Natural Convection Solar Dryer Research Articles

Assessing mathematical models for the intermittent drying of cocoa (Theobroma cacao L.) beans

Fine flavor cocoa quality is significantly impacted by its postharvest drying process which can be enhanced through mathematical modeling. The objective of this study was to carry out the mathematical modeling of cocoa bean drying kinetics for a greenhouse dryer and considering intermittent drying. In this study, a natural convection solar greenhouse dryer was used to dry cocoa beans with negligible losses to an acceptable moisture content (6.6%) and cotyledon pH (5.25). Models based on Fick’s second law of diffusion, Newton’s model, and Hii, Law and Cloke’s model were developed considering (i) the entire drying period, and (ii) intermittent drying for Fick’s and Newton’s. Effective diffusivities and drying constants increased up to 1.01 ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document} 10–11 m2/s and 0.0165 1/h respectively during drying. Newton’s model slightly outperformed Fick’s model, and the models considering intermittency showed slight improvement over the models for the entire drying period. Considering intermittency when modeling cocoa drying may be useful since a better fit to experimental data resulted, and variation of effective diffusivity and the drying constant was observed over the drying period.

Experimental investigation on a solar dryer assisted with minimum phase change material (PCM) placed on the inner walls of drying chamber

Solar dryers assisted with phase change material (PCM) speed up the drying process by compensating the negating effect of reduced or absence of solar energy under cloudy or non-sunshine hours respectively. The study of the relevant and recent literature indicated that the minimum quantity and proper placement of this PCM have not been explored to take full advantage of using them in solar dryers. Hence in this research work, experimental investigations on banana slice drying were carried out with 4 and 10 numbers of copper tubes filled with 176 and 494 kg of commercial paraffin wax respectively (correspondingly designated as SD-PCM1 and SD-PCM2). The copper tubes were placed in vertical and horizontal orientations on the inner wall of the drying chamber so that the upward movement of air would not disturbed. A comparison of the drying performance of a PCM-based unit with a natural convective solar dryer without PCM (SD) was also presented. As no appreciable differences between the mass loss during drying under SD and SD-PCM1 modes were observed, it was concluded that a mass of PCM greater than 176 g would enhance drying rates. Thus for the same final mass of dried banana slices, the drying time was about 15 and 9 h with SD and SD-PCM2 respectively. As the operating conditions of SD and SD-PCM vary considerably in terms of the thermal energy supplied during the drying process, the concept of a generalized drying curve with dimensionless time was used to study the drying kinetics. A close alignment of experimental data of moisture content ratio with the generalized drying curve under SD and SD-PCM modes indicates similar dryer performance irrespective of the differences in thermal energy supplied. The average exergetic efficiency of SD, SD-PCM1 and SD-PCM2 was 21, 26 and 28 % respectively. The sustainability index and environmental impact factor for SD-PCM2 were 1.41 and 2.5 respectively which was better compared to the respective values of 1.27 and 3.77 in SD mode favoring the use of PCM in solar dryers.

Design and Construction of a Mixed-Mode Natural Convection Solar Dryer for Mango Slices

Fruits like mangoes are produced in large quantities during the peak season, and high postharvest losses occur due to lack of appropriate storage and handling structures. The main goal of this study was to design and construct a mixed-mode natural convection (MMNC) solar dryer for drying of mango slices. The dryer was designed using AutoCAD and constructed with wood and glass using basic woodworking tools and processes. The developed dryer has a direct collector, a vertical collector, and an indirect collector. The drying chamber has two removable frames with 5 shelves each, a total drying area of 2.54 m2 and a capacity of 10 kg of mango slices per batch. The dryer is fitted with caster wheels for easy turning and positioning. Test conducted with 940 g of fresh mango slices resulted in effective drying after 17 hours, from a moisture content of approximately 90% (wb) reduced to 17% (wb). The drying rate was found to be 4.3%/hr. The maximum temperature obtained in the drying chamber was 54.3 ℃ at a maximum ambient temperature of 37.6 ℃. The average temperature-rise in the drying chamber compared to the ambient temperature was 11.5 ℃. The dryer is therefore recommended for use both domestically and by small-scale food processors since it is more hygienic and has proven to be more efficient than open-air sun drying.

