scholarly journals EXERGY ANALYSIS OF SOLAR DRYER WITH A BACKUP INCINERATOR

Author(s):  
Barki. E ◽  
Ukwenya J ◽  
Idoko F

Solar dryer with backup incinerator was fabricated with the aim of improving the efficiency of the drying rate of selected agricultural products. The dryer consist of three main parts, the collector, the drying chamber and the incinerator. 1000g of chill pepper was sun dried and 1000g was charged into the dryer for the experiment. Drying using solar drying process was carried out during clear weather while incinerator drying process was carried out during cloudy weather and at nights The collector, dryer and incinerator energy efficiencies were determined and reported elsewhere. Exergy analysis of the dryer was carried out for both solar drying and incinerator drying using the experimental values. The average exergy inflow and outflow during solar drying was found to be 266.97 KJ/Kg and 20.85 KJ/Kg respectively. The average exergy loss at airflow velocity of 2.7 m/s was found to be 269.3 KJ/Kg for incinerator drying. The exergy efficiency of the incinerator fluctuates as it starts from 7.9, 11.1, 5.2, 13.5, 8.0 and 3.6 % for 8.00, 10.00, 12.00, 14.00, 16.00, 18.00 hrs respectively. The result also shows exergy efficiency of 83.1, 85.9, 91.7, 92.4, 89.0 and 73.4 % for 8.00, 10.00, 12.00, 14.00, 16.00, 18.00 hrs respectively during solar drying. The experimental and analytical temperatures values were observed to be solar radiation intensity dependants and are directly proportional with it. Although the heat losses are high for both drying processes, the dryer is suitable for drying agricultural produce during clear, cloudy weather and at nights.

2021 ◽  
Vol 11 (2) ◽  
pp. 19
Author(s):  
Isaac N. Simate

The energy and exergy analysis of an indirect-mode natural convection solar dryer for maize grain is presented. Two different sizes of maize grain bed depths of 0.04 m and 0.02 m translating into grain loads of 10 kg and 5 kg respectively, are used in the study to determine their effects on the collector energy and exergy efficiencies and the drying chamber exergy efficiency. Experiments were carried out using an indirect-mode laboratory solar dryer under a solar simulator with a radiation setting of 634.78 W/m2. The analysis gave average collector energy efficiencies of 33.3 % and 46.2 % for the 10 kg and 5 kg loads, respectively, which are higher than the collector exergy efficiencies of 2.4 % and 2.6 % for the 10 kg and 5 kg loads, respectively. The drying chamber exergy efficiencies are 45.2 % and 28.4 % for the 10 kg and 5 kg loads, respectively. In view of this, the 5 kg load is considered to be more efficient at extracting energy from the collector due to higher air flow resulting from its relatively thin grain bed depth of 0.02 m, but less efficient in utilising the extracted energy to evaporate moisture from the grain which has resulted in a lower drying chamber exergy efficiency. Further, the exergy loss in the drying chamber for the 5 kg load is higher than that in the 10 kg load as 72.3 % of the exergy entering the drying chamber is lost through emissions as well as destroyed through internal irreversibility compared to 57.0 % for the 10 kg load. 


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 350 ◽  
Author(s):  
Wengang Hao ◽  
Shuonan Liu ◽  
Baoqi Mi ◽  
Yanhua Lai

A new hybrid solar dryer was designed and constructed in this study, which consisted of a flat-plate solar collector with dual-function (DF-FPSC), drying chamber with glass, fan etc. The DF-FPSC was firstly applied in drying agricultural products. The innovative application of hybrid solar dryer can control the drying chamber air temperature within a suitable range by different operation strategies. Drying experiments for lemon slices in the hybrid solar dryer were conducted by comparing open sun drying (OSD). Eight mathematical models of drying characteristics were employed to select the most suitable model for describing the drying curves of lemon slices. Furthermore, energy, exergy economic and environment (4E) analysis were also adopted to analyze the drying process of lemon slices. The results show that under the same experimental condition, the drying capability of the hybrid solar dryer was stronger than that of OSD. Meanwhile, it was found that the Two term and Wang and Singh models were the most suitable for fitting the lemon slices’ drying characteristics inside the hybrid solar dryer. The drying chamber air temperature can be controlled under about 60 °C during the process of lemon slices’ drying. The experimental results show the feasibility and validity of the proposed hybrid solar dryer.


Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2841 ◽  
Author(s):  
Yaovi Ouézou Azouma ◽  
Lynn Drigalski ◽  
Zdeněk Jegla ◽  
Marcus Reppich ◽  
Vojtěch Turek ◽  
...  

This study investigates the industrial-scale application of a simple convective solar drying process of pineapples as part of a circular economy strategy for developing countries. A renewable energy concept is presented, which follows the circular economy aims by effectively employing a simple system for biogas production and a two-stage drying system. Both these systems meet the requirements for implementation in the specific conditions of developing countries, of which Togo, where pineapple is a major crop, is taken as an example. With respect to earlier findings available in the literature, the paper focuses on the solar drying process, which is critical to the proposed strategy. A portable solar dryer working in indirect heating mode was built and later also modified to enhance its performance. Three main factors influencing the convective drying process, namely, drying time (270 min, 480 min), solar radiation intensity (650 W/m2, 1100 W/m2), and slice thickness (6–8 mm, 12–14 mm), were considered. The statistical Design of Experiments (DOE) method was applied to reduce the number and scope of experiments. In the best case, the moisture content was reduced from 87.3 wt % in fresh samples to 29.4 wt % in dried samples, which did not meet the quality requirements for dried fruit. An additional conventional post-solar drying procedure would, therefore, still be necessary. Nonetheless, the results show that in the case of pineapple drying the consumption of fossil fuels can be decreased significantly if convective solar pre-drying is employed.


Author(s):  
Dalvi Piyush Hemant ◽  
Yeolekar Gaurav Laxman ◽  
Jadhav Akash Sampat ◽  
Prof. H. B. Wagh

Solar Drying or solar dehydration is one of the important processes required for preservation of food and agriculture products. Bacterial growth and moisture is being removed in this process. It helps for preserving the food products for more long time. Solar drying is the oldest & effective method used for drying food products. The device used for preservation of food products using solar energy is called as solar dryer or solar dehydrator. The solar dryer is classified on the basis of mode of drying, circulation of air, type and arrangement of solar air collector. In this project, a solar powered indirect type food dryer is designed and developed. The dryer design is consisting of solar collector unit along with absorber made up of extended surface of aluminum sheet with staging, drying chamber with three columns of each rack shelves, chimney for exhaust air, a solar powered fan. The dryer collector and drying chamber are connected with a hose pipe clamped to both ends. The project model of solar dryer is consisting of a monitoring unit for data logging of continuous updatation of parameters like temperature inside the dryer and temperature at ambient condition, humidity at inside and outside of dryer also the atmospheric pressure, etc. At the end we are going to investigate the effectiveness of solar dryer with above parameters.


2020 ◽  
Vol 13 (2) ◽  
pp. 84-93
Author(s):  
Muhammad Yasar ◽  
Raida Agustina ◽  
Mustaqimah Mustaqimah ◽  
Diswandi Nurba

