Hybrid Drying Research Articles

The Optimization of Hybrid (Microwave-Conventional) Drying of Sweet Potato Using Response Surface Methodology (RSM).

Hybrid microwave-hot air (MW-HA) drying of sweet potatoes was optimized using a face-centered central composite design (FCCCD) with response surface methodology through the desirability function. The independent variables were drying temperature (50-70 °C) and microwave power (0-180 W), while the investigated responses were the drying time (Dt), the rehydration ratio (RR), the water-holding capacity (WHC), the antioxidant activity change (AA-PC), the total phenolic content change (TPC-PC), and the beta-carotene content change (BC-PC). The main criteria for the optimization of hybrid drying of sweet potatoes was to produce dried potatoes in the shortest drying time with a maximum RR and WHC and with minimum bioactive content (AA, TPC, and BC) loss. The optimum conditions were found to be a drying temperature of 54.36 °C with a microwave power of 101.97 W. At this optimum point, the Dt, RR, WHC, AA-PC, TPC-PC, and BC-PC were 61.76 min, 3.29, 36.56, 31.03%, -30.50%, and -79.64%, respectively. The results of this study provide new information about the effect of the hybrid drying method (MW-HA) on the rehydration ability and bioactive compounds of sweet potatoes, as well as the optimum values of the process.

Energy and exergy-based threshold setting for the auxiliary heating source of a hybrid solar/IR drying system

In special case of spirulina drying, the energy and exergy investigations were performed for a pure solar dryer and a hybrid solar/infrared (IR) drying system. For three drying temperatures 40, 50 and 60 °C, the specific energy consumption (SEC) and energy utility ratio (EUR) were evaluated and it was found that the maximum contribution of IR to the drying process was at 40 °C, in which SEC was reduced by 12.18 % and EUR was increases by 14.4 %. But at higher temperatures, negligible contribution of auxiliary heat source was found and less fraction of supplied power was used for removing the water content of the samples. The variation of exergy efficiency was also evaluated at different temperatures, and it was noted that the hybrid dryer had the best performance at 40 °C, while the conventional solar dryer showed better exergy efficiencies at 50 °C and 60 °C. As a result, a convenient criterion was established for optimum use of IR source in a hybrid system. Uncertainty analysis was performed.

Effect of combined convective hot air and far-infrared radiation on physic-chemical aspects of black raspberry powder produced by foam mat method

In recent years the use of hybrid drying methods has been noticed because of the improvement of the dried products quality. The effect of infrared (IR) power (0, 400, 600, and 800 W) in combination with convective hot air (60 °C, 3 m/s) on the quality properties of black raspberry pulp during foam mat drying was investigated in this study. According to the findings, increasing the IR power, (IR-CHA) had no effect on the moisture content, moisture ratio, or drying rate of the product; however, the effective moisture diffusion coefficient (Deff) was significantly increased. The effect of IR power on the physicochemical properties of black raspberry powder revealed that combining infrared with convective hot air (IR-CHA) improved the powder's flowability and total polyphenol content while decreasing its moisture content (p < 0.05). Furthermore, FESEM images revealed that the increase in IR power resulted in particles with smooth surfaces.

Design and development of solar-electrical hybrid dryer and its performance evaluation using shrimps

Design and development of solar-electrical hybrid dryer and its performance evaluation using shrimps

Drying behavior, color change and rehydration of lingzhi mushroom (Ganoderma lucidum) under convection-assisted microwave drying

