The first heat pump dryer (HPD) patent applications were started in 1973, while recently, there h... more 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.
In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms... more In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms of applications and performance evaluations. In this regard, these systems were classified in terms of type of heat pump systems, type of dryer and product types first. The performance assessments included coefficient of performance (COP), specific energy consumption (SEC) and specific moisture extraction rate (SMER), while types of energetic, exergetic and cost analyses were covered. It may be concluded that the most preferred method used to determine the HPD efficiency is SMER, while in recent years exergetic analysis method has been widely used.
It is well known that micro-level system parameters may have some great impact on macro-level ene... more It is well known that micro-level system parameters may have some great impact on macro-level energy aspects, the environment, and sustainability. Of course, if one wants to approach these thermodynamically, there are two ways: energy analysis through the first law of thermodynamics and exergy analysis through the second law of thermodynamics. Exergy analysis is an essential tool to expose the impacts of a power generating device on exergy-based sustainability; sustainability is necessary to overcome current ecological, economic, and developmental problems (Dincer and Rosen, 2005). In this regard, some new exergy-based sustainability parameters for a PEM fuel cell have been developed and studied parametrically to investigate how they will help measure the level of environmental impact and sustainable development (Midilli and Dincer, 2009). These types of parameters may also be applied to other energy-related systems.
... Neslihan Colak, Mustafa T. Balta, Filiz Içier, Ebru Kuzgunkaya, Arif Hepbasli and Zafer Erbay... more ... Neslihan Colak, Mustafa T. Balta, Filiz Içier, Ebru Kuzgunkaya, Arif Hepbasli and Zafer Erbay ... of a power generating device on exergy-based sustainability; sustainability is necessary to overcome current ecological, economic, and developmental problems (Dincer and Rosen ...
This article deals with the exergy analysis of a single layer drying process of mint leaves in a ... more This article deals with the exergy analysis of a single layer drying process of mint leaves in a ground source heat pump tray dryer, which was designed and constructed in the Solar Energy Institute, Ege University, Izmir, Turkey. The drying process was realized at three various drying air temperatures of 40, 45 and 50C, and mass flow rate from 0.01 to 0.05 kg/s at a constant relative humidity of 16%. The effects of temperatures and mass flow rates on the exergy losses, exergy efficiencies and improvement potentials of the drying process were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 50C and a drying air mass flow rate of 0.05 kg/s. The exergy efficiency values were obtained to vary from 76.03 to 97.24% at drying air temperatures of 40-50C with drying air mass flow rates of 0.01-0.05 kg/s.
This paper deals with the performance evaluation of a single layer drying process of green olives... more This paper deals with the performance evaluation of a single layer drying process of green olives in a tray dryer using exergy analysis method. Green olive was used as the test material being dried. Drying process was realized at four different drying air temperatures (40, 50, 60 and 70°C) and a constant relative humidity of 15%. The effects of temperatures and mass flow rates were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 70°C and a drying air mass flow rate of 0.015 kg/s with 0.0004 kg/s of olive. The exergy efficiency values were found to be in the range of 68.65%-91.79% from 40°C to 70°C with drying air mass flow rates of 0.01 kg/s-0.015 kg/s.
The performance of a tray dryer system for the parsley drying process was assessed using energy a... more The performance of a tray dryer system for the parsley drying process was assessed using energy and exergy analysis methods in this study. The drying temperature ranged from 40°C to 60°C, while the drying air velocity varied from 0.5 m/s to 1.5 m/s. The higher temperature and lower velocity led to higher exergy and energy efficiencies. The exergy efficiency value for the overall system on a product/fuel basis was found to be 3.62%. The values for Specific Moisture Extraction Rate (SMER) and Specific Moisture Exergetic index (SMExR) were obtained to be 0.08 and 2.47 kg/kWh, respectively.
... Neslihan Colak1, Zafer Erbay2 and Arif Hepbasli3,*,† 1Faculty of Engineering, Department of F... more ... Neslihan Colak1, Zafer Erbay2 and Arif Hepbasli3,*,† 1Faculty of Engineering, Department of Food Engineering, Pamukkale University, 20020 Denizli, Turkey 2Faculty of Engineering, Department of Food Engineering, Ege University, 35100, Bornova, Izmir, Turkey 3Department ...
