ENERGY, EMERGY AND ENVIRONS

Environs are a model of J. von Uexkull's theory of environment. They have affinities with embodied energy (emergy), transformity and energy value in H.T. Odum's energy-circuit theory. Energy circuits and output environs are both networks defined by a single input; environ theory also has reciprocal input environs which extend back from outputs. Feedback cycling exerts control functions in Odum's model. In environs, control is distributed nonspecifically over highly reticulated cyclical pathways. These networks can be unfolded into straight chains with an indefinite number of steps. Distance from sources motivates Odum's measure of energy quality as embodied energy, or emergy, measured by transformity. Any unfolded network may have such measures computed for individual output (or input) environs. Each transfer level contains contributions from many compartments, and each compartment occupies many transfer levels. The subnetworks of output (or input) environs become commingled to form the whole-system network, which environ analysis unravels mathematically, preserving the reticulated (vs. straight-chain) conception. Transformities measure network value, in individual environs or entire systems. A different approach to energy value is provided by utility measures; both direct (local) and direct plus indirect (global) values may be computed. Comparison of local vs. global utilities has both quantitative and qualitative aspects. The latter define ecological interaction types (competition, predation, etc.) from internodal flows. Network organization tends to synthesize global positive relationships from local negative ones. Environ-value theory differs from embodied-energy theory, but is not in conflict with it. Together, they provide complementary perspectives on quantifying subjective values from objective flow processes.