Lingzhi mushrooms (Ganoderma lucidum) are a highly valued agricultural product that is used for medicinal purposes due to its range of important nutrient contents. However, the mushroom is perishable, as it is sensitive to moisture. To increase its shelf life and maintain the quality, a hybrid drying technique of convection-assisted microwave drying was investigated in this study. In the experiment, 3-mm thick slices of lingzhi mushrooms were dried at a hot air velocity of 1 m/s, hot air temperatures (Tdry) of 50, 60, and 70 °C, and microwave powers (Mp) of 200, 400, and 600 W. The mass of lingzhi mushrooms was recorded every 5 min until there was no further change in mass. The experimental results presented drying behaviors in terms of dry basis moisture content (Mdb) and drying rate (DR). Additionally, the overall color differences (ΔE) and the percentage of rehydration (Rd) were assessed. The results demonstrated that the increase in Tdry and Mp resulted in the DR and ΔE increasing, while the drying time and Rd decreased. The highest DR of 8.6 gwater/min and the shortest drying time of 25 min were observed at a Tdry of 70 °C and Mp of 600 W. The L*, a*, and b* values of the dried lingzhi mushrooms showed significant statistical differences (p < 0.05) compared to the fresh samples. The ΔE was significantly affected by both Tdry and Mp, while the Rd was more influenced by Tdry than Mp, with a significance level of p < 0.05. The lowest ΔE and highest Rd values were achieved at Tdry = 50 °C and Mp = 200 W. Furthermore, the developed empirical model accurately predicted the moisture ratio (R2 > 0.9982 and RMSE < 0.0210).

Assessment of hybrid solar-thermal multi-chamber dryer integrated with desiccant dehumidifier for uniform drying

Dried food industry consumes a significant amount of energy which requires more attention to renewable energy resources. Non-uniform solar drying has been deemed a drawback of solar dryer commercialization due to low-quality products influenced by the sun's off hours. Drying uniformity may be enhanced by using the hybrid solar-thermal technique that provides uniform operation conditions. The present work aims to evaluate the hybrid solar-thermal dryer that uses a desiccant dehumidifier based on the uniformity of process air temperature and humidity. The desiccant regeneration process has been assessed based on the temperature and humidity of the regeneration air. Power saving due to hybrid technique usage has been analyzed. The drying process has been conducted using 5 kg of red chili. The rehydration ratio of the product has been tested as an indication of product quality which is a key parameter for dryer performance. The results revealed that the process air at the drying cabinet inlet has a 95% relative thermal uniformity with a 0.95 standard deviation in absolute humidity. The hybrid technique has helped to achieve around 67% power saving while only 22% of power has been held when operating with solar mode. In comparison to other techniques the current hybrid dryer showed better product quality. The current results could develop the solar drying industry in terms of homogeneous quality-product.

Comparative, numerical, and experimental study of the influence of infrared radiation on a radiative-convective drying system for kaolin clay

This study investigates the effect of radiation intensity on the drying of kaolin clay using a redesigned radiative-convective dryer set. The convective and hybrid drying curves are evaluated, and the radiant system is characterized through numerical and experimental analysis of the view factor profile and radiation contour by discrete ordinates model (DOM). The results demonstrate that radiation intensity and air velocity have a greater impact on the drying process than the air temperature. Notably, the air velocity is particularly influential at 2 m/s. A multivariate linear regression model is developed to represent the relationship between these variables with an R2 coefficient of determination of 82%. Under optimal hybrid drying conditions (air velocity: 2 m/s, air temperature: 40 °C, radiation intensity: 6.8 kW/m2), the mass flux is 15.1 times higher compared to convective drying conditions. Additionally, the discrete ordinates model accurately captures the behavior of radiation distribution in the 2D study, highlighting the need for further investigation in 3D to address magnitude of radiation deviations. These findings have significant implications for optimizing the drying process of kaolin clay and provide insights for the design of more efficient drying systems, as well as suggesting further research on the simulation and simplification of phenomena involving radiation heat transfer.

Performance of a solar greenhouse-biogas hybrid dryer for dehydration of water hyacinth (Eichhornia crassipes)

The development of a solar greenhouse dryer combined with an anaerobic digester for biogas production can reduce carbon emissions and create zero waste. This paper presents the performance of a solar greenhouse biogas dryer (SGBD) that burns biogas to supplement the drying of water hyacinth. The SGBD has an overall efficiency of 87% for 100 kg of fresh water hyacinth. The auxiliary heating system enabled the SGBD to achieve drying temperatures of 24.5 to 45.0 degrees during cloudy and rainy days and produce high quality dried products. There was a fivefold increase in drying capacity and a reduction in drying time of six hours (38%) using the SGBD. End users of the dried product judged it to have improved consistency in color and shape. The SGBD cost less than US$3800 to build with a payback period of five months. This design demonstrates a low-cost and simple technology for small businesses.

