i consulted with an engineering friend of mine regarding temperature and
efficiency. this is what i have. see what you think.
"... Every system has it's own optimal temperature. For engines,
they generally operate more efficiently at higher temperatures because less
of the energy produced is being "wasted" as heat. That's assuming the
ambient temperature is lower than the temperatures produced inside the
engine. For every engine there's some magic temperature where it's
efficiency start to go down as the temperature increase, and that's due
to things like thermal expansion of metal parts.
In general, the efficiency of a thermodymanic reaction is a function of
the temperature difference between the surrounding environment and the
area of the reaction. The bigger the temperature gradient, the more of
the energy produced by the reaction that's wasted in heating up the
nearby areas. As the reaction continues, it heats up the surrounding
environment so the temperature gradient decreases and the efficiency of
the system increases. That's why your car engine runs better after it's
"warmed up".
So, to answer your original question, higher temperature does generally
lead to higher efficiency, but only until the temperature begins to alter
the system."
-dao
>>
>> Well then maybe there were some other variables involved that somehow
>>managed
>> to get you greater mileage.
>>
>> All I am saying that it is a thermodynamic principle that clearly states
>>the
>> lower the temperature, the lower the efficiency of the cycle... and of
>> course, the opposite holds true... the higher the temps, the better the
>> efficiency.
>>
>> Keep in mind, I am talking about the operating temperatures... and not the
>> incoming air temperatures... we all know the cooler the incoming air, the
>> more dense it is... the more dense it is.. the more oxygen it contains...
>>
>> This is not a flame in any way... all I am simply stating is that, "all
>> things held constant... going from a 200 to a 180 degree t-stat will yield
>> lower mpg"
>>
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