Refrigerant-134a is expanded adiabatically from 100 psia and 100°F to a saturated vapor at 10 psia. Determine the entropy generation for this process, in Btu/lbm⋅R.<image 1>
['$0.00147\\frac{Btu}{lbm\\cdotR}$', '$0.00047\\frac{Btu}{lbm\\cdotR}$', '$0.00247\\frac{Btu}{lbm\\cdotR}$']