The use of solar energy in open sun drying in traditional way of drying crops, fruits, vegetables etc. The greenhouse drying is one of the techniques which overcome the problems associated with open sun drying. In the present work, an... more
The use of solar energy in open sun drying in traditional way of drying crops, fruits, vegetables etc. The greenhouse drying is one of the techniques which overcome the problems associated with open sun drying. In the present work, an effort is made to improve the drying rate of traditional greenhouse dryer. An experimental investigation using tomato flakes has been done to compare the drying rates of both traditional as well as modified greenhouse dryers. Better drying conditions- high temperature & low relative humidity are found out to be for modified greenhouse dryer. Experiments were performed in October 2016.
Moisture removal from crops and other food items is one of the ways to preserve them for longer duration. Previously, drying openly in sun was used to reduce moisture content. But it had some disadvantages like contamination due to dirt... more
Moisture removal from crops and other food items is one of the ways to preserve them for longer duration. Previously, drying openly in sun was used to reduce moisture content. But it had some disadvantages like contamination due to dirt and other unwanted elements as well as attack by rodents and birds. Drying in covered close space with vents would be helpful in overcoming these problems. Solar greenhouse dryers are the close conduits in which crops can be dried without negatively affecting the nutrition value. The factors affecting the crop drying are solar radiation, climatic conditions, material of which the dryer is made of and shape of the dryer. A lot of experimental investigations have been done to improve the drying rate. With the advances in computational power and numerical techniques, Computational Fluid Dynamics (CFD) has emerged as a powerful tool to optimize any design. In the present study, simulations have been done on greenhouse dryer with modifications to identify the temperature distribution with variation in wind velocity. Different radiation levels have also been found out at different locations in the dryer. The model of the dryer has been created in CREO 5.0 and analysis has been performed using ANSYS 14.0. The simulation has been done for both forced and natural convection. Obtained results have been validated with the experimental work done by previous works. Better drying rate has been obtained for forced circulation as compared to natural convection which is in agreement with the available experimental results.
The greenhouse solar dryer which has the capacity of 1kg was designed, fabricated and tested for the main parameters measurement. The main parameters of temperature, relative humidity, correlation with solar radiation, initial and final... more
The greenhouse solar dryer which has the capacity of 1kg was designed, fabricated and tested for the main parameters measurement. The main parameters of temperature, relative humidity, correlation with solar radiation, initial and final moisture contents, reduced weigh measurement and drying efficiency of the designed greenhouse dryer were measured and calculated. In relative humidity measurement session, it is almost the same in relative humidity inside and outside of the greenhouse dryer. In drying temperature measurement results, while the open sun drying is around 40°C, the greenhouse dryer reach 50°C as a maximum result for all three test products. In moisture reduced measurement, GH dryer is 20% better for moisture removing in tomato, 10% in okra and banana.
