Green Fridge

Hello sb,

A little more info needed.

What are your cooling requirements at what ambient temp?

Just of the cuff I'm compelled to ask why you're not looking to buy a chiller?

Refrigeration is done through the energy transfer involved in phase change. Most accessible phase change materials are gasses, and also ozone depleting.

But it does not sit in your shop depleting ozone, it depletes ozone if released from the refrigerator plumbing.

Ensure responsible disposal and you have no problem.

And if you must go non-CFC, there is amonia cycle available from Servel and others.

Non-CFC, but still ozone depleting.

We infact chill it at approximately -30 deg C (for bearings assembly), ambient varies between 4-5 deg c to 30-35 deg C as per season. (the fridge is in fact a chiller we call deep fridge) - capacity is medium- about 4 m³ .

We normally do not use liquid nitrogen for these purposes for the thermal shock. Dry ice is one option, but due to the mass we prefer a freezer.

As far as the other comment, we as usual do not prefer the gas to escape the cycle, but due to what ever reason, if it escapes- then the hazard must be avoided (My earlier home fridge i had to re-fill the gas at least once)

The problem as I look at it is

a) The safety hazard in a work shop, in case of accidental hazard - the gas toxicity

b) The supplier will definitely have gas leakages during filling the gas in the fridge.

Why should we add to the environmental hazard.

Ammonia is not a ODC and there are hydrocarbons too that are non ODC , but both are inflammable.

There are some laboratory refrigerators that use propane - but a leak could be an explosive experience. I know they are sold in Europe - I'm not sure if they are sold in the US

In my old EA falcon that died last year, I did a drop in replacement of LPG for R12. This I carried out in 2001. Instead of using 1kg of R12 I used 330g of LPG.........the only thing I could not do, was use the sight glass in fault finding for obvious reasons.

Whereas most CFCs and some HFCs are very searching gases and you can lose the charge if you not regularly run the a/c unit in winter. However using LPG I never ran the a/c unit in winter and I never had to recharge it and it was still running well at the vehicle's death. (About the only thing that was running).

Bearing in mind that CFCs are banned in the Western world and R22 among others is next on the hit list probably R404A is a good ghoice..............OR............LPG.

Whilst LPG is highly flammable, detectors and alarms cold be fitted to the system. (R290 is propane). The only reason we never used it in marine applications was its flammability, even though it has an extremely low flammability range

The appliance you need is a blast freezer

Although not what you are looking for, new iceboxes namely the ice cream giants like Ben and Jerry's started to use propane. Combustible, yes. How green is it ? I don't know. It is probable that the "greener" the gas, you may not get the same results such as desired climate change in the summer, etc. Good luck.

R404A is HCFC, and as per EPA directive, we have to phase out these too, i think by 2010 ?

Has no substitute been formed as yet ? then how it s expected to phase out these ?

The point is - not academic, we are a sufficiently large corporation, and will like to take the lead, where smaller ones may have more eye at the moment on economy.

But being a large manufacturing industry, as mentioned, with every yhing - assembly, welding, heating etc carried out in proximity, it is a big safety hazard to have any type of combustible or toxic nearby unless i take special evacuation measures.

Looks like no substitute has been found yet, and have to surrender to HCFC.

My mail reads that R404A is zero ODP.

It is of interest to note that R134a is zero ODP but is an unacceptably high greenhouse gas...........much worse than CO₂

At this point in time some of the acceptable refrigerants for Class II HCFCs are:-

R404A, R407C, R417A, R507A......these and others are classed as acceptable by the EPA...........since July 2008.

As you rightly said sb the perfect substitute has yet to be found.

For the temperatures you mention, R-410a is the only safe material to use. It is the 'approved' replacement for R-22. It IS a hydro-fluoro-carbon, non ozone depleting, non-flammable but will burn in a flame releasing noxious fumes, stable, and in wide and growing commercial and residential use.

Ammonia will not cool to the -40 (C or F, which are identical at -40) needed without operating the evaporator under a vacuum.

Same with propane.

