DIY Refrigerated Air Dryer

pinballlooking · 06-18-19, 04:08 PM

I would like to add an air dryer to my compressor. Plasma cutters need dry air to not go through consumables more often than necessary.
Harbor freight has one but it is $400
https://www.harborfreight.com/compre...yer-40211.html

I have a Aquarium Chiller could I use this to as a air dryer?
They seem to do similar things.

Any suggestions on how to make this work or if this would work are welcome.
I would love to save $400.

The HF air Dryer is 1/4 Hp my chiller is 1/4 HP also.

Another option would be using this to cool off the air. I had this in my greenhouse but don't use it anymore. It would be a lot cheaper to run.

CrankyDoug · 06-18-19, 08:11 PM

I can offer some observations from my experience with air dryers. Perhaps it will give you a place to start.

All of the refrigeration cycle air dryers I've worked with use flooded evaporators to tightly regulate the temperature above the freezing point of the condensate. All of them remove water from the high pressure side of the air compressor. This is more efficient because water condenses more readily as pressure rises.

The dryer manufacturers all stipulated that the dryer should be placed after the primary air tank (receiver) and never between the compressor and the tank. One employer violated this rule and had endless problems (which they never learned from). The receiver provides most of the cooling and generally removes most of the water. The dryer removes enough additional water so that what remains cannot condense during subsequent air expansion in your plasma gun.

Most dryer manufacturers recommend a secondary receiver after the dryer so that the air flow through the dryer is somewhat continuous. At least two dryers I worked on had small internal receivers, probably because the designers knew the purchasers of their equipment would be too cheap to install the secondary receiver.

Years ago there were attempts to remove moisture prior to the compressor in the railroad industry. This was done to reduce moisture problems in the compressor itself. It wasn't very successful and I don't think it is used anymore.

The refrigerant/air interface is usually a coiled tube-in-tube heat exchanger. The largest one I worked on was tube-in-shell - can't remember if the refrigerant was in the shell or in the tubes. Air velocity in the heat exchanger must be slow enough to prevent condensate from being carried in the airstream.

Your aquarium chiller should be adequate if you follow the basic principles outlined above. You will need some form of condensate drain. Float drains are very reliable as long as you prevent them from freezing and keep them free of compressor oil. Without these two requirements, timed solenoid drains are preferable.

dremd · 06-30-19, 09:39 PM

I "built" one for my plasmacam setup using an old drinking water cooler and a large metal air dryer. I just filled up the water coolers reservoir with old antifreeze and dropped the air dryer inside. I drain it reguarly by picking it up and opening the drain ****. Been working great for 5 years now.

06-18-19, 04:08 PM	#1
pinballlooking Super Moderator Join Date: Jun 2013 Location: SC Posts: 2,923 Thanks: 172 Thanked 564 Times in 463 Posts	DIY Refrigerated Air Dryer I would like to add an air dryer to my compressor. Plasma cutters need dry air to not go through consumables more often than necessary. Harbor freight has one but it is $400 https://www.harborfreight.com/compre...yer-40211.html I have a Aquarium Chiller could I use this to as a air dryer? They seem to do similar things. Any suggestions on how to make this work or if this would work are welcome. I would love to save $400. The HF air Dryer is 1/4 Hp my chiller is 1/4 HP also. Another option would be using this to cool off the air. I had this in my greenhouse but don't use it anymore. It would be a lot cheaper to run. Attached Thumbnails __________________ Current project Aquaponics system , Passive Solar Greenhouse build To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Solar Install 12.5 Kwh- To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Mini Split installs - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. EV Chevy Volt - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by pinballlooking; 06-18-19 at 05:16 PM..

06-18-19, 08:11 PM	#2
CrankyDoug Apprentice EcoRenovator Join Date: Jul 2016 Location: Georgia Posts: 100 Thanks: 6 Thanked 14 Times in 11 Posts	I can offer some observations from my experience with air dryers. Perhaps it will give you a place to start. All of the refrigeration cycle air dryers I've worked with use flooded evaporators to tightly regulate the temperature above the freezing point of the condensate. All of them remove water from the high pressure side of the air compressor. This is more efficient because water condenses more readily as pressure rises. The dryer manufacturers all stipulated that the dryer should be placed after the primary air tank (receiver) and never between the compressor and the tank. One employer violated this rule and had endless problems (which they never learned from). The receiver provides most of the cooling and generally removes most of the water. The dryer removes enough additional water so that what remains cannot condense during subsequent air expansion in your plasma gun. Most dryer manufacturers recommend a secondary receiver after the dryer so that the air flow through the dryer is somewhat continuous. At least two dryers I worked on had small internal receivers, probably because the designers knew the purchasers of their equipment would be too cheap to install the secondary receiver. Years ago there were attempts to remove moisture prior to the compressor in the railroad industry. This was done to reduce moisture problems in the compressor itself. It wasn't very successful and I don't think it is used anymore. The refrigerant/air interface is usually a coiled tube-in-tube heat exchanger. The largest one I worked on was tube-in-shell - can't remember if the refrigerant was in the shell or in the tubes. Air velocity in the heat exchanger must be slow enough to prevent condensate from being carried in the airstream. Your aquarium chiller should be adequate if you follow the basic principles outlined above. You will need some form of condensate drain. Float drains are very reliable as long as you prevent them from freezing and keep them free of compressor oil. Without these two requirements, timed solenoid drains are preferable.

06-30-19, 09:39 PM	#3
dremd Need More Eco Join Date: Sep 2008 Location: Scott, La Posts: 172 Thanks: 2 Thanked 6 Times in 6 Posts	I "built" one for my plasmacam setup using an old drinking water cooler and a large metal air dryer. I just filled up the water coolers reservoir with old antifreeze and dropped the air dryer inside. I drain it reguarly by picking it up and opening the drain ****. Been working great for 5 years now.