Thermal performance of a passive, mixed-type solar dryer for tomato slices (Solanum lycopersicum)

López-Vidaña, Erick César; Lilia, César-Munguía Ana; Garcı́a-Valladares, O.; Isaac, Pilatowsky Figueroa; Rogelio, Brito Orosco

doi:10.1016/j.renene.2019.09.018

Cited by 118 publications

(24 citation statements)

References 31 publications

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“…Tomato slices in tray 1 dried faster compared to tomato slices in tray 3 and 5 because, products in tray 1 received more heat from the collector than those in tray 3 and 5. Drying tomatoes under the mixed mode dryer saves about 3 days, Ćesar, et al [12] in their work stated that mass transfer in mixed mode is faster compared to indirect mode due to increase in heating of the samples in the mixed mode creating a difference in vapor pressure greater than in the indirect mode dryer. Fig.…”

Section: Methodsmentioning

confidence: 99%

Comparative Studies of Two Developed On-farm Solar Dryers for Vegetables

Okaiyeto¹,

Unguwanrimi²,

Ogijo³

et al. 2020

JERR

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This research work was carried out to provide local farmers with on-farm solar dryers to minimize post-harvest losses of vegetables. Two dryers (Mixed mode and Indirect mode on-farm solar dryers) were constructed using locally available materials. The dryers basically consist of a blower, a collector area and a drying chamber. Aluminum sheet is placed inside the collector which serves as the absorbing material. An electrical axial fan was placed before the air duct to supply air responsible for forcing heated air to blow over the vegetables to be dried. Incorporated in the drying chamber are trays which provide a platform where the products to be dried were spread evenly. Transparent polythene material of 0.2 mm thickness with wooden frame was used as cover for the dryers. The dryers were evaluated to determine drying time and performance efficiencies, using Baobab leaves, Tomato and Okra slices as test crops. Collected data were analyzed using Statistical Analysis Software (SAS). The effects of variation of the independent factors were verified using Analysis of variance (ANOVA) at 1% and 5% levels of significant. Mean separation was carried out on significant factors using Duncan Multiple Range Test (DMRT). The results obtained showed the performance of the developed dryers, which indicates that drying time of mixed mode on-farm solar dryer stood at 56 hrs and 46 hrs while that of the indirect mode dryer was 76.67 hrs and 57 hrs and that of open sun drying was 154 hrs and 127 hrs for tomato and okra slices respectively. Results obtained showed that average system drying, energy collection and pick up efficiencies for the three test crops were 16.35%, 21.1% and 8.05% for mixed mode dryer respectively and 28.63%, 45.3% and 0.3% for indirect mode dryer, respectively. From the results obtained the mixed mode dryer dried all the products faster while indirect mode has superior energy efficiencies.

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Section: Methodsmentioning

confidence: 99%

Comparative Studies of Two Developed On-farm Solar Dryers for Vegetables

Okaiyeto¹,

Unguwanrimi²,

Ogijo³

et al. 2020

JERR

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“…The RMSE values, ideally close to 0, provide information about the deviation of the experimental data from the predicted one. A value of R 2 close to 1 means that there is a good fit of the data (Erick César, Ana Lilia, Octavio, Isaac, & Rogelio, 2020). The R 2 , χ 2 , and RMSE can be calculated using the following formulas:

R^{2} = 1 - \frac{\sum_{i = 1}^{N} {({italicMR}_{pre, i} - {italicMR}_{\exp, i})}^{2}}{\sum_{i = 1}^{N} {(\overset{false¯}{{MR}_{pre}} - {italicMR}_{\exp, i})}^{2}}

x^{2} = \frac{\sum_{i = 1}^{N} {({italicMR}_{\exp, i} - {italicMR}_{pre, i})}^{2}}{N - z}

italicRMSE = {[\frac{1}{2} \sum_{i = 1}^{N} {((), {MR}_{italicpre, i} - {MR}_{italicexp, i})}^{2}]}^{\frac{1}{2}}

where MR exp , i and MR pre , i refer to the experimental and predicted dimensionless moisture ratios, respectively; N to the number of observations; and z to the number of constants.…”

Section: Methodsmentioning

confidence: 99%

Investigation of performance and drying kinetics of the closed, partially open, and open heat pump drying systems

Tunçkal

2020

J Food Process Engineering

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In this study, the slices of "starking delicious" apple were dried at 40 C and an air velocity of 1 m/s in the heat pump drying system which was operated in three modes, that is, closed, open, and partially open. The model developed by Midilli and Kucuk was found to be the best model to explain the experimental data of apple slices drying. The effective moisture diffusivity values ranged from 2.33 × 10 −8 to 3.06 × 10 −8 m 2 /s. The evaporator and condenser side for open, partially open, and closed circuits are designed to operate with 100% fresh air or partial fresh air, which is controlled using dampers. Moisture content reduction of the apple slices from 4.631 to 0.126 g-water/g-dry matter moisture content took 404 min in the system operation with the condenser side partially open. Open heat pump drying system evaporator and condenser sides were completed in 27.4% less time than the open system application. The average performance coefficient (COP sys) of the entire system was found to be the highest in the closed system operation with 2.505. The SMER sys average was 80.80 g/kWh and the minimum total energy consumption was 5.580 kWh in the open heat pump drying system with the condenser side open. Practical Applications: In this study, a heat pump dryer has been developed that can

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“…Erick César et al. (2020) designed and evaluated a PSD with the option operate as an ISD or MSD for drying tomato slices and found an overall efficiency of 8.8% and 10.7% for the ISD and MSD, respectively. Mahapatra and Tripathy (2019) tested the thermal performance of PSD under no load conditions and found efficiency of 31.4%, 27.6%, and 41.4% for DSD, ISD, and MSD, respectively.…”

Section: Introductionmentioning

confidence: 99%

Experimental evaluation of a passive indirect solar dryer for agricultural products in Central Mozambique

Matavel

Hoffmann

Rybak

et al. 2021

Food Processing Preservation

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Post‐harvest losses are one of the major livelihood challenges for farmers in the Global South. The use of drying technologies to preserve agricultural products has been promoted as a particular solution to address this challenge. In this regard, we designed and tested a passive indirect solar dryer for drying agricultural products as an alternative to open sun drying (OSD) in Gurue district, Central Mozambique, using amaranth leaves and maize. In addition, a sensorial analysis was conducted by randomly selecting a group of 60 adults who evaluated the texture, aroma and color of dried amaranth and maize grains. Compared to OSD, the passive indirect solar dryer reduced drying time and increased the thermal efficiency. Evaluation of sensory quality attributes showed that passive indirect solar drying outperforms OSD. Practical applications This study evaluates the performance of a passive indirect solar dryer, a sustainable alternative to conventional food preservation technologies (e.g., refrigeration) that are not affordable to resource‐constrained communities. The use of passive solar dryers, if carried out correctly, creates the possibility for poor rural households to safely store and increase shelf life of food. In addition, the acceptability of products dried in the passive indirect solar dryer is evaluated. Thus, the study also provides insights on passive solar dryer potential for preserving the quality of the final product.

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Thermal performance of a passive, mixed-type solar dryer for tomato slices (Solanum lycopersicum)

Cited by 118 publications

References 31 publications

Comparative Studies of Two Developed On-farm Solar Dryers for Vegetables

Comparative Studies of Two Developed On-farm Solar Dryers for Vegetables

Investigation of performance and drying kinetics of the closed, partially open, and open heat pump drying systems

Experimental evaluation of a passive indirect solar dryer for agricultural products in Central Mozambique

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