Performance analysis of hot-wall condensers used in household refrigerators

• Grant number: 13/21783-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2014
• End date: December 31, 2014
• Field of knowledge: Engineering - Mechanical Engineering - Thermal Engineering
• Principal Investigator: André Luiz Seixlack
• Grantee: Tiago Simino Macedo
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

This work presents a mathematical model to analyze the performance of hot-wall condensers, commonly used in domestic refrigerators. Such analysis involves modeling the steady state refrigerant flow inside a condenser tube and free convection and radiation heat transfer between the outer surface of the condenser and the external environment. The refrigerant flow inside the tube is considered to be one-dimensional and is divided into a superheated vapor single-phase region, a two-phase flow region and a subcooled liquid single-phase region. The homogeneous flow model is employed for the two-phase flow, namely, hydrodynamic and thermal equilibrium between phases is taking into account. The refrigerant pressure drop inside the tube is also taken into account. A Finite Volume approach is used to obtain the discretization of the governing equations of: mass conservation, momentum and energy conservation. The resulting set of algebraic equations is solved by successive iterations. A sensitivity analysis of the model will be carried out to determine the influence of the constitutive equations used in the calculation of pressure drop due to friction along the tube and the convective heat transfer coefficients between the refrigerant and the inner wall of the tube and between the external surface and the environment. The results obtained are compared with experimental data available in the literature.