Drying Chamber Temperature Research Articles

Observed performances of the hybrid solar-biomass dryer for fish drying

This experiment aimed to configure the performances of hybrid dryer operated with solar and biomass energies for fish drying. The dryer consisted of a structure made of light steel frame and covered with UV plastic 12% equipped with drying chamber, a chimney, a heat collector, a furnace, and a heat exchanger. The biomass was coconut shell and the sample of fish was Pepetak Leiognatus spp. Operating with solar energy and without fish inside the dryer increased the temperature and relative humidity of the drying chamber respectively 13.4°C higher and 37.6% lower than those of the ambient air. When the dryer without fish was biomass operated using 3 kg fuel of the first supply and 1.5 kg fuel of subsequent supplies per 20 minutes, it was able to generate the drying chamber temperature and relative humidity about 60°C and nearly 0% in averages. Utilizing 20% fish moisture content as the threshold for dry fish, operating with solar energy, the dryer completed drying process in 20.47 h which was faster that of the sun drying (24.20 hours). The dryer needed to finish drying processes in 14.37 h and 15.43 h when operated by respectively biomass energy and solar energy continued with biomass energy. The rate of fuel supply for fish drying was 0.633 kg coconut shell per kg wet fish.

Dataset on performance of solar dryer for scotch bonnet pepper drying

The use of solar drying systems to preserve agricultural products has been proven to be cheap, reliable, and environmentally friendly. Solar dryers offer advantages of shorter periods of drying, reduced loss of raw materials and larger scale of production. This paper presents method followed in evaluating the performance of three different solar dryers with different materials used for solar collectors in order to determine the best among the three. The evaluation was performed twice, and each evaluation was done for three weeks. The parameters recorded in these experiments are drying chamber temperature and humidity, solar collector temperature, ambient temperature and humidity and the weight loss of the pepper. It was observed that the temperature of all drying chambers was higher than ambient temperature during most hours of the day. While three different metals were used as solar collectors in dryers and attained significant different temperature through radiation from the sun, the energy transmitted through natural convection to the drying chambers of the dryers was not significantly different (at p ≤ 0.05) from one dryer to the other. The efficiency of the dryers was an average of 29.7%, 29.1% and 30.3% for stainless steel, mild steel and galvanized steel solar collectors respectively.

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

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%.

Performance analysis of solar air dryer for drying different spices

The present work is confined to the fabrication of a solar dryer for drying spices and evaluates the performance of the collector and dryer system. The materials for each component of the dryer system is chosen considering different parameters effecting the performance of the dryer which includes design, operational, meteorological and environmental parameters. The experiments were carried out for 1 kg of two different types of spices and the drying efficiency is estimated to be 3.81 % for red chilly and 2.04 % for turmeric. The collector temperature is varying between 58ºC to 90ºC and the drying chamber temperature is varying between 46ºC to 60ºC during the entire observation period for an ambient temperature of 36ºC to 41ºC. The collector efficiency is varied from 28% to 45 %. The variation in moisture content and drying rate over the drying period are analysed and presented.

PENGARUH PENGGUNAAN KOLEKTOR PLAT DATAR PADA PENGERING PADI TIPE DRUM DRYER

Rice is one of food items consumed by most Indonesian people. Rice quality is a matter that must be considered in rice production. Rice quality can be improved by proper post-harvest handling, one of which is the drying process. The drying process can be done by drying under the sunshine and drying by using a dryer. Drying under the sunshine takes a long time, is difficult to control, depends on the weather, is easily contaminated and requires a large place. To overcome this problem, a dryer is needed. The dryer used is the drum dryer type. This drum dryer also utilizes mechanical energy from the gasoline engine so that it can rotate the drum. On the inner surface of the drum, stirring blades are installed. This dryer also uses heat coming from internal channel wall solar collectors. In this experiment was carried out with 4 free variations, namely: motor rotation, air flow velocity, intensity of solar radiation and cycle time. Three or four data are taken from each variation. When the experiment is taking place, varied parameters and planned parameters such as temperature absorber, ambient temperature, collector outlet air temperature and drying chamber temperature are measured. And at the final of the experiment for each variation, final mass of dried rice are measured. From the result of research, it can be concluded that the optimum rice mass reduction rate was obtained for each variation, namely at 905.1 rpm motor rotation, 10 m/s air flow rate, 948 W/m2 intensity of solar radiation and 30 minutes rotation time.

