  Simulations of nano- to micro-meter scale fluidic systems under thermal
gradients require consistent mesoscopic methods accounting for both
hydrodynamic interactions and proper transport of energy. One such method is
dissipative particle dynamics with energy conservation (DPDE), which has been
used for various fluid systems with non-uniform temperature distributions.
Despite the success of the method, existing integration algorithms have shown
to result in an undesired energy drift, putting into question whether the DPDE
method properly captures properties of real fluids. We propose a modification
of the velocity-Verlet algorithm with local energy conservation for each DPDE
particle, such that the total energy is conserved up to machine precision.
Furthermore, transport properties of a DPDE fluid are analyzed in detail. In
particular, an analytical approximation for the thermal conductivity
coefficient is derived, which allows the selection of a specific value a
priori. Finally, we provide approximate expressions for the dimensionless
Prandtl and Schmidt numbers, which characterize fluid transport properties and
can be adjusted independently by a proper selection of model parameters, and
therefore, made comparable with those of real fluids. In conclusion, our
results strengthen the DPDE method as a very robust approach for the
investigation of mesoscopic systems with temperature inhomogeneities.
