No. If it were, then food would have to be first converted into heat and that heat then converted to mechanical etc. energy forms. This is not the case. Most, if not all, of the conversion from food to mechanical energy is direct and not subject to the laws of thermodynamics as is the heat engine. If we were a heat engine with a hot source at 37C and cold at say 20C we'd be strugging to reach 5% efficiency even if we could equal Carnot and we couldn't operate at all above 35C. In fact the body's thermal to mechanical efficiency is around 20%
No, if by 'heat engine' you mean a device exchanging heat with two reservoirs at different temperatures etc. etc.
http://en.wikipedia.org/wiki/Heat_engine
no, humans convert food to energy and heat
Hello Sidra :
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Yes, a human may be thought of as a heat engine.
The nutrients turned to energy can be the heat absorbed by the heat engine.
The net work done by the body to be alive and perform daily activities are like the net work of the
heat engine.
The body , normally at 37 C , must reject some of the heat absorbed to a low temperature heat sink.
Explain?
