  We analyze the fluctuations of the dissipated energy in a simple and general
model where dissipation, diffusion and driving are the key ingredients. The
large deviation function for the dissipation follows from hydrodynamic
fluctuation theory and an additivity conjecture. This function is strongly
non-Gaussian and has no negative branch, thus violating the fluctuation theorem
as expected from the irreversibility of the dynamics. It exhibits simple,
universal scaling forms in the weak- and strong-dissipation limits, with large
fluctuations favoured in the former case but strongly suppressed in the latter.
The typical path associated to a given dissipation fluctuation is also analyzed
in detail. Our results, confirmed in extensive simulations, strongly support
the validity of hydrodynamic fluctuation theory to describe fluctuating
behavior in driven dissipative media.
