[Info-vax] Intel junk...Kernel-memory-leaking Intel processor design flaw

[George Cornelius]

In article <omU4C.245892$Cr5.165305 at fx36.iad>, Wolf K <wolfmac at sympatico.ca> writes:
> On 2018-01-08 17:26, Jan-Erik Soderholm wrote:
> [...]
>> A water powered electrical station has an average loss of 10%.
>> A coal powered electrical station has an everage loss of approx 60%.
> [...]
> 
> The maximum theoretical efficiency of a heat engine is 1/3rd (33.3...%). 
> Hence the minimum energy loss (converted to waste heat) is 2/3rds 
> (66.6...%).

In case no one has corrected you yet, this is entirely inaccurate.

Per Carnot and others, the efficiency limit is

  eta = (T2-T1)/T2

where T2 is the absolute input temperature and T1 is the
absolute output temperature.  Absolute temperatures are
generally measured in degrees Kelvin or Rankine.

The argument has to do with comparison to an ideal, perfect,
Carnot cycle engine, which must have heat flows at the input
and output in proportion to temperature, with all heat emitted
out the lower temperature representing the energy loss.

There is a clever argument involving reversibility that proves
that no heat engine can be more efficient than an ideal Carnot
cycle.

Example:

 T2=700K
 T1=300K

Efficiency:

 eta = (700-300)/700 = 4/7, which to 2 digits accuracy is 0.57 .

I understand that currently available combined cycle gas turbine
generating stations can achieve an eta of 0.6 .

George

> If you are talking about practical efficiency, then you are talking 
> about what percentage of the available 1/3rd is used. IIRC, in a 
> high-efficiency gas-turbine engine, that's about 90%. Or about 30% of 
> the fuel energy.
> 
> Reciprocating internal combustion engines have lower efficiency, perhaps 
> that's what you have in mind with your 60% loss. External combustion 
> engines have even lower efficiency of course.
> 
> -- 
> Wolf K
> kirkwood40.blogspot.com
> "The next conference for the time travel design team will be held two 
> weeks ago."