scholarly journals Performance Enhancement of Natural Convection Indirect Solar Dryer by Integrating Reflectors

2021 ◽  
Vol 12 (2) ◽  
pp. 212-222
Author(s):  
Hailay Teklu ◽  
Mulu Bayray ◽  
Dawit Abay ◽  
Millerjothi Kalamegam
Keyword(s):  
Natural Convection ◽  
Fruits And Vegetables ◽  
Performance Enhancement ◽  
Load Test ◽  
Maximum Temperature ◽  
Stagnation Temperature ◽  
Solar Dryer ◽  
Moisture Balance ◽  
Similar Temperature ◽  
Drying Efficiency

Natural convection indirect type solar dryer integrated with reflectors that can be used for drying fruits and vegetables was designed, constructed, and evaluated. The study mainly tried to improve the performance of a prototype natural convection indirect solar dryer. The solar dryer was integrated with reflectors and its thermal performance was experimentally analyzed and results were compared with the same dryer without reflectors. The experiments conducted included a no-load test to determine the stagnation temperature that can be reached and drying tests using tomato slices. During the drying test, moisture content at the initial and final stages was measured using a moisture balance instrument. The mass of the tomato slices was measured every two hours to find the drying efficiency. Temperatures were measured using thermocouples located at the absorber plate and at the trays inside the drying cabinet. Solar radiation was also measured using a pyranometer located near the dryer. During no load experiments, the maximum temperature reached the collector was around 98oC for the dryer without reflectors. The maximum temperature was improved to around 154oC during the test with reflectors. Similar temperature improvement was obtained during the drying tests as well. Due to the improvement in the temperature in the collector, the drying rate was also improved by 8% for 10 kg and 14% for 5 kg load. The experimental results indicate that the dryer performance was improved when the reflectors were added.

scholarly journals Experimental Studies on Natural Convection Open and Closed Solar Drying Using External Reflector

2021 ◽  
Author(s):  
Abd Elnaby Kabeel ◽  
Paul Durai Leon Dharmadurai ◽  
Sathiyaseelan Vasanthaseelan ◽  
Prof. Dr. Ravishankar Sathyamurthy ◽  
Bharathwaaj Ramani ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Natural Convection ◽  
Removal Rate ◽  
Experimental Studies ◽  
Heat Energy ◽  
Moisture Removal ◽  
Solar Drying ◽  
Solar Dryer ◽  
Drying Efficiency ◽  
Food Dryer

Abstract This work presents the experimental investigation on a solar food dryer equipped with external reflectors to enhance the rate of drying efficiency by removing the moisture content available in the anchovy fish. A comparison on conventional open solar drying is carried out to assess the parameters such as drying efficiency, moisture removal rate, and heat energy required for drying the anchovy fish using the modified solar dryer using natural convection technique. The physical examination results on the dried products proved that using modified solar dryer, the dried product are free from insects, dust. Also, it is found that the loss of colour from the product is minimum while compared to conventional open solar drying. The results showed that the thermal efficiency of dryer 1 and dryer 2 are comparatively higher as compared to that of conventional open solar drying and found as 16.73 and 19.34 % respectively.

scholarly journals Study of Temperature Profile of the Solar Pyramid Dryer

2021 ◽  
Vol 10 (10) ◽  
pp. 252-258
Author(s):  
O. S. Karpe A. G. Mohod ◽  
Y. P. Khandetod R. T. Thokal ◽  
R. M. Dharaskar
Keyword(s):  
Temperature Profile ◽  
Fruits And Vegetables ◽  
Maximum Temperature ◽  
Energy Sources ◽  
Temperature Pattern ◽  
Drying Temperature ◽  
Solar Dryer ◽  
Bottom To Top

The experiment was conducted at ‘Energy Park’, Department of Electrical and Other Energy Sources CAET, Dr. Balasaheb Sawant Konkan Krushi vidyapeeth Dapoli, Dapoli. The readings of temperature inside the dryer has been taken from 9:00 AM TO 5:00 PM with interval of thirty minute. It is recorded that maximum temperature inside the solar pyramid dryer was at 12:00 noon that is 55.5 0C and corresponding solar radiations where 552 W/m2.After analysing the temperature pattern from the graphs we can say that the temperature of air inside the dryer at various places varies such that, temperature of air at bottom of dryer was minimum, and it goes on increasing as the air moves from bottom to top of the solar pyramid dryer. Subsequently the maximum temperature found at the exhaust of the solar dryer. The average drying temperature is found to be suitable for drying of fruits and vegetables.

