Empowering Women through CIFT Solar-Electric Backup Fish Dryers: Enhancing Livelihoods and Environmental Sustainability in the Coastal Districts of Nagapattinam and Puducherry

Preliminary analysis of systems for integrating solar thermal energy into processes with heat demand

The fish products can be stored for longer period in dry condition, but most of the fresh fish in remote areas of our country are spoils due to lack of proper preservation. To overcome this problem, hybrid solar dryer can play an important role to make drying continuous during night and daytime also off sunshine hours. In this project, a hybrid solar cabinet dryer has been designed, constructed, and performance tested for fish drying. The dryer consists of a drying chamber, solar collector, two trays of dimensions (60×60) cm and paraffin wax as PCM. It also consists of photovoltaic cell modules, heating element, electric battery, and other electric equipment such as inlet and outlet fans. The dryer has been operated as both a solar energy dryer during normal sunny days and a hybrid solar dryer during cloudy days. Paraffin wax system inside drying chamber absorbed heat energy in Sunny time. At the same time the battery is charged from the solar system and therefore the water kept in the tank reaches a certain temperature by absorbing heat from nature, which provides heat by circulating the water inside the drying chamber during inclement weather. Electric fans are used at the inlet of the solar collector and outlet of the dryer to maintain adequate air flow inside the drying chamber. During the night and cloudy weather paraffin wax and heater system deliver heat to maintain the set temperature in drying chamber. The grain bed in the dryer is heated by air that comes from a separate solar collector, and at the same time, the drying cabinet collects solar energy directly through the transparent walls and roof. The dryer demonstrated the capacity to dry fish to an appropriate moisture level in a reasonable amount of time, and concurrently, it insured that the fish would be of high quality. The drying rate of hybrid solar dryers is evaluated on fresh fish and compared with solar dryers and sun drying under the same climatic conditions.

The global food crisis calls for aggressive food production campaign as well as drying and storage of some of these food items so produced.This paper illustrates how free and inexhaustible supply of solar energy was used to dry yam pellets, thereby preserving the yam in powdered form for the lean periods. The dehydrator used is a solar dryer, using air as a drying medium and requiring minimal electrical power for its operation. Yam was used for the drying experiments because of its economic value in Nigeria and other African countries. The average drying time for yam pellets was 6 hours, (between 11.00am – 5.00pm during the months of November – April) .The author succeeded in producing approximately 1kg of yam flour from a simple solar dryer daily. Construction of the Solar Energy dryer and drying of the yam pellets was carried out at Nsukka in South Eastern Nigeria. Very fine flour of various species of yam was produced. Average moisture loss was 66.5% and 53.8% respectively for the two yam specimens that was dried in the solar dryer. The solar dryer produced daily average 1kg flour daily respectively. The Solar dryer with its average capacity of drying 1kg of flour can serve a family of four persons for a single meal. Industrial production of dried yam flour can be carried out by building larger type of the solar energy dryer based on the same principle like the prototype used for this study. Keywords: Solar Energy; Solar dryer; food production; storage, preservation

A laboratory-scale passive solar grain dryer was developed and its performance evaluated in Makurdi metropolis, Benue State, Nigeria. The dryer consist of a solar collector panel, a thermal storage unit and a drying chamber. The top of the collector is made of one layer of 4 mm thickness of colourless glass sheet as glazing. The absorber material used was corrugated 0.5 mm thick zinc roofing sheet painted black. The thermal storage unit and the drying chamber were built of wood because of its good insulation properties. The dryer was evaluated using 10 kg of freshly harvested maize at 32.8%wb. The performance evaluation results obtained showed that the mean drying rate of the dryer was 0.7 kg/day per every 10 kg of corn whereas sun-drying rate was 0.3125 kg/day comparatively. The solar dryer has considerable advantages over the traditional sun drying method in terms of faster drying rate, less fear of spoilage by micro-organisms when crop is harvested at high moisture content and handling convenience. Savings in time was achieved by using the solar grain dryer as against the traditional sun drying. It took 4-days to dry the corn to moisture content of 13.1%wb using the passive solar dryer while it took 8-days to dry to 13.4%wb under sun drying. Commercial sizes of the solar dryer can be amplified and produced for community level cooperative use and for prospective investors to fast track agricultural development in the rural areas. Key words: Passive, solar, grain dryer, development, performance, laboratory-scale

