Energy, economic, and environmental (3E) impacts assessment of low-grade waste heat recovery in a food dryer incorporating an innovative porous [formula omitted] core heat exchanger

Abstract

This research focused on evaluating the effects on energy consumption, economic aspects, and environmental consequences associated with the utilization of low-grade waste heat recovery (WHR) within a small-scale food drying apparatus known as a laboratory-scale food dryer (LSFD). A regenerative heat exchanger comprising a porous Al2O3 core resistant to corrosion and rust is used for WHR. The operation duration of the LSFD was considered 10 hour/day, and 365 day/year. The emission intensity value of 506 gCO2/kWh was taken into account for fossil-fuel-based power generation. Investigations were conducted via the Taguchi optimization method in conjunction with cost-benefit analysis. Results indicated that WHR within LSFD can achieve energy savings ranging from 5.148 to 12.966 MWh/year with a saving efficiency of 26.32 %, leading to saving 219.54–552.88 USD2023/year with a payback period of 1.06–2.67 years and 848.36–2136.45 USD2023/year with a payback period of 0.27–0.69 years for the average (0.162 USD2023) and maximum (0.626 USD2023) electricity prices, respectively. This strategy prevents emitting the 2.61–6.56 tCO2/year with a mitigation rate of 112.98–284.53 kgCO2 with every 1 ℃ rise in temperature of preheated air. CO2 emission conversion factors were ultimately presented for diverse parameters.