Rotary vs standard compressors

[TheShoura]

I am planning on going phase soon... I have a couple of conflicts

Rotary is quieter, 'better', but also an assload more money and a lot bigger

What is the noise difference between the rotary and standard compressors... the only reason why I considered Rotary was for noise, I want to reduce the amount of sound my PC will make while getting awesome cooling

[Sgrios]

"Better" is a interesting term.
Generally, Rotary compressors are louder than Hermetic.

[sdumper]

"Better" is a interesting term.
Generally, Rotary compressors are louder than Hermetic.

A good bit louder and they also tend to vibrate more....

[BNDMOD]

But rotary keep lower temps... i thought....
Of course they are noirser than normal one... but... i think if you want to bench you need a rotary one, but if you only want to have a better overclock to play think in a standar one...

That's my thought

[teyber]

"Better" is a interesting term.
Generally, Rotary compressors are louder than Hermetic.

as tim- once corrected me, a rotary is a hermetic. You must have read modern refrigeration and air conditioning, Although the book is correct i got the same misconception from reading it (not carefully enough apparently )

A hermetic compressor is just a sealed dome. One that, for instance, the motor is separate and attaches via a belt is a non-hermetic compressor. What you mean, i think, is reciprocating vs. rotary.

Rotary:window air conditioning compressor, usually. tall, skinny, round
reciprocating: "mini bbq", like danfoss nf11fx, sc18clx, aspera nek2134gk
centrifugal: costs more then you do
scroll: expensive, not used for computer cooling
screw: not used for computer cooling

[Sgrios]

Teyber, you must be able to read minds; I guess I didn't read the material as careful as I thought. Thanks for the clarification.

[TheShoura]

Lol, thanks for Teyber

Anyhow now that we know what is what, can someone answer the question on Rotary versus reciprocating compressor?

[teyber]

Lol, thanks for Teyber

Anyhow now that we know what is what, can someone answer the question on Rotary versus reciprocating compressor?

Rotary is not necessarily more expensive, you can often find perfectly good ac units laying around and get them free from those, or look around on ebay. rotary's are.... loud. Recip's are definately not cheap but is much more bearable. If this is going on a daily build, keep it simple and go recip

[harvshark]

Rotary is not necessarily more expensive, you can often find perfectly good ac units laying around and get them free from those, or look around on ebay. rotary's are.... loud. Recip's are definately not cheap but is much more bearable. If this is going on a daily build, keep it simple and go recip

My SC12MLX has been running for almost 2 years 24/7....and still achieving -30c temps with a quad load running flat out crunching Seti.......I dunno about screw compressors........but this one has surely done it's bit.........

[vab206]

if your looking for a compressor, heres a good place to find a recip. if you have a lowes around you go there and ask the store manager if you can get a shelf or something out of a fridge in their appliance haul off trailer, go through find the newest looking fridge you can find and gank the compressor out of it. make sure to also grab a shelf/drawer or whatever out of it and seal the ends off good on the compressor. then go back and show the guy the drawer/shelf and be on your merry way to phase changin.

all the stuff in the haul off trailers arent really lowes property, they cannot sell anything in that trailer they haul it off and have it disposed of. thats where i got my compressor for my SS

[mytekcontrols]

My two cents...

Rotary compressors tend to produce a higher pitched noise than reciprocating compressors. I don't know if it is actually louder if you were to compare the overall decibel level.

Note: higher pitched noise is more easily controlled with sound proofing materials, then lower pitched noise sources.

As for vibration; I wouldn't necessarily agree that they are worse, especially if we are talking about matching actual mass flow. Keep in mind that a rotary achieves twice the mass flow for a given displacement vs. a reciprocating, due to the fact that it is simultaneously compressing in one half while sucking in the other half (rolling piston/vane technology -- see animated gif below). It is because of this increased efficiency that rotaries are much more powerful for a given physical size then their reciprocating counterparts.

Note: rotary compressor manufacturers say that the vibration is often less than a comparable reciprocating design, due to a rotary's significantly fewer moving parts.

Also having the discharge common to the compressor shell, allows for better heat dissipation, which can be further enhanced by adding extended heat sink surfaces.

So I would prefer a rotary compressor for my projects

[[XC] gomeler]

A properly tuned rotary will run as quite as a reciprocating compressor while typically offering more performance. The problem with most rotary builds is that people typically undercharge them to achieve lower temps.

[t800]

imho, rotatys gives a bit lower temps, but are too noisy,too hot, too power hungry

[teyber]

My SC12MLX has been running for almost 2 years 24/7....and still achieving -30c temps with a quad load running flat out crunching Seti.......I dunno about screw compressors........but this one has surely done it's bit.........

i hear you, but
http://www.xtremesystems.org/forums/...&postcount=474

[Xeon th MG Pony]

There is all so semihermetic, same as a recipicating but servicible.