Abstrak. Diantara permasalahan yang dihadapi oleh sektor usaha perikanan ialah  belum efisiennya teknis pengelolaan  dan tidak stabilnya kontinuitas produksi. Hal ini disebabkan oleh kurangnya sarana prasarana untuk mengolah ikan serta sistem pemasaran ikan segar yang masih konvensional, sehingga cepat membusuk apabila tidak diolah lebih lanjut. Penanganan dan pengolahan yang cepat dan tepat diperlukan untuk mengurangi resiko pembusukan dan dapat meningkatkan nilai jual hingga sampai kepada konsumen. Salah satu teknologi untuk meningkatkan masa simpan ikan ialah dengan cara proses pengeringan. Sebuah alat pengering ikan Green-House Effect (GHE) telah dikembangkan. Pengujian dan analisis alat pengering untuk ikan tersebut disajikan dalam makalah ini. Pengering surya ini menambahkan ventilator berupa exhaust fan guna memaksimalkan proses sirkulasi udara di dalam ruang pengeringan. Parameter yang diukur dalam pengujian ini adalah distribusi suhu, kelembaban relatif, iradiasi dan pengukuran kecepatan udara. Hasil penelitian menunjukan bahwa temperatur di dalam ruang pengering terlihat lebih tinggi yaitu 67°C dibandingkan dengan temperatur di lingkungan karena sifat absorber yang mampu menyerap panas. Sementara itu kelembaban relatif di dalam ruang pengering lebih rendah jika dibandingkan dengan kelembaban di lingkungan yaitu sebesar 30,1%. Nilai iradiasi surya yang diperoleh sangat berfluktuasi dengan nilai tertinggi adalah sebesar 180,6 W/m2. Kecepatan udara di dalam ruang pengering surya lebih stabil dibandingkan dengan kecepatan udara lingkungan karena adanya penambahan ventilator berupa exhaust fan. Hal inilah yang menyebabkan proses pengeringan menjadi lebih cepat.Performance of Green House Effect (GHE) Vent Dryer for Fish DryingAbstract. The problems that occur in the fishery business sector are inefficient and unstable continuity of production. The reasons for this include the lack of infrastructure for processing fish and also the very limited marketing of fresh fish due to its fast-rotting nature if not further processed. Fast and precise handling and processing are needed to reduce the risk of spoilage. One of the technologies to increase the shelf life of fish is the drying process. A greenhouse effect vent dryer type fish dryer has been developed. The testing and analysis of the dryer for these fish are presented in this paper. This solar dryer adds a ventilator in the form of an exhaust fan to maximize air circulation in the drying chamber. The parameters measured in this test are temperature distribution, relative humidity distribution, solar irradiation, and air velocity measurement. The results show that the temperature in the drying chamber is 67 ⸰C higher than the temperature in the environment due to the nature of the absorber which can absorb heat. Meanwhile, the relative humidity in the drying chamber was lower than the humidity in the environment, which was 30.1%. The value of solar irradiation obtained fluctuates where the highest irradiation is 180.6 W / m2. The air velocity in the solar dryer is more stable than the ambient airspeed due to the addition of a ventilator in the form of an exhaust fan. This causes the drying process to take place faster.


2016 ◽  
Vol 36 (01) ◽  
pp. 96
Author(s):  
Lamhot Parulian Manalu ◽  
Armansyah Halomoan Tambunan

Java turmeric (Curcuma xanthorrhiza Roxb.) is a medicinal plant used as raw material for making herbal medicine, its rhizome cut into slices and dried so called simplicia. Curcuma has a harvest moisture content is high enough to need a great energy for drying. Generally, the theory used to analyze the energy efficiency is the first law of thermodynamics that describes the principle of conservation of energy. However, this theory has limitations in measuring the loss of energy quality. To determine whether the energy used in the drying process has been used optimally in terms of quality, the second law of thermodynamics -known as exergy analysis- is used. The purpose of this study is to determine the efficiency of the thin layer drying of curcuma slices with exergy analysis. The results show that the process conditions affect the energy utilization ratio and exergy efficiency of drying. Exergy analysis method based on the second law of thermodynamics has been used to determine the amount of exergy destroyed so that the efficiency of the drying process can be determined more accurately. Exergy efficiency varies between 96.5%-100% for temperatures of 50 °C to 70 °C at 40% RH and 82.3% - 100% for 20% to 40% RH at 50 °C.Keywords: Drying, energy, exergy efficiency, curcuma slices ABSTRAKTemulawak (Curcuma xanthorrhiza Roxb.) merupakan tanaman obat yang simplisianya digunakan sebagai bahan baku pembuatan jamu atau obat tradisional. Pengeringan merupakan proses utama dalam memproduksi simplisia. Untuk menganalisis efisiensi energi suatu proses pengeringan umumnya digunakan hukum termodinamika pertama yang menjelaskan tentang prinsip kekekalan energi. Akan tetapi teori ini mempunyai keterbatasan dalam mengukur penurunan kualitas energi. Untuk mengetahui apakah energi yang digunakan pada proses pengeringan sudah digunakan secara optimal dari sisi kualitas, digunakan hukum termodinamika kedua atau yang dikenal dengan analisis eksergi. Tujuan penelitian ini adalah menentukan efisiensi proses pengeringan lapisan tipis irisan temulawak dengan metode analisis energi dan eksergi. Dalam studi ini, metode analisis energi dan eksergi berdasarkan hukum termodinamika pertama dan kedua telah digunakan untuk menghitung rasio penggunaan energi dan besaran eksergi yang musnah (exergy loss). sehingga efisiensi proses pengeringan irisan temulawak dapat ditentukan secara akurat. Hasil penelitian menunjukkan bahwa kondisi proses pengeringan mempengaruhi rasio penggunaan energi dan efisiensi eksergi pengeringan. Semakin tinggi suhu dan RH pengeringan maka rasio penggunaan energi semakin rendah dan efisiensi eksergi semakin tinggi. Efisiensi eksergi pengeringan temulawak bervariasi antara 96,5%-100% untuk selang suhu 50 oC hingga 70 oC pada RH 40% serta 82,3% - 100% untuk selang RH 20% hingga 40% pada suhu 50 oC. Kata kunci: Pengeringan, energi, efisiensi eksergi, temulawak


