Design and Evaluation of a Novel Solar Biomass Hybrid Dryer with Cutting-Edge Resistive Heating Backup Technology

Abstract

Over population can have adverse effects on the food balance of a county. One of the major issues is the poor processing and preservation of food. it is a very big challenge for any country to meet the demand of the increasing mass. Many countries are still far away from ensuring electricity to the rural areas, let alone better food processing and storage technologies. In these scenarios solar dryer, which is, a very promising technology can be used to mitigate some of the problems related to food processing. However, traditional types of solar dryers have some disadvantages. A better efficient drying system can ensure more food safety and can be of financial help to farmers. This research was done to assess and enhance the drying efficiency of a hybrid solar-biomass dryer. Load of 4, 8 and 12 kg of cabbage were taken for the drying operation. The dryer was operation in three configurations based on energy source; sunlight heating, biomass heating and combination of sunlight and biomass heating. Different process parameters such as temperature of inlet, drying compartment and outlet, solar intensity, relative humidity, moisture amount of the product has been recorded. For 4 Kg batch, time require for drying were recorded to be 13, 8 and 7 hours for sunlight heating, biomass heating and combination of sunlight and biomass heating respectively. For 8 Kg load, the needed time was 19, 13 and 12 hours respectively and for 12 Kg load it was 20, 17 and 12 hours of drying. The highest moisture evaporation rate was observed to be 766.15 g water per hour for 12 Kg load during drying with combined source of sunlight heating and biomass heating. Lowest margin of 261.53 g water per hour was found for sunlight heating. From the analysis it is found out that Hybrid heating configuration has the highest thermal efficiency of 61%. Compared to hybrid, using only biomass heating and sunlight heating has efficiency of 33% and 39% respectively. Exergy efficiency was also analyzed which showed that hybrid configuration has the height exergy efficiency of 46% followed by 37.7% and 33% by sunlight heating and biomass heating combinedly. The results shown that the combination of sunlight and biomass heating has better drying rate and efficiency thus can be a very promising method for food drying. To increase the efficiency and drying performance even more resistive heating mechanism in place of biomass heating has been considered. It was observed that the sun intensity has a major influence on the system's total efficiency. To reduce dependency on the sun and ensure continuous drying capability even in off sunshine hours resistive heating coil has been selected as alternative power source. Solar energy combined with resistive heating makes the system lighter and more portable in the field, where it is essential to have this 6 alternative in rural areas. It may also be powered by energy from the main grid, making it more useful for residential use and food processing when necessary. The assessment of the resistive heating dryer's performance will also make it possible to determine whether the technology is still viable for use in large-scale industrial production with a precise drying process control system. The study's discussion of future possibilities and adaptability in light of the Fourth Industrial Revolution will serve as a foundation for further research on this technology.