Drying characteristics, environmental and economic analysis of a solar dryer with evacuated tube solar collector for drying Nile Tilapia slices.

Lake Nasser in Egypt contains significant tilapia fish quantities, yet consumption remains low due to its geographical isolation from marketing and consuming areas. Therefore, investigating efficient and economical Tilapia fish drying methods is essential. The current study developed and tested a solar dryer based on solar energy collection, using evacuated tubes at three Nile Tilapia slice (NTS) thicknesses of 4, 8, and 12 mm, and an air velocity of 0.5 m/s. The obtained result of the solar dryer with evacuated tubes (SDET) was compared with the other results of the oven liquid petroleum gas (OLPG) as an industrial drying method. The results obtained showed that the air temperature inside the drying room of the SDET ranged between 44 and 75 °C. The average initial moisture content (MC) was 74.83% (w.b.). For both systems, the drying time ranged between 13 and 17 h at the same slice thickness. The effective moisture diffusivity was in the range of 0.87 × 10 to 5.66 × 10 m/s. Furthermore, the mathematical modeling revealed the Modified Midilli (II) and Modified Henderson and Pabis models as the most suitable models to describe the drying behavior of NTS dried on SDET. On the other hand, the environmental analysis indicates that the developed SDET can mitigate approximately 273.6 tons of CO during its lifetime, resulting in a carbon credit equivalent of approximately 19,838.89 $. Additionally, the economic analysis of the SDET showed that the annual production of dried fish was 450 kg; this may result in substantial cost savings, amounting to a total of 608.4 $ per year. Also, the developed SDET had a payback period of approximately 0.413 years or less than half a year.