I think this clears up my confusion. I had in mind an ideal gases for which I do not think there would be a temperature change, since h1=h2 and h is a function of temperature only. But, I guess ideal gasses aren't used in refrigeration cycles, so this makes sense to me now. Thanks ione.
Why is there a temperature difference across a thermal expansion valve, such as one used in a refrigeration cycle? If there is no work or heat transfer in the device then the internal energy of the fluid remains the same and so should the temperature, regardless of pressure difference across...
