Solar Assisted Dehydrator for Decentralized Controlled and Homogeneous Multi-Product Drying

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Waseem Amjad ◽  
Muhammad Waseem ◽  
Anjum Munir ◽  
Abdul Ghafoor ◽  
Furqan Asghar ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Air Distribution ◽  
Drying Time ◽  
Specific Product ◽  
Heating Source ◽  
Batch Type ◽  
Evacuated Tube Collector ◽  
Drying Rates ◽  
Evacuated Tube ◽  
Drying Chamber

Abstract Batch type food dryers are common for drying agricultural produce due to simple in design, but they are prone to nonuniform drying and significant heat cost exclusively if they fall in the medium to large size range. The current study illustrates a solar hybrid food dryer using a gas burner and solar collector (evacuated tube collector, ETC) as heating source along with an inline perforation inside the drying chamber to obtain spatial drying homogeneity. Air distribution was assessed through three-dimensional simulation using computational fluid dynamics (CFD) analysis. Performance trials were conducted under three heating options (ETC, gas, and dual) using green chilies at 60 °C. Throughout drying chamber, under all heating modes, the average difference in drying rates ranged from 0.61 to 1.30 kg water/kg dry matter, demonstrating homogeneous drying. Simulated and experimental results of air distribution were found to be in agreement with each other. Using three options for thermal heating (ETC, gas, and dual) and an overall 58% efficiency for evacuated tube collector, the specific energy for moisture evaporation was found to be 4.5–5.7 MJ/kg and specific product energy 19.2–24.9 MJ/kg. In case of dual heating option, the energy supplied by solar and gas sources for a 20 hours period was 50.64% (160.22 MJ) and 49.35% (156.13 MJ), respectively. Compared with dual heating option, energy cost can be reduced by 68% if only solar energy is used as a heating option but with a protracted drying time.

Experimental Investigation and Theoretical Modelling of Solar Dryer Using Evacuated Tube Collector

2015 ◽  
Vol 787 ◽  
pp. 147-151 ◽  
Author(s):  
R. Manivel ◽  
S. Sivakumar ◽  
T. Rajagopal
Keyword(s):  
Theoretical Modelling ◽  
Drying Time ◽  
Evacuated Tube Collector ◽  
Solar Dryer ◽  
Coimbatore District ◽  
Temperature Ranges ◽  
Drying Models ◽  
Evacuated Tube ◽  
Drying Chamber

An indirect type solar dryer is fabricated with the components like evacuated tube collector, drying chamber and blower. The performance of the drier is evaluated by carrying out drying experiments with copra at Coimbatore district Tamilnadu, India. A short survey of these showed that applying the indirect type solar dryer not only significantly reduced the drying time but also resulted in many improvements in the quality of the dried products. The temperature of the drying chamber ranges from 55°C to 75°C while the ambient temperature ranges from 28°C to 38°C. Nine basic solar drying models were used to fit the experimental data of copra. For experimental results, the logarithmic model showed the best curve fitting with highest correlation coefficient (R2) and lowest value of RMSE (Root Mean Square Error). Solar dried copra obtained is free from smoke, dust, bird and rodent damage.

scholarly journals An Experimental Study and Analysis on Solar Drying of Bitter Gourd Using an Evacuated Tube Air Collector in Thanjavur, Tamil Nadu, India

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
AR. Umayal Sundari ◽  
P. Neelamegam ◽  
C. V. Subramanian
Keyword(s):  
Moisture Content ◽  
Tamil Nadu ◽  
Research Work ◽  
Bitter Gourd ◽  
Sun Drying ◽  
Solar Dryer ◽  
Drying Rates ◽  
Evacuated Tube ◽  
Drying Chamber

The objective of this research work is to design and develop a forced convection solar dryer using evacuated tube air collector and study its performance on bitter gourd in Thanjavur District, Tamilnadu, India. The designed solar dryer consists of a drying chamber, evacuated tube air collector, a blower, and a chimney. Drying parameters, moisture ratio and drying rates, are calculated and their performance is compared with natural sun drying. The results of the present study show that the proposed solar dryer has greater efficiency, and the moisture content of bitter gourd is reduced from 91% to 6.25% in 6 hours as compared to 10 hours in natural sun drying. In this solar dryer, the products are uniformly dried, and the moisture content of the sample is controlled. It is found that the quality of the dried bitter gourd using solar dryer is higher than the natural sun-dried bitter gourd.

Improvement of Air Homogeneity in Paddy Dryer With Central Air Flow Channel

2017 ◽  
Vol 13 (10) ◽  
Author(s):  
Sidrah Ashfaq ◽  
Manzoor Ahmad ◽  
Anjum Munir ◽  
Abdul Ghafoor
Keyword(s):  
Moisture Content ◽  
Flow Behavior ◽  
Design Feature ◽  
Distribution Model ◽  
Air Distribution ◽  
Ansys Fluent ◽  
Batch Type ◽  
Computational Fluid Dynamics Cfd ◽  
Drying Curves ◽  
Drying Chamber

AbstractAir heterogeneity in the drying chamber of the batch-type dryer is a major problem because uneven air distribution within the drying chamber reduces the product quality and dryer efficiency. To surmount this problem, a new dryer with central air distribution model has been designed and developed. This is the distinct design feature of the dryer, which ensure the uniformity in the moisture content of the final dried paddy grains. ANSYS-Fluent (Computational Fluid Dynamics [CFD]) was used to predict the flow behavior of the air with respect to pressure and velocity within the drying chamber by applying actual boundary conditions and standardk−εturbulence model. Pressure and velocity profiles in the drying chamber were determined using CFD to optimize the drying uniformity. An estimated value for velocity input was used and air distribution was found good. For the validation of simulation results several drying tests were performed at different dryer depths of 18, 36, 54 and 72 cm in the drying chamber. The drying results expressed as percentage moisture content reduction, along the length of the dryer and measured the uniformity in the drying rate. The drying curves for each depth showed highR2value. Numerical simulation and experimental results showed that the newly developed solar-assisted paddy dryer is capable to produce uniform air distribution throughout the length of the drying chamber in the dryer for uniform and quality drying. This approach improved the overall performance of the solar-assisted paddy dryer.

