Low Cost Solar Dryer Research Articles

Low-cost solar dryer dehydrates silver banana with a prediction of diffusion approximation model

Solar dryers made from recycled materials offer a cost-effective solution for promoting the widespread adoption of this technology and reducing food production costs. In this study, a low-cost solar dryer was constructed using repurposed materials, employing indirect exposure, and its performance was evaluated through a kinetic study on banana slice drying (Musa spp.). Drying was carried out until equilibrium moisture, reaching constant mass. The drying air's temperature and relative humidity (RH, %) were monitored. Fourteen empirical models were used to fit the experimental data. The banana slices took approximately 300 min to dry, with final moisture of 1.8%. The mean operational conditions during natural drying were 59.08±9.16 °C and RH = 39±4%. The diffusion Approximation model fitted the drying curve better, as it presented the lowest reduced Chi-square (χ2 = 2.9×10-5) and a high coefficient of determination (R2 = 0.9998). The effective diffusion coefficient (Def = 5.4×10-9 m2/s, R2 = 0.9935) was determined. Thus, the solar dryer demonstrated efficient performance in the banana drying process, requiring minimal design effort. Furthermore, despite the limitations in controlling the drying conditions, most of the mathematical models successfully predicted the drying process due to the dryer's ability to maintain the continuity of the drying curve, suggesting potential viability for this low-cost dryer.

Preparation and physical-chemical characterization of cashew raisins in a low-cost solar dryer

Cashew is a very consumed fruit due to its sensory characteristics and because it is a fruit rich in vitamin C. Due to the high rate of perishability and losses in production, techniques are sought to increase the shelf life of the product, minimizing these losses. Among these techniques we have osmotic dehydration and drying. The objective of this work was to dry the cashew apple, previously osmotically dehydrated, in a solar dryer and to evaluate its efficiency by comparing it with the oven, through the construction of kinetic curves of drying and evaluation of the dehydrated product. Thus, sliced ​​cashew apples were osmotically dehydrated in syrups with 40 and 50 ºBrix, at 30ºC, followed by solar drying using a solar dryer with air circulation and an oven with air circulation with average temperature obtained in the solar dryer. The osmotic dehydration process was evaluated through weight loss, moisture loss and solid incorporation. An analysis of the physical and physical-chemical characteristics (pH, soluble solids, titratable acidity, vitamin C and color) of cashew nuts “in natura” and dried was carried out. Furthermore, the experimental data were fitted to the Page, Logarithm and Midili models. The Midili model was the one that best represented the drying kinetics, the solar dryer showed a shorter drying time and a higher value of ascorbic acid, being a low-cost alternative that delivers a quality product.

Design And Implementation of Low-Cost Solar Dryer For Sun-Dried Guava Production

Crystal guava (Psidium guajava) is a commodity that is widely cultivated in Kebumen. Innovation is needed to increase its selling value, one of which is by producing dried guava. The production of dried guava can be achieved using a solar dryer. In this research, the design and testing of a low-cost solar dryer for producing dried guava were conducted. The main materials used were wood, aluminum pipes, aluminum foil as solar collectors, and solar panels to supply power to DC fans, thus enhancing drying efficiency. The energy analysis revealed that the average collector efficiency, drying efficiency, and specific energy consumption were 73%, 8.84%, and 0.182 kWh/kg, respectively, for the forced convection solar dryer (FCSD), and 42%, 4.61%, and 0.236 kWh/kg, respectively, for the natural convection solar dryer (NCSD). Moreover, in this research, the moisture content of guava, initially at 85%, decreased to 10.73% for FCSD and 25.05% for NCSD. The payback period for this project is estimated to be 1.79 years, enabling guava farmers to use this solar dryer to enhance the selling value of their products.

Design and Implementation of Low-Cost Solar Dryer Based Android for Agricultural Crops

Smartphone technology is developing very quickly and becoming an integral part of our lives. The technology provides many conveniences the users can obtain, including in agriculture. One such convenience is in providing better way to dry horticultural crops for farmers, since the traditional drying method has many drawbacks. In addition to the long drying processing time, the traditional method also damages many crops and reduces net production. To overcome this problem, the convenience that exists in smartphone technology can be combined with PV (Photovoltaics) technology, producing an alternative solution to replace the traditional drying process. This study aims to design a low-cost drying agricultural product using a wi-fi Sonoff module to control and send signals using the E-WeLink application installed on smartphones that can be applied to small-scale agro-industrial farmers. A solar dryer was tested on chili and corn seeds. Experimental results revealed that the time efficiency has improved by about 26.67% for chili and 27.27% for corn seeds compared to conventional processes. Meanwhile, in terms of energy required for the drying process, this system succeeded in producing 25% - 45.11% efficiency compared to the energy required with conventional processes. In addition, the system can be used as a source of lighting, which can be monitored and controlled from a smartphone application via a wi-fi network