Simulation On Natural Convection Semi-Glazed Flat Plate Solar Collector For Green Bell Pepper Drying Application

A simulation on semi-glazed flat plate solar collectors under natural convection mode used for green bell pepper drying has been conducted. The solar collector has a 60% glazed area which was installed to the drying chamber with a 45o slope. The simulation consisted of the heating and drying process. For the heating process, a semi-empirical model of the buoyancy effect and heat balance was proposed. To determine the constants of the model, the non-linear least square method based on the experimental data of irradiation, ambient air temperature and the drying chamber temperature for no-load operation was used. Furthermore, for the drying process simulation was carried out based on the mass and energy balance of the product and the drying air as well as the drying characteristics of green bell pepper. The simulation results showed that in clear weather conditions, the temperature and air flow rate produced by the collector can be used to dry a stack of ten trays within effective time less than 20.6 hours or equal to less than three days sunshine.

Experimental investigation on biomass fired dryer for drying of agricultural products

This study focuses on the development and performance evaluation of a biomass-fired dryer. The system was designed after considering the needs of small-scale rural entrepreneurs. The designed system consisted of the combustion chamber, drying chamber, the passage of flue gases, flue gas chimney, etc. The thermal performance of the developed system was tested in terms of moisture removal rate, drying rate, thermal efficiency, and heat transfer efficiency. In order to check performance, the dryer was loaded with 4 kg of Coriander leaves having an initial moisture content of 89.40% (w.b.) were dried to the final moisture content of 9.54% (w.b.) in 7 h of operation, 6 kg of babul wood (Acacia nilotica) was consumed during the drying process. The average drying chamber temperature was 51.84°C. The thermal and heat transfer efficiency of the dryer was 28.22 and 56%, respectively. The economic parameters reveal that the developed system is technically viable and economically feasible as the payback period is very low. The net present worth, benefit-cost ratio and payback period were 3398 US$, 2.68 and 0.38 years, respectively.

Investigation of the efficiency of a solar dryer with thermal storage by rock salt and by pebble bed

Storage materials by salt rocks and pebbles were introduced in an indirect solar dryer. Experiments were carried out by using rock salt and pebbles (0.076 m3) as thermal storage materials. To overcome the thermal behaviour with storage materials, the solar dryer was modelled by SolidWorks flow simulation. Rock layers were arranged as superimposed sphere beds. The maximum reached temperature during the sunny period and the duration of the thermal discharge phase are strongly affected by the location of rocks in the drying chamber. These storage media maintained consistent the drying chamber temperature in the absence of the solar radiation by four more hours. Experimental tests were performed on lemon with and without the storage medium. Finally, the insertion of storage medium could increase the dryer efficiency by about 13.83%. Pebbles seem to be more suitable for thermal storage not for their thermal capacity but especially for their density.

Mathematical modeling of an innovative hybrid solar-gas dryer

This paper is devoted to develop a multivariable model (MM) of an innovative hybrid solar-gas dryer issued from a CFD study. The proposed (MM) was explored to predict the drying chamber temperature in forced convection (0.025kg/s) in two main operating modes (solar mode and gas mode). There is an indirect heating of drying air instead of direct heating inside the drying chamber as it was reported in conventional hybrid solar-gas dryers. CFD technique was used to simulate the temperature and airflow distribution inside the drying chamber. However, CFD simulation requires huge capacity of the processor for calculating and takes significant simulation time. Therefore, the multivariable model was developed to predict the drying temperature instantly with a notable reduction in simulation time. Root Mean Square (RMSE) was used to measure the difference between the predicted values by CFD and (MM) model. It was found that the results shown fairly good agreement with an RMSE lower than 2.35 confirming the pertinence of the proposed model. The developed model led to a quick output parameters estimation related to each climatic condition. Thus, it is very useful for synthesizing a control system of the temperature as well as the optimization of gas consumption.