Modelling Heat and Mass Transfer in High-Capacity Natural Convection Solar Dryers

Predicting solar dryer performance under different environmental conditions or assessing their performance to dry different grains is challenging since repeatable full-scale tests are expensive and time consuming. In the present study, computational fluid dynamics approach was used to model the drying of maize in high-capacity dryers such as greenhouse and solar bubble dryer. The absorption of short-wave radiation and the greenhouse effect in the dryer with incident solar radiation was modelled using a dual-band spectrum. The distribution of airflow, temperature, and absolute humidity was analysed in this study to optimise the drying process of maize. Additionally, these results were also used to quantify the drying rate of both greenhouse and solar bubble dryer. The greenhouse dryer model overpredicted the dryer temperatures by an average of 0.12%, and overpredicted absolute humidity by 0.38 per cent. The average Root-Mean-Square Error (RMSE) of temperature prediction was 1.8 °C, and the average RMSE for absolute humidity was 0.0042 for the greenhouse model. On the other hand, the solar bubble dryer model underpredicted temperatures by 1.7%, and underpredicted humidity values by 0.3 per cent. The mean absolute percentage error for the temperature and absolute humidity prediction of the solar bubble dryer model was 1.69% and 0.28%, respectively. The predicted and observed spatial variation in the temperature was similar for both dryers.

Natural convective solar dryer powered by stepped fin plate integrated trough array solar air heater for agricultural produce preservations

In this work, heat energy analysis and economic feasibility of natural convection mixed mode solar dryer under three different methods viz., normal flat plate collector solar dryer (NFPSD), step fin plate integrated trough array collector solar dryer (SFPTSD) and SFPTSD with latent heat storage (LHS) are experimentally investigated. The drying time in SFPTSD – LHS (setup 3) to reach its safe moisture content for paddy, wheat, green chilli are 5.5 h, 6 h and 7 h respectively and it is significantly lowered to a maximum of 47 % as compared with NFPSD (setup 1). Also, the average maximum heat efficiency of 62.19 % for collector and 38.32 % for drying cabinet is obtained in setup 3. The specific heat energy consumption is lowered by 20.65 % and specific moisture extraction rate increases to 21.73 % for this proposed setup in comparison with setup 1. The improvement potential is reduced to a substantial margin of 136.5 W and yields an exergetic efficiency increase of 12.38 % than setup 1. An average annual saving increase of 193.08$ with its present value 94.33$ is achieved for setup 3 as compared with setup 1. We recommend this setup can dry edible produce at low cost and affordable to economically weak farming communities.

Energy, Exergy and Economic Analysis of a Mixed-mode Natural Convection Solar Tunnel Dryer for Banana Slices

The energy, exergy and economic analysis of a mixed-mode natural convection solar tunnel dryer for drying banana slices is presented. The collector, drying chamber and chimney energy and exergy are analysed for a load of 3.75 kg of fresh banana slices. Further, the economic analysis in terms of Net Present Value (NPV), Profitability Index (PI), the Payback Period (PB) and the Discounted Payback Period are presented. Drying experiments were done in a period of two days. During the experiment, solar radiation varied from 206.1 W/m2 to 934.5 W/m2; drying chamber temperature varied from 51.7ºC to 81.84ºC while the ambient temperature varied from 21.7ºC to 31.9ºC. The relative humidity ranged from 4.63% to 28.46% for the drying chamber and, 14.9% to 31.8% for the ambient. Under these conditions, the moisture content of the bananas was reduced from 73.89% to 14.27% in seven hours of drying on the first day. Energy and exergy efficiencies ranged from 5.56% to 57.32%, and 0.33% to 2.81%, respectively on Day 1. For Day 2 the energy and exergy efficiencies were from 14.15% to 59.16%, and 0.75% to 3.76%, respectively. For the drying chamber, the efficiency increased gradually in the first two hours to a maximum of 5.36%, corresponding to the period when there was maximum evaporation. The chimney, which is a bare flat plate type without glazing and insulation, lost heat from its surfaces. Nonetheless, it generated enough buoyancy to move air through the dryer. With the solar dryer lifespan of 10 years and the Discounted Payback Period of four years, the project is attractive and worth investing in.

