outside. So if it's a 95-degree day in Tucson, that means every bit cool air you feel blowing out of that Tripplite has an equal amount of 95-degree hot air being pulled into that room from outside through cracks and gaps in your garage.

Thanks for this deeper analysis. I think that if the portable HVAC unit turns on, pulling the air from outside of the room is fine because 90% of the time, the main workshop will not have its dedicated 24,000 BTU/hr HVAC running. That being said, the adjacent office to the equipment room has its own dedicated 7000 BTU/hr indoor coil and that will likely be temperature controlled 24/7.

Another option for cooling the equipment room is for the environmental sensor for the Tripplite HVAC to be placed in a general location that senses overall ambient room temperature. Additionally, the HVAC, instead of having its cooling output directed into the server rack enclosure can be set to cool the room in its entirety. This would serve to aid the computer equipment and the compressor when active. Does that sound like a better plan based on the compressor's thermal load?

This is the guy: https://www.tripplite.com/smartrack...-small-server-rooms-network-closets~SRCOOL12K

 

[American Locomotive]

What I'm saying is that on a 95+ degree day, that portable air conditioner won't be doing much to actually cool the room down. The hot air it exhausts outside of the room through the duct will cause a negative pressure, pulling just as much 95 degree outside air right back into the room. If it doesn't directly pull the air into the equipment room, it will instead pull 95+ degree air into the rest of the space, making the rest of the space get hotter.

You'd be much better served by a through-wall unit, or a mini-split. Or really, just get a 500+ CFM exhaust fan, and install an intake duct as well. That way when the fan turns out, it just pulls in outside air directly into the room.

 

[Mesozoic]

Well, while it's not my worst nightmare, it sounds like a fresh air inlet for the equipment room is out of the question at this point. The only saving grace is that this is an attached residential garage addition, so will not be used as much as a real shop.

 

[wyliesdiesels]

Thanks for this deeper analysis. I think that if the portable HVAC unit turns on, pulling the air from outside of the room is fine because 90% of the time, the main workshop will not have its dedicated 24,000 BTU/hr HVAC running. That being said, the adjacent office to the equipment room has its own dedicated 7000 BTU/hr indoor coil and that will likely be temperature controlled 24/7.

Another option for cooling the equipment room is for the environmental sensor for the Tripplite HVAC to be placed in a general location that senses overall ambient room temperature. Additionally, the HVAC, instead of having its cooling output directed into the server rack enclosure can be set to cool the room in its entirety. This would serve to aid the computer equipment and the compressor when active. Does that sound like a better plan based on the compressor's thermal load?

This is the guy: https://www.tripplite.com/smartrack...-small-server-rooms-network-closets~SRCOOL12K

Thats the issue though. The portable will be sucking in the hot shop air.

If you dont want hot air being sucked into the room, you either need to get a dual hose portable (which intakes hot outside air to cool the compressor and then blows the hotter exhaust air back out the other hose) or get either a mini split, which doesnt have an exhaust or a wall unit with an exterior exhaust.

 

[Mesozoic]

I do have a 3-ton Daikin mini split going in, but I've only got 2 out of 4 ports scheduled for connection. I think I'm going to wait and see what the inlet temperature on the server equipment and overall room temps will look like before committing to any additional HVAC. The equipment room shares only interior walls, so a wall unit would not work in this case.

 

[wyliesdiesels]

I do have a 3-ton Daikin mini split going in, but I've only got 2 out of 4 ports scheduled for connection. I think I'm going to wait and see what the inlet temperature on the server equipment and overall room temps will look like before committing to any additional HVAC. The equipment room shares only interior walls, so a wall unit would not work in this case.

then a mini split is the way to go

 

[Mesozoic]

I wonder how much the sub will charge for adding a 7000 BTU/hr indoor coil after the garage is finished.

 

[American Locomotive]

7,000 BTU/hr will not be able to remove all the heat generated by the compressor and air-dryer during sustained use. It'd probably do okay as long as you're not running your compressor for more than 30 minutes continuously.

 

[Mesozoic]

I finally got my compressor running and with the aftercooler installed and everything, it heats up that equipment room FAST. I've even had the motor go into thermal overload and shutdown while running it continuously (DA sanding). I need to do something better than a 110cfm fan in there to exhaust the heat. The only way it seems to stay cool enough to run continuously is by setting up a high velocity floor fan blowing directly at the motor, have the 110cfm exhaust fan running at max speed, and have the equipment room door open so the floor fan can **** in cooler air from outside the room.

I'd like to be able to **** the heat out using a higher capacity exhaust fan, but not really sure how much capacity is needed. Is it even possible to do this or would it require a 2000 cfm fan or something impractical like that? I'd prefer to avoid having the floor fan altogether and would like to keep the equipment room door shut too (has a 1'x2' fresh air grill installed at the bottom of the door).

 

[wyliesdiesels]

Evap cooler? window air conditioner mounted in the wall?