Numerical analysis on solar air collector provided with artificial square shaped roughness for indirect type solar dryer

Abstract Drying agricultural food products in an indirect type solar dryer (ITSD) is a topic of frequent research. Heat transfer rate to the fluid flow in the solar collector can be enhanced by providing artificial roughness on the surface of the absorber plate. The present work concentrates on air flow and heat transfer characteristics in a solar air collector provided with roughness of square shaped rib over the absorber of ITSD. 2D numerical simulations are performed for flow through the solar air collector for relevant Reynolds number (Re) which ranges from 3800 to 18,000. The Re, relative roughness pitch (P/e), relative roughness height (e/D) and thermo-hydraulic performance parameter (THPP) are chosen as design variables. The governing equations for turbulent flow field are solved using RNG k–ɛ turbulence model. The simulation results are compared with smooth duct which shows that the duct with roughened surface enhances the heat transfer and friction factor (fr) by 2.13 and 3.54 times, respectively. The solar air collector with roughness of square shaped rib with P/e = 7.14 gives better THPP of 1.45 at Re of 15000. It is found that the additional drying chamber temperature of 4 K and heat gain of 106% when the dryer is upgraded to roughened surface from smooth surface. The present simulation model is validated with experimental outcomes of existing literature and good agreement is noticed.

A numerical model for drying of spherical object in an indirect type solar dryer and estimating the drying time at different moisture level and air temperature

ABSTRACTA numerical model for simultaneous heat and mass transfer was developed for solar drying of spherical objects and the object considered is green peas. Solar collector outlet temperature is assumed as drying chamber temperature and justified through energy balance equations. Assumptions are imposed on heat and mass transfer governing equations without losing the physics of the problem. Discretization is performed by finite difference method with implicit scheme. To generalize, the governing equation and boundary conditions are non-dimensionalized. The set of finite difference equations was solved by Tridiagonal Matrix Algorithm and a computer code in MATLAB was developed to solve them. The drying curves showed two stages of drying, initial, and secondary drying stage. At all drying temperatures and drying time, the center moisture was maximum and it was minimum at the boundary. A percentage of 85.67 surface moisture content and 25.33% center moisture was eliminated in the first 1 hr at 348 K. The product should be dried up to 7.45, 4.74, and 3.74 hr at air drying temperatures of 318, 333, and 348 K respectively, to maintain 10% of the product’s initial moisture content. The result is compared with the experimental result from literature and they are found to be in good agreement.

DRYING OF THOMPSON SEEDLESS GRAPES IN THIN-LAYER USING A BIOGAS DRYER

A biogas dryer was developed to study experimentally drying behavior of Thompson seedless grapes under Alexandria Governorate, Egypt conditions. Drying experiments are carried out in the month of August 2016. During the experimentation, temperatures of air at various places in the dryer, ambient relative humidity and humidity variation in drying chamber and mass of the dried grape are measured on hourly basis. four kg of Thompson seedless grapes are dried in forced convection heat transfer mode from initial moisture content of 79% (wb) to final moisture content 14% (wb) in 44 hours. The drying was carried out under uncontrolled condition. The average drying chamber temperature was around 51.98 °C. The biogas burner efficiency was 62.06 %. The effect of heating source on color change of the dried grapes was investigated. Color data were obtained using a high-resolution digital camera and lighting box and the images were analyzed quantitatively using Photoshop to get the L, a and b in the Histogram Window. Statistical analysis showed that there was a significant effect of heating source on color data of the dried grapes. Regardless of the heating source, all raisins had varying degrees of brown coloring. The dried grapes by the biogas dryer had lower browning index (BI) of 43.52 indicating good quality. It could be concluded that the farmers can use biogas energy to enhance its utilization to produce good quality raisins.

Design and Development of an Agricultural and Bio-materials Cabinet Tray Dryer

A locally made agricultural and bio-material dryer to be operated bylocal farmers was designed and developed to reduce Agricultural material wastage and improve their storage conditions. It consists of three units: drying chamber, blower and heat exchanger. The performance test and evaluation were conducted using analysis of variation (ANOVA) using okro, pepper and groundnut as the test materials at an average drying chamber temperature of 50°C for safe drying of the produce. The three crop, (okro, pepper and groundnut) and drying time (9hours), the kilogram weight of the crops decreased with increase in drying time as drying progressed, hence there was no significant different at 5% level of significance in the drying rates of the three crops. The dryer which has a mean drying capacity of 60.3kg per batch with a thermal efficiency of 76.9% and drying rate of 0.041kg/hr, at relative humidity of 35% improved the drying time of the agricultural materials and is recommended for local farmers.

