Coffee Cup Engine Efficiency
Posted: Tue Jan 21, 2003 12:06 am
I'm curious as to the efficiency of the coffee cup engine.
Has anyone made some measurements?
I envision that the average input wattage could be calculated by
simply using the water's heat capacity to find energy storage, and
then distributing that energy over the time it takes for the engine
to no longer run. A linear relationship may be approximately
appropriate; assigning said Qavg where t = .5 T and Q = 0 at t = T.
Output energy is somewhat easier, a model airplane tachometer and a
plexiglass disk with dark line across a diameter would be suitable
to make a time-to-speed measurement.
Anyone?
Has anyone made some measurements?
I envision that the average input wattage could be calculated by
simply using the water's heat capacity to find energy storage, and
then distributing that energy over the time it takes for the engine
to no longer run. A linear relationship may be approximately
appropriate; assigning said Qavg where t = .5 T and Q = 0 at t = T.
Output energy is somewhat easier, a model airplane tachometer and a
plexiglass disk with dark line across a diameter would be suitable
to make a time-to-speed measurement.
Anyone?