Pankaj Pathare | Sultan Qaboos University (original) (raw)

Papers by Pankaj Pathare

Practice, progress, and proficiency in sustainability, 2019

It is widely known that the defrosting operation of evaporators of commercial refrigeration equip... more It is widely known that the defrosting operation of evaporators of commercial refrigeration equipment is one of the main causes of inefficiency on these systems. Several defrosting methods are used nowadays, but the most commonly used are still time-controlled defrosting systems, usually by either electric resistive heating or reverse cycle. This happens because most demand defrost methods are still considered complex, expensive, or unreliable. Demand defrost can work by either predicting frost formation by processing measured conditions (fin surface temperature, air humidity, and air velocity), operative symptoms of frost accumulation (pressure drop and refrigerant properties), or directly measuring the frost formation using sensors (photoelectric, piezoelectric, capacitive, resistive, etc.). The data measured by the sensors can be directly used by the system but can also be processed either by simple algorithms or more complex systems that use artificial intelligence and predictive methods. This chapter approaches frost sensing and prediction for command of demand defrost systems.

Energy Conversion and Management, Sep 1, 2019

Sub-Saharan African region currently suffers from the lack of clean energy and heavy postharvest ... more Sub-Saharan African region currently suffers from the lack of clean energy and heavy postharvest loss. Hence, a biogas driven combined cooling, heating and power generation system that harmonises power generation with food drying and cold storage is studied in the context of current renewable energy policies of the Nigerian government. Wastes from a community cattle market are assessed for biogas generation that is subsequently used to power a 72 kW internal combustion engine. Heat is recovered from the engine to drive a cabinet dryer, an absorption chiller and maintain anaerobic digestion process. The model is developed in Aspen Plus and the results are used to evaluate the economic viability of the system. The electricity and tri-generation efficiencies are 25.7% and 74.5%, respectively. Results also suggest that energy demand of 407 farmers can be met including drying of 12,190 kg of cassava, 3,985 kg of maize and cold-storage of 6,080 kg of tomato per farmer every year. At $0.05•kWh −1 of electricity, the discounted payback period varies between 2.5 and 4.7 years depending on agricultural product processed. Levelised cost of energy and profitability index are also sensitive to both interest rate and plant's availability which become uneconomical above 9% and below 80%, respectively.

Scientific African, Sep 1, 2019

Pomegranate juice processing produces large amount of peel as by-product or waste which is a pote... more Pomegranate juice processing produces large amount of peel as by-product or waste which is a potential source of raw material for food and other bioprocessing industries. Drying the peel offers opportunities for value addition into novel products, thus reducing waste from the fruit processing operations. This study presents the mathematical models of thin layer drying behaviour of pomegranate peels (initial thickness 5.00 ± 0.05 mm and moisture content 70.30% wet basis) using three air temperatures (40 °C, 50 °C and 60 °C) at a constant air velocity of 1.0 m/s. The results obtained showed that drying time decreased as the oven drying temperature increased. The drying process took place mainly in the falling rate period. Ten thin layer drying models were evaluated based on coefficient of determination (r 2) and standard error (e s). Among the tested drying models, Midilli et al. mathematical model was found to be the best fit for establishing the drying kinetics of pomegranate peel. Furthermore, the effective moisture diffusivity of pomegranate peel ranged from 4.05 × 10 −10 to 8.10 × 10 −10 m 2 /s over the temperature range investigated, with mean activation energy (Ea) of 22.25 kJ/mol.

Applied Energy, 2019

Quests for sustainability, food security and need to decouple food prices from fluctuating prices... more Quests for sustainability, food security and need to decouple food prices from fluctuating prices of finite fossil fuels are the drivers to sustainable processing and storage of agricultural products. Farming predominantly takes place in rural areas where conventional energy technologies may either be expensive or sometimes technically infeasible to be obtained. This necessitates deployments of renewable energy technologies to remote areas for sustainable power generation, cooling and drying of agricultural product. Renewable systems e.g. solar dryers, solar hybrid dryers, combined power and drying system take leading roles in sustainable drying of farm produce. A number of research studies have been carried out in the past one decade, which mainly concentrate on modelling, simulation and experiment of different sustainable drying techniques. Therefore, this paper mainly aims to present a state of the art review on the contributions of combined power and drying, application of phase change materials and hybrid drying systems with regard to agricultural products. Based on this comprehensive summarization, it is indicated that deployment of biomass powered combined heat and power systems might be a good solution to post-harvest wastes since both electricity and heat for drying of agricultural products can be simultaneously obtained.

