Entropy­based methods applied to the evaluation of a real refrigeration machine

• Main Authors: Larisa Morozyuk, Viktoriia Sokolovska-Yefymenko, Sergey Gayduk, Andrii Moshkatiuk
• Format: Article
• Language: English
• Published: PC Technology Center 2018-11-01
• Series: Eastern-European Journal of Enterprise Technologies
• Subjects: entropy methods; real refrigeration machine; air­cooled condenser; solid fouling
• Online Access: http://journals.uran.ua/eejet/article/view/147710
• ISSN: 1729-3774; 1729-4061

The aim of the research is the thermodynamic analysis of a real refrigerating machine with solid fouling on the heat­exchange surface of an air­cooled condenser with the help of entropy methods such as: the entropy­cycle method, the entropy­statistical method and the entropy generation minimization method. The experimental data of the refrigerating machine with solid fouling in the form of dust on the external surface of the air­cooled condenser was used for the thermodynamic analysis. The influence of irreversible losses in separate elements of the refrigerating machine caused by the presence of external solid fouling on the external heat exchange surface of the air­cooled condenser was determined according to the entropy­cycle and entropy­statistical methods. The entropy­cycle method has estimated the absolute value of energy losses in each element. The entropy­statistical method was used to determine the excessive consumption of work in the real cycle in comparison with the theoretical compression process in the compressor. The irreversible losses associated with aerodynamics and heat transfer during air motion through a finned surface in an air­cooled heat exchanger were estimated by using the entropy generation minimization theory. The influence of growing fouling on the thermal and mechanical components of the total entropy generation in the heat exchanger was determined. In addition, the fouling mass that determines the time of its cleaning was defined. Application of entropy methods for analyzing the real refrigerating machine at the design stage allows minimizing irreversible losses associated with operating conditions. Moreover, it allows predicting a maintenance schedule which contributes to energy saving