Design and fabrication of a double- chamber solar dryer

Object of research: This paper discusses the design and construction of a modified, cost effective solar dryer for use by the average Nigerian farmer or agri-business entrepreneur.
 Investigated problem: Local farmers often have a lot of difficulties in properly drying harvested agricultural produce for storage and processing purposes, safely and efficiently due to capital constraints. There was therefore a need for an efficient, low cost solar dryer design to aid in this pursuit.
 Methodology: The designed dryer is a passive dryer that makes use of heat energy tapped through glass collectors placed over the drying and air inlet chambers respectively. The dryer was designed and constructed with carefully selected, inexpensive materials with dimensions of 40cm x 40cm x 60cm for the drying chamber and dimensions of 10cm x 80cm x 40cm for the heating chamber. The glass collectors (4mm thick) were inclined at an angle of incidence of 17.26°. Okra slices were used to test the performance of the dryer.
 Results / Area of practical use: The study yielded a low cost (€145.60) modified solar dryer capable of drying agricultural produce in a safe and clean way. During eight (8) hours of drying under a temperature range of 39 °C – 45 °C, the initial weight of the okra slices reduced from 150g to 9g, 9g, 10g and 9g on each of the four trays of the drying chamber respectively. Local farmers and agripreneurs will be encouraged to make use of this clean alternative of drying food produce without the drawbacks from regular sun drying.
 Conclusion: There is need for more work to be done in terms of installation of solar panels to enhance dryer performance. More work should also be carried out on tests during the dry season for increased dryer efficiency.

Traditional fish processing in Odisha, India

The present study documents the traditional fish drying techniques used by the fisher folk communities of Bhadrak district, Odisha, India. Information on local knowledge and the use of different fish drying methods within the study area was collected from 72 fisher folk through semi-structured questionnaires, free interviews, informal conversations and direct observations. The results showed that sun drying was the most extensively used method for fish preservation. About 19.4% of the informants preferred to spread the fishes directly on earth, 34.8% on the mat, 5.5% on palm leaves, 29.2 % over bamboo bars and 11.2% followed interlocking of snouts/jaws on bamboo sticks. Almost all the fish drying devices are handmade with bamboo, wooden pole and sometimes nylon threads following traditional technologies. The quality of the dry fish could be improved by educating fishermen on hygiene, sanitation, use of good water quality and raw materials for processing. In this context, the low-cost solar dryer can be constructed by using locally available materials, thus preventing contamination and dependence on weather conditions. The dry fish production can play a crucial role in socio-economic upliftment, employment generation and poverty alleviation particularly to women as they depend on it directly for their livelihoods.

Traditional sour cassava starch obtained with alterations in the solar drying stage

After natural fermentation and solar drying, sour cassava starch acquires expansion property. Traditionally, solar drying occurs without protection, and consequently physical contamination can arise. Thus, the aim of this study was to produce sour cassava starch using a low-cost solar dryer to prevent contamination, whilst retaining the expansion property. The samples were characterized in relation to chemical composition, microscopy and physical contaminants, as well as expansion, thermal, pasting, structural and technological properties. In addition, biscuits were prepared and compared with commercial samples. The solar dryer provided faster drying and lower moisture levels than the control. The specific volumes of the sun-dried products were similar to the control, with minimized contamination. The granules of the starches showed slight erosion on their surface, which was probably due to amylolytic enzymes. X-ray diffraction showed a typical A-type pattern. DSC analysis resulted in higher gelatinization temperatures and enthalpy changes for the sour cassava starch. The pasting properties showed a reduction in the viscosity peak at neutral pH. Although the cassava starch biscuits made with sour cassava starch dried in the solar dryer presented lower expansion levels in relation to the other biscuits produced with commercial sour cassava starch, they had desirable sensory characteristics.

Design, construction and performance testing of a simple low-cost solar dryer for agricultural and food products

This paper presents the design, construction, and testing of a simple solar dryer for food preservation, which is designed, constructed and tested in the Department of Mechanical Engineering, Guruk...

Design, construction and performance testing of a simple low-cost solar dryer for agricultural and food products

Design, construction and performance testing of a simple low-cost solar dryer for agricultural and food products

Development and modelling of heat and mass transfer analysis of a low-cost solar dryer integrated with biomass heater: Application for West African Region

The main objective of this study is to design and fabricate a low-cost hybrid solar drying system and present the drying kinetics, heat transfer coefficient and thin layer models for the dried product. For this purpose, two solar dryers one equipped with biomass heater and the other without biomass heater were constructed and tested. The results show that the developed solar dryers can save between 27.78% and 58.33% of drying time compared to open sun drying method at ambient temperature ranging between 30 and 40 °C and a humidity ranging from 55% to 70%. Under these operating conditions, the collector efficiency is 20.81–21.89%. The values for the heat transfer coefficient ranged from 0.64 to 10.5 W/m2 °C. Verma et al. model gave the best result for drying with biomass heater while logarithmic model was best for drying without biomass heater.

