  Herschel-HIFI observations of high-J lines (up to J_u=10) of 12CO, 13CO and
C18O are presented toward three deeply embedded low-mass protostars in NGC1333.
The observations show several energetic components including shocked and
quiescent gas. Radiative transfer models are used to quantify the C18O envelope
abundance which require a jump in the abundance at an evaporation temperature,
T_ev ~25 K, providing new direct evidence of a CO ice evaporation zone around
protostars. The abundance in the outermost part of the envelope, X_0, is within
the canonical value of 2x10^-4; however the inner abundance, X_in, is found
around a factor of 3-5 lower than X_0.
