A Digital Modelling Framework for Low-Pressure Distillation: Thermodynamic Performance and Desalination Comparison

The escalating global freshwater crisis, exacerbated by climate change, industrialization, and population growth, necessitates sustainable and energy-efficient desalination technologies. While conventional methods like Reverse Osmosis (RO) and thermal distillation are widely adopted, they pose significant challenges in terms of energy consumption, operational complexity, and environmental impact. This research introduces and evaluates Low Pressure Distillation (LPD) as a promising alternative to overcome the limitations of existing systems. LPD capitalizes on the thermodynamic principle that lowering ambient pressure reduces the boiling point of water, allowing evaporation at significantly lower temperatures. This study investigates the theoretical and empirical underpinnings of LPD, developing a mathematical model based on energy balance and Rohsenow's correlation to simulate mass and heat transfer under sub-atmospheric conditions. Simulation parameters—such as vacuum pressures (0.1–0.05 atm), varying heat inputs (500–1500 W), and surface area—are explored to estimate freshwater yield and energy efficiency. The findings demonstrate that LPD achieves substantial energy savings (up to 50%) compared to conventional methods while maintaining effective desalination performance. Additionally, integration with low-grade heat sources like solar thermal energy is shown to be feasible and scalable for decentralized applications. Graphical analysis and validation against experimental data confirm the model's accuracy and practical relevance. Overall, LPD presents itself as a sustainable, modular, and environmentally friendly solution for water-stressed regions, especially where access to conventional infrastructure or grid power is limited. This study lays a foundational framework for the development and deployment of next-generation desalination systems optimized for low-energy, off-grid environments.