Energy, Exergy and Economic Analysis of a Mixed-mode Natural Convection Solar Tunnel Dryer for Banana Slices

Energy, Exergy and Economic Analysis of a Mixed-mode Natural Convection Solar Tunnel Dryer for Banana Slices

Investigation on the performance of a natural convection solar dryer with novel palmitic and sebacic acid eutectic phase change material for thermal energy storage applications

Solar drying has got enormous opportunity in the agricultural sector for hygienic processing of various crops which leads to value addition and high return to farmers. One of the drawbacks associated with solar drying is its usage during non-solar hours. This demerit could be effectively alleviated by integrating latent heat thermal energy storage system based on PCM with the solar dryer and extend its usage beyond sunshine hours. The present study encompasses the development of a novel eutectic phase change material (PCM) consisting of palmitic and sebacic acids (PA-SA) with an individual composition of 80 wt% and 20 wt%, respectively. Using a differential scanning calorimeter, the melting point and enthalpy of fusion of the PA-SA eutectic mixture were determined as 61.10 °C and 161.14 J g−1, respectively. Fourier transform infrared spectroscopy analysis ensured the chemical durability of the fresh eutectic materials and 1000 thermal cycled samples, which proved the suitability of the material for long-term applications. Accelerated thermal cycles up to 1000, and thermal conductivity tests accentuated the superior thermal reliability, and competency of the developed PA-SA PCM. Thermo-gravimetric analysis observed a degradation temperature of 215.13 °C, which is >3 times higher than the operating temperature and hence qualifies the thermal stability test. Corrosion analysis carried out as per ASTM G O1 using three metals such as stainless steel, aluminium and copper revealed the compatibility of using stainless steel as heat exchanger material. Corrosion rates were found to be zero, 0.4015 and 8.6505 mg cm−2 year−1 over 365 cycles respectively for stainless steel, aluminium and copper. Extensive experimental analysis was undertaken to compare the effectiveness of a natural convection solar dryer with and without PA-SA eutectic PCM. The study conducted with 3 kg of eutectic PCM encapsulated in stainless steel cylindrical tubes as heat exchanger elucidated the use of solar with PCM for a duration of four and half hours after sunshine. For solar drying applications, an organic PA-SA eutectic PCM has been developed with a melting range of 61.1 °C and a latent heat of 161.14 J g−1.

Effect of Outlet at the Bottom of the Drying Chamber on the Performance of Natural Convection Solar Dryers

Effect of Outlet at the Bottom of the Drying Chamber on the Performance of Natural Convection Solar Dryers

Experimental and numerical study of a natural convection indirect solar dryer with PCM tubes: Dynamic, thermal and nutritional quality analysis

A natural convection solar dryer was investigated in this paper with a storage unit in the form of copper tubes filled with Paraffin wax as a PCM, experimentally and numerically using the ANSYS Fluent software. The storage unit was placed in a side-mounted plenum chamber for air uniformity and heat recovery. The validations made for the drying chamber’s temperature with and without storage, the outlet air temperature, and velocity of the SAH, show good accordance with the experimental results, which promote the use of this method in investigating the solar dryer numerically. The drying of orange slices in different modes were studied; open sun drying, in a solar dryer with and without PCM. The drying time required to reduce the moisture content from 81.19% (wb) to 19% (wb) was respectively 216 h, 144 h, and 168 h. In terms of the quality of orange slices, the open sun drying showed the poorest quality in terms of color, texture, shape, and odor. However, all these properties were enhanced with the solar dryer, particularly with the use of PCM tubes. The most valuable nutritional value of oranges is vitamin C, which was measured per slice in all mentioned cases. One fresh orange slice contains 11.34 mg of vitamin C, while it contains 7.77 mg, 7.34 mg, and 5.99 mg in the drying cases with and without PCM as well as in open sun drying respectively.

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.

