Design and Performance Evaluation of a Mixed-Mode Solar Crop Dryer

Abstract

This study is concerned with development and performance evaluation of a mixed-mode solar yam dryer. It was done to address the problems of uneven drying of product on different trays coordinate position in a typical indirect multiple trays dryer. Solar energy drying system was designed using the meteorological conditions of Zaria, Nigeria to dry yam slices in the mixed-mode natural convection. The dryer was designed to dry (7 kg) of yam slices. The dimensions of the dryer were: collector length, collector area, height of the drying chamber, chimney height, length of the drying chamber, and Width of the drying chamber were 0.65 m, 0.27 m2, 0.9 m, 0.7 m, 0.5 m, and 0.43 m, respectively. The solar yam dryer was exposed to solar radiation from 10:00 am to 06:00 pm and tested without load and with yam chips of 5 mm average thickness. Meteorological conditions were monitored during the dehydration process. The average drying rate, collector efficiency and drying efficiency were 2.55 kg/s, 42.20% and 25.35%, respectively. The results of performance evaluation of the solar dryer showed that the drying rate decreases by 3% and 8% in the second and third trays relative to the first tray. This shows that the drying rates did not vary significantly with the coordinate positions of the trays.

Design, Construction and Performance Evaluation of Ginger Mixed Mode Solar Dryer Integrated with Latent Heat Storage

“…At 17:00 hours, the drying tray temperature started rising above the temperature of the other part of the system and sustained till the 21:00 hours. The plot above is in agreement with the studies conducted by (Abubakar et al, 2018) as regards to how the collector outlet air temperature varies with the tray temperature. Although, the tray temperature has to be higher than the collector outlet temperature as it implies that the drying chamber has actually sustained substantial amount of heat energy to effect the drying of ginger.…”

“…The presence of PCM has helped to compensate for the fluctuation between 12:00 hours and 14:00 hours as the tray temperature did not drop much like others. Among all research works done on solar crop drying in Zaria before this present study, only (Abubakar et al, 2018) explored the concept of thermal energy storage. He used black coated gravels as materials, he placed reasonable quantity of gravels in the solar collector then channelled to a drying chamber to dry 7kg of yam slices.…”

Design and performance evaluation of a passive flat plate collector solar dryer for agricultural products

“… The drying s assumed to occur in steady state condition. Velocity of the drying air ( v c ) at the exit of the FPC is considered between 0.2 and 0.5 m/s (Abubakar, Umaru, Anafi, Abubakar, & Kulla, 2018; Macedo & Altemani, 1978). Mass flow rate of the air during natural convection in solar dryer is 0.02 to 0.9 kg/s (Forson, 1999).…”

“…• Velocity of the drying air (v c ) at the exit of the FPC is considered between 0.2 and 0.5 m/s (Abubakar, Umaru, Anafi, Abubakar, & Kulla, 2018;Macedo & Altemani, 1978).…”

Nuevo diseño y aplicación para secadores solares activos y pasivos en la región Huetar Norte de Costa Rica

“…La alta humedad hace que los cultivos sean propensos a infección por hongos, ataque de insectos y plagas. Los secadores solares remueven la humedad sin el ingreso de polvo, y el producto puede ser preservado por un periodo más largo de tiempo [10], [12].…”