PERFORMANCE OF AN ACTIVE SOLAR STILL COUPLED TO EVACUATED TUBE COLLECTOR

2014 ◽  
Vol 13 (2) ◽  
pp. 333-344
Author(s):  
Karuppusamy Sampathkumar ◽  
Palanisamy Senthilkumar
Keyword(s):  
Solar Still ◽  
Evacuated Tube Collector ◽  
Evacuated Tube

A Transient Simulation of Heated Soil Vapor Extraction System

Volume 1 ◽  
2004 ◽  
Author(s):  
T. Roy ◽  
R. S. Amano ◽  
J. Jatkar
Keyword(s):  
Heat Source ◽  
Three Dimensional ◽  
Soil Vapor Extraction ◽  
Extraction System ◽  
Vapor Extraction ◽  
Predictive Tool ◽  
Heating Source ◽  
Time Required ◽  
Heated Soil ◽  
Remediation Process

Soil remediation process by heated soil vapor extraction system has drawn considerably attention for the last few years. The areas around chemical companies or waste disposal sites have been seriously contaminated from the chemicals and other polluting materials that are disposed off. Our present study is concentrated on modeling one transient Heated Soil Vapor Extraction System and predicting the time required for effective remediation. The process developed by Advanced Remedial Technology, consists of a heating source pipe and the extraction well embedded in the soil. The number of heat source pipes and the extraction wells depends on the type of soil, the type of pollutants, moisture content of the soil and the size of the area to be cleaned. The heat source heats the soil, which is transported in the interior part of the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then driven out of the soil by the extraction well. The extraction well consists of the blower which would suck the vaporized gases out of the system. A three-dimensional meshed geometry was developed using gambit. Different boundary conditions were used for heating and suction well and for other boundaries. Concentrations of different chemicals were collected from the actual site and this data was used as an initial condition. The analysis uses the species transport and discrete phase modeling to predict the time required to clean the soil under specific conditions. This analysis could be used for predicting the changes of chemical concentrations in the soil during the remediation process. This will give us more insight to the physical phenomena and serve as a numerical predictive tool for more efficient process.

scholarly journals Heating source localization in a reduced time

2016 ◽  
Vol 26 (3) ◽  
pp. 623-640 ◽  
Author(s):  
Sara Beddiaf ◽  
Laurent Autrique ◽  
Laetitia Perez ◽  
Jean-Claude Jolly
Keyword(s):  
Heat Conduction ◽  
Source Localization ◽  
Conjugate Gradient ◽  
Regularization Method ◽  
Three Dimensional ◽  
Gradient Algorithm ◽  
Iterative Regularization ◽  
Heating Source ◽  
Ill Posed ◽  
Reduced Time

Abstract Inverse three-dimensional heat conduction problems devoted to heating source localization are ill posed. Identification can be performed using an iterative regularization method based on the conjugate gradient algorithm. Such a method is usually implemented off-line, taking into account observations (temperature measurements, for example). However, in a practical context, if the source has to be located as fast as possible (e.g., for diagnosis), the observation horizon has to be reduced. To this end, several configurations are detailed and effects of noisy observations are investigated.

scholarly journals Convective Drying of Sewage Sludge Layer in Through-flow

2020 ◽  
Vol 66 (9) ◽  
pp. 481-493
Author(s):  
Andraž Lipolt ◽  
Brane Širok ◽  
Marko Hočevar ◽  
Lovrenc Novak
Keyword(s):  
Sewage Sludge ◽  
Drag Force ◽  
Layer Structure ◽  
Measured Data ◽  
Matter Content ◽  
Convective Drying ◽  
Coefficient Of Determination ◽  
Dry Matter Content ◽  
Drying Time ◽  
Drying Rates

Drying of the sewage sludge layer was investigated in a convective laboratory dryer at air temperatures of 65 °C and 80 °C and air speeds of 0.53 m/s and 0.83 m/s. The sludge layer was formed by loading cylindrical extrudates on a grate of 0.5 m × 0.5 m size. The drying air was directed through the layer, as typically encountered in industrial belt dryers. Under such setup, the sludge layer structure and porosity significantly affect the air flow conditions and thus the drying rates. Shrinkage and cracking of the material during drying caused changes in the layer’s porous structure, that affected the pressure drop and the drag force due to passing of air through the layer. The decreasing of drag force over time was modeled by a simple function that showed excellent agreement to the selected measured data. The sludge layer drying kinetics was determined by fitting the measured data to the most common drying models. Two models, the modified Nadhari and the Wang Singh model, were determined as most suitable for modeling of drying curves. The total drying time per kilogram of sludge was modeled as a function of drying air temperature, drying air velocity and initial sludge dry matter content. The coefficient of determination (R2) of the model is 0.944. Total drying times between 43 minutes per kilogram and 76 minutes per kilogram of sludge were obtained for the investigated range of drying air conditions.

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