Thermoeconomic Cost Allocation Approaches in a Simultaneous Heating and Cooling Heat Pump System.

Abstract

Thermoeconomics is a branch of engineering that combines concepts from thermodynamics and economics to tackle problems that are hard or cannot be solved by these sciences, separately. The main applications of thermoeconomics are cost allocation, optimization, and malfunction diagnosis of energy systems. Defining the productive structure plays a critical role in thermoeconomic modeling, and exergy is a highly appropriate thermodynamic quantity to correlate with costs. For systems containing dissipative equipment, the use of total exergy in conventional productive diagrams need a subsequent decision, by the analysts, on how to define its fuel and product. In some applications, exergy disaggregation can be elegant options, mostly to deal with dissipative components. Nevertheless, all of them increase the complexity in thermoeconomic modelling. In this work, thermoeconomic cost allocation approaches in a simultaneous heating and cooling heat pump system were performed from the application of some thermoeconomics methodologies. The studied system has one dissipative component (valve) and generates no waste. There are three specific objectives. Firstly, to present the different possibilities to treat and isolate the valve in the thermoeconomics modelling. Secondly, to compare the methodologies presented from the thermoeconomic point of view through the cost allocation in a simultaneous heating and cooling heat pump system. And finally, to show the pros and cons of each methodology applied in this study to support future decision-makings in thermoeconomic modelling. The research demonstrates that the differences between the methodologies used were not significant, and the choice of methodology should depend on factors such as the need for disaggregated equipment. In conclusion, the findings of this study indicate that without certain models that may overestimate the cost of particular components, the thermoeconomic results fall within a narrow range of 4% of the solution line. This suggests that the methodologies used did not yield significantly different results.