Comparative performance study of different types of solar dryers for sustainability in agriculture applications

Postharvest food loss increases rapidly every year in the world due to the inability to preserve food. Crop drying, which aims to reduce the moisture content to a certain level, is a method used to extend the shelf life of the food, and prevent it from spoiling. Solar drying is becoming a popular option to replace mechanical dryers due to the high cost of energy, and the increased awareness of consumer orientation to clean energy products. In this study, three different low-cost solar dryers of natural convection dryer (NCD), forced convection dryer (FCD), and heat pump integrated solar dryer (HPD) were examined, and mushroom (agaricus bisporus) drying experiments were carried out on each. In this study, three main research topics were determined: (i) to analyse the drying characteristics of mushroom slices in different thicknesses (0.5cm, 1cm and in half), (ii) to determine the effect of pretreatment on the drying time, (iii) to compare the collector efficiencies. For these purposes, 12 experiments were conducted between 9:00-18:00, the average daily solar irradiance was around 790W/m 2 . In 10 drying experiments out of 12, it was observed that the samples were completely dried out within the experiment period, while the drying process of the half-cut mushrooms in NCD and FCD were completed after 18:00. The results show that cutting thin slices of mushrooms reduced the drying time by an average of 40.83 mins. Also, the process of pretreatment caused shorter drying time by an average of 26.66 mins, almost 7% in all cases. The average thermal efficiencies were found 59.74%, 67.66%, and 77.45% for NCD, FCD and HPD, respectively. According to the results of this study, the most affecting factor in the overall drying process is found to be drying air which is hot and holds less moisture. In addition, it turned out that the drying rate increases with the increase of the temperature and speed of the drying air.

Evaluation of different drying processes by energy consumption in an insulated and not insulated laboratory convection dryer

Drying is a process to increase the shelf-life of fruits by decreasing their water content. It is one of the energy consuming processes in food engineering. In many studies, the drying time duration and quality of dried fruits were investigated. In this study, the energy consumption in different drying conditions was investigated for the apple in a laboratory convection dryer. The drying conditions were the application of the temperatures of 40, 50, and 60°C and the speeds of 0.5 and 1 ms-1 for the drying air using the insulated and non-insulated drying chambers. Independent from drying duration, the highest energy consumption was recorded as 11.2 kWh for the non-insulated dryer under the drying air condition of 40°C and 0.5 ms-1 . While the lowest energy consumption was only 5.8 kWh for the insulated dryer with the drying air condition of 40 and 50°C and the same 0.5 ms-1 . The drying duration for these conditions was 537, 313, and 233 mins. To achieve the shortest drying time (153 mins), the condition of 60°C and 1 ms-1 in the insulated dryer was used which caused the energy consumption of 7.2 kWh.

Experimental studies of fruits drying processes

The article raises the question of the need to solve the drying and storing fruits problem. The actuality of drying is the simplest and most economical method of fruit preservation. The analysis of recent studies and publications devoted to the consideration of theoretical and practical aspects of the development of fruit drying is made and highlighted in the works of domestic and foreign scientists. Drying plants main requirements are given. Methods of fruit drying are considered. The goals and necessity of carrying out experiments to study the influence of changes in air temperature and air velocity on the drying process are formulated. The main conditions for obtaining high-quality raw materials at the output in a short period of time with minimal energy consumption have been determined. The design of a convection dryer chamber in which experiments were carried out in the laboratory of the Department of Heat and Gas Supply, Ventilation and Heat Power Engineering of the National University "Yuri Kondratyuk Poltava Polytechnic" is presented. The results of its verification for aerodynamic and thermal performance are presented. Drying plums experiments, their analysis and comparison have been spent. The most expedient variant of plum drying was chosen. The main conclusions based on the results of the conducted field laboratory experiments are made. The necessity and prospects of further research on fruit drying have been proved.

TEKNOLOGI PENGERING PADI UNTUK KETAHANAN PANGAN DI DESA WRINGIN PUTIH, BANYUWANGI

Desa Wringin Putih merupakan salah satu desa di Kabupaten Banyuwangi yang mengalami permasalahan dalam penanganan pasca panen padi. Selama ini penanganan yang dilakukan adalah dengan mengeringkan padi dibawah sinar matahari, cara ini terkendala disaat musim hujan, sehingga tidak bisa melakukan pengeringan. Jika proses ini terlambat, maka mengganggu tingkat kestabilan produktivitas beras dan pasokan beras ke masyarakat menjadi terlambat sehingga pada akhirnya mengganggu ketahanan pangan. Pengering dengan konsep natural convection menjadi salah satu solusi untuk membantu petani dalam meningkatkan nilai jual gabahnya. Pada prinsipnya pengering ini akan mengurangi kadar air secara perlahan-lahan karena udara panas secara alami mengalir kedalam ruang pengering tanpa bantuan blower mirip dengan pengering sinar matahari tetapi tidak perlu ruang yang luas, disamping itu kontaminasi oleh debu dan kotoran dapat dihindari. Berdasarkan hasil sosialisasi dan workshop alat pengering yang dilakukan di desa Wringin Putih didapatkan bahwa penerapan teknologi pengering sangat membantu petani dalam penanganan pasca panen khusunya dimusim hujan. Prototipe alat pengering ini dirancang dengan konsep yang sederhana untuk dapat dibuat dalam skala rumah tangga. Bed pengeringnya dengan diameter 60 cm dan lebar 30 cm, serta menggunakan motor listrik dengan daya 1 HP. Diharapkan dengan adanya penerapan teknologi pengering ini dapat membantu penanganan pasca panen dari petani di desa wringin putih. Keywords— Padi, Natural Convection Dryer