scholarly journals Design and Performance Evaluation of a Mixed-Mode Solar Crop Dryer

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Shitu Abubakar ◽  
Samaila Umaru ◽  
Fatai O Anafi ◽  
Aminu S Abubakar
Keyword(s):  
Performance Evaluation ◽  
Mixed Mode ◽  
Meteorological Conditions ◽  
Drying Rate ◽  
Coordinate Position ◽  
Collector Efficiency ◽  
Drying Rates ◽  
And Performance ◽  
Drying Efficiency ◽  
Drying Chamber

This study is concerned with development and performance evaluation of a mixed-mode solar  yam dryer. It was done to address the problems of uneven drying of product on different trays coordinate position in a typical indirect multiple trays dryer. Solar energy drying system was designed using the meteorological conditions of Zaria, Nigeria to dry yam slices in the mixed-mode natural convection. The dryer was designed to dry (7 kg) of yam slices. The dimensions of the dryer were: collector length, collector area, height of the drying chamber, chimney height, length of the drying chamber, and Width of the drying chamber were 0.65 m, 0.27 m2, 0.9 m, 0.7 m, 0.5 m, and 0.43 m, respectively. The solar yam dryer was exposed to solar radiation from 10:00 am to 06:00 pm and tested without load and with yam chips of 5 mm average thickness. Meteorological conditions were monitored during the dehydration process. The average drying rate, collector efficiency and drying efficiency were 2.55 kg/s, 42.20% and 25.35%, respectively. The results of performance evaluation of the solar dryer showed that the drying rate decreases by 3% and 8% in the second and third trays relative to the first tray. This shows that the drying rates did not vary significantly with the coordinate positions of the trays.

Performance Evaluation of a Solar Greenhouse Dryer at Different Bed Conditions Under Passive Mode

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Asim Ahmad ◽  
Om Prakash
Keyword(s):  
Performance Evaluation ◽  
Heat Storage ◽  
Superior Performance ◽  
Small Scale ◽  
Passive Mode ◽  
Maximum Heat ◽  
Gravel Bed ◽  
Drying Efficiency ◽  
Small Scale Industries ◽  
Drying Chamber

Greenhouse drying shows a significant role in the bulk level of drying. In the present setup, a greenhouse dryer operating under natural convection mode was designed and fabricated. The sensible heat storage concept was applied to the bed of the drying chamber. Four different beds, namely, gravel bed, ground bed, concrete bed, and black painted gravel bed was being selected for the comparative heat transfer analyses of the proposed setup. The maximum heat gain takes place at the black painted gravel bed conditions, i.e., 53%, while for concrete bed, gravel bed, and ground bed, it is 33%, 49%, and 29%, respectively. Hence, black painted gravel bed condition is strongly recommended for maximum heat storage. The proposed setup was used for drying of tomato flakes in black painted gravel bed condition. It has been found that the moisture content in the tomato flakes has been removed from 96% to 9.10% in 13 h. The average drying efficiency of the proposed greenhouse dryer is found to be 23.49%. The comparative analysis of the performance evaluation has been done with other investigators, and it was found that the drying rate of the proposed setup shows superior performance as compared with others. The design of the proposed greenhouse setup with black painted gravel bed condition is strongly recommended for small-scale industries and farmers.

scholarly journals Design, Building and Performance Evaluation of a Mixed-Mode Solar Dryer for Agricultural Products

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Performance Evaluation ◽  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Solar Collector ◽  
Mixed Mode ◽  
Ambient Air ◽  
Agricultural Products ◽  
The Third ◽  
And Performance

This research work presents the detailed explanation of the design, construction and performance evaluation of mixed-mode solar agricultural products dryer. The experimental set up used for testing the performance of the mixed-mode solar agricultural products dryer and determining the influence of various drying methods on the drying behaviour of agricultural products. Evaluation of the dryer was centered on the moisture content reduction, temperatures and relative humidities variations. 1680 g of freshly potato slides were used for evaluation. The test results gave that the temperatures inside the dryer cabinet and the solar collector were much higher than the ambient temperature during most hours of the daylight. The temperature inside the solar collector was up to 27 o C approximately higher than the ambient temperature. The temperature inside the drying cabinet was up to 22 o C approximately higher than the ambient temperature for about three hours immediately after 12.00 h (noon). The relative humidity in the solar collector and drying cabinet were lower than the ambient air relative humidity, with the ambient air recording the highest relative humidity at each reading followed by the drying cabinet and finally by the solar collector. Because of the decreased relative humidity inside the dryer, all the time, the temperature inside the dryer was high which is sufficient enough to dry the potato at an early time. Based on the results obtained during the test, temperature above 65 o C was recorded inside the drying cabinet. This high temperature in the drying cabinet causes 419 g of moisture to be removed on the first day, 257 g on the second day, 191 g on the third day, 136 g on the fourth day and finally 108 g on the fifth day. At the end of the five days of drying process, the mass of 1680 g of potato was reduced to 569 g. Total amount of moisture removed was 1111 g and total moisture loss was 66.1 %, which is the required amount of moisture to be removed for safe drying of freshly potato slides. The moisture content of the freshly potato slides was 24.9 % at the end of drying for the first day at about 5:00 pm, 20.4 % at the end of drying for the second day, 19 % at the end of drying for the third day, 16.7 % at the end of drying for the fourth day and finally 15.9% at the end of drying for the fifth day. It was observed that the drying rate increased from the end of one day to another, which shows the earlier and faster removal of moisture from the dried item.