A New Mode of a Natural Convection Solar Greenhouse Dryer for Domestic Usage: Performance Assessment for Grape Drying

It is known that the natural convection (NC) solar drying process is a simple and cheap method for drying foodstuffs, but it is not preferable for common users in the case of drying high-moisture content agro-products due to the slow rate of drying. Meanwhile, the forced convection (FC) drying process is most appropriate for such products, but its economic feasibility may be affected due to high initial and maintenance costs. Therefore, the present study proposed a controlled natural convection (CNC) drying mode using a solar greenhouse dryer (SGD) for drying grapes with two types of cover materials, glass and Plexiglas, through intermittent operation with a PV system to save energy as a simple and inexpensive domestic dryer instead of the common forced convection SGD and the conventional natural convection SGD. The obtained results of the new CNC drying mode using a Plexiglas SGD showed a higher drying rate than the NC drying mode and are close to the FC drying mode using the same cover material. The initial moisture content of the grapes was reduced from 5.91 g water/g dry matter to the final moisture content of 0.15 g water/g dry matter within 12 h and 15 h for the CNC and NC drying modes, respectively, using the Plexiglas SGD. Moreover, the thermal drying efficiency for the two mentioned drying modes was 12.5 and 9.7%, respectively. The Page model was found to be the most appropriate model to predict the kinetics of the SGD in all drying modes, regardless of the cover type. The new CNC drying mode using the Plexiglas SGD achieved the lowest cost per kg of dried grapes (1.26 USD/kg), the highest total saved costs over the lifespan of the dryer (USD 245.46) and the shortest payback period (1.08 years) compared to the other two dryers, NC-SGD and FC-SGD. Generally, the CNC-SGD had good performance over the NC-SGD because it is not affected by the fluctuation in the volume, velocity and direction of the inlet ambient air/wind during drying grapes as a high-moisture content product without external heating sources or complicated parts. Thus, the proposed drying system has the advantage in terms of simplicity, cheapness and saving energy compared to FC-SGD.

CFD Simulation of Temperature and Air Flow in a Natural Convection Solar Tunnel Dryer with a Bare Flat-Plate Chimney

Computational Fluid Dynamics simulation of a natural convection solar tunnel dryer with a bare flat-plate chimney is presented. The chimney’s function is to create airflow in the dryer through the buoyancy effect by re-heating the air coming from the drying unit and is therefore a major factor in the drying rate. CFD simulation was therefore employed to study the temperature and airflow in the dryer and determine the areas that could be improved upon. The design of the solar tunnel dryer geometry used in this simulation was done in SOLIDWORKS 2016 whereas the simulation of temperature distribution of airflow inside the dryer was performed using SOLIDWORKS 2016 flow simulation program in a steady-state regime. The boundary conditions were set using the obtained experimental data. The simulation results showed that the chimney losses heat, that there is air recirculation in the collector, that the airflow experiences some pressure loss as it moves from the drying chamber to the chimney, and that there is some reduction of the velocity in some parts of the dryer. The simulated and experimental collector efficiencies were found to be 33.09 and 37.63%, respectively, giving a mean relative deviation of collector temperature of 5.1%. To improve the performance of the dryer, insulating and glazing of the chimney is suggested as well as using a curved joint between the chimney and the drying chamber.

Energy and exergy investigation of indirect solar dryer under natural and forced convection while drying muskmelon slices

• Energy-exergy analysis was performed in an indirect solar dryer without and with fans (NISD and FISD) • The average energy efficiency of drying chamber were 9.39% in NISD and 12.11% in FISD, respectively • The average exergy efficiencies of drying cabinet were found to be 45.87 and 55.73 % in both dryers • The environmental impact factor ranged from 0.2−15.51 and 0.07−7.90, in NISD and FISD, respectively. • 2E analysis concluded that FISD dryer works fine compared to NISD dryer The energy and exergy (2E) analysis were executed in the present work on indirect natural and forced convection solar dryers (NISD and FISD) and the outcomes were compared. The NISD consisted of a collector and a drying cabinet whereas, for FISD, the NISD was updated by fixing a divergent tunnel integrated with DC fans activated with PV panels at the inlet of the collector. Therefore, no commercial energy was used for both setups. The transient temperature and moisture distribution in the trays of the drying cabinet and energy efficiencies of the collector and drying cabinet were evaluated for both dryers. The exergy inflow, outflow, losses and efficiency of collector and drying cabinet and sustainability indices were examined in both dryers. The energy efficiency of collector and drying efficiency were 58.5% and 9.39% in NISD and 66.37% and 12.11% in FISD, respectively. In NISD, the exergy inflow of the collector and drying section were 409.9−1344.15 W and 2.73−96.63 W, whereas, in FISD, the same were 375.5−1344.28 W and 1.03−65.75 W, respectively. The exergy efficiencies of the drying cabinet and collector were found to be 45.87 and 3.46%, 55.73 and 2.43% in NISD and FISD, respectively. The improvement potential and environmental impact factor ranged from 0.11−29.1 W, 0.2−15.51 and 0.012−11.35 W, 0.07−7.90, in NISD and FISD, respectively. The sustainability index was increased by 60.69% and the waste exergy ratio decreased by 18.52% in FISD compared to NISD. The 2E analysis revealed that the performance was enhanced in FISD compared to NISD. Uncertainty analysis was conducted for all parameters and shown as error bars in all plots.

