The study linked below, from Virginia Tech (2013), contains some interesting conclusions (and a lot of math that you can safely skip):
The general gist is that energy (heat) lost during flue-curing is mostly from ventilation during the "leaf drying" phase. That is, considerable energy is lost as latent heat carried off by evaporation. Improving insulation of the flue-curing chamber can potentially reduce energy consumption by 8-25% overall. But only an elaborate, forced condensation apparatus (impractical for home flue-curing) can recover heat lost during the ventilation required during "leaf drying".
Bob
The general gist is that energy (heat) lost during flue-curing is mostly from ventilation during the "leaf drying" phase. That is, considerable energy is lost as latent heat carried off by evaporation. Improving insulation of the flue-curing chamber can potentially reduce energy consumption by 8-25% overall. But only an elaborate, forced condensation apparatus (impractical for home flue-curing) can recover heat lost during the ventilation required during "leaf drying".
Bob