What size air lines do you use in your shop?

Maybe PVC is ok, maybe not. My shop has 3/4 PVC for the main line with 1/2 inch drops. This system is two years old and I have had three, count them, three, explosions. These don't hurt anyone, but scares the living shit out of you when they happen and now my garage buddies (dog's) won't come near my shop. When I start it up, they haul ass to the house.... .

This winter I will switch to pipe with hoses for drops. Life is full of quirks. Thats what makes it fun I suppose.

 

Three explosions in two years? I have never heard of that kind of failure rate. Something is wrong. I don't blame ya for wanting to revamp that system.

 

I don't think I've ever read such a totally ignorant load of hogwash in my life.

For starters, there's no such phenomenon as "radiant conduction" or "radiant convection". There are three distinct common modes of heat transfer. Radiant, Convective, and Conductive.

The heat picked up by air moving across a hot pipe is an example of primarily convective transfer. But that moving air does not affect the radiant transfer of heat from the pipe. So long as the pipe's surface remains at a constant temperature, the amount of heat it will radiate will be constant regardless of whether its in a 100mph wind or in dead still air. This is a very basic principle of heat transfer, and one well known to anyone with even elementary knowledge of the subject.

Immersing the same hot pipe in cooler water produces an example of conductive transfer. It is not "radiant conduction" as radiation has nothing to do with the process.

ALL warm materials, even plastic, radiate heat to cooler ones at a rate that varies according to the difference in temperature of the two and the square of the distance between the two. The claim that plastic cannot radiate heat is patently false. That all warm bodies radiate heat to colder bodies is another basic heat transfer principle.

If an airline is run thru a hot attic that's at 120* and the airline itself is also at 120*, there will be no heat transferred from the pipe to the air or other surroundings because the temperature difference is the driving force for all modes of heat transfer.

The ability to cool a material, air, water, or whatever, within a pipe is dependent on the ability of the pipe material to conduct heat to its outer surface since that's the only place where the heat can be given up to the surroundings. Thermal conductivity is the measure of the pipe material's ability to move heat from its interior to the outer surface, and, as stated previously, copper can do that more than 9 times as fast as steel of the same thickness because its thermal conductivity is more than 9 times greater than that of steel.

Anyone who thinks steel is better than copper for transferring heat needs to look at a home air conditioner and see what material is used for the condenser and cooling coils. It'll be copper tubing every time even though copper tube costs 5 to 6 times as much as equivalent size steel tube. Anyone here think manufacturers spend that additional money on every product they make when steel would work better? Maybe they just like the color of copper. Anyone have a car with a steel radiator? Car makers have gone to aluminum because its cheaper than brass (a copper alloy), but they sure ain't cheaped out to the point of steel radiators so far. If steel was better at shedding heat, don't you think they'd be using it tomorrow?

Maybe Mr Buick can state the specific principles of physics that negate all the above. If so, I'm all ears, and every engineering school and every manufacturer of heat transfer equipment in the world would be sorta interested too.

 

O.K. - Now we have all been schooled. Yeah but guess everyone has an opinion regardless how they want to interpret the facts or confuse them. But I am not here to get into a pissing contest. I got my biophysics degree and have done very well with it over the last 35 plus years so I am content.

Thanks for the schooling though but you really don't need to comb out all the chest hairs and shout hogwash though Do you? No harm done but take a deep breath anyways.

But for the record, for what I actually tried to convey in my last few posts was copper conducts it's localized heat along it's own axis better than steel. Steel is a better heat sink and works best for our manifold systems and pales out other materials such as copper and plastic when you want a nice cold surface in which moisture ridden air can condense onto at any given point. What do you think would heat up faster copper piping at 2/32 wall thickness or steel piping at 5/32 wall thickness ? And which material would you think would allow a superior static transfer of heat "away" from the material or allow heat to go along the axis of the wall material or be confined and act as a local heat sink? Industry uses copper and brass for uses usually in association with aids such as fans, coolants and flexibility. That is why they use it as it is a site specific material for the site specific purposes and functions it is used in. But however with that said, large diameter steel piping is best for use in what we were "actually" talking about on this post without going into an engineering rant and that is in the use as a cold wall manifold system for the dissipation of heat trapped moisture laden air coming out of a hot compressor. etc, etc, etc. We want things to chill out right?

Anyways .... Welcome to the club . I have had my learned say and so have you and tried not to belittle your ego. Hope that made your day. It made mine. - Peace

 

I didn't mention my system, only the volume gig. I have a Speedaire 10HP single phase compressor. The pump/motor is on a horizontal 80gal tank, that feeds into a vertical 125gal tank. From the vertical it goes through a simple trap and into a 50' hose reel on the wall. The shop is 1200sqft, the compressor runs for 7min to fill from empty, runs for 1min 20sec to cycle from 125 to 150. Never runs long enough to cause grief and I rarely drain it because I never get anything out of the bottom of the tanks but a few seconds of mist. As I revamp the shop layout I do have a very severe duty black hose that's too big to use for anything but a nice long run. I'll probably plumb that in, clamp it to the top of the walls and hook up a bench drop and a place to drag more hose outdoors (although I've yet to need air outside in 10yrs). Why would I use a big diameter hose? Because I have it already and it was free. Science usually can't address free...