Assessment of eco‐thermal sustainability potential of a cluster of low‐cost solar dryer designs based on exergetic sustainability indicators and earned carbon credit

This research aims to establish the interconnectivity between solar dryer designs and the exegetic-sustainability performance of solar dryers. This is to assist energy policymakers and fabricators to establish design standards and make the right choice for waste exergy management strategy for environmental sustainability. Therefore, in this study, the exergy-based sustainability indicators and earned carbon credit were used to assess and compare the performance of four different designs of solar dryers of equal collector capacity under the same external environmental conditions in the same town. In terms of better sustainability indicators that include high exergy efficiency, lower waste exergy emission, higher sustainability index and lower lack of productivity, solar dryer designs with single-pass triple air movement direction with inlet air powered by wind generator had the best indices for environmental sustainability. In contrast, the natural convection mix-mode solar dryer design had the lowest environmental effect factor and destruction coefficient while the indirect natural convection solar dryer had the highest energy recovery ratio based on exergy output from water evaporation. However, the mix-mode solar dryer powered by the wind generator earned the highest carbon credit. The exergy efficiency ranged from 19.09 to 52 % for the four cases, whereas the waste exergy ratio ranged from 0.52 to 0.81. The LOP value ranged from 2.95 to 19.96. Similarly, the sustainability index ranged from 1.28 to 2.5, the average environmental destruction coefficient varied from 3.96 to 20.96, the exergy recovery ratio for the four dryers varied from 0.001825 to 0.12405, and the earned carbon credit ranged from $442. 3 to $2630.5.

Convective and evaporative heat transfer coefficients during drying of ivy gourd under natural and forced convection solar dryer.

In the present work, a study on convective heat, mass transfer coefficients and evaporative heat transfer coefficient of the thin layer drying process of ivy gourd is performed. The experiment was conducted in three drying modes such as natural, forced convection solar dryer and open sun drying. The hourly data for the rate of moisture removal, sample temperature, relative humidity inside and outside the solar and ambient air temperature for complete drying have been recorded. The drying air temperature varied from 55, 65, 70 and 75°C, and the air velocity was 1, 1.5 and 2m/s. All the drying experiments had shown a falling rate period. The data obtained from experimentation have been used to evaluate the experimental constant values of C and n by simple regression analysis. Based on the values of "C" and "n", convective and evaporative heat transfer coefficients for ivy gourd were determined. The average convective heat and mass transfer coefficients varied between 2.64 and 8.30W/m2 °C and 0.0025 to 0.0076m/s for temperature ranges, at the different air velocities, respectively. The average evaporative heat transfer coefficient for ivy gourd varied from 181.89 to 421.84W/m2 °C. It was observed that convective and evaporative heat transfer coefficients increase with the increase in drying air temperature. The rate of increment of evaporative heat transfer coefficient is higher than the convective heat transfer coefficient. The intensity of heat and mass transfer during solar drying depends on the drying air temperature and velocity.

An experimental and numerical investigation of absorber positioning in a natural convection solar drying system

The known advantages of drying food are long term preservation, weight reduction and, consequently, minimizing the transportation and storage costs. Drying technology can also spoil the conditions for microbial growth. In this study, an indirect solar dryer with natural convection was developed, constructed and experimentally investigated for using in remote regions. It comprises three main parts: an absorber plate with 0.5 m2 surface area, a dryer chamber and an exhaust duct. The absorber plate position can be modified in this device and change the airflow conditions from over the upper face only to the upper and lower face (double passage). Tests changing this position increased the product humidity removal rate from 0.47 g/min to 0.56 g/min, the total water removal over the day from 185 g to 220 g and the average daily thermal efficiency from 8.5% to 19.8%. The equipment performance evaluation was possible due to the presence of temperature, humidity and atmospheric pressure sensors positioned at the air inlet and outlet. A turbine-type anemometer at the air outlet was used for airflow measurements. The other three temperature sensors placed on the absorber plate and a load cell located in the drying chamber are also used. The evaporation process was recorded based on load cells installed in the drying chamber. Another model was also applied to calculate the same parameter using the mass balance. A CFD model was build to compare with the experimental results and good agreement was found. Comparison for different solar dryer setups show a better efficiency when the absorber plate is positioned in the middle of the inlet flow.

