What kind of fittings are you looking at? Swageloks are good on plastic tubing up well past 100 psi, and you can usually adapt them to most other couplings by adapters. You might also look at ColeParmer depending on pressure.

And if you want to use Swagelok fittings on your evaporator anyway, why not just fit automotive a/c hoses? Sometimes a readily available commercial product is the best solution. You can use all the time you save worrying about tubing leaks to design a really good heat exchanger.

It is very easy to find a flexible tube (may be ruber(best offer), plastic, metal) through google or yahoo or ebay search engine.

Goodluck.

Personally, I'd opt for a roll of copper or stainless tubing. Heat transfer will be better and if the materials are compatible with your liquid, they will have a longer life. I'm not sure what your ambient condidtions are, but remember, when the compresser is not running, the evaporator pressure is going to rise. Look up the saturated pressure at your highest ambient temperature and make sure your tubing can handle that. Also keep in mind that it is easier to seal water than refrigerant when you choose fittings.

Engineered Flexible Products makes flexs for refrigerants. Be carefull, refrigerants will leak through a hole that air won't.

mcmaster carr will have what you need ,james m kieffer

I would use automotive refrigeration hoses of if it's only for a day or so just use refrigeration gauge hoses; quick and easy to make up