Water-Energy Nexus highlights the relationship and mutual dependence between water and energy. Our research focuses on developing innovative waste-to-value solutions within this nexus to address global challenges in energy, water, and environmental sustainability. We designed a highly efficient hot water generation system powered by biomass gasification, doubling the efficiency of conventional setups while driving an off-the-grid climate control unit (CCU) for storage, drying, and farming applications. A modified atmospheric water harvester is designed and developed to address the freshwater scarcity, particularly in arid regions. An ultrasonic humidifier is integrated with a classical AWH system, to harvest water under extreme hot and dry conditions, showcasing its potential for sustainable water generation in harsh environments. The incorporation of eco-friendly refrigerants and modified superhydrophobic surfaces further enhances system efficiency by improving condensation and energy performance. Additionally, optimized ammonia-calcium chloride composites ensure stable and sustainable cooling solutions. These innovations meet the interconnected demands of water, food, and energy, offering scalable and environmentally conscious technologies to support global sustainability.