Drying is the oldest preservation technique of agricultural products, and sun drying is still widely used for preservation of agricultural products in the tropics and subtropics. Previous efforts on solar drying of cereal grains, fruits, vegetables, spices, medicinal plants, and fish are critically examined. Recent developments of solar dryers such as solar tunnel dryer, improved version of solar tunnel dryer, roof-integrated solar dryer, and greenhouse-type solar dryer for drying of fruits, vegetables, spices, medicinal plants, and fish are also critically examined in terms of drying performance and product quality, and economics in the rural areas of the tropics and subtropics. Experimental performances of different types of solar dryers, which have demonstrated their potentialities for drying of fruits, vegetables, spices, medicinal plants, and fish in the tropics and subtropics, are addressed, and also the simulated performances of the different types of solar dryers are discussed. The agreement between the simulated and experimental results was very good, and it is within the acceptable limit (10%). The simulation models developed can be used to provide design data and also for optimal design of the dryer components. A multilayer neural network approach was used to predict the performance of the solar tunnel dryer. Using solar drying data of jackfruit and jackfruit leather, the model was trained using back propagation algorithm. The prediction of the performance of the dryer was found to be excellent after it was adequately trained and can be used to predict the potential of the dryer for different locations and can also be used in a predictive optimal control algorithm. Finally, prospects of solar dryers for drying of fruits, vegetables, spices, medicinal plants, and fish in the tropics and subtropics are discussed.

Drying via solar energy is an environmentally friendly and inexpensive process. For controlled and bulk level drying, a greenhouse solar dryer is the most suitable controlled level solar dryer. The efficiency of a solar greenhouse dryer can be increased by using thermal storage. The agricultural products dried in greenhouses are reported to be of a higher quality than those dried in the sun because they are shielded from dust, rain, insects, birds, and animals. The heat storage-based greenhouse was found to be superior for drying of all types of crops in comparison to a normal greenhouse dryer, as it provides constant heat throughout the drying process. Hence, this can be used in rural areas by farmers and small-scale industrialists, and with minor modifications, it can be used anywhere in the world. This article provides a comprehensive analysis of the development of solar greenhouse dryers for drying various agricultural products, including their design, thermal modelling methods, cost, energy, and environmental implications. Furthermore, the choice and application of solar photovoltaic panels and thermal energy storage units in the solar greenhouse dryers are examined in detail, with a view to achieving continuous and grid-independent drying. The energy requirements of various greenhouse dryer configurations/shapes are compared. Thermodynamic and thermal modelling research that reported on the performance prediction of solar greenhouse dryers, and drying kinetics studies on various agricultural products, has been compiled in this study.

The work addresses the issue of solving a scientific-applied task on the substantiation of operation modes of the solar fruit dryer in order to improve energy efficiency of the technological process of fruit drying for small amounts of fruit processed at private farms. We have explored the use of solar energy for fruit drying at the latitude of the location of Rivne oblast, Ukraine, which has the average annual solar radiation power of the order of 3.41 kW∙h/m 2 per daylight. This makes it possible to receive from 1.5 to 2.3 kW∙h of energy per day from the air collector area of 1 m 2 . The series of analytical and experimental studies that we conducted has confirmed the possibility for a significant intensification of the process of fruit drying in the solar dryer. Compared with modern convective drying devices, the specific energy consumption when drying the fruit in the solar dryer is reduced by 3…3.7 MJ/kg. The degree of intensification grows by 3.3…12 times compared to drying devices of the mine and tunnel types. Such results were achieved by implementing the proposed design of a flat mirror concentrator, to enhance the slanting fluxes of morning and evening sun irradiation, and a heat accumulator, based on pebbles, for accumulating at night the excessive heat from the reserve source of energy. It was established that regardless of a blanching technique for fruit raw materials, the duration of drying in the solar dryer varies depending on physical parameters of the environment. In the process of drying, the experiments were carried out at a temperature of 289.15…333.15 K, and the duration of drying was from 50 to 74 hours. We have analyzed the effect of operational parameters on a change in the chemical indicators and quality of the dried fruit. Specifically, the content of vitamin C, which was 5.2 mg/% for pear, and 4.3 mg/% for apple. The acidity was 0.29 % for pear, and 0.46 % for apple. The content of dry nutrients was 87.5 % for pear, and 85.9 % for apple. The sugar content of fruit raw materials was 59.36 % for pear, and 57.8 % for apple.