scholarly journals Pengeringan biji jagung menggunakan pengkondisi udara

2019 ◽  
Vol 9 (1) ◽  
pp. 65
Author(s):  
A. Mulyanto ◽  
M. Mirmanto ◽  
I.G.B. Susana ◽  
I.B. Alit ◽  
I.M. Nuarsa
Keyword(s):  
Drying Rate ◽  
Air Conditioner ◽  
Air Velocity ◽  
Cold Air ◽  
Air Speed ◽  
Drying Rates ◽  
Drying Chamber

This study aims to determine the effect of air velocity on the rate of drying corn. Corn seeds were placed after the evaporator of an air conditioner, so that the air came out of the evaporator entered the drying chamber. The water in the corn was evaporated and sucked by dry cold air and then it was condensed in the evaporator. The results show that the mass of corn seeds decreases with the time; the drying rate also decreases with the time and mass-based drying rates at low air speeds are faster than at high air speed. The air conditioner can be used for drying seeds.

scholarly journals Sustainable Energy for Drying of Cashew Kernels – Experimental Research

2019 ◽  
Vol 8 (6S4) ◽  
pp. 1193-1198
Keyword(s):  
Energy Consumption ◽  
Moisture Content ◽  
Energy Savings ◽  
Food Preservation ◽  
Average Moisture Content ◽  
Drying Rate ◽  
Flat Plate Collector ◽  
Drying Efficiency ◽  
Air Dryer ◽  
Drying Chamber

Drying is an important process in food preservation. In cashew processing industries cashew kernels are dried for easy peeling of the thin brownish sticky layer known as testa. For this it is necessary to reduce the average moisture content of 13% to 5%. Drying is achieved by direct and indirect methods like traditional open sun and using conventional energy through dryers. Due to control of the air properties in indirect drying cashew kernels can be dried at faster rate and can retain their quality. Air flow passages also play an important role in drying process. The objective of the study is to investigate experimentally the energy consumption for drying 1 kg of cashew kernel using electrically assisted heating and to evaluate the feasibility of active solar air dryer for drying in cashew processing industries. An electrical heat-assisted dryer (EHD) and an active solar flat plate collector air dryer (ASAD) systems are designed and developed using locally available materials. Both the systems are tested for reduction in moisture content with series of experiments. EHD is tested with three different drying chambers for optimum drying rate. In its final test drying chamber without baffle plates has resulted in reduction in moisture content to required level by 5% in three hours with drying rate of 2.8 kg/h against 6.5% and 6.8% in single tray version and four trays with baffle plate version. The drying efficiency of drying chamber is found to be 30.54%. In ASAD system the experimental results ensure the drying of cashew kernels within stipulated time of 6 hours with drying rate of 1.66 kg/h and energy consumption of 255 kJ against 270 kJ of electrical heater drying. The drying chamber exhibits an efficiency of 50.89%. The study suggests that the design is feasible to small, cottage industries for cashew kernel drying. The energy savings up to 3750 kJ per day for a batch of 15 kg is possible.

scholarly journals Design and Construction of Indirect Solar Coffee Dryer

2020 ◽  
Vol 9 (4) ◽  
pp. 2943-2956
Keyword(s):  
Solar Collector ◽  
Air Inlet ◽  
Solar Dryer ◽  
Sunshine Hours ◽  
Inlet Hole ◽  
Outlet Hole ◽  
Collector Efficiency ◽  
And Performance ◽  
Drying Chamber ◽  
Design Construction

