3 2000r 



in 



1500 



e 

 u 



UJ 



-u 



< 



3 

 U 



K 



< 

 3 



1000 



500 



5r i500r 



125 



-UJII50 

 o 



I- 

 Ui 

 M 



hS 7.5 



< 

 m 



IE 



D 



- 3.75 



O"- 0*- 



UR8AN 

 ..'■' -^.ASSETS (3) 



y 

 ^-^/ --'' 



V y AGRICULTURAL ->*-< 

 X^^^ ^ASSETS (2) ^^—y'' "~-... 



Figure 11. Simulation result of Hillsborough County model with constantly 

 increasing relative fuel prices and a price jump in 1973 with an increasing 

 fuel surcharge beginning in 1973. (Sipe et al . 1979). 



USES OF ENERGETICS MODELS 



SIMULATIONS 



One of the principal uses of energetics models is the simulation of a 

 system from some historical time through the present and into the future. The 

 simulation results of the historical period permit the results of the simula- 

 tion to the present to be compared with available empirical data. Assuming 

 the simulation perfoms well in these "benchmark" tests, it is then continued 

 into the future. These simulated results — telling the researcher of likely 

 trends, given the present and historical data -- are the most common 

 application of energetics models. It is important to know that the simulation 

 results can only be as good as the modeler's ability to comprehend the system 

 under study. Construction of models that reflect actual conditions is 

 diff icul t. 



Frequently, the simulation is prepared to permit the relative advantages 

 and disadvantages of alternative courses of action to be compared. For 

 example, energetics models have been used to examine alternative methods for 

 cooling a proposed nuclear power plant (Odum 1978). This study compared cool- 

 ing towers, a man-made reservoir, and a nearby lake as possible methods by 

 which the waste heat generated as a by-product of the power generation process 

 could best be returned to the natural environment. 



327 