Rancang Bangun Rumah Pengering Kopi Hybrid Guna Meningkatkan Efektivitas Pengeringan Kopi Di Kecamatan Pinogu, Provinsi Gorontalo

Coffee has become the superior product of Pinogu District with a distinctive taste with natural processing which makes this coffee categorized as organic coffee so it has a high selling value. The problem is, the process of drying coffee in the sun is often constrained by the weather so that the product produced is less than optimal. Therefore, it is necessary to develop appropriate technology in the form of hybrid drying houses. The design of the drying housing made of steel and polycarbonate is expected to speed up the drying time. The result is that drying time efficiency is 5.6 times faster than conventional methods, and can also save space, and is able to dry as much as 240 kg of coffee in one process. In addition, drying using this method can also reduce contamination in coffee, so as to improve coffee quality

Development of sensible heat storage based solar hybrid dryer with evacuated tube collector and biomass gasifier for shrimp drying

The work was aimed at developing an energy-efficient solar hybrid dryer with a biomass-based gasifier heat backup suitable for drying shrimps even during off-sunshine hours. In this dryer, water was utilized as a sensible heat storage (SHS) material as well as heat transfer fluid and biomass gasifier as an indirect backup heat source. The performance of the solar-gasifier hybrid dryer was assessed by drying shrimp (Metapenaeus dobsoni) samples and compared it with solar, and gasifier modes. Shrimp obtained the desired moisture content of 15.09 %, 13.46%, and 14.77% (w.b.) in 9 h, 6 h, and 6 h of drying in solar mode, gasifier mode, and solar-gasifier hybrid drying mode, respectively. The average drying rate of the solar, gasifier and hybrid modes of drying were 0.33 g/g dm.h, 0.46 g/g dm.h, and 0.47 g/g dm.h, respectively. Results revealed that the evacuated tube solar water collector harnessed 193104 kJ and 160185 kJ of heat energy during sunshine hours under the solar and hybrid mode of operation. The maximum drying efficiency of 34.97%, 35.62%, and 41.66% was obtained for gasifier mode, solar mode, and hybrid mode of shrimp drying. The economic evaluation revealed that the hybrid mode of operation is highly economical with the annual savings of $10983.06 and the lowest payback period of 0.62 years.

Pengeringan Kakao Menggunakan Rumah Pengering Hybrid

Cocoa (Theobroma cacao) is one of the plantation commodities in Indonesia that has an important role for the national economy to increase the country's foreign exchange. The process of cocoa drying will result in a dried product changes color, texture, and scent. The purpose of this study was to analyze the efficiency of drying cocoa using a hybrid dryer house with three treatments namely, drying using solar energy drying, drying using solar energy drying and gas energy (hybrid) and conventional drying. The results showed that drying cocoa in a drying house using solar energy takes 270 hours or 12 days, drying using a drying house using solar energy and gas (hybrid) takes 222 hours (9 days) and drying using a winch (conventional) takes 240 hours (11 days). Keywords: Cocoa, Drying, Hybrid Dryer House.