You should ask Carrier or another similar Company for recomendations. If the heat load is significant, a compound (2 -stage) system is likely to be more economical because the compression ratio for a single stage system will be very high, meaning poor efficiency

R507 and R404A are other options and are recommended long term replacements for R22. These two options do not require the the higher pressures that R410A require.

Is this use of R410A an "American" thing?............you can use R404A or 507 down to -45⁰C quite easily and can be used effectively in freezer display cases(supermarkets), processing, cold storage, ice machines and industrial refrigeration. New units with these refrigerants are cheaper than those using R410A (pressure requirements)

Don't get me wrong I am not knocking R410A it is an excellent refrigerant.

The 404A is non OD but GWP is if i am not wrong 3600 (against 1600 of CFC)

I'm just curious if the evaporators sent out as replacements for R22 or R 410A are compatable with the higher pressures of the r410a???

You might get a hint from Greenpeace. They have designed, built (by third companies) and sold a non-ozon-depleting type of household-fridge here in Germany. May be they know manufacturers of industry-sized modells as well.

See URL:

http://www.greenpeace.de/themen/sonstige_themen/greenfreeze/artikel/kleiner_greenfreeze_leitfaden_zum_kuehlschrankkauf/

(May be there is an english version too at Greenpeace international or similar.)

---begin citation-

Vorsicht bei Preisknüllern

Wo Sie Greenfreeze kaufen können

Greenfreeze-Technik gibt es in allen Fachgeschäften, sowohl im Einzelhandel als auch in den Fachabteilungen großer Kaufhäuser. Bei den bekannten Marken der deutschen Firmen können Sie nahezu mit Sicherheit davon ausgehen, dass die Geräte dem Greenfreeze-Standard entsprechen: ohne FCKW, H-FCKW oder FKW in Kälteerzeugung und Isolierschaum und mit einer sehr guten Energieeffizienz.

Bei allen Billigangeboten, wie sie heute immer noch in den großen Kaufhäusern stehen, ist Vorsicht geboten. Sie sind immer noch häufig mit FKW (R134a) gekühlt und enthalten zum Teil FKW oder H-FCKW im Isolierschaum.

Wenn Sie unsicher sind, schauen Sie selbst auf das Typenschild an der Rückseite, meist auf dem Kompressor oder im Innenraum: Meiden Sie Geräte mit dem umweltschädlichen Kältemittel R134a zugunsten natürlicher Kohlenwasserstoffe wie R600a oder R290 (Isobutan bzw. Propan). Verlassen Sie sich nicht auf die Aussagen der Verkäufer/innen. Auch das Fachpersonal kann meist nicht zwischen FKW, FCKW und H-FCKW unterscheiden. Geben Sie sich nicht mit der Auskunft zufrieden, der Kühlschrank sei 100 Prozent FCKW-frei, denn das bedeutet häufig, dass er FKW enthält.

Was Greenfreeze eigentlich ist

Greenfreeze-Technik bedeutet: Nicht nur vollständiger Verzicht auf alle harten FCKW, sondern auch auf die Ersatzstoffe der chemischen Industrie, die eng mit FCKW verwandt sind: sowohl weiche FCKW wie insbesondere FKW. Das FKW R134a wird zum Beispiel immer noch als Kältemittel im Kühlschrank und in Autoklimaanlagen, aber auch als Treibmittel in Sprays eingesetzt.

---end --

So, one should avoid machines with cooling-agents that come from even the wider family of the chlorinated and non-chlorinated fluorcarbohydrates - like the R134a agent which is heavily promoted by the chemical industry. R134a does not destroy ozon, but has a very high greenhouse-potential - about 3000-times compared to CO2 ! The text from Greenpeace (above) states further that the best agent from a todays "green" perspective is propan or iso-propan (R600a and R290). And, when buying a machine, you should inspect the specification-plate yourself - the selling-personel often does not know the differences of the different levels of "green"....

Good luck !

M.Regier, Hamburg, Germany

The idea has struck me too and have contacted greenpeace directly and send this thread (I assume the administrator will not object) with a request to respond in the forum itself and share their view for all of us to know.

Anybody have idea aboul R600A ? it is green and loks to be promising but can it achieve the temperature ?

Greenpeace do not seem to be interested.

A ver very happy new year 2009 to you all