Oversized Air Dryer

[ElginAgai]

Is there any downside with running an oversized cycling air dryer? I mean besides the possibility of wasted energy?

I recently purchased a used Ingersoll Rand 100CFM (D170ECA100) cycling refrigerated air dryer and am planning on running it with my Quincy 340 (7.5hp so about 22cfm).

I was hoping that the gross oversize of the dryer would compensate for not having an aftercooler, but the IR sales man told me that's not how it works. Anyone have any thoughts on that? I'm guessing that air straight off the compressor will just be too hot for it to be throughly cooled during it's short trip through the dryer.

 

[engineer2]

Nice Air Dryer! There are basically two type of refrigerated air dryers. High temperature ones that you connect directly to your compressor and regular ones that should have an aftercooler.

Your model has a Max Inlet Temp. Rating of 100F. This is not a hi-inlet temp model. Whether or not you need an aftercooler depends on how much air you use. I suspect you'll want an aftercooler to be on the safe side.

This model has digital controls, glycol cooling, and a cycling compressor, so running it way under max should be OK.

 

[sberry]

Just out of curiosity what are you planning on doing with it.

 

[ElginAgai]

Thanks! I think the salesman from IR said on the phone it was max 120F. I saw on a lot of sites they were listing max of 100F, but I think that's because it's only rated at 100CFM for 100F input. I couldn't find the specs published anywhere so I've asked the salesman to provide a spec sheeI. They've already provided me the owners manual, but it doesnt have detailed specs such as the max ambient and max input temps.

I'm planning to run it between the pump and tank so it's never gonna see more that 22CFM or whatever my pump can do, but nonetheless I think a custom air-to-air aftercooler is in order to get the input down to a reasonable temp.

I'm pretty excited to have scored this bad boy for $360, I think it was a great deal and it leaves me some cash to build an aftercooler. The thing that worried me is the salesman said it wont work for my measly 22CFM because it'd cycle all the time, but I can't seem to wrap my head around why that would be. Maybe he meant if I was running 300f input temps... I got the feeling he just wanted me to buy a new 35cfm high temp dryer from him for $2k.

 

[ElginAgai]

I'm planning on using it between my Quincy 340 and my 120gal tank. The primary use for all this dry air is for sandblasting, powder coating and painting. Secondary uses would be powering mechanics tools, blowing stuff off, snowmaking machine, inflating tires, you know the usual compressed air uses.

 

[engineer2]

I'm planning to run it between the pump and tank

Normally air dryers are installed after the compressor tank.

 

[like2wheel]

I would think even with moderate use the air temp directly off the pump would exceed 120°.

 

[pcmeiners]

Agree with Engineer2, output from a compressor is way over 120° F, get an aftercooler. An aftercooler of decent size, such as a Hayden 1290 will bring compressor output air temp to near ambient, at little to no ongoing cost. The D170ECA100 could likely do it but at electrical cost, also with the aftercooler you should get a lower dew point, basically dryer air.

 

[sberry]

I sandblast and paint and don't have any of that stuff. I add an extra receiver in series and some vertical pipe on the manifold, crispy dry.

 

[engineer2]

Just because you can't see the moisture doesn't mean you don't have any. Many factors involved: ambient temperature and humidity, tank pressure and temperature, aftercooling, and ultimately pressure drop at point of use. If your ambient humidity is below 30-something percent, you may not get any condensate at point of use, depending on all the things above. For example people in Florida need an air dryer many more days than in upper Michigan.

 

[sberry]

Sure, I agree. I am not sure how a guy would really tell in practical use, how do we measure what effect it has and how much,,,? Spose there might be a speed of rust test? abut I know a **** load of career body types never worry themselves much about it. I had some old under floor plumbing and would get some water down at the ends in traps, went overhead steel and not so much as a drop, never. My building is not warm but dry, I get some in the receiver. Get it in my main comp tank.\ I changed as couple fundamental things in the main manifold seemed to help the most.

 

[sberry]

There are a couple minor glitches that matter to only the most obsessive and I got to realize because it could be better doesn't mean it has to be and it is way better than it was and it worked then.
The breaker is of off to the blue one, using it as a tank, they both T to the receiver thru 1/2 hyd hose. Make if fed from 2 hoses really, I can fully valve isolate each unit. Blue is my back up and can flip it on for demand should I wanna blast a little or want to sand more than 20 minutes at a time.
The green one is 3 HP Quincy and the master here, with the big jugs it will do the work. Less longer cycles, smaller motor starts, on 24/7 Doesn't even flutter the lights. Its quiet enough with the baffle, it could be fixed a little but it works.

 

[stonesfan68]

I'd recommend getting an after cooler and installing it between the pump and tank. Then pipe from the tank to the dryer. That dryer is oversized for sure, but since it is a cycling unit it will just run as needed. There shouldn't be any problems as long as you install the after cooler.

 

[ElginAgai]

I was initially thinking that I wanted this system to use a dry storage tank, in which the air is dried before being stored in the tank instead of a wet tank where the air is dried after the tank. It seems as though this is usually done to prevent overloading the dryer during peak demand because the dryer only needs to be able to handle the capacity of the pump.

I suppose due to the circumstances of this not being a high temp dryer and the fact that it's 100cfm capacity should meet my peak demands, there is really not much benefit to running it before the tank. Whereas there's several benefits to having a wet tank, it will allow moisture/oil to drop out and drop the temperature 8-10F, thereby improving the efficiency of the dryer and ultimately providing dryer air as long as my use is limited to less than 100CFM. Also the wet tank will take some load off the pump as it wont have to force the air through the after cooler, filter and dryer before going into the tank.

The plan now is to do as advised here, Pump > After Cooler > Tank > Filter > Refrigerated Dryer, then I'll use my existing filter/regulator setup at the point of use.