Proceedings of The Institution of Mechanical Engineers Part A-journal of Power and Energy, 2010
In this study, plum slices were dried in three different driers (tray, fluid bed, and heat pump (... more In this study, plum slices were dried in three different driers (tray, fluid bed, and heat pump (HP) driers). Drying experiments were carried out at an air temperature range of 45−55 • C with an air velocity of 1.5 m/s. The performance of the driers along with their main components was evaluated and compared by using the exergy analysis method. The most important component for improving the system efficiency was determined to be the fan-heater combination for both the tray and fluid bed driers, and the motor-compressor assembly for the HP drier. The exergy loss and flow diagram (the so-called Grassmann diagram) of the driers was also presented to give quantitative information regarding the proportion of the exergy input dissipated in the various system components. Effects of the drying air temperature on the performance of the drying process were discussed. The highest exergetic efficiency values were obtained to range from 72.72 to 75.66 per cent for the HP drier, followed by the tray and fluid bed driers varying between 37.94 and 39.46 per cent, and between 22.83 and 24.07 per cent, respectively. be feasible . The methods of drying are diversified with the purpose of the process. There are more than 200 types of dryers . For every dryer, the process conditions, such as drying chamber temperature, pressure, air velocity (if the carrier gas is air), relative humidity, and the product retention time, have to be determined according to feed, product, purpose, and method. On the other hand, drying is an energyintensive process, while its energy consumption value varies between 10 and 15 per cent of the total energy consumption in all industries in developed countries . Therefore, optimization of the drying processes and systems is important with regard to the energetic efficiencies.
This study reviews gas engine-driven heat pump (GEHP) systems for residential and industrial appl... more 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.
The first heat pump dryer (HPD) patent applications were started in 1973, while recently, there h... more 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.
In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms... more In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms of applications and performance evaluations. In this regard, these systems were classified in terms of type of heat pump systems, type of dryer and product types first. The performance assessments included coefficient of performance (COP), specific energy consumption (SEC) and specific moisture extraction rate (SMER), while types of energetic, exergetic and cost analyses were covered. It may be concluded that the most preferred method used to determine the HPD efficiency is SMER, while in recent years exergetic analysis method has been widely used.
The first heat pump dryer (HPD) patent applications were started in 1973, while recently, there h... more 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.
In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms... more In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms of applications and performance evaluations. In this regard, these systems were classified in terms of type of heat pump systems, type of dryer and product types first. The performance assessments included coefficient of performance (COP), specific energy consumption (SEC) and specific moisture extraction rate (SMER), while types of energetic, exergetic and cost analyses were covered. It may be concluded that the most preferred method used to determine the HPD efficiency is SMER, while in recent years exergetic analysis method has been widely used.
It is well known that micro-level system parameters may have some great impact on macro-level ene... more It is well known that micro-level system parameters may have some great impact on macro-level energy aspects, the environment, and sustainability. Of course, if one wants to approach these thermodynamically, there are two ways: energy analysis through the first law of thermodynamics and exergy analysis through the second law of thermodynamics. Exergy analysis is an essential tool to expose the impacts of a power generating device on exergy-based sustainability; sustainability is necessary to overcome current ecological, economic, and developmental problems (Dincer and Rosen, 2005). In this regard, some new exergy-based sustainability parameters for a PEM fuel cell have been developed and studied parametrically to investigate how they will help measure the level of environmental impact and sustainable development (Midilli and Dincer, 2009). These types of parameters may also be applied to other energy-related systems.
... Neslihan Colak, Mustafa T. Balta, Filiz Içier, Ebru Kuzgunkaya, Arif Hepbasli and Zafer Erbay... more ... Neslihan Colak, Mustafa T. Balta, Filiz Içier, Ebru Kuzgunkaya, Arif Hepbasli and Zafer Erbay ... of a power generating device on exergy-based sustainability; sustainability is necessary to overcome current ecological, economic, and developmental problems (Dincer and Rosen ...
This article deals with the exergy analysis of a single layer drying process of mint leaves in a ... more This article deals with the exergy analysis of a single layer drying process of mint leaves in a ground source heat pump tray dryer, which was designed and constructed in the Solar Energy Institute, Ege University, Izmir, Turkey. The drying process was realized at three various drying air temperatures of 40, 45 and 50C, and mass flow rate from 0.01 to 0.05 kg/s at a constant relative humidity of 16%. The effects of temperatures and mass flow rates on the exergy losses, exergy efficiencies and improvement potentials of the drying process were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 50C and a drying air mass flow rate of 0.05 kg/s. The exergy efficiency values were obtained to vary from 76.03 to 97.24% at drying air temperatures of 40-50C with drying air mass flow rates of 0.01-0.05 kg/s.
