Oversizing a compressed air dryer???

[loganb]

Perusing FB marketplace and stumbled across this compressed air dryer:





Seller says it works, filter change light is not on but he bought new and never changed it so will need it eventually, light usage in home shop

Based on their current sales lit, it appears to be the 40 CFM model:




It seems like stupid overkill for my 5 cfm compressor with intermittent usage in a more woodworking/house repair based garage. No painting, sandblasting or even heavy impact tool usage....

But it's $100 and is around 30 minutes away....so it's awfully tempting

Main question is....what is the risk or downside on these in an intermittent usage environment on something that is so oversized? I'm plumbing the 3 car garage right now with Rapidair, but I still doubt I used compressed air for more then a couple times a week for air tools or blowing some things off etc...some eventual light usage operating some small pneumatic cylinders. Big compressors generally like to just run and run so I'm assuming the same is for the dryers?

I get that it's insane overkill....and I shouldn't go after it and just put a normal air filter/regulator/dessicant dryer on and move on....but if I did do it...what's the downside to a dryer in this type of application?

 

[Doubled33]

I think these are rated off of a baseline on temperature and humidity. Change either one of those and 40 cfm is not 40 cfm is is quite lower.

I run a Quincy 325 through a Quincy 45 cfm dryer and it works well with no problems. I do live in HI where it does get hot and is midly humid. Had the came set up in CA and it worked well there too.

 

[Beerhippie]

$100? Oh, hell yeah!

There's no real drawback to being over-sized and you'll be ready for when you upgrade the comp!

Dry air is a blessing in the shop.

 

[loganb]

I think these are rated off of a baseline on temperature and humidity. Change either one of those and 40 cfm is not 40 cfm is is quite lower.

I'm fortunate in that my workspace is air conditioned, so no loss of capacity due to ambient... But yeah the adjustment factor for derating capacity based on input air temp happens quickly

 

[mike93lx]

A $1500+ dryer that is working fine for $100? And you are asking us if you should?

Be careful of a scam, though

 

[danielbuck]

I'm not sure what the power consumption would be, that might be something to consider, but I imagine it wouldn't be that much $ to run. I'd go for it if you have the space.

 

[The Cobbler]

Be careful of a scam, though

yes, it almost sounds too good to be true.

 

[loganb]

yes, it almost sounds too good to be true.

Agreed.... So far it checks out. Nice looking garage and the seller name matches the owners name via assessors lookup. It's a rental he has and the detached garage is his car workshop. I've said I'll take it.... Meeting up this later this afternoon. If I can't make the space work it'll likely go to the farm shop

 

[loganb]

Now comes the hard part

 

[Shoreline_]

I don't know about this air dryer but with most AC systems there has to be a way to divert the refrigerant if there isn't large enough heat load on the evaporator. So there is either a thermal mass, variable speed / capacity compressor, or hot gas bypass or a combination. This is the problem with having an oversized ac unit.

For my garage I just have a 60 cfm dessicant dryer coming. At the rate I use the air it'll last forever before I need to recharge it.

Anyways good luck.

 

[loganb]

Well it's home:




Seller would likely fit into this crowd well. Working out of 2 shops with a variety of car projects in process...came from working on a Willy's, Chevy Square Body panels and trim were laying around as it was coming back from paint soon and there was a straight 6 out of a Plymouth that was just refreshed on a stand. Trying to reorganize where he did what work and was moving the metal working/welding/fab and this didn't fit in the layout so he wanted it gone...so I obliged. Dolly and pair of ramps made it easy to load up


Now what to do with it...it either ends up in the purple box shown here:



Or at another home if I chicken out...if so first shot for it will be to the farm shop as it's the right sized for the compressor there.

Either way...keep any compressor related advice or feedback coming....I'll probably move the saga of "where does it go" to my main thread in my signature here...but try and toss anything dryer specific back into here.

 

[loganb]

I don't know about this air dryer but with most AC systems there has to be a way to divert the refrigerant if there isn't large enough heat load on the evaporator. So there is either a thermal mass, variable speed / capacity compressor, or hot gas bypass or a combination. This is the problem with having an oversized ac unit.

For my garage I just have a 60 cfm dessicant dryer coming. At the rate I use the air it'll last forever before I need to recharge it.

Anyways good luck.

Yeah...it short cycling/not operating properly under a light load is a concern.

Would you mind sharing what desiccant dryer/housing you're using? Before stumbling on this I assumed I'd end up with one but hadn't made a decision about which one

 

[The Cobbler]

in true GJ fashion, it's a great score in any event. deserved territory of a "YOU ****"

 

[Shoreline_]

Yeah...it short cycling/not operating properly under a light load is a concern.

Would you mind sharing what desiccant dryer/housing you're using? Before stumbling on this I assumed I'd end up with one but hadn't made a decision about which one

Oh sorry it's actually not that large it's more like 40 cfm. I got it for free used, it's an Atlas Copco. It came on a European cnc machine that my friend scrapped out so I took it. It's comparable to the Atlas Copco CD series.

My dad works for an air compressor repair company. I don't talk to him much but I remember he told me that I don't want to just match the dryer to my machine, I need to match it to my process (plant CFM).

But I might add we never turn off the air dryer at work. And there is no one using air tools at night (obv it's a repair garage) and we never have problems.

 

[mike93lx]

Well it's home:




Seller would likely fit into this crowd well. Working out of 2 shops with a variety of car projects in process...came from working on a Willy's, Chevy Square Body panels and trim were laying around as it was coming back from paint soon and there was a straight 6 out of a Plymouth that was just refreshed on a stand. Trying to reorganize where he did what work and was moving the metal working/welding/fab and this didn't fit in the layout so he wanted it gone...so I obliged. Dolly and pair of ramps made it easy to load up


Now what to do with it...it either ends up in the purple box shown here:



Or at another home if I chicken out...if so first shot for it will be to the farm shop as it's the right sized for the compressor there.

Either way...keep any compressor related advice or feedback coming....I'll probably move the saga of "where does it go" to my main thread in my signature here...but try and toss anything dryer specific back into here.

You ****.

 

[zanyad]

deserved territory of a "YOU ****"

You ****.

congrats, you ****!

 

[danski0224]

Yeah...it short cycling/not operating properly under a light load is a concern.

This problem is solved with a bigger compressor.

Duh.

 

[loganb]

This problem is solved with a bigger compressor.

Duh.

LOL

This is actually how I decided to solve it...will be hooked up to this one in a month or so:




Which is not in my garage...but the compressor back in the farm shop.....picture from 10 years ago or so when I went and picked it up as it was closer to me at the time.

I starred at it for a long time yesterday...and it's just far too much overkill and work to put in for the minor air usage I've got with none of it involving "moisture fussy" processes like painting, blasting or plasma cutting. If one more appropriately sized popped up and I could put it up on the shelf next to the compressor...I'd probably jump on it...but would have to be cheap as well....so odds of that aren't great

So sent the spec's to Dad and he said he'd be happy to take it off my hands...so I'll store it for a bit then send it on it's way next time we go back or they come up.

 

[Beerhippie]

This problem is solved with a bigger compressor.

Duh.

Not necessarily. More air storage is more often the right answer. I buy hydro-tested compressor reservoirs from a local compressor company (Portland Compressor) for about $100 each and have them stashed all over the brewery. No short cycling, and machines that use a lot of air in short bursts are never starved.