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Abstract Engineering innovations—including those in heat and mass transfer—are needed to provide food, water, and power to a growing population (i.e., projected to be 9.8 × 109 by 2050) with limited resources. The interweaving of these resources is embodied in the food, energy, and water (FEW) nexus. This review paper focuses on heat and mass transfer applications which involve at least two aspects of the FEW nexus. Energy and water topics include energy extraction of natural gas hydrates and shale gas; power production (e.g., nuclear and solar); power plant cooling (e.g., wet, dry, and hybrid cooling); water desalination and purification; and building energy/water use, including heating, ventilation, air conditioning, and refrigeration technology. Subsequently, this review considers agricultural thermal fluids applications, such as the food and water nexus (e.g., evapotranspiration and evaporation) and the FEW nexus (e.g., greenhouses and food storage, including granaries and freezing/drying). As part of this review, over 100 review papers on thermal and fluid topics relevant to the FEW nexus were tabulated and over 350 research journal articles were discussed. Each section discusses previous research and highlights future opportunities regarding heat and mass transfer research. Several cross-cutting themes emerged from the literature and represent future directions for thermal fluids research: the need for fundamental, thermal fluids knowledge; scaling up from the laboratory to large-scale, integrated systems; increasing economic viability; and increasing efficiency when utilizing resources, especially using waste products. 

Worldwide, agriculture is responsible for two-thirds of water withdrawals because many productive, food-producing areas lack sufficient rainfall to grow crops without irrigation. In much of the Great Plains, the Ogallala Aquifer is the primary water source for food production, and diminishing water levels require improvements in sustainable agriculture. Reductions in soil evaporation rates will reduce irrigation demands and overall water consumption for crop production, thereby conserving water in areas such as the Ogallala Aquifer. In this study, evaporation of water is studied in a single pore comprised of three 2.38-mm diameter beads to simulate a soil pore. Evaporation times and high-speed imaging were recorded for hydrophilic (i.e., glass) and hydrophobic (i.e., Teflon) beads. Experiments were conducted with moist air at approximately 22.5 °C and approximately 60% RH. Water evaporated faster from the hydrophilic beads; contact line and angle dynamics were documented for hydrophobic and hydrophilic cases. The study found that for droplets on hydrophobic beads the evaporation times were on average 55 minutes and contact area decreased with evaporation. In contrast, water droplets on hydrophilic beads averaged evaporation times of 40 minutes and decreasing contact angle occurred during evaporation.