Energy Procedia, Dec 1, 2017

District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

Food Reviews International, Jul 21, 2023

Journal of Food Engineering, Feb 1, 2023

AgriEngineering, May 9, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Energy Procedia, Dec 1, 2017

Biogas from anaerobic co-digestion of food waste and primary sludge for cogeneration of power and... more Biogas from anaerobic co-digestion of food waste and primary sludge for cogeneration of power and heat.

Journal of Food Quality, May 15, 2023

Fish drying is one of the traditional methods where the fshermen land their catch on the beaches ... more Fish drying is one of the traditional methods where the fshermen land their catch on the beaches for drying traditionally under sun for several days. Dried fsh provides valuable and economical sources of animal protein. Te quality of dried fsh is signifcantly infuenced by the presence of microorganisms. Terefore, this study aims to determine the physical quality changes in anchovy under three diferent solar drying methods which are open sun drying (OSD), solar greenhouse tunnel dryer (GTD), and forced convective solar dryer (FCD) and to verify the chemical and microbial contamination in solar-dried anchovy. About (20 kg) of fresh anchovy were taken for experiments. Quality analyses were conducted in the samples before, during, and after drying. Te parameters analyzed included three main analyses which are physical, chemical, and microbial analyses. Te drying rate was higher in GTD compared to the two other methods. Moisture content, drying rate, and moisture ratio were signifcantly afected by drying methods. GTD required less time (6 hr) to dry anchovies compared to other drying methods (9 hr time). Te highest reduction in lightness is in GTD dried anchovies followed by FCD and OSD. Te drying methods and drying time statistically afect the lightness (L) of dried anchovies (p ≤ 0.05). Te water activity of solar-dried anchovies was 0.3. Experimentally dried anchovies were found to have lower microbial count compared to the dried fsh quality standards. Te total viable count (TVC) in fresh anchovy was 6.44 log CFU/g compared to the greenhouse tunnel dryer 2.90 log CFU/g, open sun dryer 4.16 log CFU/g, and forced convective dryer 4.19 log CFU/g anchovies. Water activity and moisture content did not afect total viable count (TVC) signifcantly, but it afects total fungal count (TFC) (p ≤ 0.05). Tere was a signifcant diference on Krusal Wallis between the samples of three methods of drying and a fresh one on the water activity, ash content, and fat content (p ≤ 0.05).

IGI Global eBooks, 2019

Energy conservation plays a vital role towards sustainable development of meat processing. Energy... more Energy conservation plays a vital role towards sustainable development of meat processing. Energy costs for many meat plants represent the fourth highest operational cost. In meat processing, moderate levels of both electrical and thermal energy are consumed in wide range of processes and applications. However, energy efficiency improvement in the meat processing industry have been a focus to increase the sustainability of meat processing in the past decades. This chapter started with the examination of the energy use in meat processing facilities. The emerging energy-efficient technologies for meat processing were discussed in detail. Energy requirement for well-cooked meats varies with cooking method, appliances, and consumer behavior. Energy consumption reduction during meat cooking may have an influence on global energy requirement. Selection of cooking method, fuel, and cookware are beneficial for reducing the carbon footprint of the cooking unit. This chapter also presents the effects on quality characteristics of meat and meat products by different cooking methods.

