Design and fabrication of an intelligent solar-photovoltaic hybrid tunnel dryer for tomatoes with automatic temperature control and air recirculation.

The agricultural sector in most developing countries encounters a lot of post-harvest losses due to a lack of appropriate drying and storage facilities for preservation. Though many drying technologies have been developed, there is an increasing demand for automation in drying. Concerning this limitation, this work presents the design and fabrication of an intelligent solar-photovoltaic hybrid tunnel dryer for tomatoes with automatic temperature control and air recirculation. The entire dryer assembly consists of the main dryer itself, a solar photovoltaic system, and a control unit. The dryer was tested through the performance of seven experiments; three experiments where done for the sake of testing and making adjustments on the control unit to check if the current from the Arduino digital pins is sufficient enough to energise the relay coils in which in the course of these three experiments, a current booster was designed and fabricated. The fourth experiment was the no-load experiment where the average drying chamber temperature was obtained to be 59.95℃. The fifth experiment was a load experiment, the sixth experiment was to determine the collector efficiency which was 67.06%, and the seventh experiment was another Load experiment whose main purpose was to determine the energy consumed by the electric heater for drying tomatoes and dryer performance. The dryer performance was determined using the two load experiments. In the Load experiments, freshly bought tomatoes from the local market were washed and sliced to a 700g mass and placed in the drying chamber. For the first and second load experiments, the tomato was dried from an initial moisture content of 95% (wet basis) to a final moisture content of 5.30% and 9% (wet basis) respectively. The respective drying chamber efficiencies were 10.24% and 16.16%, the drying efficiency of 31.53% and 41.41%, the drying rate of 66.31g/h and 73.51g/h for an average solar irradiance of 0.678KW/ ��2 and 0.572kw/m2 average ambient temperature of 22.706 ℃ and 31.482℃, ������ average drying chamber temperature of 60.33℃ and 60.27℃, for 9 hours and 8 hours respectively. The total energy consumed by the heater in the second load experiment was 1562.87 kJ.

Grantor dc:publisher

The University of Zambia

Year dc:date.issued

2022

Author dc:creator

• Tambe, Achalle Joseph

• Food--Preservation.
• Food--Drying.
• Canning and preserving.
• Tomato drying.

Language dc:language.iso

en

Repository record dc:identifier.uri

http://dspace.unza.zm/handle/123456789/8048

OAI identifier oai:identifier

oai:dspace.unza.zm:123456789/8048