LONDON =97 Sound could be the key to engines of the future according=20
to American researchers. A team at the Los Alamos National Laboratory=20
in New Mexico has developed an environmentally friendly engine with no=20
moving parts that is powered by sound waves.The new engine is made=20
from steel tubing and is cheap to produce. Calleda thermoacoustic=20
Stirling heat engine, it consists of a long baseball-bat-shaped resonator=
=20
with an oval chamber instead of a handle. The engine is filled with=20
compressed helium and when heat is applied tothe "handle" acoustic=20
energy in the form of sound waves is produced. This can be used to drive=20
a piston and create electricity. The team isalso working on a similar=20
system to cool refrigerators. Scott Backhaus, one of the inventors of the=
=20
engine, says: "Conventionalengines are limited by the laws of=20
thermodynamics and their complexity. Typically the most efficient=20
engines are the huge turbines used in power stations. "Our small engine=20
is actually 10 percent more efficient than the bestturbine, largely=20
because of its simplicity," he says. The engine is alsomaintenance-free=20
as it has no moving parts. The team is working on a way to use solar=20
energy to power the engine andconsidering a system that uses a car's=20
exhaust heat to power its air-conditioning system. A home version of the=20
engine, also underdevelopment, could be used both to generate=20
electricity and providedomestic heating. The principle behind the engine=20
was discovered by Robert Stirling, a19th-century Scottish inventor, who=20
found that cooling and heating gasescould drive a piston. --=20
http://www.sunday-times.co.uk/
Regards,
WJ