Apart from the efficiency of the steam engine, the pump system is bound to
have had a low mechanical efficiency. The energy cost in accelerating a
long pump shaft and water column would be high. Thermodynamic efficiency of
the engine alone, would be within the Carnot maximum which is determined
from the temperature of the process end points; effectively the temperature
of the steam at delivery to the cylinder.
efficiency = (T1 - T2)/T1 all temperatures in K
For most purposes, it is the economic efficiency that matters
Burt, R John Taylor mining entrepreneur and engineer 1779-1863, Moorland
Publishing, 1997 ISBN:0 903485 36 2 references Cornish engines of the
1820's and their development.
* low pressure machines (hence T2 is low)
* sometimes 2 compound cylinders on Woolf system
* efficiency > Mewcomen and Watt engines
* Woolf convinced of possible great improvements from single cylinder
but HP steam
* Taylor arranged comparative trial of Woolf machine at Wheal Alfred
in 1824
* in 1816 old engines drained mine for consumption of 14390 bushels
coal/month
* in 1825 new and old engines drained larger and deeper workings for
8053 bushels/month
* in 1830 six engines consuming 11601 bushels/month could drain an
area twice as large and several hundred feet deeper than 30 years previously
when four Watt engines had consumed more than another 1000 bushels per month
Gordon Jeffery
> ----------
> From:
> [log in to unmask][SMTP:[log in to unmask]]
> Reply To: [log in to unmask]
> Sent: Sunday, January 02, 2000 4:12 PM
> To: [log in to unmask]
> Subject: Efficiencies of steam pumping engines
>
> I am trying to obtain typical values for the efficiencies of Cornish
> pumping and whim engines, both horizontal and beam types.
>
> Can anyone advise as to where such data can be obtained, and
> how to convert such data to SI units? Are there any subtle pitfalls
> that should be observed?
>
> My second query concerns Lean's Engine Reporter. Does anyone
> know when it was stopped being produced and exactly what data
> did it record? Is there a source of transcripts from this publication?
>
> Any advice is appreciated!
>
> Martin Roseveare
>
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