(A) 



(B) 



(E) 



(F) 



(G) 



(I) 



Figure 1. Energy circuit diagramming symbols: (A) energy storage; 

 (B) energy source; (C) heat sink; (D) self-maintaining consumer unit; 

 (E) self-maintaining production unit; (F) logic unit; (G) transforma- 

 tion or production function; (H) money energy transaction and 

 (I) energy flow sensor. 



The maximum power principle states that systems which take advantage of 

 the maximum number of energy sources and use them most efficiently have the 

 best chance of survival and are more competitive than systems which cannot 

 sufficiently use the energy sources available (Lotka 1922). Charles Darwin's 

 theory of survival of the fittest is an example of the maximum power principle 

 when the system or subsystem under study is a living organism. An industrial 

 example would be competition between two factories producing the same product; 

 one only used wood as an energy source whereas the other used wood and coal . 



ENERGY QUALITY 



In assessing the capacity of energy to do work, more must be known than 

 the total amount of available heat equivalent energy. This requirement can be 

 illustrated by comparing wood and coal as fuels. Coal is a higher quality 

 (more concentrated) fuel than wood. For example, it is more desirable to fuel 

 a foundry with coal than wood because the more concentrated coal burns at a 

 higher temperature. The difference in the energy quality of wood and coal is 



280 