Convective–Microwave–IR Hybrid Drying of Kaolin Clay—Kinetics of Process

Kaolin clay is one of the essential components of utility and technical ceramic products. Drying is one of the stages of its production and is crucial for the quality of the obtained products. Due to the low energy efficiency of the dryers, it is also one of the most energy-intensive operations performed not only in the production of ceramics but in the industry as a whole. For this reason, modern drying techniques are sought. They are required to be energy efficient, sustainable and produce high-quality products. An example is the so-called hybrid drying, which combines several drying techniques (energy sources) into one process. The aim of this work was to determine the impact of microwave and infrared radiation on the kinetics and energy consumption of convective drying of kaolin clay and the quality of the products. The interaction of convective, microwave and infrared drying was investigated. Drying times, energy consumption and visual quality were compared for the tested processes. The fastest process was convection–microwave drying, where a reduction in drying time of 70% and energy consumption of 50% was observed. Unfortunately, intensive drying had a negative impact on the quality of the products (numerous cracks on the side surface). The best drying methods are those that use all energy sources simultaneously and periodically. Hybrid processes that use all energy sources in a periodic manner had the greatest efficiency. The drying time in these programs was shortened in relation solely to the convection process by 45 to 50% while reducing energy consumption by 3–18%. The product had the best quality.

Effect of Immersion Concentration in Salt Solution, Drying Time and Air Velocity on Drying Wet Noodles Using a Tray Dryer and Solar Assistance

The noodles in the market are dry noodles with 8-10% water content. Dried noodles have a longer shelf life because they are less prone to mold growth. Drying noodles with the help of the sun and tray dryers are currently an option because they are efficient and do not require a lot of energy. Reduction of water content is also optimized by soaking wet noodles in salt water. This study aims to determine the effect of soaking noodles in salt water and the flow rate to decrease the water content of noodles. The study began with soaking wet noodles in a salt solution with a variation of 50-150 g/L, then dried for 1 hour using a hybrid method and tray dryer with a flow rate variation of 1.2-3.3 m/s. Observations were made at intervals of 0-1 hour. The results showed that the time and speed of the flow rate can reduce the humidity in the drying chamber of the tray dryer. The lowest water content reduction of up to 11% was obtained when soaking wet noodles in 150 g/L salt solution and at the highest flow rate of 3.3 m/s. The ANOVA results show that the drying method with tray dryer is more optimal than hybrid drying. Thus, this method can be a solution to optimize the noodle drying process quickly and efficiently.

Impact of the greenhouse drying modes of two-phase olive pomace on the energy, exergy, economic and environmental (4E) performance indicators

This research aims to valorize olive pomace waste as bio-combustible. Therefore, the drying of two-phase olive pomace in a solar greenhouse dryer was studied under the weather conditions of Marrakech, Morocco. The experimental results of natural, hybrid, and forced hybrid drying modes of two-phase olive pomace were used to determine the energy and exergy efficiencies of the greenhouse dryer and to analyze the kinetics of drying. Moreover, the economic viability and environmental suitability of the three drying modes were also investigated. The results indicated that the humidity level of the product dropped from 54% to 4% (wt%) in 28, 19 and 14 h for the natural, hybrid, and hybrid forced drying modes, respectively. The effective moisture diffusivity varied significantly between the drying modes with a lowest average value of 1.28 × 10−09 m2/s and a highest average value of 2.71 × 10−09 m2/s associated to the natural and hybrid forced drying modes, respectively. The drying and exergy efficiency of the hybrid forced greenhouse dryer was improved by 31.61%, 51.95%, and 36.91%, 21.05% compared to the natural and hybrid greenhouse drying modes, respectively. The environmental analysis showed that the carbon emissions, and carbon mitigation depend strongly on the greenhouse drying mode, and the material used for the construction of the drying system. The hybrid forced greenhouse dryer ensured the mitigation of 1.29 and 1.15 times more CO2, compared to the natural, and hybrid greenhouse dryers. The economic analysis revealed a payback period of 1.27 years, 1.03 years, and 0.67 for the natural, hybrid, and hybrid forced modes for a selling price of 3 (MAD), which are very small compared to the lifespan of the greenhouse dryer (35 years).