Design and development of solar dryer for food preservation

Solar thermal energy is an alternative source of energy which can be used for drying vegetables, fishes, fruits or other kinds of material, such as wood. In Bangladesh, there exist significant post-harvest losses of agricultural products due to lack of the use of proper preservation system. Drying by using solar thermal energy can be an effective solution for this loss. As Bangladesh is situated in latitude 23°43’N and longitude 90°26’E, this is very much suitable to use solar thermal energy. To reduce the limitations of the natural sun drying e.g. exposure of the foodstuff to rain and dust; uncontrolled drying; exposure to direct sunlight; infestation by insects etc., two types of solar dryer (low cost solar dryer for small production and solar dryer for large production) were developed. The design was based on the geographical location of Dhaka, Bangladesh. The experiments were conducted to dry vegetables and fishes. The obtained results revealed that the temperatures inside the dryer were much higher than the ambient temperature. The rapid rate of drying proves its ability to dry food to keep in safe moisture level in a hygienic environment. Microbiological and nutritional values ensure a superior quality of the dried product also.
 Bangladesh J. Sci. Ind. Res.54(2), 155-160, 2019

Performance comparison of mixed mode and indirect mode parallel flow forced convection solar driers for drying Curcuma zedoaria

AbstractThis study focuses on energy and drying kinetic analyses of Curcuma zedoaria (white turmeric) dried in mixed and indirect active parallel flow solar dryers. Dryer efficiency, specific energy consumption and drying rate are studied. The overall dryer efficiency of mixed mode (MFSCD) is 26.5% higher than indirect mode (IFSCD) solar dryer. Two term model and Verma model fit best for Curcuma zedoaria drying in MFSCD and IFSCD, respectively, and Logarithmic model is quite suitable for open sun drying (OSD). The effective moisture diffusivity of the product dried under MFSCD is highest as compared to IFSCD and OSD products. The quality analyses show that higher values of TFC (78.11 mg GAE/g of sample) and DPPH (120.56 μ mol of TE/g of sample) are reported in the samples dried in MFSCD as compared to IFSCD and OSD samples.Practical applicationsConventional open sun drying is a common practice followed by small farmers for drying herbs and spices. Products dried under open sun lose their nutritional and medicinal values due to slow drying rate and improper heating. The present work focusses on the development of a low cost solar dryer for drying of high value medicinal herbs like Curcuma zedoaria, curcuma caesia, and black cardamom. Study of drying kinetics helps in improving the design aspects of solar dryer and optimization of the drying systems. Drying time of the Curcuma zedoaria dried in the developed dryer is about 60% less than the open sun drying and the retention of color, antioxidant, and texture of the solar dried products is excellent. The developed solar dryer will be suitable for small small‐scale farmers and can be scaled up to any size.

Drying kinetics of black turmeric (Curcuma caesia) with optimal controller assisted low cost solar dryer

Drying kinetics of black turmeric (Curcuma caesia) with optimal controller assisted low cost solar dryer

Development of low cost solar dryer for Oman conditions

Solar dryer is one of the technologies which are used in many countries to dry the agricultural products. In the present wok, development of low cost pebble bed solar dryer was made to suit for Oman weather conditions. The system consists of solar collector with pebbles for heat storage and cost effective food drying chamber. Initially, dryer performance was studied with banana and study results revealed that maximum dryer room temperature of 68°C and the moisture loss content of 52%. In addition, dryer chamber efficiency of 34% was achieved in the study. Overall, the study results indicated that late evening drying up to 7PM was noticed and the developed dryer system gave better results than dryers available in the market.

Design, fabrication and performance evaluation of solar dryer for banana

An indirect, active-type, environmentally friendly, low-cost solar dryer was designed to dry various agricultural products. The dryer was built by locally available, biologically degradable, low-cost materials. The dryer consists of solar flat plate air heater with three layers of insulation, drying chamber and a fan with a regulator to induce required air flow in the system. Banana is the chosen crop for the experimentation since it is high in production and also has substantial loss in India. Also, dried bananas are having good nutritive value which makes it as essential diet. The experiments were conducted to dry banana slices and to study its drying characteristics like rate of drying and quality of dried banana in terms of taste, colour and shape. The dryer has the following features: two different air flow configurations (air flow between glass cover and absorber plate called as the top flow and air flow between absorber plate and the bottom insulation of solar collector called as the bottom flow), forced flow with variable flow rates from 0–3 m/s and two different mounting schemes (conventional trays and wooden skewers). In the top and bottom flow experiments, the bottom flow provided about 2.5 °C higher chamber temperatures than the top flow for the same solar energy input. The efficiency of top flow configuration was found to be 27.5 %, whereas the efficiency of bottom flow configuration was found to be higher at 38.21 %. The results also agree well with the theoretical calculations performed as 60 W of energy can be saved for the same energy input. The drying rate was found to increase when wooden skewers were used instead of conventional trays. At the end of the day, the total difference in moisture content is found to be 3.1 % which is considerable knowing that the rate of drying drastically decreases with time. Banana dried at 1 m/s air flow rate was of the best quality in terms of colour, taste and shape when compared to drying at 0.5 and 2 m/s air flow rate while the weather condition and ambient conditions were almost the same for all the cases with negligible difference.

