Thermoeconomics connects thermodynamic and economic concepts in order to provide information not available in conventional energy and economic analysis. Most thermoeconomicists agree that exergy is the most appropriate thermodynamic magnitude to associate with cost. In some applications, exergy disaggregation is required. Despite the improvement in result accuracy, the modeling complexity increases. In recent years, different exergy disaggregation approaches have been proposed, mostly to deal with dissipative components and residues, despite all of them also increasing the complexity of thermoeconomics. This study aims to present a new thermoeconomic approach based on exergy disaggregation, which is able to isolate dissipative components with less modeling complexity. This approach, called the A&F Model, splits the physical exergy into two terms, namely, Helmholtz energy and flow work. These terms were evaluated from a thermoeconomic point of view, through a cost allocation in an ideal Carnot cycle, and they were also applied and compared with the UFS Model, through a cost allocation analysis, in a case study with an organic Rankine cycle-powered vapor compression refrigeration system. The complexity and computational effort reduction in the A&F are significantly less than in the UFS Model. This alternative approach yields consistent results.

In a productive process, the achievement of products occurs simultaneously with residues generation. Environmental impact of residues is an important issue in energy systems analysis due to environmental regulations and sustainability assessment. Many waste treatment methodologies have been proposed and applied in thermoeconomics. However, this is a complex problem and the solution depends on the residue nature and its formation process. Most conventional methodologies are based on productive diagrams, using productive flows only, and allocate the residues cost among the productive equipment. This work surveys the main conventional methodologies for treatment of waste and presents an improved/updated methodology based on a comprehensive diagram, in which both physical and productive flows are represented and their flows cost are assessed and the subsystems are connected using the same physical flows presented in the flowsheet of the plant. Both the CGAM system and a combined cycle are analyzed. Comparisons are made with literature results, considering the same case studies. The presented methodology obtains consistent results from the point of view of the cost allocation in thermoeconomics. The novelty of this updated approach concerns how the residue cost is allocated in the comprehensive diagram: it is reinternalized in the internal loop of physical flows, instead of in the productive unit. It represents advantages since the equipment product/fuel ratio index is not affected, which is beneficial for thermoeconomic diagnosis application.

In the context of emissions, carbon dioxide constitutes a predominant portion of greenhouse gases (GHGs), leading to the use of the term “carbon” interchangeably with these gases in climate-related discussions. The carbon market has emerged as a pivotal mechanism for emission regulation, allowing industries that struggle to meet emission reduction targets to acquire credits from those who have successfully curbed their emissions below stipulated levels. Thermoeconomics serves as a tool for analyzing multiproduct systems prevalent in diverse sectors, including sugarcane and alcohol mills, paper and pulp industries, steel mills, and cogeneration plants. These systems necessitate frameworks for equitable cost/emission allocation. This study is motivated by the need to expand the scope of thermoeconomic modeling to encompass expenses or revenues linked with the carbon market. By utilizing a cogeneration system as a representative case, this research aims to demonstrate how such modeling can facilitate the allocation of carbon market costs to final products. Moreover, it underscores the adaptability of this approach for internalizing other pertinent costs, encompassing expenses associated with environmental control devices, licenses, and permits. Although certain exergy disaggregation models depict an environmental component within diagrams, which is integral for addressing environmental burdens, even models without explicit environmental devices can effectively internalize carbon credits and allocate them to final products. The integration of carbon credits within thermoeconomic modeling introduces the capability to assess both the financial and environmental implications of emissions. This integration further incentivizes the reduction in GHGs and supports optimization endeavors concerning system design and operation. In summary, this study delves into the incorporation of carbon market dynamics into thermoeconomic modeling. It demonstrates the potential to allocate carbon-related costs, facilitates comprehensive cost analysis, encourages emission reduction, and provides a platform for enhancing system efficiency across industrial sectors.

Thermoeconomics is a science that reconciles thermodynamic and economic concepts. It can be divided into three fields of action: cost allocation, diagnosis and optimization. Most thermoeconomicists agree that exergy is the most appropriate thermodynamic magnitude to associate with cost. In some applications, exergy disaggregation is required. Literature shows several thermoeconomic methodologies. Despite the wide use and their respective fields of action, all models have limitations in the dissipative equipment isolation and waste treatment or an increase in complexity in thermoeconomic modeling. In order to fill part of this scientific gap in thermoeconomics, a recent methodology, the A&F Model, is proposed. This new approach disaggregates physical exergy into just two terms, namely Helmholtz energy and flow work. This work presents for the first time the use of this new approach, through a cost allocation, in a cogeneration system with regenerative gas turbine, and compares it with conventional thermoeconomic methodologies.