Recent developments in greenhouse solar drying: A review

Singh, Pushpendra; Shrivastava, Vipin; Kumar, Anil

doi:10.1016/j.rser.2017.10.020

Cited by 123 publications

(53 citation statements)

References 30 publications

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“…Cabinet dryers are well known to dry small quantities of vegetables, including amaranth leaves [2,5]. The use of a solar dryer has been found to accelerate drying by 30% to 40% compared to conventional sun drying depending on the crop [6,7]. In convection dryers, airflow distribution is one of the crucial factors due to its strong impact on the drying temperature [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…An energy-efficient dryer that produces a high-quality product is still not easily accessible among farmers and processors in most developing countries [3]. Recent studies have focused on the development of solar collector and concentrators in a solar dryer [7,9,11]. Therefore, a solar tunnel dryer was developed and continuously improved at the University of Hohenheim [6,12].…”

Section: Introductionmentioning

confidence: 99%

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Technical Performance of an Inflatable Solar Dryer for Drying Amaranth Leaves in Kenya

et al. 2019

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The technical performance of an inflatable solar dryer (ISD) to dry amaranth leaves (Amaranthus spp.) was investigated. To handle the drying of lightweight materials, modification was made by adding an air deflector and trays inside the ISD. Computational performance of the ISD solar energy system was evaluated using MATLAB Simulink. The estimated air mass flow in the inlet of the ISD was 0.75 kg/s. Using computational fluid dynamics (CFD), the uniformity of air distribution in the ISD was evaluated. The solar radiation reported during good drying performance ranged between 510 and 950 W/m2. In a controlled charging system, a 100 Wp PV module typically generated voltage between 10.22 and 18.75 V. Drying conditions at temperatures of 40 °C or above were typically achieved in the ISD from 12:00 to 16:00. Temperature inside the ISD could reach up to 69.4 °C during the day and 13.4 °C during the night. The highest relative humidity of 97.4% was recorded during the night. Opening the ISD while mixing the product could lead to considerable heat loss. Fluctuation of solar radiation and shaded areas in the ISD appeared to be the major factors affecting the drying performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Technical Performance of an Inflatable Solar Dryer for Drying Amaranth Leaves in Kenya

et al. 2019

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“…Journal of Sensors (b) Once the plant is in the open field, good agricultural practices (GAP) and visual strategy can be implemented to decide correct time to clean, prune, and fertilize the coffee plant. Basing on that, GAP shares the ideas of robotics technology, electrochemical sensors, and optical technologies that can be used combined with the GPS system, to assess the presence of the pest for the fertilizer application and decide the time to clean and prune [87] (c) For the stage of sun drying, the greenhouse solar drying could be used, to reduce the time of the current sun drying process [88], combined with the use of the Wi-Fi humidity sensor to remotely and wirelessly assess and preserve an adequate moisture of the coffee cherry (see Figure 8) (2) Knowledge and Technology Management Networks. According to the lack of infrastructure for coffee processing specifically grinding and roasting, location, producer age, and labor-intensive system, the knowledge management networks could be the most relevant strategy in the short term (see Figure 6).…”

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confidence: 99%

Technology Roadmapping Architecture Based on Knowledge Management: Case Study for Improved Indigenous Coffee Production from Guerrero, Mexico

et al. 2019

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Having demonstrated its importance for economic and human developments, technological change is considered one of the biggest supports worldwide. Today, with the population increase, the inclusion of technology is considered the most appropriate way to reduce the impact of this challenge. Considering 171 indigenous coffee producers from Paraje Montero and Tierra Colorada from Guerrero, Mexico, the present study proposes technological routes for the indigenous coffee production chain and the inclusion of emerging technologies such as sensors, actuators, and processing devices basing on the requirements of the chain. During face-to-face sessions, questionaries, field visits, and literature review for knowledge management, the results expose the need of effective actions against diseases and the reduction of climate change, lack of infrastructure, old plantations, and lack of commercialization channels; for these and considering the requirement of greenhouse technology by indigenous coffee producers and following the labor value driver of the digital compass, the necessity of several kinds of sensors, technologies, and methodologies has been identified with high possibilities to be implemented by similar producers analyzed in this manuscript to help in solving the problems identified in this work. The combination of remote sensing, signal processing, and spectroscopy could be employed to explore mineralogical features of soil and help problems with fertilization; sensor modules to collect temperature, humidity, and light intensity data are a priority for greenhouse monitoring; electrochemical sensors and optical technologies could be of great help to detect the presence of diseases in coffee plants; and the installation of a greenhouse solar dryer is necessary to reduce the time of the sun drying process and protect the coffee cherry. These emerging technologies will help to improve the production of coffee. The study contributes to identify a technology roadmap proposing technological implements according to indigenous coffee production chain requirements and serves as support for future studies in indigenous regions.

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“…The maximum temperature inside the kiln exceeded the set value (43 o C), which could result from insufficient thickness of the insulation layer, with the heat potentially conducting from the black side to the white side too quickly and the material not being heat resistant. Therefore, the design of the kiln insulation needs to be improved to ensure the temperature is well maintained, as suggested in numerous studies (Luna et al 2009;Pirasteh et al 2014;Singh et al 2018).…”

Section: Kiln and Ambient Conditionsmentioning

confidence: 99%

“…Since there are many types of solar dryers for specific uses; for example, for drying timber, and for drying food. The design structure of solar kilns may require further improvements to fit their uses (Pirasteh et al 2014;Singh et al 2018). A series of modifications have been done to optimize their thermal and drying efficacy (Luna et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Quality assessment of the drying process for Eucalyptus delegatensis timber using greenhouse solar drying technology

et al. 2018

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The aim of this study was to investigate the process of drying Eucalyptus delegatensis in a greenhouse solar kiln. Specific objectives were to assess stress formation, moisture gradients and timber distortion, the moisture content distribution within various sections of the timber stack, and internal checking and collapse development within the boards. The maximal temperature and relative humidity (RH) during day time were set at 43 0 C/72% RH. In the night time the temperature was at ambient condition with 90% RH. The strain measurements were undertaken before and after the samples were sliced. The timber quality at the end of drying was assessed based on Australian and New Zealand standard (AS/NZS 4787:2001). The moisture content values in the three different sections (front, middle and end) of 2400 mm long boards were compared by Analysis of Variance. The results showed that the mean compressive strain was-2 x 10-4 mm/mm in the core layers and the tensile strain was 14 x 10-4 mm/mm in the outer layers. All sample boards were within the acceptable limits for cupping, spring and bow, even though the relative humidity level did not reach the set value. However, the amount of twist in three out of twelve sample boards was above the acceptable limit. Mean moisture gradient was 0.6%. There was a significant difference in moisture content at end section compared to the front and middle sections. Internal checking, collapse and residual stress were graded as Class "C" (class A is the highest grade and D is the lowest).

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Recent developments in greenhouse solar drying: A review

Cited by 123 publications

References 30 publications

Technical Performance of an Inflatable Solar Dryer for Drying Amaranth Leaves in Kenya

Technical Performance of an Inflatable Solar Dryer for Drying Amaranth Leaves in Kenya

Technology Roadmapping Architecture Based on Knowledge Management: Case Study for Improved Indigenous Coffee Production from Guerrero, Mexico

Quality assessment of the drying process for Eucalyptus delegatensis timber using greenhouse solar drying technology

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