Component-Oriented Modeling of a Micro-Scale Organic Rankine Cycle System for Waste Heat Recovery Applications

• Published in: Applied sciences Vol. 11; no. 5; p. 1984
• Main Authors: Moradi, Ramin, Habib, Emanuele, Bocci, Enrico, Cioccolanti, Luca
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.03.2021
• Subjects: Data points; Efficiency; Electric power; Electric power generation; Electricity distribution; Energy conversion; Energy conversion efficiency; experimental modeling; Heat; Heat exchangers; Heat recovery; Low temperature; low-grade waste heat recovery applications; Mathematical models; micro-scale ORC; Numerical models; off-design performance; Rankine cycle; Sensors; volumetric pump modeling; Waste heat; Working conditions; Working fluids
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app11051984

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.