The energy circuit language grew out of a recognition and appreciation for open system thermodynamics of ecosystems, general systems theory, and simulation. The following links will download folders containing:

Energy systems diagramming language (zip file of graphic formats)

Sample system diagrams of ecosystems and regional systems (zip file of PDFs)

Below is a brief overview of the Energy Systems Language.

Symbols characterizing specific systems properties are used to create diagrams with clearly defined forcing functions, state variables and interactions. The use of these symbols and the associated mathematical equations are discussed in detail in the following publication:

Odum., H.T. 1994. Ecological and General Systems: An Introduction to Systems Ecology. Univ. Press of Colo., P.O. Box 849, Niwot, CO, 80544. 644 pp.

 

QUICK REFERENCE GUIDE

 

Energy circuit: A pathway whose flow is proportional to the quantity in the storage or source upstream. 

Source: Outside source of energy delivering forces according to a program controlled from outside; a forcing function.
 

Tank: A compartment of energy storage within the system storing a quantity as the balance of inflows and outflows; a state variable. 

Heat sink: Dispersion of potential energy into heat that accompanies all real transformation processes and storages; loss of potential energy from further use by the system.
 

Interaction: Interactive intersection of two pathways coupled to produce an outflow in proportion to a function of both;control action of one flow on another; limiting factor action;work gate.

Consumer: Unit that transforms energy quality, stores it, and feeds it back autocatalytically to improve inflow. 

Switching action: A symbol that indicates one or more switching actions.

Producer: Unit that collects and transforms low-quality energy under control interactions of high-quality flows. 

Self-limiting energy receiver: A unit that has a self-limiting output when input drives are high because there is a limiting constant quality of material reacting on a circular pathway within.

Box: Miscellaneous symbol to use for whatever unit or function is labeled.

Constant-gain amplifier: A unit that delivers an output in proportion to the input I but is changed by a constant factor as long as the energy source S is sufficient. 

Transaction: A unit that indicates a sale of goods or services (solid line) in exchange for payment of money (dashed line). Price is shown as an external source.

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