Refrigerated Trucks

[Derek]

Does any one have any source data for typical declared leak rates on refrigerated truck units e.g. Thermoking Systems?

Also after any manufacturers declared leak rate information for any automotive A/C compressors?

[Dan]

Hhmmm. That's a good question. I will try to check with my Thermo-King contacts to see if such a thing exists. I would actually be surprised if they admit to any leakage. Do any manufacturers publish "declared leak rates?" That's a new one on me.

Dan

[Derek]

If we accept that everything leaks then maintenace activities can be planned for new equipment. As most users wont have a helium leak test chamber it would be good to think that someone, ideally the manufacturer, can advise what sort of loss is 'normal' and what sort of loss is a 'fault'

The UK legislation gives a requirement not to operate a system we know to be leaking e.g. 'fault' condition and a requirement to minimise leakage. There is to my knowledge no definition of a 'leak' other than the US EPA loss rates for fixed systems over 50lb.

Clodic (Zero Leaks ASHRAE) suggested 30gm per year for a desirable domestic automotive system leak rate.

I just wondered if anyone had been up-front in providing this data for larger mobile systems or if any independant studies had been done.

[Dan]

Interesting. By the EPA standards, if I recall, a supermarket can leak 30% of its charge annually before it is mandatory to repair the equipment. That is ridiculous, of course, since a supermarket can have as much as 6000 lbs of refrigerant. Unitary equipment has harsher restrictions since it is all done within the factory environment.

In my opinion, automobile and mobile refrigeration fall somewhere in between since they have such rugged duty even though they are assembled in a factory. I have e-mailed your question to a thermo-king representative, let's see if I get a response.