Editing Enthalpy (section)

====Example 1====
Point&nbsp;'''c''' is at 200&nbsp;bar and room temperature (300&nbsp;K). A Joule–Thomson expansion from 200&nbsp;bar to 1&nbsp;bar follows a curve of constant enthalpy of roughly 425&nbsp;{{sfrac| kJ |kg}} (not shown in the diagram) lying between the 400 and 450&nbsp;{{sfrac| kJ |kg}} isenthalps and ends in point&nbsp;'''d''', which is at a temperature of about 270&nbsp;K&nbsp;. Hence the expansion from 200&nbsp;bar to 1&nbsp;bar cools nitrogen from 300&nbsp;K to 270&nbsp;K&nbsp;. In the valve, there is a lot of friction, and a lot of entropy is produced, but still the final temperature is below the starting value.