Comparison of the performance of a modified temperature-controlled microwave dryer to improve heat-mass transfer, increase energy efficiency and preserve quality characteristics of shad (Alosa fallax nilotica)

In this study, shad (Alosa fallax nilotica) was dried in microwave (360, 720 W), developed heat controlled microwave (50, 70 °C), hybrid microwave (350 W + 50 °C, 350 W + 70 °C) dryers. Drying time, drying rate-rate, effective diffusion, color, hardness, energy consumption (SMER, SEC), exergy energy, energy efficiency, heat-mass transfer value of the drying processes were investigated. The shortest drying process was determined as 450 seconds at 720 W power, while the longest was 414minutes at 50 °C. Effective diffusion values calculated for microwave, temperature controlled microwave and hybrid drying processes are 1.32–9.43 × 10−8 m2/s, 2.43 × 10−8-2.41 × 10−7 m2/s and 8.52 × 10−7-2.76 × 10−6 m2/s, respectively. Has changed between It has been determined that the most suitable drying method in terms of total energy consumption and energy efficiency values is the drying process performed in a temperature-controlled microwave dryer. Exin and Exout values of the temperature-controlled microwave drying process were calculated to vary between 2.20 and 5.16 J/s and 1.82–4.68 J/s, respectively. Exin and Exout values of the hybrid drying process were calculated to vary between 1.94 and 4.84 J/s and 1.70–4.68 J/s, respectively. The heat transfer values calculated for the temperature-controlled drying process varied between 0.104 and 0.00269 W/m2K and the heat transfer values calculated for the hybrid drying process ranged between 0.100 and 0.00270 W/m2K. It was determined that the most suitable drying processes for color characteristics were 360 W and 350 W + 50 °C. For the hardness value, it was determined that the 350 W + 70 °C drying process was statistically more appropriate (P < 0.05).

Advanced exergoeconomic and exergy performance assessments of a wind and solar energy powered hybrid dryer

Classical and advanced exergoeconomic and exergy performance values of a hybrid dryer operating with solar and wind energies are discussed and compared in this work. The effects of all equipments of the drying unit on the energy consumption cost are evaluated and their contribution to the system performance is examined. According to both classical and advanced exergy and exergoeconomic analysis data, it is concluded that the most significant system equipment to be improved is the wind turbine. Considering the results of advanced exergy analysis, it has been observed that 66.95% of the total exergy loss is avoidable and the wind turbine accounts for 46.35% of this loss. In terms of advanced exergoeconomic performance, it has been detected that 83.34% of the total cost is avoidable and from 35.34% of the total cost can be saved if the wind turbine is improved. The results clearly show that advanced exergy and exergoeconomic analysis is a very effective approach in revealing the real potential of the system and in determining the modifications to be performed to increase the system efficiency.

Performance assessment of an evacuated tube solar-electric hybrid dryer for lotus seeds drying: Moisture removal behavior, GHG emission and thermodynamic analysis

A novel evacuated tube solar-electric hybrid dryer (ETSED) was developed and evaluated to contribute to global food security from the perspective of optimized processing while reducing energy consumption and greenhouse gas (GHG) emissions. The performance of the ETSED was assessed compared with solar heating drying (SHD), and mixed heating drying (MHD) at temperatures of 55, 65 and 75 °C by studying the drying behavior of the samples as well as the thermodynamic analysis and GHG emissions of the system. Results revealed that under all studied experimental conditions, the evacuated tube solar collector provided more than 60% of the thermal supply in the drying process, and significantly improved the fluid exergy. Moreover, the roller shutter mechanism and the heating tube were used together to achieve precise control of the drying temperature. In terms of thermodynamic analysis, the heating tube further enhanced the ETSED performance by providing high quality energy in combination with solar energy in MHD mode. Furthermore, compared with SHD, MHD-65 and 75 °C shortened the drying time by 10.4 and 28.2%, improved the drying efficiency by 0.7% and 6.29%, and increased the drying chamber's exergy by 14.99 and 19.36%, respectively. Remarkably, the lowest emissions of CO2 (872.06 g/kg removed water), SO2 (0.13 g/kg removed water) and NOx (0.19 g/kg removed water) were seen in the case of SHD. Based on the obtained results, the increased drying temperature in the MHD led to higher CO2, SO2 and NOX emission levels. Interestingly, when the lotus seeds were dehydrated, the accumulated electric energy generated by the photovoltaic cells almost met the electric consumption of mechanical energy. The results of this study identified the potential of ETSED equipment for food industrial production.