Journal of Food Process Engineering, Nov 4, 2022

Acta horticulturae, Oct 1, 2013

Optimal packaging and storage are critical technologies in maintaining quality of fresh produce. ... more Optimal packaging and storage are critical technologies in maintaining quality of fresh produce. Computational fluid dynamic (CFD) model was used to investigate airflow, heat and mass transfer characteristic during cooling and handling of packed table grapes. The model was applied to study effects of plastic liner, bunch carry bag and box stacking on airflow, heat and mass transfer characteristics. The model was also used to study alternative cooling and handling procedures. The carton box was explicitly modeled, and grape bunch with the carry bag was treated as a porous media. Plastic liner was modeled as porous jump. The porous media and porous jump loss coefficients were determined using separate wind tunnel experiments. The presence of bunch carry bag and plastic liner increased the cooling time of the grapes significantly. The lowest moisture loss was observed for the package that used non-perforated plastic liner. However, packing with non-perforated plastic liner generated the highest amount of condensate inside the package. Cooling of bulk grapes using a relatively high RH air before covering with the plastic liner has a potential for improving the cooling rate while minimizing moisture loss and amount of condensation. Airflow and heat transfer characteristics were also highly influenced by the orientation and stacking pattern of packages. award of research grant on "Packaging of the Future" project is acknowledged. Literature Cited cevedo C, nche oung. 2007. Heat and mass transfer coefficients for natural convection in fruit packages.

Processes

In this study, coriander leaves were subjected to three different drying techniques; direct sun, ... more In this study, coriander leaves were subjected to three different drying techniques; direct sun, shade, and using an indirect solar dryer. In the developed dryer, hot air obtained from a black-body solar collector was pushed by a blower powered by a solar panel, and sent to the drying chamber with multiple trays for thin-layer drying. Experiments were conducted for summer and winter seasons, and temperature and relative humidity variations in the drying chamber were measured using a data acquisition system. Indirect solar dryer performance was evaluated and compared with sun drying and shade drying for drying kinetics, moisture diffusivity, and product quality. The drying rate curves show a linear falling rate throughout the drying process. The drying kinetic models are well-fitted with the Midilli and Kucuk thin-layer drying model. The effective moisture diffusivity of the dried coriander shows a decreasing trend, sun drying (2.63 × 10−10 m2/s and 1.05 × 10−10 m2/s) followed by sol...

Advances in biological sciences research, 2023

Practice, progress, and proficiency in sustainability, 2019

It is widely known that the defrosting operation of evaporators of commercial refrigeration equip... more It is widely known that the defrosting operation of evaporators of commercial refrigeration equipment is one of the main causes of inefficiency on these systems. Several defrosting methods are used nowadays, but the most commonly used are still time-controlled defrosting systems, usually by either electric resistive heating or reverse cycle. This happens because most demand defrost methods are still considered complex, expensive, or unreliable. Demand defrost can work by either predicting frost formation by processing measured conditions (fin surface temperature, air humidity, and air velocity), operative symptoms of frost accumulation (pressure drop and refrigerant properties), or directly measuring the frost formation using sensors (photoelectric, piezoelectric, capacitive, resistive, etc.). The data measured by the sensors can be directly used by the system but can also be processed either by simple algorithms or more complex systems that use artificial intelligence and predictive methods. This chapter approaches frost sensing and prediction for command of demand defrost systems.

Energy Conversion and Management, Sep 1, 2019

Sub-Saharan African region currently suffers from the lack of clean energy and heavy postharvest ... more Sub-Saharan African region currently suffers from the lack of clean energy and heavy postharvest loss. Hence, a biogas driven combined cooling, heating and power generation system that harmonises power generation with food drying and cold storage is studied in the context of current renewable energy policies of the Nigerian government. Wastes from a community cattle market are assessed for biogas generation that is subsequently used to power a 72 kW internal combustion engine. Heat is recovered from the engine to drive a cabinet dryer, an absorption chiller and maintain anaerobic digestion process. The model is developed in Aspen Plus and the results are used to evaluate the economic viability of the system. The electricity and tri-generation efficiencies are 25.7% and 74.5%, respectively. Results also suggest that energy demand of 407 farmers can be met including drying of 12,190 kg of cassava, 3,985 kg of maize and cold-storage of 6,080 kg of tomato per farmer every year. At $0.05•kWh −1 of electricity, the discounted payback period varies between 2.5 and 4.7 years depending on agricultural product processed. Levelised cost of energy and profitability index are also sensitive to both interest rate and plant's availability which become uneconomical above 9% and below 80%, respectively.