This paper deals with the performance evaluation of a single layer drying process of green olives... more This paper deals with the performance evaluation of a single layer drying process of green olives in a tray dryer using exergy analysis method. Green olive was used as the test material being dried. Drying process was realized at four different drying air temperatures (40, 50, 60 and 70°C) and a constant relative humidity of 15%. The effects of temperatures and mass flow rates were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 70°C and a drying air mass flow rate of 0.015 kg/s with 0.0004 kg/s of olive. The exergy efficiency values were found to be in the range of 68.65%-91.79% from 40°C to 70°C with drying air mass flow rates of 0.01 kg/s-0.015 kg/s.
The performance of a tray dryer system for the parsley drying process was assessed using energy a... more The performance of a tray dryer system for the parsley drying process was assessed using energy and exergy analysis methods in this study. The drying temperature ranged from 40°C to 60°C, while the drying air velocity varied from 0.5 m/s to 1.5 m/s. The higher temperature and lower velocity led to higher exergy and energy efficiencies. The exergy efficiency value for the overall system on a product/fuel basis was found to be 3.62%. The values for Specific Moisture Extraction Rate (SMER) and Specific Moisture Exergetic index (SMExR) were obtained to be 0.08 and 2.47 kg/kWh, respectively.
... Neslihan Colak1, Zafer Erbay2 and Arif Hepbasli3,*,† 1Faculty of Engineering, Department of F... more ... Neslihan Colak1, Zafer Erbay2 and Arif Hepbasli3,*,† 1Faculty of Engineering, Department of Food Engineering, Pamukkale University, 20020 Denizli, Turkey 2Faculty of Engineering, Department of Food Engineering, Ege University, 35100, Bornova, Izmir, Turkey 3Department ...
Proceedings of The Institution of Mechanical Engineers Part A-journal of Power and Energy, 2010
In this study, plum slices were dried in three different driers (tray, fluid bed, and heat pump (... more In this study, plum slices were dried in three different driers (tray, fluid bed, and heat pump (HP) driers). Drying experiments were carried out at an air temperature range of 45−55 • C with an air velocity of 1.5 m/s. The performance of the driers along with their main components was evaluated and compared by using the exergy analysis method. The most important component for improving the system efficiency was determined to be the fan-heater combination for both the tray and fluid bed driers, and the motor-compressor assembly for the HP drier. The exergy loss and flow diagram (the so-called Grassmann diagram) of the driers was also presented to give quantitative information regarding the proportion of the exergy input dissipated in the various system components. Effects of the drying air temperature on the performance of the drying process were discussed. The highest exergetic efficiency values were obtained to range from 72.72 to 75.66 per cent for the HP drier, followed by the tray and fluid bed driers varying between 37.94 and 39.46 per cent, and between 22.83 and 24.07 per cent, respectively. be feasible . The methods of drying are diversified with the purpose of the process. There are more than 200 types of dryers . For every dryer, the process conditions, such as drying chamber temperature, pressure, air velocity (if the carrier gas is air), relative humidity, and the product retention time, have to be determined according to feed, product, purpose, and method. On the other hand, drying is an energyintensive process, while its energy consumption value varies between 10 and 15 per cent of the total energy consumption in all industries in developed countries . Therefore, optimization of the drying processes and systems is important with regard to the energetic efficiencies.
This study reviews gas engine-driven heat pump (GEHP) systems for residential and industrial appl... more 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.
The first heat pump dryer (HPD) patent applications were started in 1973, while recently, there h... more 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.
In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms... more In the second part of this study, heat-pump drying systems were comprehensively reviewed in terms of applications and performance evaluations. In this regard, these systems were classified in terms of type of heat pump systems, type of dryer and product types first. The performance assessments included coefficient of performance (COP), specific energy consumption (SEC) and specific moisture extraction rate (SMER), while types of energetic, exergetic and cost analyses were covered. It may be concluded that the most preferred method used to determine the HPD efficiency is SMER, while in recent years exergetic analysis method has been widely used.
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