Natural and forced air convection operation in a direct solar dryer assisted by photovoltaic module for drying of green onion

Solar Energy ◽  
2021 ◽  
Vol 220 ◽  
pp. 24-34
Author(s):  
Letícia Ferraresi Hidalgo ◽  
Mariana Nascimento Candido ◽  
Karina Nishioka ◽  
José Teixeira Freire ◽  
Gustavo Nakamura Alves Vieira
Author(s):  
Humberto Armando Camacho-Martinez ◽  
Diana Montserrat Antonio-Gordillo ◽  
José Billerman Robles-Ocampo ◽  
Perla Jazmín Sevilla-Camacho

In this work the design of a solar dryer for the dehydration of fruits is presented. Banana is used as raw material for analysis and evaluation purposes. The system is supplied with solar energy in the form of (photovoltaic) PV and (photothermic) PT. The PV part of the dehydrator consists of a solar panel, whose energy supplies electrical resistances to increase the temperature, also feeding a forced air convection system which is carried out with a pair of fans that are at the entrance and exit of the dehydrator, also a control and measurement system. In the other side the PT part consist in a passive storage system of heat direct and indirect catchment of radiation. For the development of the solar dryer it is necessary to take into account certain parameters such as: weather conditions (solar radiation, ambient temperature and wind speed), thermal conductivity, temperature and properties of the components.


Author(s):  
Jhonatas C. Rosa ◽  
Andreza P. Mendonça ◽  
Angélica dos S. Oliveira ◽  
Sylviane B. Ribeiro ◽  
Andréia do R. Batista ◽  
...  

ABSTRACT ‘Babassu’ mesocarp flour has been used by the pharmaceutical, human food and animal feed industries. However, there is lack of standardization in the production, as well as absence of information on the management of the product’s quality. Thus, the objective of this study was to dry the ‘babassu’ mesocarp in forced-air oven and solar dryer, adjust different mathematical models to the experimental data, as well as to quantify the levels of proteins and crude fiber of the produced flour. The criteria for the adjustment were the coefficient of determination, magnitude of the mean relative error, standard deviation of estimate and the residual distribution trend. Drying in the shortest time occurred in oven at 60 °C (370 min), leading to water content of 4.62%, while in the solar dryer the final water content was 8.07% in 6 days. The mathematical model Two Terms showed the best fit to the experimental data for oven drying and the Midilli model showed the best fit in solar dryer. There was an increase in protein content with the drying in solar dryer and oven at 40, 50 and 60 °C (1.36, 1.33, 1.15 and 1.37%, respectively) in relation to fresh mesocarp (0.88%). Drying in both oven and solar dryer promoted increase of protein in the flour.


Author(s):  
Nick Hofmann ◽  
Michael P. Hennessey

Due to recent technological developments in advanced materials, the integration of shape memory alloys (SMAs) into new machines and mechanisms is becoming more common and it offers tremendous potential for the future. Using currently available properties of common SMA materials, the paper’s contribution is to: Study through dynamic simulation the potential offered by SMA springs to serve as the basis for rotary actuation. In the process, the SMA displaces a rocker arm rotating about an axis to induce rotational motion of a driveshaft, in effect converting a force into rotational motion. When embedded in a cycle with heating & cooling phases and a resetting mechanism, unidirectional rotational motion can be achieved. Regarding heating and cooling cycles, forced air convection is used to reduce thermal cycle cooling and is calculated via transient thermal analyses. Using typical parameter values for the representative design considered, through forced air convection, cooling cycles are reduced from approximately 30 seconds (natural) to 5.5 seconds (forced) and as a result, a complete system cycle can occur in 10 seconds, with the applied inertial load of 2.0 kg-m2. Using MATLAB and Simulink, a nonlinear 3rd order dynamic system model was created and simulations were performed. One complicating factor concerned angular limits and the necessary thermal cycling, which was solved through appropriate sequencing and resetting of integrators for different phases. Simulation results for the design considered show that a peak torque of 1.72 N-m is possible and that relatively smooth motion and approximately constant torque output is also possible through the addition of a few more rocker arm systems, properly commutated. Lastly, the design analysis framework and results may inspire future realization of actual devices.


Meat Science ◽  
2001 ◽  
Vol 58 (3) ◽  
pp. 239-246 ◽  
Author(s):  
T.E Lawrence ◽  
D.A King ◽  
E Obuz ◽  
E.J Yancey ◽  
M.E Dikeman

2002 ◽  
Vol 96 (Sup 2) ◽  
pp. A505
Author(s):  
Kenji Hasegawa ◽  
Chiharu Negishi ◽  
Fumitoshi Nakagawa ◽  
Makoto Ozaki ◽  
Daniel I. Sessler

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