Studies were conducted to evaluate the drying performance of rotating and solar tunnel dryer for the production of high quality dried fish products. Three marine fish species : Silver jew fish (Johnius argentatus), Bombay duck (Harpodon nehereus) and Ribbon fish (Trichiurus haumela) were used for drying in a rotating dryer and solar tunnel dryer. Temperature and relative humidity were measured at time interval during the whole drying period. During 20 hours of drying in rotating dryer, temperature and humidity varied from 15-20oC and 45 to 72%, respectively. On the other hand, air temperature outside the tunnel dryer varied from 28 to 32.83oC. Temperature inside the tunnel dryer varied from 31.33oC at 3.00 pm to 47.78oC at 12.00 pm. Humidity outside the tunnel dryer ranged from 58.83 to 74% and inside from 33.83% to 68% showing an inverse relationship between temperature and humidity. Moisture content of the fresh Ribbon fish, Silver Jew fish and Bombay duck was in the range of 78.7% to 85.47% with highest value was found in Bombay duck and lowest value in Ribbon fish. After 31 hours of drying in solar tunnel dryer, moisture content decreased in the range of 14.05 to 16.19%. whereas, after 20 hours of drying in rotating dryer final moisture content reached in the range of 16.36 to 19.1%. The present study indicated that drying performance of rotating dryer with low humidity was faster than that of solar tunnel dryer producing quality dried products.DOI: http://dx.doi.org/10.3329/pa.v20i1-2.16869 Progress. Agric. 20(1 & 2): 173 – 181, 2009

This article performed various analysis on Red chilli by hybrid collector with solar dryer (HCSD). This study was carried out forced convection solar dryer which performed better in all aspects such as drying time, moisture removal rate, electrical efficiency, electrical thermal efficiency, thermal efficiency and overall thermal efficiency. In general, solar radiation was provided a sources of generating energy to drive a solar dryer. Hybrid collector has been provided the electrical and thermal energy to run a solar dryer. The solar dryer was tested by drying 12 kg of red chilli in the drying air temperature in the range of 32 0C – 56 0C. The initial moisture content of the red chilli was 71.5 % (weight basis) and was reduced to the final moisture content of 16.2 % (weight basis) in 6 consistent days with clear sunny days. The HCSD was operated between 9 hrs to 16 hrs. Finally, comparative study was also handled for better understanding in HCSD, in which solar dryer drying made better outcome than open sun drying.

Micronutrient deficiencies affect over two billion people globally, with Africa facing significant challenges in ensuring adequate nutrition for its growing population. African leafy vegetables (ALVs) are a traditional part of local diets and hold potential to combat hunger and micronutrient deficiencies if their availability and consumption are increased. Solar drying, a simple and sustainable post-harvest technology, can extend the shelf life and marketability of these vegetables and is also a cost-effective solution to improve food preservation and security. The objective of this review is to provide a comprehensive understanding of the solar drying process, as applied to ALVs, its effects and benefits. It is a structured narrative review of online sources including peer-reviewed articles, books, theses and various publications that focus on solar drying technologies, conditions, effects and challenges related to ALVs. A thorough search was carried out using search engines including Google search, Google Scholar and ResearchGate, with terms such as ‘drying of indigenous leafy vegetable,’ ‘solar- drying,’ ‘solar dryers,’ ‘solar-dried African leafy vegetables,’ ‘effects of solar drying on ALVs,’ ‘nutritional value of dried ALVs’ and ‘bacterial load of solar-dried ALVs’. Solar drying methods include direct, indirect, mixed-mode, and hybrid technologies, with optimal conditions ranging from 10 - 30°C above ambient temperatures. Mixed-mode solar dryers offer several advantages over other methods which rely fully on solar energy. Drying takes 2 - 5 days depending on the dryer, the vegetable type and the prevailing weather conditions. While solar drying helps reduce microbial contamination, extends shelf life and antinutrients, it can also lead to nutrient loss – proximate, vitamins, minerals, phytochemicals and affect the sensory quality of the vegetables, depending on factors like drying method, vegetable type and environmental conditions. Other variables influencing the dried product's quality include the variety of vegetables, its maturity, climate during growth and the time between harvest and drying. Despite its challenges and limitations, solar drying preserves food, conserves resources, and promotes sustainable food systems, contributing to food security, environmental sustainability and economic efficiency. Key words: Solar drying, African leafy vegetables, nutrients, shelf-life, safety, acceptability

