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US Iceman
19-05-2007, 05:11 AM
Here is an interesting link using a different combination of refrigerants for supermarket systems.
http://www.airah.org.au/downloads/2004-02-02.pdf

Dan
19-05-2007, 07:20 PM
Nice and current link Iceman. Not a bad way to go to get ride of 404A or other greenhouse refrigerants - and it overcomes the lack of familarity in tooling and practise supermarket techs have with Ammonia.

Latte
19-05-2007, 09:20 PM
Very good link and something that is going to happen more often (Co2 anyway). I think there will a lot of discussion before it becomes the norm though.
CO2 emmissions seem to be the big thing at the moment and this will only slow down the progress. I havnt made my mind up on this one yet.

propane :eek: , dont think it has a chance. too bigger risk of explosions. Cant see this going any bigger than integral units and even then when compressors go or they have a gas leak the get replaced with 134/404

Regards

Raymond

Dan
20-05-2007, 02:11 AM
Very good link and something that is going to happen more often (Co2 anyway). I think there will a lot of discussion before it becomes the norm though.
CO2 emmissions seem to be the big thing at the moment and this will only slow down the progress. I havnt made my mind up on this one yet.

rdocwra, I presume you are not thinking that using CO2 as a refrigerant has anything to do with adding CO2 to the environment.

TXiceman
20-05-2007, 04:19 AM
I proposed a propane/CO2 cascade system several years ago and was beat out due to the plant insisting on cast steel compressor casings on the propane compressor. It was an 800 HP twin screw and lower HP twin screw on the bottom stage. Power beat the "*****" system by several percentage points, but the added cost of steel case on the propane killed me.

They would not consider ammonia on the high temp system as "it was too dangerous", but nothing like some of the other chemicals they made at this plant.

Ken

US Iceman
20-05-2007, 05:09 AM
I have also ran into the same problem with large propane & propylene systems. And had the same luck proposing ammonia systems in chemical plants.

Some of the chemicals found in these plants make ammonia look like water, but... there is no way I know of to convince people otherwise.

It seems to me the cast steel requirement is in case of a fire. Apparently, the steel casings are more forgiving when the water hits the hot casing when trying to extinguish a fire. Much more so than the normal cast iron housings. At least that's what I remember.

We use natural gas & LPG all over the world without many accidents. I don't see why propane should be a big deal. It behaves almost the same as R-22, except the oil solubility problem is worse with propane.

The MG Pony
20-05-2007, 07:38 AM
Because some idiot once upon a time blew him self up, and if it is dangerous to the stupidest person, by mythology, it got to be illegal for the rest of us!

That and same BS the Oil industry pulls with hydrogen it is as the ***** companies do about HC refrigerants & Ammonia

Andy P
20-05-2007, 05:02 PM
except the oil solubility problem is worse with propane.

Spoken like an ammonia man to the core!! Presumably what you mean is that mineral oil is too soluble in propane - usually "the oil solubility problem" is that it isn't soluble enough. Some folks are never satisfied!!:D

cheers

Andy P

US Iceman
20-05-2007, 10:13 PM
Presumably what you mean is that mineral oil is too soluble in propane


That would be the reason Andy. This also serves to remind me I should be more specific in my statements!:o

750 Valve
22-09-2007, 12:02 PM
and it overcomes the lack of familarity in tooling and practise supermarket techs have with Ammonia.

Well look out, first supermarket in australia on co2/nh3 soon to be installed :eek: .

As you say should be interesting, fair bit of training involved, the guys are just getting their heads around the co2 side.

And also a transcritical system in the works