“TEKO BERSAYAP” MODEL SOLAR DRYER FOR FISH DRYING

This objective of this research was to design a dryer called “Teko Bersayap” model and then to test its performance in drying fish in order to solve problems arising from open air sun drying. The dryer consisted of drying chamber with trays inside, heat collectors equipped with air inlets at their lower ends, chimney with an exhaust fan inside and humid air outlet at its upper end, was constructed to dry fish, “Bleberan (Pepetak Leiognatus spp)” species. The results of the experiment indicated that the dryer produced the drying chamber temperature 8.83oC higher than the ambient temperature and the relative humidity 13.91% lower than the ambient relative humidity. The fish moisture content decreased exponentially with drying time and the dryer completed the fish drying process in 18.9 hours compared to 27.6 hours of drying time needed to complete the sun drying for the fish, suggesting that the dryer was ready for utilization

The Multi-objective Optimization by the Restricted Area Method to Determine the Technological Mode of Cold Drying Process of Carrot Product

Finding the technological mode of cold drying process of carrot product was the major aim of this study. The experiments were carried out according to experimental plannings. Results obtained were to build the multi-objective optimization problem to describe relationships between objective functions with technological factors (temperature of moisture condensation, temperature of cold drying chamber, velocity air (or drying agents) and time of cold drying) of cold drying process of carrot product. By the Restricted Area Method (RAM), solving the multi-objective optimization problem was found out the technological mode of the cold drying process of carrot product as follows: temperature of moisture condensation was $Z_1^{opt} = 15.62°C$, temperature of cold drying chamber was $Z_2^{opt} = 35.79°C$, velocity air (or drying agents) was $Z_3^{opt} = 11.74m/s$ and the time of cold drying process was $Z_4^{opt} = 16.05h$. Corresponding to these optimal factors, the objective functions reached the minimum value in terms of the final product, including the energy consumption of $y_{1P}^R = 1.62kWh/kg$, the residual water content of $y_{2P}^R = 4.52%$, the anti-rehydration capacity of $y_{3P}^R = 6.43%$ (Correspondingly IR = 93.57%) and the loss of total β-caroten inside carrotof $y_{4P}^R =4.45%$.

Design and Performance Evaluation of a Solar Assisted Heat Pump Dryer Integrated with Biomass Furnace for Red Chilli

The performance of a solar assisted heat pump dryer integrated with biomass furnace has been designed and evaluated for drying red chillies, and drying kinetics of red chillies were evaluated. The red chillies were dried from 22 kg with moisture content of 4.26 db to moisture content of 0.08 db which needed 11 hours, with the average drying chamber temperature, drying chamber relative humidity, and an air mass flow rate of 70.5°C, 10.1%, and 0.124 kg/s, respectively, while the open sun drying needed 62 hours. Compared to open sun drying, this dryer yielded 82% saving in drying time. The drying rate, the specific moisture extraction rate, and thermal efficiency of the dryer were estimated in average to be about 1.57 kg/h, 0.14 kg/kWh, and 9.03%, respectively. Three mathematical models, the Newton, Henderson-Pabis, and Page models, were fitted to the experimental data on red chillies dried by solar assisted heat pump dryer integrated with biomass furnace and open sun drying. The performance of these models was evaluated by comparing the coefficient of determination (R2), mean bias error (MBE), and root mean-square error (RMSE). The Page model gave the best results for representing drying kinetics of red chillies.