scholarly journals DEVELOPMENT, FABRICATION, AND PERFORMANCE EVALUATION OF INDIRECT MULTI-PORTIONED TYPE SOLAR DRYER FOR AGRICULTURAL PRODUCE

2021 ◽  
pp. 11-15
Author(s):  
IJAZ UL HAQ ◽  
HUSNAIN AZAM ◽  
NIDA FIRDOUS ◽  
MUHAMMAD MUDDASSIR ◽  
AMNA SAHAR ◽  
...  
Keyword(s):  
Initial Moisture Content ◽  
Primary Objective ◽  
Load Test ◽  
Maximum Temperature ◽  
Drying Rate ◽  
Temperature Elevation ◽  
Inlet Velocity ◽  
Storage Chamber ◽  
Solar Dryer ◽  
Agricultural Produce

OBJECTIVE: The primary objective of this study was to minimize post-harvest damages and improve the handling of agricultural commodities. The secondary objective was to assess the performance of the dryer by varying inlet velocity of air on temperature, final moisture of the product, drying period, and drying rate METHODS: The present research was carried out for the development, fabrication, and testing of a multi-portioned type solar dryer. The multi-portioned dryer consisted of a collector unit, air storage chamber, drying cabins, and a chimney. A fan assembly was also attached at the inlet of the collector and at the outlet of the drying compartment to control the air velocity and to remove the moist air. RESULTS: The data obtained from the experiments revealed that the maximum temperature elevation of 36.5oC was attained during a no-load test. The results obtained after carrying out load tests revealed that the maximum drying rate of 47 g/hr was achieved at the air inlet velocity of 3.2 m/s. The initial moisture content of 80.50% was brought down to 3.31% in five sunshine hours of 150 gram sliced potatoes. Each portion received air at varying speeds, and it was observed that the portion receiving air at the lowest speed had the maximum temperature. CONCLUSION: The lowest temperature elevation was recorded for the portion receiving air at the highest speed. The dryer was also found to be suitable for the on-field practical application for the drying of perishable commodities.

Konsumsi Energi Pada Alat Pengering Surya dan Tipe Bak Untuk Pengeringan Biji Kakao

2019 ◽  
Vol 17 (3) ◽  
Author(s):  
Lamhot P. Manalu
Keyword(s):  
Specific Energy ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Solar Irradiation ◽  
Drying Process ◽  
Food Industries ◽  
Solar Dryer ◽  
Agricultural Applications ◽  
Drying System ◽  
Drying Efficiency

Crop drying is essential for preservation in agricultural applications. It is performed either using fossil fuels in an artificial mechanical drying process or by placing the crop under the open sun. The first method is costly and has a negative impact on the environment, while the second method is totally dependent on the weather. The drying process requires a lot of energy in relation to the amount of water that must be evaporated from the product. It is estimated that 12% of the total energy used by the food industries and agriculture absorbed in this process. Due to the limitation of energy resources, it is important to keep researching and developing of diversification and optimization of energy This study aims to assess the use of energy for cocoa drying using solar energy dryer and bin-type dryer, as well as to determine the drying efficiency of each type of dryer. The results showed that the efficiency of the solar dryer drying system ranges between 36% to 46%, while the tub-type dryers between 21.7% to 33.1%. The specific energy of solar dryer ranged from 6.17-7.87 MJ / kg, while the tub-type dryers 8.58-13.63 MJ / kg. Dryer efficiency is influenced by the level of solar irradiation and the amount of drying load, the higher the irradiation received and more cocoa beans are dried, the drying efficiency is also higher and the specific energy further down.Proses pengeringan memerlukan banyak energi sehubungan dengan banyaknya air yang harus diuapkan dari bahan yang dikeringkan. Pengeringan dapat dilakukan dengan menggunakan pengering mekanis berbahan bakar fosil atau dengan menempatkan produk di bawah matahari terbuka. Metode pertama adalah mahal dan memiliki dampak negatif pada lingkungan, sedangkan metode kedua sangat tergantung pada cuaca. Diperkirakan bahwa 12% dari total energi yang dipergunakan oleh industri pangan dan pertanian diserap untuk proses ini. Mengingat semakin terbatasnya sumber energi bahan bakar minyak maka usaha diversifikasi dan optimasi energi untuk pengeringan perlu terus diteliti dan dikembangkan. Salah satunya adalah pemanfaatan energi surya sebagai sumber energi terbarukan. Penelitian ini bertujuan untuk mengkaji penggunaan energi untuk pengeringan kakao dengan memakai pengering energi surya dan pengering tipe bak, serta untuk mengetahui efisiensi pengeringan dari masing-masing tipe pengering. Hasil kajian menunjukkan bahwa efisiensi total sistem pengeringan alat pengering surya berkisar antara 36% dan 46%, sedangkan pengering tipe bak antara 21.7% dan 33.1%. Kebutuhan energi spesifik alat pengering surya berkisar antara 6.17-7.87 MJ/kg, sedangkan alat pengering tipe bak 8.58-13.63 MJ/kg. Efisiensi alat pengering dipengaruhi oleh tingkat iradiasi surya dan jumlah beban pengeringan, semakin tinggi iradiasi yang diterima pengering serta semakin banyak biji kakao yang dikeringkan, maka efisiensi pengeringan juga semakin tinggi dan kebutuhan energi spesifik semakin turun.Keywords: energy, efficiency, cocoa, solar dryer, bin-type dryer.

