Entropy generation and thermoeconomic analysis of the wire-and-tube condenser

Abstract

In this work, entropy generation analysis of an air-cooled natural draft wire-and-tube condenser commonly used in the domestic refrigerator is carried out to investigate geometrical and operating parameters. The Bejan number formulation is used for the analysis because of its ability to relate the heat transfer to pressure drop entropy generation. The analysis also incorporates thermoeconomics by combining the second law of thermodynamics with economic principles. The analytical study is carried out by varying geometrical parameters of the condenser such as tube outer diameter, wire diameter, number of wire pairs, number of tube rows, tube pitch, wire pitch and refrigerant (R134a) properties such as mass velocity, saturation temperature and dryness fraction. The behaviour of entropy generation due to heat transfer and pressure drop, Bejan number and thermoeconomic variables such as relative cost difference and exergoeconomic factor are analysed. These results are used in obtaining the values of condenser dimensions leading to better performance.

Keywords:

• entropy
• heat transfer irreversibility
• pressure drop irreversibility
• air-cooled condenser
• household refrigerator
• refrigerant R134a