OPTIMIZATION OF SOLAR DRYER FOR THE DEHYDRATION OF FRUITS AND VEGETABLES

ABSTRACT Currently, several solar dehydrator designs exist on the market, and some of these designs require expensive materials, which makes the prototype expensive and difficult to obtain for small producers. The aim of this study was to build a low-cost solar dryer with high energy efficiency based on a previous solar dryer model. The optimization of the previous solar dryer model was characterized via temperature profiles and drying kinetics to identify gaps. Theoretical and numerical modeling was used to correct the gaps, and a new prototype was then built. The inclination angle was changed from 45° in the previous model to 20° in the new model. As compared with the old model, the results indicated that the new model improved the efficiency by 43.75% for banana fruit, thereby demonstrating the optimization of the new model. PRACTICAL APPLICATIONS The solar dryer developed in this study will be applied to dehydrate fruits and vegetables with a capacity of up to 10 kg. It is a dryer built with low-cost materials, simple operation and high energy efficiency. Preserved safe products are obtained with solar dryer.

The use of solar dryer to control insect infestation in stored grains in Ghana

A study was carried out to assess the effectiveness of a simple solar dryer, built from local materials, to control cowpea bruchids, Callosobruchus maculatus (Fabricuis) and maize weevils, Sitophilus zeamais (Motsch.) in infested cowpea and maize. The effect of the heat generated in the solar dryer on the mortality of the insects, viability of the cowpea and maize seeds and the emergence of F1 progeny of C. maculatus and S.zeamais were the parameters assessed. The result obtained showed the reliability of the simple, low cost solar dryer in controlling the insects to an appreciable level. Complete (100%) mortality was obtained when theinfested cowpea and maize were placed in the solar dryers, for 60 minutes and 120 minutes, respectively. The highest mean percent seed viability of the infested cowpea was 66.4% after being exposed for 120 minutes inthe solar dryer and least viability was 48.5%. However, the mean percent seed viability of the infested maize decreased from 85% after 30 minutes of exposure in the solar dryer to 59.0% after 4 hours. The test indicatedthat exposure of the seed to the heat in the solar dryer reduced viability. The control for both cases gave higher percentage seed viability 73% and 86% for cowpea and maize, respectively. The period of exposure of theinfested grains in the solar dryer for one hour or more also effectively reduced the number of F1 progeny that emerged from the stored grains. The result for solar-treated seeds was only effective as post-harvest reduction in weevil injury and may not be viable for planting due to loss in germination.Keywords: mortality, viability, F1 progeny, C. maculatus, S. zeamais.

Low cost solar dryer for fish

Prawns (Kolambi) were selected as drying material in low cost solar dryer (LCSD). Time required for reducing the moisture content from 75 to 16% were observed in open sun drying and solar drying for its comparison. Salted fish inside the dryer required 8 h in order to dry prawns up to 16.15% while unsalted fish required 15 h to reach moisture content up to 15.15% in open condition. Overall collection efficiency was found as 70.97%. Average drying efficiency for salted fish was 14% and unsalted fish was 11% whereas pickup efficiency for salted and unsalted fish was found as 10 and 9% respectively. Salted prawns were found most liked for its colour and texture than unsalted solar dried sample in sensory evaluation. Unsalted prawns sample dried in solar dryer was overall accepted, while traditionally open sun dried sample was least liked for its colour and texture. The value of F is calculated as 1.98 during the sensory evaluation. The economic cost of solar dryer was compared with mechanical drying for beneficial to local fishermen. The cost of LCSD in Rs. 1700/- is affordable to poor fisherman comparing to other costly mechanical dryer. Local fisherman could recover solar dryer cost within the period of 0.19 years by adopting solar drying technology. Key words: Collection efficiency, system drying efficiency, pick-up efficiency, economics.

Development of a low-cost solar agricultural dryer for arid regions of India

The design details and performance of a low-cost solar dryer which can be used for dehydrating 10–15 kg fruit and vegetables are described in this paper. Field tests indicated that by the use of a solar dryer, the drying time for chillies can be reduced to nearly half of that by the open drying method.