전기히터식 및 히트펌프식 식품 건조기의 에너지 성능 비교

In this study, energy performance of two types of food dryers which are electric heater and heat pump is studied experimentally. With drying chamber temperatures controlled at 45, 50 and , sliced radish is dried from an initial mass of 90 to final 7 kg. Moisture content, drying time, total power consumption, MER (moisture extraction rate, kg/h) and SMER (specific moisture extraction rate, kg/kWh) are measured and analyzed. As the drying chamber temperature is increased, drying time is shortened but energy efficiency is reduced for both types. For an electric heater dryer, the effect of chamber temperature on drying time is significant but less significant on energy efficiency. For a heat pump dryer, the dependence of chamber temperature on drying time is weak but strong on energy efficiency. Temperature levels have little effect on electric heater dryer performance but strong effect on heat pump dryer which operates on a vapor compression refrigeration cycle. The energy performance of the heat pump dryer is superior with an average SMER of 2.175 kg/kWh which is 2.22 times greater than that of the electric heater dryer with SMER of 1.224 kg/kWh.

Solar Drying Kinetics of Cass Ava Slices in a Mixed Flow Dryer

Abstract Drying characteristics of cassava slices was investigated in a mixed mode natural convection solar dryer to obtain a suitable mathematical model describing the drying. The average drying chamber temperature was between 34 ±2 °C and 50 ±1.8 °C, while 10 commonly used thin layer drying models were used for drying curve modelling. Coefficient of determination (R2) and root mean square error (RMSE) were used to determine the models performances. The drying curve of cassava slices showed a reduction of moisture content with increased drying time in the solar dryer, and the variation of moisture ratio exponentially decreased with increased drying time. The Midilli and Logarithmic models showed better fit to the experimental drying data of cassava slices. As compared with other models tested, there were no significant differences (p >0.05) in the R2 values obtained for the Midilli and Logarithmic models; hence, the Logarithmic model was preferable because of the lower RMSE. The diffusion mechanism could be used to describe the drying of cassava slices that was found to be in the falling rate period. A diffusion coefficient (Deff) of 1.22 × 10-8 m2 s-1 was obtained, which was within the established standard for food products.

Drying characteristics and quality of red ginseng using far-infrared rays

BackgroundThe current typical drying methods for red ginseng are sun drying and hot-air drying. The purpose of this study was to investigate drying characteristics of red ginseng by using far-infrared drying. MethodsThe far-infrared drying tests on red ginseng were conducted at two drying stages: (1) high temperature for 24 h drying and (2) low temperature drying until the final moisture content was 13 ± 0.5% (wet basis). The high temperature drying stage included three drying chamber temperature conditions of 60°C, 65°C, and 70°C. The low temperature drying stage was conducted at temperatures of 45°C and 50°C. Drying characteristics were analyzed based on factors such as drying rate, color changes, energy consumption, and saponin content. The results were compared with those of the hot-air and sun drying methods. ResultsThe results revealed that increases in drying temperature caused a decrease in drying time and energy consumption for far-infrared drying. The saponin content decreased under all drying conditions after drying, the highest value (11.34 mg/g) was observed at drying conditions of 60∼50°C. The sun drying condition showed the lowest color difference value when compared with far-infrared and hot-air drying. ConclusionThe far-infrared drying showed a faster drying rate, higher saponin content, lower color difference value, and a decrease in energy consumption than seen in hot-air drying.

STUDY ON PALM OIL LEAF STEM AS BIOMASS FUEL FOR YTP-UNIB-2013 DRYER

Purpose of this research was to determine the relation between fuel supply and temperature in the drying chamber of YTP-UNIB-2013 Biomass Dryer; and to describe performance of the dryer operated using palm oil leaf stem as the biomass fuel. The stems were cleaned out of leaves, cut into 5-7 cm in length, dried so that their water content less then 10%.Temperature and humidity were recorded every 15 minutes p to 3 hours of burning. In order to maintain maximal temperature in the drying chamber, biomass fuel was added at the time the temperature start decreasing. The time for the additional sample to be burned was recorded. Each of burning sample process was repeated three time to have accurate data. Result of regression analysis showed that drying chamber temperatures (T) were related to the amount of palm oil stems as biomass fuel by following an equation of T = 12.013Q + 16.293 with coefficient of determinant R² = 0.8706. Performance tests of the Biomass Dryer indicated that by using 4.4 kg/hour of palm oil stem as biomass fuel, average temperature of the chamber dryer was 65°C and capable of evaporating clear water up to 2,548 kg/hour. Therefore it could be concluded that in general, workability of the YTP-UNIB-2013 Biomass Dryer by using palm oil leaf stem as the biomass fuel was effective.