A review of heat pump drying: Part 1-Systems, models and studies

The first heat pump dryer (HPD) patent applications were started in 1973, while recently, there has been a great interest in utilizing HPDs for drying fruits, vegetables and biological materials. This study deals with reviewing heat pump drying studies and consists of two parts. In the first part of this study, historical development of HPDs was briefly given first. Description of these systems was then presented. Finally, studies conducted on HPD were reviewed in terms of process efficiency modeling and progress of quality. (C) 2009 Elsevier Ltd. All rights reserved.