[TheShoura]

if your looking for a compressor, heres a good place to find a recip. if you have a lowes around you go there and ask the store manager if you can get a shelf or something out of a fridge in their appliance haul off trailer, go through find the newest looking fridge you can find and gank the compressor out of it. make sure to also grab a shelf/drawer or whatever out of it and seal the ends off good on the compressor. then go back and show the guy the drawer/shelf and be on your merry way to phase changin.

all the stuff in the haul off trailers arent really lowes property, they cannot sell anything in that trailer they haul it off and have it disposed of. thats where i got my compressor for my SS

Dude thats horrible... I work at Lowes lol

And I don't understand what you are trying to say anyhow.. buy a fridge, gank the compressor, and return the fridge? Yeah Lowes has an awesome return policy as I have worked in returns a lot and we take back anything but does it have to be a $500 refrigerator?

Rotary is not necessarily more expensive, you can often find perfectly good ac units laying around and get them free from those, or look around on ebay. rotary's are.... loud. Recip's are definately not cheap but is much more bearable. If this is going on a daily build, keep it simple and go recip

What the ? I thought the rotary compressor equivalents were supposed to be the quiet ones, not the reciprocating ones......

The rotary compressor is the taller, larger, sometimes more expensive unit, right? Isnt that what you said in your last post?

[vab206]

nonono, i work at lowes as well... but, delivery has a appliance haul off trailer. its where they put peoples old appliances when they deliver new ones. go to your store manager and ask him if you can get a piece off of a fridge in the trailer. bring some pliers and an adjustable wrench snip the high side line and get out of the trailer, wait about 5 minutes (best to do this on lunch break that way you can eat a burger or something while you wait for it to clear out... i know im gonna get flamed for that lol) go back after you eat, cut the other line (high side is usally a bit smaller then the low side) unbolt the compressor and remove it. simple ez and sometimes you can find a freezer/fridge that comes from the factory with a leak and isnt charged at all sitting in there (my case) that makes it really easy. but its a good place to find a compressor, just gotta keep your eye out for a newer looking fridge/freezer to get one out of.

[EliTE22]

WHAT YOU ARE DOING ILLEGAL

Venting refrigerant to atmosphere (old fridges use R12)

flamed lucky i don't know you, if did i be rich reporting you and you have a room with bubba for 5yrs so stock up on the KY

1+ people think vent is no bigy

[teyber]

WHAT YOU ARE DOING ILLEGAL

Venting refrigerant to atmosphere (old fridges use R12)

flamed lucky i don't know you, if did i be rich reporting you and you have a room with bubba for 5yrs so stock up on the KY

the ironic and funny thing is your completely 100% right

vab, thats not really something to lol about

[teyber]

If you guys refuse to buy recovery units at least buy a recovery cylinder. this is a must. BUy it local, Vacuum it, you will most likely be able to recover all the gas in the system and still be in a vacuum, then swap tanks for a new one and vacuum it even this is illegal but is 100x better then venting

[boshuter]

The problem with most rotary builds is that people typically undercharge them to achieve lower temps.

The problem with most recip builds is people overcharge them to achieve unrealistic capacity. I've yet to have an "undercharged" rotary compressor fail, how many recips have you seen with problems due to overcharging?

[Xeon th MG Pony]

If you guys refuse to buy recovery units at least buy a recovery cylinder. this is a must. BUy it local, Vacuum it, you will most likely be able to recover all the gas in the system and still be in a vacuum, then swap tanks for a new one and vacuum it even this is illegal but is 100x better then venting

All you need is:
A: Bullet valve
B: A hose
C: A tank (Any that will hold the gas)
D: Vise grips

Procedure:
A: firmly crimp the capillery tube with the vice grips, leave attached!
B: Attach hose to tank and bullet valve (Helps if the tank is vacuumed)
C: Firmly attach bullet valve to the filter dryer.
D: Screw in bullet valve to peirce filter drier shell, purge air from hose.
E: Open tank wide (And put it into a bucked of ice if handy)
F: Turn on fridge and let run as long as possible, Untill compressor is HOT.
G: Close tank and bullet valve and remove, you should have succefully recovered the bulk of the charge and avoid being a total venting loser!

So there is literaly NO excuse not to recover, simply drop off the small tank to a local shop and tell them it's waste refrigerant.

Cost you say? Recovery tanks are so expensive and hard to move you protest? Nope not excuses! here:
http://www.xtremesystems.org/forums/...ight=diy+tanks
So far mine have held up to heavy use and hold R-22 with no leaks! and yes that is the same one I made in the post still going strong!

[Moc]

Venting sucks so much... sry but everyone who is venting refrigerant is a complete idiot!

[teyber]

xeon, around here they wouldnt' take that form me. they only swap my 30lb recovery cylinders, at $80 or so a pop its not an option not to. (i do have a recovery unit though)

moc: yup

[Northwood]

Rotarys are no good for 24/7 usage because of the low back pressures we use in computer phase change, running a rotary in vacuum will knacker it within months.

Recips are a better alternative for 24/7 setup, they are mainly low back pressure, but won't reach the temps a rotary can unless it's a massive and noisy lump.

If it's a now and again benching unit you're after, then go rotary, if it's 24/7, go reciprocating

and no i'm not a phase expert, just read it somewhere :p