scholarly journals Effects of Blanching and Natural Convection Solar Drying on Quality Characteristics of Red Pepper (Capsicum annuum L.)

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
James Owusu-Kwarteng ◽  
Francis K. K. Kori ◽  
Fortune Akabanda
Keyword(s):  
Natural Convection ◽  
Quality Characteristics ◽  
Red Pepper ◽  
Plain Water ◽  
Drying Methods ◽  
Solar Drying ◽  
Drying Time ◽  
Sun Drying ◽  
Overall Acceptability ◽  
Solar Dryer

The objective of this work was to determine the effects of blanching and two drying methods, open-sun drying and natural convection solar drying, on the quality characteristics of red pepper. A 2 × 3 factorial design with experimental factors as 2 drying methods (open-sun drying and use of solar dryer) and 3 levels of pepper blanching (unblanched, blanched in plain water, and blanched in 2% NaCl) was conducted. Dried pepper samples were analysed for chemical composition, microbial load, and consumer sensory acceptability. Blanching of pepper in 2% NaCl solution followed by drying in a natural convection solar dryer reduced drying time by 15 hours. Similarly, a combination of blanching and drying in the solar dryer improved microbial quality of dried pepper. However, blanching and drying processes resulted in reduction in nutrients such as vitamin C and minerals content of pepper. Blanching followed by drying in natural convection solar dryer had the highest consumer acceptability scores for colour and overall acceptability, while texture and aroma were not significantly (p>0.05) affected by the different treatments. Therefore, natural convection solar dryer can be used to dry pepper with acceptable microbial and sensory qualities, as an alternative to open-sun drying.

Effect of Periodic Imposed Heat Flux on Three-Dimensional Natural Convection in a Partially Heated Cubical Enclosure

2016 ◽  
Vol 831 ◽  
pp. 83-91
Author(s):  
Lahoucine Belarche ◽  
Btissam Abourida
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Study ◽  
Control Volume ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Cubical Enclosure ◽  
Simplec Algorithm ◽  
Volume Method

The three-dimensional numerical study of natural convection in a cubical enclosure, discretely heated, was carried out in this study. Two heating square sections, similar to the integrated electronic components, are placed on the vertical wall of the enclosure. The imposed heating fluxes vary sinusoidally with time, in phase and in opposition of phase. The temperature of the opposite vertical wall is maintained at a cold uniform temperature and the other walls are adiabatic. The governing equations are solved using Control volume method by SIMPLEC algorithm. The sections dimension ε = D / H and the Rayleigh number Ra were fixed respectively at 0,35 and 106. The average heat transfer and the maximum temperature on the active portions will be examined for a given set of the governing parameters, namely the amplitude of the variable temperatures a and their period τp. The obtained results show significant changes in terms of heat transfer, by proper choice of the heating mode and the governing parameters.

scholarly journals Comparative study of different drying methods regard to the phenols and flavonoids content of dried Citrus aurantium L. leaves

