CO2 Systems

[Argus]

There?s a lot of interest in CO2 systems, particularly in cars to replace HFCs.

Having spent my working life with the more traditional systems, it?s not a subject I?m knowledgeable about, so can anyone help me with a brief explanation of the process?

I?m making the assumption that the process is trans-critical. Is this so? If not how is the liquid stage managed?

What sort of pressures are we looking at?

Any help is much appreciated.
________
herb scales

[Gary Collins]

Please clarify CO2. We use CO2 (Carbon Dioxide) as a once through cooling media what are you refering to? our terminology seems to be different.

[bersaga]

Yes, the same CO2 or technically in Refrigeration known as R744.

Yes, the condensing pressures are in the trans-critical stage.

Pressures are very high ( -5 C evap is about 30 bars)

Special condensor design and piping design are required to manage the high side.

Have some material at home somewhere if you're interested.

[Argus]

Thank you for the replies.

I am familiar with direct discharge systems in transit storage. That was not what I had in mind.

My question was about the CO2 mechanical cycle that is appearing as an industrial alternative to HFCs and to its extended use in MAC.

Pressures are a prime consideration. What happens on the high side? Is it transcritical in practical use or is there a condensation stage and if so, what are the typical pressures / temperatures? What is the cooling medium?

A description of a typical cycle used in an actal installation would be useful.
________
herbalaire

[Carlo Hansen]

Hi Argus

Maybee this can help You.

http://www.mst.dk/homepage/default.a.../kap02_eng.htm

Best regards
Carlo

[bersaga]

Carlo,

That was helpful to me.

Thanks

Bernard

[Carlo Hansen]

happy to help, I have some new things about CO2 in mac systems. Diagrams, test conditions , HX, etc.
The description is in PDF and is to big to bring in this forum,-1.2 MB and 0.6 MB. If anyone would like to see them. just mail me, and I will mail back, direct to you.

Best regard
Carlo

[Peterson]

For CO2 refrigeration system info, please visit my website. There are several research links you can make understand about that.

http://www.geocities.com/krasaein

[Andy]

Thank you for the replies.

I am familiar with direct discharge systems in transit storage. That was not what I had in mind.

My question was about the CO2 mechanical cycle that is appearing as an industrial alternative to HFCs and to its extended use in MAC.

Pressures are a prime consideration. What happens on the high side? Is it transcritical in practical use or is there a condensation stage and if so, what are the typical pressures / temperatures? What is the cooling medium?

A description of a typical cycle used in an actal installation would be useful.

Argus the system you are thinking of is not trancritcal.

The high stage R717 or 404a system is simply in design a glycol chiller, only it condenses co2 instead of cooling glycol. It is also possible to pump the liquid co2 from the condenser outlet around a chill load and back to the vapour connection on the condenser, this puts load on the high stage system to cool the volitile secordary (the pumped co2) but not the low stage co2 system, which is simply a pumped co2 system, ver like a pumped R717 system. Condensing of the co2 takes place at -8 to -14 deg C, by virtue of the R717 (R404a) high stage system evaporating off.

Not much like thre theretical systems seen on student sites

Very like an ammomia glycol system on the high stage and an ammonia pumped system on the low side (on steroids) with co2 instead of ammonia.

Hope this helps.

Kind Regards. Andy.

[750 Valve]

just posted some pics of r744 supermarket rack under supermarket forum if anyones interested

[Andy]

just posted some pics of r744 supermarket rack under supermarket forum if anyones interested

750 Valve,
nice looking system, all stubs probably to keep pipe sizes and then wall thicknesses down.

Kind Regards, Andy

[arkay]

Hi!

I know that Coca-Cola has been developing bottle coolers that works on CO2 for some time now.
Latest news I had is that Sanyo compressors were the only one that could do the job, and samples have been tested already.
Have anyone got some information about same?

[Carlo Hansen]

Hi Arkay

As you said Sanyo made this bottle cooler for Coca Cola and they has now a heat pump running on CO2.
Danfoss has made a small CO2 compresser for test in small aplications.

http://www.sanyoaircond.com/comune/d...dwld/e_C02.pdf

http://www.ecn.purdue.edu/Herrick/Ev...ku-shimada.pdf

Best regards
Carlo Hansen

[patrickj]

happy to help, I have some new things about CO2 in mac systems. Diagrams, test conditions , HX, etc.
The description is in PDF and is to big to bring in this forum,-1.2 MB and 0.6 MB. If anyone would like to see them. just mail me, and I will mail back, direct to you.

Best regard
Carlo

Dear carlo Hansen
Re CO2 Please let me know you E mail address or Mail to patrickj@time.net.my

[nova]

Car a/c systems also start to convert to co2, here's Denso's co2 a/c for passenger vehicles:
http://www.theautochannel.com/news/2...04/151245.html
http://www.sae.org/automag/techbriefs/04-2002/page2.htm

Regards,
Nova

[issachaer]

happy to help, I have some new things about CO2 in mac systems. Diagrams, test conditions , HX, etc.
The description is in PDF and is to big to bring in this forum,-1.2 MB and 0.6 MB. If anyone would like to see them. just mail me, and I will mail back, direct to you.

Best regard
Carlo

Carlo,

I would be grateful if you could e-mail me the Co2 Pdf files.

My e-mail is

issa_chaer@hotmail.com

Kind Regards

Issa