In the light of and the balance concerns about the
environmental effects of hot air balloons (due to
the amount of propane gas they burn to heat the
air in the envelope and so cause the balloon to
raise), we are delighted to hear about this Hot
Air Balloon related innovation.
Dr Ian Edmonds of www.solartran.com.au
has described the concept and basic theory of reciprocal
balloon engines intended to operate to heights of
several thousand metres.
The principles described concern use of hot air
ballons (preliminary calculations being based on
figures for commercially available hot air balloon
envelopes) as a means of harnessing renewable energy
from the sun. That is, the hot air used to cause
the balloon to rise is generated by drawing ambient
air through a glazed solar collector that encloses
black pipes filled with water. The balloon is then
allowed to rise and, in doing so, do work on a generator
that remains on the ground. Then, at a pre-decided
altitude, a large proportion of the hot air inside
the envelope of the balloon is vented and the balloon
returns to the ground.
Obviously significant component costs would be involved
and the efficiency of the overall "engine" is a
key factor. Dr Edmonds' report discusses the possibility
of full scale trials which, so far as we know, have
not taken place to date (5th Feb. '09).
To be clear - this technology is not proposed as
a means of replacing the conventional use of propane
gas to fuel pleasure flights in Hot Air Balloons,
but as another - as yet undeveloped - idea for increasing
use of energy from renewable and so "environmentally
friendly" sources. There would, of course be certain
constraints on its use, such as the weather (sufficient
sun for the solar collector to be effective, and
relatively still conditions as high winds would
not be appropriate) and location (which obviously
could not be too close to an airport, for example).
The description we read was particularly concerned
with Australia's targets for use of renewable energy,
and hence technologies suitable for use in Australia.
Thanks to EnvironmentalGraffiti.com
for Karl Fabricius's post pointing us in the direction
of more information about this interesting idea.
Date of this News Page: 5 February
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