Drying kinetics, quality assessment and socio environmental evaluation of solar dried underutilized arid vegetable Cucumis callosus

A natural convection solar tunnel dryer of capacity 100 kg was used to analyse the drying kinetics of naturally grown arid vegetable kachri (Cucumis callosus). The moisture reduction was found from 86.10 % to 7.02 % (on wet basis) in two solar days (15 hours). Solar drying curves were estimated using six different drying kinetic models and were compared based on their modeling efficiency. The statistical analysis revealed that Page and Midilli kinetic drying models accurately estimated solar drying characteristics of kachri with a modeling efficiency of 0.971 as compared to other models. Nutritional, microbial, and organoleptic analysis showed that dried kachri product was nutritionally healthy for human consumption. A significant (p<0.01) relationship was found between rehydration characteristics and rehydration time. Techno-economic indicators show that the drying system was economically feasible and could recover investment in 8.70 months. The net carbon dioxide mitigation potential was found 77.05 tons over the lifespan of the dryer.

Thermal Performance Study of Solar Air Dryers for Cashew Kernel: A Comparative Analysis and Modelling Using Response Surface Methodology (RSM) and Artificial Neural Network (ANN)

In this study, a new procedure for drying of cashew kernels is proposed. The new methodology involves the use of solar air dryers to remove the dark sticky coating called testa on the surface of the cashew kernel to get the final product. There are several challenges in the new procedures, especially with respect to the moisture level to be retained in the cashew kernel post drying for facilitating the optimal peeling activity. In this regard, thermal performance is carried out through a set of experimental and computational trials. The experiments have revealed that the natural and forced convection solar dryers with drying speeds of 1.0 kg/h and 1.66 kg/h, respectively, showed drying efficiencies of 51.7% and 50.9%, which is within the permissible acceptable limit, thus ascertaining a moisture reduction of 40 to 42% in each of case and keeping the moisture content within the band of approximately 5%, required for effective peeling of the testa from the cashew kernel to obtain the final product. This new method has resulted in batch drying of cashew kernels of up to 30 kg capacity in a time span of 360 minutes of solar irradiation with an average consumption of 255 kJ. The results of the experiments are also validated from the artificial neural network (ANN) and response surface methodology (RSM) modelling, resulting in better prediction and optimization of the performance parameters. The error between the actual and experimental values is well within the permissible limit of +/-5%, thereby correlating the experimental and statistical values for deriving an ANN model for predicting the results for different time duration and solar irradiation. In this way, the thermal analysis of the solar dryers for drying cashew kernels has resulted in findings, which shall be utilized to improve the overall performance efficiency and the methodology adopted for maximum yield.

Life cycle assessment and economical valuation of a natural convection solar greenhouse dryer in Western Maharashtra, India

The current study focuses on the life cycle assessment and an economic valuation of a natural convection solar greenhouse dryer in Western Maharashtra, India. The Solar Greenhouse Dryer is an active device that gains solar radiation incident on to the surface of the dryer and along with wind energy, it removes moisture from agricultural yield. The combination of solar energy and wind energy removes moisture from agricultural yield. The Solar Greenhouse Dryer is primarily used in rural settings; hence, it is very important to analyse the environmental and economic aspects associated with the dryer to obtain the maximum benefit from the dryer with less investment possible. The experiment involving a natural convection solar dryer was conducted at Bahe, Borgaon, Tal-Walwa, Dist- Sangli, Maharashtra, India located at 17.115o N and 74.33o E. The environmental parameters taken into considerations during the analysis covered energy, energy payback time and CO2 emissions, mitigation and carbon credits earned by the dryer. The economic analysis of the solar dryer consists of the annual cost of the dryer, the salvage value, the annual saving obtained and the payback period respectively.