What Is Resource Consumption and How Can It Be Measured?

In the first part of this series of two articles, an approach was presented that takes the entropy production associated with any process as a measure of the resource consumption of that process. Entropy production is thereby used to approximate the intuitive notion of consumption, which can best be described by the term “loss of potential utility.” This article presents an application example from the metallurgical sector. The related concept of exergy analysis is discussed and compared against the entropy approach. It was found that the production of 1 ton of refined copper generates 90.2 megajoules per Kelvin of entropy. A comparison with exergy analyses of copper production processes from the literature shows agreement at least on the order of magnitude. While results in one case deviate from the entropy analysis by about 40%, in another case the deviation is about 160%. One can only speculate on the reasons for this discrepancy, without knowing the exact process specifications of the processes analyzed. For entropy production as a measure for resource consumption, a baseline for comparison and interpretation of the results based on natural entropy disposal and reduction mechanisms is suggested.