Exergy analysis of a wood-stack during dehumidifier drying

Abstract

We present a first order model of airflow within the wood stack of a timber dryer during the constant-rate drying period, allowing the exergy destruction and entropy generation rates to be determined for heat, mass and momentum transfer. The effects of varying timber stack and airflow variables on the entropy generation rate are determined. We find that heat transfer is the dominant contribution to entropy generation and observe a well defined minimum in the specific exergy loss rate as a function of relative humidity. Stack design parameters that minimise the overall exergy destruction rate are determined.