An idea recently put into use in the Score-Stove
to generate electricity from waste heat may provide the 3rd world,
and possibly extra-terrestrial explorers, with electricity. The thermo-acoustic
engine was first demonstrated by LANL researchers Scott Backhaus and Greg Swift in 1999 and has a
theoretical basis in the Stirling engine. Unlike
Mr. Sterling's engine, the thermo-acoustic engine does not move a piston, but
instead uses temperature
differences to generate soundwaves which move a microphone-like component at
one end to produce electricity. The Score-Stove's engine claims to have no moving
parts, and creates 150W from the stove's waste heat.
Thermo-Acoustic Engines have an
overall efficiency of nearly 30%, which is high compared to the RTGs used on Curiosity, whose
thermoelectric converters have an overall efficiency of 6%. The lower
efficiency of thermoelectric converters is offset by the lack of moving parts
and experience using them, in turn making thermoelectric converters much
more reliable than other alternatives, such as a Sterling Engine. The
commercialization and expanded use of thermo-acoustic engines could allow them
to be used in future missions. The higher efficiency translates into less fuel
being needed, which means the engine can be light and cost less to launch.
Back on Mars, the weather yesterday in Gale crater was a high of
0°C with a low of -73°C. The pressure remains constant at 7.4 hPa (7.3
the wind continues to come from the east at 7.2kph.