An Object-Oriented R744 Two-Phase Ejector Reduced-Order Model for Dynamic Simulations

Autor: Michal Haida, Rafal Fingas, Wojciech Szwajnoch, Jacek Smolka, Michal Palacz, Jakub Bodys, Andrzej J. Nowak
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Energies, Vol 12, Iss 7, p 1282 (2019)
Druh dokumentu: article
ISSN: 1996-1073
DOI: 10.3390/en12071282
Popis: The object-oriented two-phase ejector hybrid reduced-order model (ROM) was developed for dynamic simulation of the R744 refrigeration system. OpenModelica software was used to evaluate the system’s performance. Moreover, the hybrid ROM results were compared to the results given by the non-dimensional and one-dimensional mathematical approaches of the R744 two-phase ejector. Accuracy of all three ejector models was defined through a validation procedure for the experimental results. Finally, the dynamic simulation of the hybrid ROM ejector model integrated with the R744 refrigeration system was presented based on the summer campaign at three different climate zones: Mediterranean, South American and South Asian. The hybrid ROM obtained the best prediction of ejector mass flow rates as compared with other ejector models under subcritical and transcritical operating conditions. The dynamic simulations of the R744 ejector-based system indicated the ejector efficiency variations and the best efficiency at the investigated climate zones. The coefficient of performance (COP) varied from 2.5 to 4.0 according to different ambient conditions. The pressure ratio of 1.15 allowed a more stabilised system during the test campaign with an ejector efficiency from 20% to over 30%.
Databáze: Directory of Open Access Journals
Nepřihlášeným uživatelům se plný text nezobrazuje