[Gasification] THERMAL EFFICIENCY

[Benjamin Domingo Bof]

Kevin & Gregg this site explains how run Humphrey engine . It is simply an
"ram" device.
http://www.steamengine.com.au/ic/history/humphrey_pumps/
Regards, Ben

Kevin Chisholm <kchisholm at ca.inter.net> escribió: Dear Greggfwhell at aol.com wrote:
> The heat engine efficiency theorems were applied to the 4 stroke Humphrey engine,and  were given an efficiency rating of over 90%.by the engineering examining body.
> The exhaust gas temperature leaving the engine was less than 15 Deg F above ambient.
> Does this mean, 90% of the fuel was converted into work?
> GF
>   

It depends on how they set up the study. It is extremely unlikely that 
the Humphrey Engine got 90% of Carnot Efficiency. However, the Humphrey 
Engine could perhaps have attained "90% of Carnot Efficiency."

OR, in comparison with a Boiler and Steam Engine System, the Humphrey 
Engine may have been 90% as efficient as a Boiler/Steam Engine system 
doing the same work.

You would really have to see teh original study to see what their 
evaluation basis was.

best wishes,

Kevin
>
> -----Original Message-----
> From: Benjamin Domingo Bof 
> To: Discussion of biomass pyrolysis and gasification 
> Sent: Thu, 7 Feb 2008 11:33 am
> Subject: [Gasification] THERMAL EFFICIENCY
>
>
>
> Heat engines When transforming thermal energy into mechanical energy, the 
> hermal efficiency of a heat engine is the percentage of heat energy that is 
> ransformed into work. Thermal efficiency is defined as
>
>  
>
>  
> [edit] Carnot efficiency The second law of thermodynamics puts a fundamental 
> imit on the thermal efficiency of heat engines. Surprisingly, even an ideal, 
> rictionless engine can't convert anywhere near 100% of its input heat into 
> ork. The limiting factors are the temperature at which the heat enters the 
> ngine, , and the temperature of the environment into which the engine exhausts 
> ts waste heat,, measured in the absolute Kelvin or Rankine scale. From Carnot's 
> heorem, for any engine working between these two temperatures:
>
>  
>    
>
> This limiting value is called the Carnot cycle efficiency because it is the 
> fficiency of an unattainable, ideal, lossless (reversible) engine cycle called 
> he Carnot cycle. No heat engine, regardless of its construction, can exceed 
> his efficiency.
>
> Examples of  are the temperature of hot steam entering the turbine of a steam 
> ower plant, or the temperature at which the fuel burns in an internal 
> ombustion engine.  is usually the ambient temperature where the engine is 
> ocated, or the temperature of a lake or river that waste heat is discharged 
> nto. For example, if an automobile engine burns gasoline at a temperature of  
> nd the ambient temperature is , then its maximum possible efficiency is given 
> y:
>
>  
>    
>
> In practice, because no practical implementation of the Carnot cycle exists 
> oupled with other irreversibilities such as the combustion process itself and 
> riction, real engines fall far short of the Carnot efficiency. Real automobile 
> ngines are only around 25% efficient, combined cycle power stations have 
> fficiencies much higher however will still fall at least 15% points short of 
> he Carnot value. As Carnot's theorem only applies to heat engines, devices that 
> onvert the fuel's energy directly into work without burning it such as fuel 
> ells, can exceed the Carnot efficiency.
>        
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