Exergetic evaluation of drying of laurel leaves in a vertical ground-source heat pump drying cabinet

WOS: 000244215700003This paper is concerned with the exergy analysis of the single layer drying process of laurel leaves in a ground-source heat pump drying cabinet. which was designed and constructed in the Solar Energy Institute, Ege University, Izmir. Turkey. The effects of drying air temperature on exergy losses, exergy efficiencies and exergetic improvement potential of the drying process are investigated. The results have indicated that exergy efficiencies of the dryer increase with rising the drying air temperature. Moreover, the laurel leaves are sufficiently dried at the temperatures ranging from 40 to 50 degrees C with relative humidities varying from 16 to 19% and a drying air velocity of 0.5 m s(-1) during the drying period of 9 h. The exergy efficiency values are obtained to range front 81.35 to 87.48% based on the inflow. outflow and loss of exergy, and 9.11 to 15.48% based on the product/fuel basis between the same drying air temperatures with a drying air mass flow rate of 0.12 kg s(-1). Copyright (c) 2006 John Wiley & Sons, Ltd

A review of gas engine driven heat pumps (GEHPs) for residential and industrial applications

WOS: 000260972200004This study reviews gas engine-driven heat pump (GEHP) systems for residential and industrial applications in terms of energetic and exergetic aspects for the first time to the best of the authors' knowledge. These systems are novel heat pump systems (one of today's promising new technologies). Although the first investigations had been performed at late 1970s, the first merchandized GEHP was produced and introduced in the market in 1985. Gradually, it has become widespread all over the world for various purposes. Main application of GEHPs are for space and water heating/cooling purposes. However, they call be integrated to industrial applications, especially to drying processes. In this study, historical development of GEHP systems was briefly given first. Next, the operation of these systems was described, while studies conducted on them were reviewed and presented in tabulated forms. GEHPs were then modeled for performance evaluation purposes by using energy and exergy analysis methods. Finally, an illustrative example was given, while the results obtained were discussed. In addition, a new project on integration of GEHP systems to food drying processes in Turkey initiated by the authors was introduced. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the energetic and exergetic design, simulation, analysis and performance of assessment of GEHP systems. (C) 2007 Elsevier Ltd. All rights reserved.The Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [106M482]The authors are grateful for the financial support provided for the project entitled "Design, test and performance evaluation of a gas engine driven solar assisted band conveyor heat pump drying system" under Project No. of 106M482 by The Scientific and Technological Research Council of Turkey (TUBITAK)

A review of gas engine driven heat pumps (GEHPs) for residential and industrial applications

This study reviews gas engine-driven heat pump (GEHP) systems for residential and industrial applications in terms of energetic and exergetic aspects for the first time to the best of the authors' knowledge. These systems are novel heat pump systems (one of today's promising new technologies). Although the first investigations had been performed at late 1970s, the first merchandized GEHP was produced and introduced in the market in 1985. Gradually, it has become widespread all over the world for various purposes. Main application of GEHPs are for space and water heating/cooling purposes. However, they can be integrated to industrial applications, especially to drying processes. In this study, historical development of GEHP systems was briefly given first. Next, the operation of these systems was described, while studies conducted on them were reviewed and presented in tabulated forms. GEHPs were then modeled for performance evaluation purposes by using energy and exergy analysis methods. Finally, an illustrative example was given, while the results obtained were discussed. In addition, a new project on integration of GEHP systems to food drying processes in Turkey initiated by the authors was introduced. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the energetic and exergetic design, simulation, analysis and performance of assessment of GEHP systems.Gas engine heat pump Gas engine driven heat pumps Heat pumps Exergy Sustainable development

Exergetic analysis of a continuous Bi-axially Oriented Polypropylene (BOPP) film unit in a plastic processing plant

WOS: 000267086200009This paper deals with an exergy analysis of the stretching process of bi-axially oriented polypropylene films using a hot oil coiler along with stretching and crystallising unit. Exergy destructions and efficiencies in each of the system components are calculated, while the exergy loss and flow diagram (the so-called Grassmann diagram) is presented for the transverse direction (TD) unit. The so-called functional (on the product or benefit/fuel basis) and universal (on the output/input basis) exergy efficiency values of the TD unit are calculated to be 26.40% and 28.46% at a recommended exhaust air relative humidity of 0.0098 kg water/kg air, respectively