Session: 12-13-02: Heat Transfer in Electronic Equipment II

Paper Number: 165375

A New Frost Growth Correlation for Refrigeration Applications 

Frost accumulation on cold heat exchanger surfaces presents a significant challenge in refrigeration and air-conditioning systems, as it forms an insulating layer that adversely impacts heat transfer efficiency. This accumulation not only reduces the overall system performance but also obstructs airflow through heat exchangers, leading to increased flow resistance and a subsequent reduction in system airflow for a given fan capacity. Additionally, periodic heating or defrosting cycles implemented to mitigate frost buildup further degrade the system’s coefficient of performance (COP), highlighting the necessity for accurate predictive models to forecast frost growth and develop effective mitigation strategies.

Several frost growth models have been developed to predict the formation and progression of frost layers under different thermal and flow conditions. Among these, the models proposed by Lee et al. (1997), Hermes et al. (2012), and Wang et al. (2012) have been widely cited in the literature and recognized for their contributions to understanding frost formation dynamics. Given their significance, our present study focuses on these three models, aiming to evaluate their predictive accuracy and identify potential areas for improvement.

To achieve this, we first reconstructed the aforementioned models and validated their predictions against the experimental datasets provided in their respective studies. A comparative analysis was then conducted using three independent experimental datasets to assess the accuracy of these models under varying conditions of temperature, humidity, and airflow. The performance of each model was systematically analyzed by comparing predicted frost thickness, density, and thermal conductivity with the corresponding experimental measurements.

Key areas of agreement and divergence between the models and experimental data were carefully identified. In particular, discrepancies were analyzed in relation to governing parameters such as heat and mass transfer coefficients, thermophysical properties, and boundary layer effects. Special attention was given to potential sources of uncertainty within the models, particularly in the characterization of the airside Reynolds number in the Lee model, as it plays a crucial role in determining convective heat and mass transfer. The analysis also considered the influence of environmental variables, including variations in air velocity and temperature differentials, on frost accumulation behavior.

Our findings provide valuable insights into the limitations of the existing models, highlighting their applicability across different operating conditions while also revealing areas where refinements are necessary. The study suggests that improvements can be made by incorporating a more comprehensive treatment of frost density, thermal conductivity, and airside heat and mass transfer coefficients. By refining these aspects, the predictive capability of frost growth models can be enhanced to achieve more reliable forecasts across a wider range of practical refrigeration applications.

Based on these findings, we aim to propose an improved frost growth model that overcomes the limitations identified in existing approaches. This enhanced model will integrate refinements in key governing parameters and offer greater accuracy and applicability for industrial and commercial refrigeration systems. Through this work, we seek to contribute to the ongoing development of robust predictive tools for frost formation, ultimately supporting more energy-efficient refrigeration and heat exchanger designs.

 

Presenting Author: Sunil Mehendale Michigan Technological University

Presenting Author Biography: Sunil Mehendale is an Associate Professor in the Department of Manufacturing and Mechanical Engineering Technology at Michigan Technological University. Prior to joining Michigan Tech as a faculty member in the College of Engineering, he worked for Carrier Corporation, Syracuse, NY as a Staff Engineer and Scientist in the Heat Transfer Technology and Components group. There, he was responsible for developing and implementing advanced heat exchanger technologies as well as state-of-the-art design and simulation tools in the areas of energy efficiency, heat transfer, and fluid flow. Before Carrier, he worked for seven years at Delphi Thermal Systems, Lockport, NY, where he was engaged in the research, design, and development of advanced energy-efficient heat exchangers, primarily evaporators for automotive climate control systems. Before joining Delphi, Dr. Mehendale worked as a post-doctoral research associate in the Department of Mechanical and Industrial Engineering at the University of Illinois, Urbana-Champaign, where he designed and developed micro-scale heat exchangers intended for US military personnel in a project sponsored by DARPA, US Department of Defense.

Dr. Mehendale’s area of teaching and research interest and expertise is primarily in the thermal-fluids sciences, with emphasis on the design and optimization of high-efficiency energy conversion systems and heat exchangers, boiling and condensing flows, and two-phase flow distribution in heat exchanger.

Authors:

Kiran Sapali Michigan Technological Univeristy
Sunil Mehendale Michigan Technological University