The objective of this study was to see if year-to-year variation in size-specific growth rate and body condition of adders, Vipera berus, was correlated with any of four environmental variables: mean summer temperature, number of sunny days during summer, number of days when the temperature was over 15 °C during summer, and vole density as an index of food abundance. Growth rate and body condition were measured during 5 years in two insular populations of adders (at localities A and I) in central Sweden. At locality A, vole density remained constant among years (range 0.86–3.00/ha), whereas at locality I it changed significantly (0.67–22.67/ha). The two localities were approximately 2 km apart and therefore experienced the same weather conditions. At locality A, growth rates (after sex and snout–vent length were controlled for) remained stable, whereas at locality I they varied significantly among years and showed a significant positive correlation with yearly estimates of vole density. I conclude that the growth rate was affected positively by food abundance, but less so by weather. Body condition of male adders (females were excluded because the sample size was small) varied significantly among years in both populations. At locality A, body condition was positively correlated with number of sunny days, whereas at locality I, where vole density changed over the years, body condition was positively correlated with both vole density and number of sunny days. This suggests that both food abundance and weather may be important in determining body condition.

Intermediate pyrolysis can be used to obtain high-quality biofuels from low-value residues such as sewage sludge or digestate. A major obstacle is the high water content of sludgy biomass, which requires an energy-intensive and expensive drying step before pyrolysis. Solar greenhouse drying is an efficient and sustainable alternative to a thermally heated belt dryer. In this study, a techno-economic assessment of intermediate pyrolysis with solar drying is carried out. Marketable products of the process are bio-oil, a substitute for diesel or heating oil, and bio-char with various possible applications. Chile is chosen as the setting of the study as its 4000 km long extension from north to south gives the opportunity to evaluate different locations and levels of solar irradiation. It is found that solar drying results in higher capital investment, but lower fuel costs. Depending on the location and solar irradiation, solar drying can reduce costs by 5–34% compared to belt drying. The break-even price of bio-char is estimated at 300–380 EUR/ton after accounting for the revenue from the liquid bio-oil.

Design and performance evaluation of a new hybrid solar dryer for banana

The performance evaluation of Mixed-Mode Passive Solar Dryer for drying codfish (Gadusmorhua) was conducted. The dryer is comprised of among other things, materials for sensible heat storage to discharge heat during the off-sunshine period. The drying chamber is integrated with a suction device to aid the convective airflow to avoid reversible reaction during the discharge of accumulated moisture. The solar dryer was evaluated with fresh codfish samples at the initial moisture content of 79% (wet basis). The samples were divided into sets. A set was treated with Moringa Oleifera and the second set with salt solution. The results showed that, for Moringa and salt treatments, the moisture content of the codfish was reduced to 16.03% and 13.33% (wet basis) respectively using the solar dryer while 19.55% and 13.46% respectively under ambient condition in six days. Laboratory tests showed that bacteria and fungi count for Moringa and salt treated codfish under solar dryer were below consumable limits.

A solar dryer and hybrids incorporating back up incinerators were designed and constructed for performance evaluation and analysis of efficiencies for selected farm produce of cassava grates, okra and chilli pepper in two climatic locations (sub-tropical of Nsukka and humid of Makurdi in Nigeria) at the University of Nigeria, Nsukka and Federal University of Agriculture, Makurdi, Nigeria. It consists of a solar collector, drying chamber, and incinerator. The dryer was used for drying at night; sunshine days and cloudy days. They were used for test drying, termed ‘no-load’ test (without any farm produce) and ‘onload’ (cassava grates, okra and chilli pepper) as selected farm produce. Their respective weight losses were used to determine the reduction in moisture content. Drying was Original Research Article British Journal of Applied Science & Technology, 4(3): 525-539,. 2014 526 assumed to have taken place in the falling rate periods, which enabled the use of only one drying rate constant. Graphs of drying rates against time were plotted in each case and used to obtain the drying rate constant, K for the various conditions and locations. Comparison was made for the drying rate at the two locations. The efficiencies of the equipment at various locations were calculated and the drying rate efficiencies were also obtained. Results obtained showed that drying was fastest during the solar drying and least during the incinerator drying and the control drying respectively. The drying rate was also faster at Nsukka tropical location than Makurdi humid location. The mean location drying rate efficiencies obtained were 98.8%, 94.7%, and 87.4% for solar dryer, solarincinerator dryer and incinerator dryer respectively. The computed efficiencies for the equipment were 56%, 13% and 16% for solar dryer, solar incinerator dryer and incinerator dryer respectively. The dryers can be used to substitute garri dehydration and drying of other farm produce in rural and semi-urban areas for improved quality.