Experiment and Analytical Studies Jujube Drying by the Solar Assisted Convection Drying

Solar Energy ◽  
2004 ◽  
Author(s):  
Minghu Cui
Keyword(s):  
Solar Energy ◽  
Drying Process ◽  
Drying Characteristics ◽  
Hot Air ◽  
Air Convection ◽  
Jujube Fruit ◽  
Save Energy ◽  
Drying Curves ◽  
Mass Transfers ◽  
And Behavior

An experimental setup, a mini-cabinet with reflector at its top, has been designed to study the drying process of jujube fruit by the convection and the solar radiation with hot air convection. The research experimentally investigated the drying characteristics and behavior of heat and mass transfer. Also, drying curves were analyzed. It demonstrated that solar energy could play an important role in promoting heat and mass transfers and saves energy consumed. The optimum conditions of appropriated temperature and humidity were obtained to save energy in solar energy convection drying process.

scholarly journals Mathematical Modeling and Performance Analysis of a New Hybrid Solar Dryer of Lemon Slices for Controlling Drying Temperature

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 350 ◽  
Author(s):  
Wengang Hao ◽  
Shuonan Liu ◽  
Baoqi Mi ◽  
Yanhua Lai
Keyword(s):  
Air Temperature ◽  
Dual Function ◽  
Suitable Model ◽  
Drying Process ◽  
Drying Characteristics ◽  
Solar Dryer ◽  
And Performance ◽  
Drying Curves ◽  
Flat Plate Solar Collector ◽  
Drying Chamber

A new hybrid solar dryer was designed and constructed in this study, which consisted of a flat-plate solar collector with dual-function (DF-FPSC), drying chamber with glass, fan etc. The DF-FPSC was firstly applied in drying agricultural products. The innovative application of hybrid solar dryer can control the drying chamber air temperature within a suitable range by different operation strategies. Drying experiments for lemon slices in the hybrid solar dryer were conducted by comparing open sun drying (OSD). Eight mathematical models of drying characteristics were employed to select the most suitable model for describing the drying curves of lemon slices. Furthermore, energy, exergy economic and environment (4E) analysis were also adopted to analyze the drying process of lemon slices. The results show that under the same experimental condition, the drying capability of the hybrid solar dryer was stronger than that of OSD. Meanwhile, it was found that the Two term and Wang and Singh models were the most suitable for fitting the lemon slices’ drying characteristics inside the hybrid solar dryer. The drying chamber air temperature can be controlled under about 60 °C during the process of lemon slices’ drying. The experimental results show the feasibility and validity of the proposed hybrid solar dryer.

scholarly journals Influence of Different Hot Air Drying Temperatures on Drying Kinetics, Shrinkage, and Colour of Persimmon Slices

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo
Keyword(s):  
Moisture Content ◽  
Quadratic Model ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Hot Air

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.

scholarly journals Kinetic parameters identification of conductive enhanced hot air drying process of food waste

2020 ◽  
pp. 223-223
Author(s):  
Mihailo Milanovic ◽  
Mirko Komatina ◽  
Ivan Zlatanovic ◽  
Nebojsa Manic ◽  
Dragi Antonijevic
Keyword(s):  
Food Industry ◽  
Convective Drying ◽  
Diffusivity Coefficient ◽  
Drying Method ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Drying Curves

The efficient utilization of waste from food industry is possible after thermal treatment of the material. This treatment should be economically feasible and compromise the energy efficient drying process. The main goal of this investigation is to determine drying characteristics of nectarine pomace as a waste from food industry. The measurements were performed in an experimental dryer by combined conductive-convective drying method with disk-shaped samples of 5, 7 and 10mm thickness and 100 mm in diameter at the air temperatures of 30, 40, 50, 60 and 70oC, hot plate temperatures of 50, 60 an 70oC and air velocity of 1.5 m/s. The drying curves were compared to a few semi-theoretical mathematical models. The Logarithmic model showed the best correspondence. On the basis of experiments, it is determined that the drying process takes place in a falling rate period and it is accepted that the main mechanism of moisture removal is diffusion. The effective coefficient of diffusion was determined using experimental results by calculating the slope of the drying curves. Drying time and equilibrium moisture are determined for each experiment. Analysis of drying curves showed that the conductive-enhanced drying method reduces drying times and increases the diffusivity coefficient. The character of drying rate curves for conductive-enhanced drying was analyzed and compared with pure convective drying of nectarine pomace.

scholarly journals Modelling the Drying Characteristics and Kinetics of Hot Air-Drying of Unblanched Whole Red Pepper and Blanched Bitter Leaf Slices

