Materials hosting tilted Dirac/Weyl fermions upgrade the solid-state
phenomena into a new spacetime structure. They admit a geometric description in
terms of an effective spacetime metric. Using this metric that is rooted in the
long-distance behavior of the underlying lattice, we formulate the
hydrodynamics theory for tilted Dirac/Weyl materials in 2+1 spacetime
dimensions. We find that the mingling of space and time through the
off-diagonal components of the metric gives rise to: (i) heat and electric
currents proportional to the "temporal" gradient of temperature, ∂tT
and (ii) a non-zero Hall conductance σij∝ζiζj where
ζj parametrizes the tilt in j'th space direction. The finding (i)
above that can be demonstrated in the laboratory, suggests that thanks to the
non-trivial spacetime geometry in these materials, naturally available sources
of ∂tT in hot deserts offer a new concept for the conversion of
sunlight heating into electric energy. We further find a tilt-induced non-Drude
contribution to conductivity which can be experimentally disentangled from the
usual Drude pole