atec77 <atec77NOSPAM@[EMAIL PROTECTED]
> wrote:
> This particular unit is for use in North America but once this is sorted
> Ill be doing something similar in Unzud down the bottom end ( west of
> gore) , simple stuff like painting the lpg cylinder the right shade of
> dark will offer a couple of degrees heating avoiding that energy
> expenditure should see it going , wind was considered but the site Ill
> be dealing with gets gusts exceeding 200 kl/h during storms so gas seems
> a better option as replacement will be every couple of months .
How far below ground level do you need to go to get away from the
atmospheric temperature variation? Enough distance below ground with an
insulated door will see a temperature consistently over 0C.
If it's on a hill, go part way down the side of the hill and do a
horizontal bore shaft and put the tank in the end of the shaft or a small
carved room if in rock. The shaft only needs to be big enough to crawl
into or for the diameter of the tank, whichever is larger. If the ground
is unstable, large diameter concrete drain pipes can be used to form the
shaft.
All of the pipework including the outlet of the relief should be piped
away in hose, with lagging if necessary. The idea is to make sure that
cooling such as from conduction of heat away along the lines does not
exceed the rate at which heat in the ground is able to transfer into the
tank to maintain a consistent "off" temperature.
Is it going to be liquid withdrawal or vapour? Small engines will be
vapour, while bigger ones will be liquid. The difference is im****tant
because it affects the rate of tank cooling while the genset is running.
In a vapour withdrawal system, the liquid in the tank is continually
boiling off to maintain vapour pressure and the latent heat of
va****isation of that has to be compensated for by heat going into the
tank from outside. Liquid withdrawal has a pro****tionally smaller rate
of vapourisation relative to rate of fuel withdrawal as it only has to
vapourise a quantity of liquid pro****tional to the liquid withdrawal to
maintain vapour pressure.
In a vapour withdrawal system, you'd virtually have to heat the tank
from the waste heat (not exhaust) of the genset. With liquid withdrawal,
the majority of the latent heat of vapourisation is handled in the
convertor at the engine. An engine oil cooler under the tank would be an
effective form of heating, but might need a pair of bypass thermostats,
one to stop excessively cold flow and another to stop excessive heating
of the tank...
--
Athol
<http://cust.idl.com.au/athol>
Linux Registered User # 254000
I'm a Libran Engineer. I don't argue, I discuss.
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