2017 ◽  
Vol 5 (1) ◽  
pp. 24
Author(s):  
Samuel Enahoro Agarry
Keyword(s):  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Red Pepper ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Curves ◽  
Kinetics Of

The objective of this study was to investigate the drying characteristics and kinetics of red pepper and bitter leaf under the influence of different drying temperatures. The drying experiments were carried out at dry bulb temperature of 35, 45, 55 and 75oC, respectively in an oven dryer. The results showed that as drying temperature increased, drying rate also increased and the drying time decreased. It was observed that un-sliced red pepper and sliced bitter leaf would dry within 2.5-12 h and 1.67-7 h, respectively at temperature ranging from 75 to 35oC. The drying of red pepper and bitter leaf was both in the constant and falling rate period. Four semi-empirical mathematical drying models (Newton, Page, Henderson and Pabis, and Logarithmic models) were fitted to the experimental drying curves. The models were compared using the coefficient of determination (R^2) and the root mean square error (RMSE). The Page model has shown a better fit to the experimental drying data of red pepper and bitter leaf, respectively as relatively compared to other tested models. Moisture transport during drying was described by the application of Fick’s diffusion model and the effective moisture diffusivity was estimated. The value ranges from 15.69 to 84.79 × 10-9 m2/s and 0.294 to 1.263 × 10-9 m2/s for red pepper and bitter leaf, respectively. The Arrhenius-type relationship describes the temperature dependence of effective moisture diffusivity and was determined to be 37.11 kJ/mol and 32.86 kJ/mol for red pepper and bitter leaf, respectively. A correlation between the drying time and the heat transfer area was also developed.

scholarly journals Design of an Indirect Dryer with Coupling of Solar Collectors and its Thermal Characterization by Drying the Mint Leaves (Mentha spicate)

2021 ◽  
Vol 10 (1) ◽  
pp. 411
Author(s):  
Margarita Castillo Téllez ◽  
Beatriz Castillo-Téllez ◽  
Alberto Mejía Pérez Gerardo ◽  
Rachid Marzoug ◽  
Diana C. Mex Álvarez
Keyword(s):  
Solar Energy ◽  
Energy Savings ◽  
Thermal Characterization ◽  
Solar Air Heater ◽  
Drying Process ◽  
Efficient Technology ◽  
Water Heaters ◽  
Hot Air ◽  
Evacuated Tubes ◽  
Dry Food

Man has used solar energy to dry perishable products for many years, managing to preserve a wide variety of foods naturally; drying is a method that highly respects the food's properties and nutritional content. The consumption of medicinal and aromatic herbs in Mexico is traditional and widespread. In this work, an analysis of an indirect solar dryer's thermal behavior was carried out with the coupling of solar technologies (water heaters and air collectors and photovoltaic pumping as an aid to the generation of hot air) comparing with electric oven drying in Campeche, Campeche, Mexico. The experimental results showed that the indirect tunnel type dryer that works with evacuated tubes and solar air heater simultaneously is the most efficient technology, with average drying times of 300 min and final humidity of 9.6%. A study of colorimetry, water activity, and drying speed was carried out to control the drying process. It was found that it is possible to use solar energy to dry food as a means of conservation in warm-humid climates, also obtaining significant energy savings and contributing to caring for the environment.

Hot Air Drying and Vacuum Drying Characteristics of Scarlet Runner Beans

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Yoshiki Muramatsu ◽  
Eiichiro Sakaguchi ◽  
Takahiro Orikasa ◽  
Akio Tagawa
Keyword(s):  
Diffusion Coefficient ◽  
Moisture Content ◽  
Initial Moisture Content ◽  
Vacuum Drying ◽  
Drying Method ◽  
Drying Process ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air

Abstract The drying characteristics and volume changes of scarlet runner beans were measured under various conditions to obtain useful basic information for the optimum drying method and conditions. The sample was dried using two drying methods: hot air drying and vacuum drying. The measured changes in moisture content of the sample with the hot air drying process were in good agreement with the exact solution of the infinite plane sheet model. The estimated diffusion coefficients were 3.8×10 -7 -7.4×10 -7 (m 2 h -1) for hot air drying and were related to absolute temperature by an Arrhenius-type equation. The hull of the scarlet runner bean is hard and thick, and the drying rate of the sample was much slower than that of other beans. To establish an efficient drying method without the quality loss, the vacuum drying characteristics of the sample were measured at several levels for temperature and initial moisture content. For the vacuum drying process, an exponential model could be used to estimate the changes in moisture content of the sample. The values of diffusion coefficient for vacuum drying were approximately twice as much as the values of diffusion coefficient for hot air drying at the same temperature. The effects of drying method, temperature, and initial moisture content on the sample quality were investigated, and the optimum drying method and conditions for scarlet runner beans were proposed. Volumetric changes in the sample were determined by measuring particle density. The specific volume of the sample was represented as a linear function of moisture content.