Effect of Drying Temperature on Proximate Composition and Viability of Maize Dried in a Solar Biomass Hybrid Dryer

Maize is an important cereal produced for food and feed and its nutritional composition and viability could be affected when subjected to inappropriate drying conditions. This study investigated the effects of drying temperature on the proximate composition and viability of maize grains dried at different levels in a solar biomass hybrid dryer. Proximate analysis was performed using standard A.O.A.C. methods. Germination test was done using sterilized Petri–dishes lined with filter papers to determine the viability of dried grains. Overall mean temperature, 43.63 ± 8.6 ˚C in the dryer was 9 ˚C higher than the average ambient temperature. The moisture content (MC) of grains in the dryer reduced from average 17 % to 11 % (w.b.) in 8 h at an average drying rate of 0.64 %/h. The overall drying efficiency was 12.7 % compared to 5.7 % for the open-sun drying process. The viability of grains dried in the dryer (avg. 95%) compared favourably to the viability of sun-dried grains (96%). The results show that, the temperature in the dryer had no adverse effect on the proximate nutritional composition and viability of dried maize grains. The adoption of solar biomass hybrid dryers for use by smallholder farmers is encouraged due to its suitability in providing a viable drying option to open-sun drying.

Drying Vanilla Using A Hybrid Dryer

Vanilla (Vanilla planifolia Andrew) is a plant that has high economic value; the plant is oriented for export. Postharvest handling is necessary to produce good quality vanilla; One of them is the drying process. This study aims to measure the drying time of vanilla, measure the decrease in moisture content, and analyze the efficiency of drying wet vanilla using a rack-type hybrid dryer. The research was conducted with three treatments, namely: drying using solar energy, drying using electrical energy, and drying using solar energy and electrical energy (hybrid). Based on the results of the study, it was found that drying using solar energy, drying using electrical energy, and drying using solar energy and electrical energy (hybrid) took 15 days, 17 days, and 13 days, respectively. The initial moisture content of drying is about 91.25% which decreases to about 32.44% at the end of drying. The efficiency of the three treatments was 6.39%, 1.58%, and 0.92%, respectively. Keywords: Drying, Hybrid postharvest, Vanilla

KARAKTERISTIK PENGERINGAN CABAI RAWIT (Capsicum Frutescens L) MENGGUNAKAN ALAT PENGERINGAN HYBRID TIPE RAK1)

ABSTRACT&#x0D; &#x0D; Chili plants are an agricultural commodity with great potential in Indonesia. The price of agricultural products is greatly influenced by the availability of materials in the market if the available goods are much less than the demand, the price will soar and vice versa. Therefore, to maintain chili peppers so that they can last for a long period of time it is necessary to carry out preservation in the form of drying. The temperature distribution during the drying process of cayenne pepper starts from the highest air temperature of each shelf, namely 13:00 with a temperature of 55,100C material temperature at 13:00 with a temperature of 55,400C, a collector temperature at 13:00 with a temperature of 63,800C and an ambient temperature of 360C. Air humidity greatly affects the drying process. The process of observing 46-hour air humidity, relatively low humidity occurs at 35 o'clock with the lower shelf hovering around 21.30%, the middle rack hovering around 14.30% hour to 46, the upper rack hovering around 13.40% while the environmental Rh hovering around 57.90% at 20 o'clock. The length of time for drying cayenne pepper using a rack-type hybrid dryer takes a span of 36 hours with the moisture content of cayenne pepper material on shelf 1 of 7.14%, shelf 2 of 7.14% while shelf 3 of 14.04%. The drying rate of cayenne pepper lower shelf, middle rack and upper rack is 11.61%/hour, 11.61%/hour and 2.91%/hour, respectively.