(498f) Integrated Thermochemical Conversion and Energy Modeling Strategies for Decarbonizing Controlled Environment Agriculture

As the demand for year-round food production accelerates, Controlled Environment Agriculture (CEA) has emerged as a promising yet energy-intensive strategy for growing fruits and vegetables. This study presents a techno-environmental framework that integrates quasi-steady state greenhouse energy modeling with catalytic hydrothermal liquefaction (HTL) of biomass residues to reduce the carbon footprint of greenhouse operations. This work is a component of a USDA-funded Sustainable Agricultural Systems (SAS) project aimed at reimagining CEA through integrated plant breeding, waste valorization, energy efficiency, and systems-level modeling.

A quasi-steady state energy model was developed for a passively ventilated greenhouse located in Auburn, Alabama, incorporating local climate data and detailed envelope characteristics. The analysis revealed annual thermal loads of 434 kWh/m², with heating (231 kWh/m²) and cooling (203 kWh/m²) demands highly sensitive to transmittance, ventilation rate, and U-values. Design interventions based on parametric analysis highlighted strategies for passive energy savings and climate resilience.

Simultaneously, tomato plant residue (TPR), a major waste stream from greenhouse cultivation, was converted via HTL under subcritical conditions (260–320 °C) using various solvents and catalytic blends of MgO and ZSM-5. Optimal biocrude yield (35 wt.%) and ester selectivity (~91%) were achieved with methanol at 290 °C and a MgO:ZSM-5 ratio of 2:1. GC–MS analysis revealed abundant methyl esters and phenolic compounds, suggesting strong potential for downstream fuel or chemical applications. The process also demonstrated energy densification and improved HHV.

This work exemplifies the circularity principles at the heart of the SAS project—converting underutilized biomass into value-added fuels, reducing greenhouse energy inputs, and supporting system-wide decarbonization. By combining energy systems modeling with catalytic reaction engineering, this study provides a pathway for designing scalable, low-carbon CEA infrastructures that can contribute to a more climate-resilient food system.