Combined Thermoelectric Power Generation and Passive Vacuum Desalination

This paper proposes a passive water desalination system combined with thermoelectric power generation. Desalination is achieved by reducing the saturation temperature of saline water through vacuum. The vacuum is generated using 5m of negative head (drop), which significantly reduces the boiling temperature of water. The thermoelectric generator unit (TEGU) uses four thermoelectric cells to generate electricity using Seebeck effect. The cold side temperature of TEGU is maintained by the reduced saturation temperature of saline water, and temperature for hot side can be provided by low grade heat source, e.g. solar, waste heat. The heat transfer through the system is a transient to steady state conduction, and theoretical calculations show that an absolute pressure of 50 kPa can be achieved in the system which reduces the saturation temperature to around 80 °C. Thermal resistance and heat flow networks are used to validate fresh water output, evaporation, and condensation rates based on input heat. The objective is to achieve proof of concept through experimental model, and thermal analysis. Further research is directed into elimination of non-condensable gases in the system and use of passive condensation techniques to reduce energy input.