2011 ◽  
Vol 6 ◽  
pp. 583-591 ◽  
Author(s):  
Amel Boulemtafes-Boukadoum ◽  
Ahmed Benzaoui

2020 ◽  
Vol 9 (1) ◽  
pp. 131-139
Author(s):  
Suherman Suherman ◽  
Hasri Widuri ◽  
Shelyn Patricia ◽  
Evan Eduard Susanto ◽  
Raafi Jaya Sutrisna

In this study, hybrid solar drying of coffee beans was performed, and energy analysis was carried out, to assess the system’s performance, in terms of energy efficiency, compared to solar drying and the open sun drying method. The dryer has three compartments: solar collector for collecting solar radiation, drying chamber, and a Liquid Petroleum Gas burner, which acted as an auxiliary heater to assist the thermal energy. The drying chamber has four trays for placing the dried product. The initial moisture content of coffee beans was 54.23% w.b and was reduced to the final moisture content between 11-12% w.b. The coffee beans dried faster when subjected to the solar hybrid drying method, compared to other methods, with the dryer temperature of 40°C, 50°C, and 60°C. Results indicated that the coffee beans’ drying times varied from 10 to 14 hours. However, at temperature 50°C and 60°C for the 1st tray, the water content was reduced more rapidly compared to the other tray. From the results of this study, we can see the different efficiency of solar collector that shows of 54.15% at variable temperature 60°C for drying time 12:00 to 14:00 p.m for hybrid solar drying and for the solar drying process is 50.07% at the range of drying time 12:00 to 14:00 p.m. Mathematical modelling shows that Page model is the most suitable for describing the coffee beans’ drying behaviour using a hybrid solar dryer. The effective diffusivity values found in this experiment are all in the acceptable range for most agricultural products. ©2020. CBIORE-IJRED. All rights reserved


Author(s):  
Mr. Jeevan Gaikwad

This paper presents experimentation on model developed to compare the performance of solar drying with and without dehumidification system. Basic components of system consist of flat plate solar collector, drying chamber, desiccant bed and blower to maintain forced air circulation inside the system. Humidity of fresh air supplied to collector reduced by passing it through two stationary desiccant beds, which work alternately for adsorption and regeneration. Exhaust heat used for regeneration thereby overall efficiency of system increased. Drying rate obtained from solar drying with desiccant bed, solar drying without desiccant bed and open sun drying are 0.1094 Kg/hour, 0.09375 Kg/hour, and 0.0775 Kg/hour respectively. It concluded that by use of desiccant bed increases drying rate that takes near about three hours less to reach same moisture content compared with solar drying without desiccant bed. From results obtained it further found that desiccant bed based solar dryer gives higher drying chamber efficiency than without desiccant bed system due to increased moisture pick-up capacity. Also, in built latent heat thermal storage was able to provide 7 to 8 0C higher temperature than surrounding after sunset for about 2 hours.


2021 ◽  
Vol 8 (2) ◽  
pp. 135-138
Author(s):  
TH BIDYALAKSHMI DEVI ◽  
YOGESH B KALNAR

A sensor based solar dryer was designed to control the drying environment for precision drying of agricultural produce. The system entirely used solar energy utilizing both thermal and electrical effect. Paraffin wax (PCM) was used for storage of thermal energy whereas solar battery was used to store the electrical energy. Hot air blower was also provided to supply heat when there is less or no solar radiation. Temperature sensors were provided to control the environment of drying chamber. The exhaust fan started operating depending on the set temperature and thus control the drying environment. Load cells were provided below each tray to measure the dry weight. The drying chamber was made of mild steel with glass wool insulation. The capacity of the designed dryer was 10-15 kg with 6 trays. The designed dryer has target temperature of 55-60oC.


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