Scientific African, Sep 1, 2019

Pomegranate juice processing produces large amount of peel as by-product or waste which is a pote... more Pomegranate juice processing produces large amount of peel as by-product or waste which is a potential source of raw material for food and other bioprocessing industries. Drying the peel offers opportunities for value addition into novel products, thus reducing waste from the fruit processing operations. This study presents the mathematical models of thin layer drying behaviour of pomegranate peels (initial thickness 5.00 ± 0.05 mm and moisture content 70.30% wet basis) using three air temperatures (40 °C, 50 °C and 60 °C) at a constant air velocity of 1.0 m/s. The results obtained showed that drying time decreased as the oven drying temperature increased. The drying process took place mainly in the falling rate period. Ten thin layer drying models were evaluated based on coefficient of determination (r 2) and standard error (e s). Among the tested drying models, Midilli et al. mathematical model was found to be the best fit for establishing the drying kinetics of pomegranate peel. Furthermore, the effective moisture diffusivity of pomegranate peel ranged from 4.05 × 10 −10 to 8.10 × 10 −10 m 2 /s over the temperature range investigated, with mean activation energy (Ea) of 22.25 kJ/mol.

Applied Energy, 2019

Quests for sustainability, food security and need to decouple food prices from fluctuating prices... more Quests for sustainability, food security and need to decouple food prices from fluctuating prices of finite fossil fuels are the drivers to sustainable processing and storage of agricultural products. Farming predominantly takes place in rural areas where conventional energy technologies may either be expensive or sometimes technically infeasible to be obtained. This necessitates deployments of renewable energy technologies to remote areas for sustainable power generation, cooling and drying of agricultural product. Renewable systems e.g. solar dryers, solar hybrid dryers, combined power and drying system take leading roles in sustainable drying of farm produce. A number of research studies have been carried out in the past one decade, which mainly concentrate on modelling, simulation and experiment of different sustainable drying techniques. Therefore, this paper mainly aims to present a state of the art review on the contributions of combined power and drying, application of phase change materials and hybrid drying systems with regard to agricultural products. Based on this comprehensive summarization, it is indicated that deployment of biomass powered combined heat and power systems might be a good solution to post-harvest wastes since both electricity and heat for drying of agricultural products can be simultaneously obtained.

Energy Procedia, Dec 1, 2017

District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

Food Reviews International, Jul 21, 2023

Journal of Food Engineering, Feb 1, 2023

AgriEngineering, May 9, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Energy Procedia, Dec 1, 2017

Biogas from anaerobic co-digestion of food waste and primary sludge for cogeneration of power and... more Biogas from anaerobic co-digestion of food waste and primary sludge for cogeneration of power and heat.

Journal of Food Quality, May 15, 2023

Fish drying is one of the traditional methods where the fshermen land their catch on the beaches ... more Fish drying is one of the traditional methods where the fshermen land their catch on the beaches for drying traditionally under sun for several days. Dried fsh provides valuable and economical sources of animal protein. Te quality of dried fsh is signifcantly infuenced by the presence of microorganisms. Terefore, this study aims to determine the physical quality changes in anchovy under three diferent solar drying methods which are open sun drying (OSD), solar greenhouse tunnel dryer (GTD), and forced convective solar dryer (FCD) and to verify the chemical and microbial contamination in solar-dried anchovy. About (20 kg) of fresh anchovy were taken for experiments. Quality analyses were conducted in the samples before, during, and after drying. Te parameters analyzed included three main analyses which are physical, chemical, and microbial analyses. Te drying rate was higher in GTD compared to the two other methods. Moisture content, drying rate, and moisture ratio were signifcantly afected by drying methods. GTD required less time (6 hr) to dry anchovies compared to other drying methods (9 hr time). Te highest reduction in lightness is in GTD dried anchovies followed by FCD and OSD. Te drying methods and drying time statistically afect the lightness (L) of dried anchovies (p ≤ 0.05). Te water activity of solar-dried anchovies was 0.3. Experimentally dried anchovies were found to have lower microbial count compared to the dried fsh quality standards. Te total viable count (TVC) in fresh anchovy was 6.44 log CFU/g compared to the greenhouse tunnel dryer 2.90 log CFU/g, open sun dryer 4.16 log CFU/g, and forced convective dryer 4.19 log CFU/g anchovies. Water activity and moisture content did not afect total viable count (TVC) signifcantly, but it afects total fungal count (TFC) (p ≤ 0.05). Tere was a signifcant diference on Krusal Wallis between the samples of three methods of drying and a fresh one on the water activity, ash content, and fat content (p ≤ 0.05).

