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BDE
introduction |
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The Barton Drying Engine* * patent pending |
Sunoba Renewable Energy Systems |
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The BDE is a heat
pump with opposite function to the BEE: power + moist air
→ heated dry air + water In
addition to drying the air and removing impurities, the BDE might be useful
for air heating in cool moist climates.
Other applications might be as a hot water heater, frost protection
for crops, drying of goods or foodstuffs, and de-fogging public spaces. |
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The BDE
uses a low-pressure gas cycle, in which moist air is expanded and then
undergoes condensation at reduced pressure and temperature. Condensation occurs rapidly when the air
becomes super-saturated during the expansion process. Work is required to complete the
thermodynamic cycle, which can be implemented in continuous-flow or
piston-in-cylinder configurations. As an
example, take saturated air at 15°C and expand it to 1.32 of its original
volume. That requires expansion work
of − 4,252 J/kg dry air, and
will result in condensation of 5.1 ml of water per kg of dry air. The condensate is removed from the air in
the chamber where the temperature will be just above freezing. On allowing the air to re-compress back to
atmospheric pressure, work of + 3,743 J/kg dry air can be reclaimed. The nett specific work associated with the
cycle is w = − 509 J per kg
of dry air where the minus sign denotes that work must be supplied. For the
above example, the outlet temperature is 13.1°C warmer than the inlet and the
Coefficient of Performance of the BDE (CP*ΔT/w)
is 25.9. If it
could be economically manufactured, the BDE would be a superb heat pump for
saturated inlet air in the range 10-20°C, which corresponds to conditions
when humans start to feel the need of extra warmth. In addition to the heat pump effect, the
BDE will dry and purify the air, which might be important in various
applications. |
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© Sunoba Pty Ltd 21 April 2010 |
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