2021 ◽  
Author(s):  
Geovanni Hernandez Galvez ◽  
Margarita Castillo Téllez ◽  
Jorge de Jesús Chan González ◽  
Francisca Méndez Morales ◽  
Damianys Almenares López ◽  
...  
Keyword(s):  
Natural Convection ◽  
Forced Convection ◽  
Design Methodology ◽  
Total Phenol ◽  
Drying Methods ◽  
Total Flavonoids ◽  
Citrus Aurantium ◽  
Solar Drying ◽  
Solar Dryer ◽  
Total Flavonoids Content

Objective: To determine the effects of different thermal drying technologies on the total phenol and flavonoid contents (TPC) and total flavonoids (TFC) in sour orange (Citrus aurantium L.) leaves. Design/methodology/approach: Solar drying was carried out in outdoor sunny conditions using two direct solar dryers; one with natural convection, the other with forced convection. The total phenol and flavonoid contents in gallic acid equivalents (GAE) and quercetin (Q), respectively, of ethanolic extracts of C. aurantium were assessed with spectrophotometric techniques. Results: The results demonstrated maximum phenol values for the direct natural convection solar dryer (161.4 mg EAG/g MS) and minimum values for shade drying (61.43 mg EAG/g MS). As for flavonoids, the highest values were obtained in the direct forced convection solar dryer (32.22 ± 1.6 mg EQ/g MS), while the lowest was registered in the open air sun (11.72 mg EQ/g MS). Conclusions: Direct solar dryers are technologies effective for maintaining the phenols and total flavonoids content in dried leaves of C. aurantium.  

Experimental Investigation of Drying Cucumber in a Double Slope Solar Dryer Under Natural Convection and Open Sun Drying

2021 ◽  
pp. 41-52
Author(s):  
E. Elavarasan ◽  
Sendhil Kumar Natarajan ◽  
Anagh S. Bhanu ◽  
A. Anandu ◽  
M. H. Senin
Keyword(s):  
Experimental Investigation ◽  
Natural Convection ◽  
Sun Drying ◽  
Solar Dryer

Analytical Study of Natural Convection in a Cavity With Volumetric Heat Generation

Volume 1 ◽  
2004 ◽  
Author(s):  
Mandar V. Joshi ◽  
U. N. Gaitonde ◽  
Sushanta K. Mitra
Keyword(s):  
Natural Convection ◽  
Aspect Ratio ◽  
Heat Generation ◽  
Central Region ◽  
Analytical Study ◽  
Vertical Direction ◽  
Maximum Temperature ◽  
Small Aspect Ratio ◽  
Governing Equations ◽  
Volumetric Heat Generation

A semi-analytical method for natural convection in a two dimensional rectangular enclosure, with uniform volumetric heat generation, having insulated horizontal boundaries, and isothermal vertical boundaries, has been studied here. In this method, the governing equations for natural convection, have been solved under the assumption that for a cavity with small aspect ratio, the flow in the central region of the cavity is only in the vertical direction. It is found that for the cavities with small aspect ratio, the temperature in central region of the cavity is nearly constant along the horizontal direction. However, there is a uniform temperature gradient in the vertical direction, which can be related to the maximum temperature in conduction. The velocity profiles and temperature profiles obtained in the present work, are compared with the numerical simulations by Fluent and a fair agreement is found between these results.

Application of Generalized Regression Neural Network in Predicting the Performance of Natural Convection Solar Dryer

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
M. Sridharan
Keyword(s):  
Neural Network ◽  
Natural Convection ◽  
Network Architecture ◽  
Experimental Studies ◽  
Generalized Regression Neural Network ◽  
Atmospheric Conditions ◽  
Time Duration ◽  
Transient Nature ◽  
Solar Dryer ◽  
Generalized Regression

Abstract The performance evaluation of a natural convection solar dryer is a complex one because of the transient and non-linear nature of atmospheric conditions. In this comparative study, a smart neural network -based tool was developed for estimating the performance of such a transient nature solar dryer. For this purpose, a series of experimental studies are conducted through four successive days and compared with the generalized regression neural network (GRNN) modeling. GRNN architecture proposed in this study consists of three inputs (time duration, irradiance, and ambient temperature) and four outputs (drying chamber temperature, the mass of moisture removed, drying rate, and dryer efficiency). Such generalized regression neural network architecture was trained, tested, and validated with real-time experimental variable data sets. The results of the GRNN model are in good agreement with experimental results. The overall accuracy of the proposed GRNN model in predicting the performance is 96.29%.

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