Heat and Mass Transfer in the Melting of Frost

This Brief is aimed at engineers and researchers involved in the refrigeration industry: specifically, those interested in energy utilization and system efficiency. The book presents what the authors believe is the first comprehensive frost melting study

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William F. Mohs Francis A. Kulacki

Heat and Mass Transfer in the Melting of Frost

123

SpringerBriefs in Applied Sciences and Technology Thermal Engineering and Applied Science

Series Editor Francis A. Kulacki, Minnesota, USA

More information about this series at http://www.springer.com/series/8884

William F. Mohs • Francis A. Kulacki

Heat and Mass Transfer in the Melting of Frost

William F. Mohs Christchurch, New Zealand

Francis A. Kulacki Department of Mechanical Engineering University of Minnesota Minneapolis, MN, USA

ISSN 2191-530X ISSN 2191-5318 (electronic) SpringerBriefs in Applied Sciences and Technology ISBN 978-3-319-20507-6 ISBN 978-3-319-20508-3 (eBook) DOI 10.1007/978-3-319-20508-3 Library of Congress Control Number: 2015942245 Springer Cham Heidelberg New York Dordrecht London © Springer International Publishing Switzerland 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www. springer.com)

Preface

An important problem in the refrigeration industry is the formation and removal of frost layers on subfreezing heat exchanger surfaces of air coolers. Frost is a porous structure of ice and air pockets that grows on the finned surfaces of the heat exchanger. It directly diminishes the performance and efficiency of the entire cooling system by increasing resistance to air flow and heat transfer. To return the system to pre-frosted performance, the frost layer is melted by surface heating. This method is inherently inefficient, with the majority of the applied energy being lost to the surrounding environment. A validated model for heat and mass transfer in frost melting and defrost efficiency is developed based on local conditions at a vertical surface. Noninvasive measurements of frost thickness are taken from digitally reduced in-plane and normal images of the frost layer through time. The visual method eliminates disturbances cau