scholarly journals DRYING CHARACTERISTICS AND KINETICS OF LOVASTATIN DEGRADATION OF OYSTER MUSHROOM (PLEUROTUS OSTREATUS) SLICES

2019 ◽  
Vol 49 (4) ◽  
pp. 269-274
Author(s):  
Engin Demiray
Keyword(s):  
Reaction Model ◽  
Oyster Mushroom ◽  
Coefficient Of Determination ◽  
Drying Process ◽  
Chi Square ◽  
Drying Characteristics ◽  
First Order ◽  
Hot Air ◽  
Air Dryer ◽  
Kinetics Of

Oyster mushroom slices were dried using hot air dryer. The lovastatin content in oyster mushroom slices during drying was evaluated at 45, 55 and 65˚C. The first-order reaction model adequately described degradation of lovastatin. In this study, the modeling of the drying process was also performed. Four mathematical models were fitted to the experimental data. The performance of these models is evaluated by comparing the coefficient of determination, root mean square error and reduce chi-square between the observed and predicted moisture ratio. The Page model gave the best results for describing drying of oyster mushroom slices.

The Experimental Study on Infrared Dryer for Corn

2015 ◽  
Vol 723 ◽  
pp. 711-714
Author(s):  
Chun Shan Liu ◽  
Si Yu Chen ◽  
Wen Fu Wu ◽  
Jun Fa Wang ◽  
Hai Bo Zhou
Keyword(s):  
Experimental Study ◽  
Energy Consumption ◽  
Moisture Content ◽  
Air Temperature ◽  
Load Condition ◽  
Air Distribution ◽  
Drying Process ◽  
Drying Characteristics ◽  
Infrared Drying ◽  
Hot Air

To understand the drying characteristics of corn in infrared drying process, the research of corn post-harvest drying experiment was developed on self-developed infrared grain dryer. Analysing the influence of hot air temperature by blast capacity and the outlet size of air distribution under the full load condition, the change rules of the corn moisture content, the temperature change and the energy consumption characteristics during the drying process have been researched.

scholarly journals AN EXPERIMENTAL STUDY ON THIN-LAYER DRYING CHARACTERISTICS OF APPLE SLICES

2021 ◽  
Vol 51 (2) ◽  
pp. 119-126
Author(s):  
İbrahim Doymaz ◽  
Mehmet Soydan
Keyword(s):  
Experimental Study ◽  
Ascorbic Acid ◽  
Citric Acid ◽  
Potassium Carbonate ◽  
Acid Mixture ◽  
Drying Process ◽  
Drying Characteristics ◽  
Hot Air ◽  
Apple Slices ◽  
Control Samples

In this experimental study, cultivar of Granny Smith apple slices were dried by using convective hot air tray dryer. Before drying process, the pretreatment methods with ascorbic acid and citric acid solution (0.5% + 0.5%), blanching (80°C and 1 min) and potassium carbonate solution (4%) were carried out. Control samples were dried naturally without any pretreatments. Temperatures for hot air convective drying were decided as 50, 60, 70 and 80°C with constant air velocity of 2 m/s in the cabinet dryer. Throughout the drying process, constant drying period was not observed. Once the temperatures increased from 50 to 80°C, drying rate also increased. Well-known mathematical models such as Henderson & Pabis, Page, Midilli & Kucuk, Wang & Singh and Agbashlo et al. were compared with each other to specify the change of moisture inside the material. Consequently, Midilli & Kucuk model was chosen the best model to explain the drying characteristics of the samples with all slice thicknesses and all drying conditions. Diffusivity coefficients of the moisture transfer inside the apple slices at different temperatures (50, 60, 70 and 80°C) were calculated with the help of Fick’s second law of diffusion. The values of diffusion coefficients over the mentioned temperature range changed between 4.804´10-10 and 1.739´10-9 m2/s. The activation energy values of the drying process were calculated by Arrhenius type equation and found to be 36.1, 32.5, 29.8 and 32.1 kJ/mol for potassium carbonate, citric acid and ascorbic acid mixture, blanching and control samples, respectively.

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