What is it about?

World Food Program reports that more than 821 million people are subjected to acute hunger despite sufficient amount of food being produced. One of the underlying reasons is the food wastage due to poor preservation techniques and the energy cost of the established processing methods. Drying techniques are an effective means for reducing post-harvest food loss. However, the existing industrial drying techniques consume 20–25% of the energy used in the food processing chain. A system that utilizes the waste heat recovered from a diesel engine exhaust flue gas is proposed and an initial prototype tested. The system requires no external energy to operate the drying process; hence no CO2 is generated as a result of this process. Furthermore, the entropy is reduced by 0.206 kJ/kg.K as the overall thermal efficiency increases by 8.46%. It is estimated that the payback period is in the range of 321 days. Drying experiments were conducted to assess the dried food quality of five different staple food products, i.e. potato, pumpkin, carrot, radish, and apple. The drying performance (moisture removal rate) and product quality (Color analysis) conformed to the current industry standard. The overall performance assessment suggests that the system has the potential to reduce current levels of emission in food drying process and could be a stepping stone towards the development of energy-efficient food preservation technique.

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Why is it important?

Our findings show that waste heat recovered from various types of heat engine (diesel engine) can be used to dry food. Waste heat convective dryer (WHCD) can potentially reduce portion of fossil-based energy used for drying (25% of total consumed energy) in food industry. Change of color delta E for all WHCD dried products ranges between 11 and 17. This is an inexpensive technology which can be integrated with any existing heat engine plant. Moreover, the system has low break even point and easy maintenance process.


I hope this innovation will reduce the carbon emission from drying industry and reduce the cost of food preservation.

Anan Ashrabi Ananno
Rajshahi University of Engineering and Technology

Read the Original

This page is a summary of: Experimental investigation of a novel waste heat based food drying system, Journal of Food Engineering, March 2020, Elsevier, DOI: 10.1016/j.jfoodeng.2020.110002.
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