Exergy Analysis of a Sugarcane Crop: A Planting-to-Harvest Approach

Abstract

The objective of this study was to conduct an exergy analysis of sun–plant interactions in sugarcane using mathematical models, aiming to estimate plant production and exergy flows and describe their photosynthetic efficiency during sugarcane cultivation. Sugarcane productivity was determined based on the Brazilian BRCANE model. The efficiency of this crop was evaluated through a simple control volume, where the exergy of solar radiation serves as the sole energy input, and the exergy of the culms and straw represents the useful exergy. The findings revealed an average second-law efficiency of 5% for sugarcane photosynthesis production from solar radiation, with an estimated harvest of approximately 16.29 kWh/m2 of useful extended exergy after a year, and an estimated water consumption of 111.2 m3/ton of harvested stalks. Moreover, this study highlights that exergy efficiency varies significantly in response to seasonal changes. The method developed here can be utilized in future studies to estimate mass and energetic flows and exergy analyses.