Effect of Relative Humidity on compressors

[TravisD]

So @rob.mwpropane and I were talking elsewhere, and the topic of "should you run the compressor on a humid day" came up.

Kind of what was in another thread:

RIX SA3. How to monitor the filter stack

That’s at ambient pressure and freezing to super hot we’re talking modest changes in temp and, at pressure. At scuba pressures we’re talking grains per lb. I understand, but it's a pretty substantial difference. Only pumping when ambient temps are lower makes a lot of sense on paper (to me)...

scubaboard.com

Mainly (I think) the concern is about impact on filter life - does pumping humid air result in more moisture making it's way to the filter stack, in an otherwise correctly functioning compressor?

I know heat is our enemy... so is it better to run the compressor when it's cool, but damp out, or wait until it's dryer, but might be warmer?

I'm kind of getting the impression that the compressor is going to squeeze all of the H2O out of the air regardless - and as long as it's not overwhelming the water separators, what comes out (and into the filter stack) is dry regardless?

 

[rhwestfall]

How Summer Heat Affects Your Compressed Air System

The heat and humidity of summer can put extra strain on your compressed air system. Read how Summer heat affects your compressed air system

www.walkerfiltration.com

 

[rhwestfall]

 

[TravisD]

So my reading of that - and the "5 top tips..." that they link to, is that they are speaking to a market where water coalescers (coalesci?) are not the norm - unlike the Breathing Air compressor market.

If the water separator can remove "99%" of the water from the air, then what's left is really going to vary very little with intake air humidity, right?

 

[rjack321]

So my reading of that - and the "5 top tips..." that they link to, is that they are speaking to a market where water coalescers (coalesci?) are not the norm - unlike the Breathing Air compressor market.

If the water separator can remove "99%" of the water from the air, then what's left is really going to vary very little with intake air humidity, right?

Correct what's left is 100% saturated and the amount of water it holds has nothing to do with outside humidity. It has everything to do with the temperature.

On for instance a 25C day, the drains on a Key West compressor will vent more liquid than drains on a compressor in Phoenix. The amount of water going into the filters in Key West is exactly the same as the amount of water going into a filter running in Phoenix however - cause that outlet temp is going to be the same.

 

[rob.mwpropane]

@TravisD as we discussed, I always shoot for cooler temps. Do not care what the humidity is, the only thing that I end up doing (because of humidity) is draining the coalesers more in the summer. Not all of us are blessed with automatics!

I have a timer that goes off on my phone, so I'll start with every 10 min in the summer and switch up to every 15 or even 20 in the winter. Depends of how much I see at the 1st bleed.

@RayfromTX has a few good posts about this and helped me to change my understanding;

Financial planning, compressor

sorry for a potential thread hijack, but i noticed temperature was mentioned several times throughout this thread. would running a compressor and or booster out of a backyard shed become an issue if summer temperatures run well into the 90s at times? The more humid the air is the faster you'll...

scubaboard.com

 

[TravisD]

Good thread pointers! Thanks! Off to read more....