Drying is the process of removing moisture contents from solid. Solar drying refers to a technique that utilizes incident solar radiation to convert it into thermal energy required for drying purposes. This project presents the design, construction and performance of an indirect type solar dryer for coffee product. In the dryer the air inters into the solar collector from the atmosphere through air inlet hole. This air will be heated in the collector and then pass to the drying chamber through the hole. Then the air exhausts through the outlet hole at the top of the drying chamber. The system designed can handle a capacity of up to 50kg of wet coffee per m2 at a depth of 100 mm. The average sunshine at Bale Robe was found to be 12 hours per day. The daily solar insolation at the site was found to be 5.86kW/m2 of surface per day. By utilizing the solar collector in question and assuming a collector efficiency of 20 %, the total solar energy received is 5.86 kW-hrs/m2 /day or 46.88 kW-hours per day (assuming the sunshine hours per day to be 8 hours). This solar dryer has a collector efficiency of 39.1%, a pick-up efficiency of 49.3%, and a system efficiency of 32.2%. the collector area of the system is calculated to be 1.11m2 and the total length of 1000mm by 300mm. The drying chamber is essentially a cabinetry dryer and measures 1020mm × 800mm × 30mm. It accommodates a drying bin which acts as the holding compartment for the wet coffee to be dried. The base of the drying chamber is made of a block of wood material 50mm deep, since wood is a good thermal insulator. The wood must be well seasoned and pre-treated to ensure it is protected from the humid environment. The air outlet is fitted at the top of the drying chamber which serves as the exit for the moisture ridden air. It is important since it ensures that moisture does not condense at the top of the drying chamber and speeds up the rate of drying through creating the suction effect. The drying bin measures 800mm × 800mm × 20mm.

The separation characteristics and performance evaluation of the silica-based poly(pentabromostyrene) stationary phase in capillary electrochromatography

2021 ◽  
Author(s):  
Zhihua Zhong ◽  
Zhanying Chu ◽  
Ziyi Dong ◽  
Weibing Zhang ◽  
Lingyi Zhang
Keyword(s):  
Performance Evaluation ◽  
Stationary Phase ◽  
Capillary Electrochromatography ◽  
Mixed Mode ◽  
Capillary Column ◽  
Benzene Rings ◽  
And Performance

A mixed-mode capillary column packed with silica-based poly(pentabromostyrene) particles (denoted as SiO2@pPBS) was prepared and applied to capillary electrochromatography (CEC) separation. With the presence of benzene rings and bromine atoms...

scholarly journals Comparative Studies of Two Developed On-farm Solar Dryers for Vegetables

2020 ◽  
pp. 26-35
Author(s):  
S. A. Okaiyeto ◽  
Y. A. Unguwanrimi ◽  
S. I. Ogijo ◽  
B. J. Jonga ◽  
A. M. Sada
Keyword(s):  
Mixed Mode ◽  
Research Work ◽  
Axial Fan ◽  
Drying Time ◽  
Wooden Frame ◽  
Average System ◽  
Absorbing Material ◽  
And Performance ◽  
On Farm ◽  
Drying Chamber

This research work was carried out to provide local farmers with on-farm solar dryers to minimize post-harvest losses of vegetables. Two dryers (Mixed mode and Indirect mode on-farm solar dryers) were constructed using locally available materials. The dryers basically consist of a blower, a collector area and a drying chamber. Aluminum sheet is placed inside the collector which serves as the absorbing material. An electrical axial fan was placed before the air duct to supply air responsible for forcing heated air to blow over the vegetables to be dried. Incorporated in the drying chamber are trays which provide a platform where the products to be dried were spread evenly. Transparent polythene material of 0.2 mm thickness with wooden frame was used as cover for the dryers. The dryers were evaluated to determine drying time and performance efficiencies, using Baobab leaves, Tomato and Okra slices as test crops. Collected data were analyzed using Statistical Analysis Software (SAS). The effects of variation of the independent factors were verified using Analysis of variance (ANOVA) at 1% and 5% levels of significant. Mean separation was carried out on significant factors using Duncan Multiple Range Test (DMRT). The results obtained showed the performance of the developed dryers, which indicates that drying time of mixed mode on-farm solar dryer stood at 56 hrs and 46 hrs while that of the indirect mode dryer was 76.67 hrs and 57 hrs and that of open sun drying was 154 hrs and 127 hrs for tomato and okra slices respectively. Results obtained showed that average system drying, energy collection and pick up efficiencies for the three test crops were 16.35%, 21.1% and 8.05% for mixed mode dryer respectively and 28.63%, 45.3% and 0.3% for indirect mode dryer, respectively. From the results obtained the mixed mode dryer dried all the products faster while indirect mode has superior energy efficiencies.

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