Drying is one of the most energy‐intensive operations in biomass and food processing, influencing both economic viability and environmental sustainability. Intermittent drying (ID) is often regarded as a more energy‐efficient alternative to continuous drying (CD), but this assumption has rarely been validated under fair conditions. This review and meta‐analysis systematically reassessed the energy performance of ID and CD using published quantitative data. A structured search and selection strategy identified studies directly comparing both drying modes. Published results were quantitatively reassessed and integrated across studies. Reported energy data were recalculated under fair comparison conditions (equal total drying time and comparable final moisture content) to eliminate artefacts such as over-drying. This approach enabled a robust evaluation of the central question: under what conditions does ID deliver genuine energy savings over CD? Three parameters—biomass wetness, sample thickness, and drying temperature—emerged as strongly associated parameters determining when ID can outperform CD in energy use. The study introduces conceptual explanations, including the thermodynamic minimum drying energy, the ‘energy-river’ regime of practical dryers, and the role of over-drying in CD. Moreover, it was concluded that higher CD temperatures enhance moisture diffusivity, often offsetting the advantages attributed to ID. Therefore, ID can provide energy savings only under specific experimental conditions and for particular biomass properties. This meta-analysis links thermodynamic limits with experimental performance, redefining the criteria for evaluating drying efficiency and clarifying when ID achieves real energy benefits. • Meta-Analysis establishes thermodynamic limits for intermittent drying. • ID saves energy only for thick, wet biomass under specific conditions. • The “energy river” model explains true efficiency losses in drying systems. • Reported energy savings from intermittent drying are often overestimated.
Nazemi et al. (Wed,) studied this question.