IGI Global eBooks, 2019

Energy conservation plays a vital role towards sustainable development of meat processing. Energy... more Energy conservation plays a vital role towards sustainable development of meat processing. Energy costs for many meat plants represent the fourth highest operational cost. In meat processing, moderate levels of both electrical and thermal energy are consumed in wide range of processes and applications. However, energy efficiency improvement in the meat processing industry have been a focus to increase the sustainability of meat processing in the past decades. This chapter started with the examination of the energy use in meat processing facilities. The emerging energy-efficient technologies for meat processing were discussed in detail. Energy requirement for well-cooked meats varies with cooking method, appliances, and consumer behavior. Energy consumption reduction during meat cooking may have an influence on global energy requirement. Selection of cooking method, fuel, and cookware are beneficial for reducing the carbon footprint of the cooking unit. This chapter also presents the effects on quality characteristics of meat and meat products by different cooking methods.

Journal of Food Process Engineering, Nov 4, 2022

Acta horticulturae, Oct 1, 2013

Optimal packaging and storage are critical technologies in maintaining quality of fresh produce. ... more Optimal packaging and storage are critical technologies in maintaining quality of fresh produce. Computational fluid dynamic (CFD) model was used to investigate airflow, heat and mass transfer characteristic during cooling and handling of packed table grapes. The model was applied to study effects of plastic liner, bunch carry bag and box stacking on airflow, heat and mass transfer characteristics. The model was also used to study alternative cooling and handling procedures. The carton box was explicitly modeled, and grape bunch with the carry bag was treated as a porous media. Plastic liner was modeled as porous jump. The porous media and porous jump loss coefficients were determined using separate wind tunnel experiments. The presence of bunch carry bag and plastic liner increased the cooling time of the grapes significantly. The lowest moisture loss was observed for the package that used non-perforated plastic liner. However, packing with non-perforated plastic liner generated the highest amount of condensate inside the package. Cooling of bulk grapes using a relatively high RH air before covering with the plastic liner has a potential for improving the cooling rate while minimizing moisture loss and amount of condensation. Airflow and heat transfer characteristics were also highly influenced by the orientation and stacking pattern of packages. award of research grant on "Packaging of the Future" project is acknowledged. Literature Cited cevedo C, nche oung. 2007. Heat and mass transfer coefficients for natural convection in fruit packages.

Processes

In this study, coriander leaves were subjected to three different drying techniques; direct sun, ... more In this study, coriander leaves were subjected to three different drying techniques; direct sun, shade, and using an indirect solar dryer. In the developed dryer, hot air obtained from a black-body solar collector was pushed by a blower powered by a solar panel, and sent to the drying chamber with multiple trays for thin-layer drying. Experiments were conducted for summer and winter seasons, and temperature and relative humidity variations in the drying chamber were measured using a data acquisition system. Indirect solar dryer performance was evaluated and compared with sun drying and shade drying for drying kinetics, moisture diffusivity, and product quality. The drying rate curves show a linear falling rate throughout the drying process. The drying kinetic models are well-fitted with the Midilli and Kucuk thin-layer drying model. The effective moisture diffusivity of the dried coriander shows a decreasing trend, sun drying (2.63 × 10−10 m2/s and 1.05 × 10−10 m2/s) followed by sol...

Advances in biological sciences research, 2023