Moist air conversion to water and power by a system that uses atmospheric water vapor as its fuel is described. Water vapor is separated from moist air using a vapor separation barrier system. This system has atmospheric pressure on one side of the barrier and the opposite side has a low pressure maintained by the inlet of a vacuum pump/compressor system. The pressure difference across the barrier promotes water-vapor transport through the barrier into the vacuum-pump inlet. Additional compression is necessary to raise the water-vapor pressure and temperature to values appropriate for efficient energy transfer and condensation. The magnitude of compression depends on the ambient water-vapor concentration that varies with location and season. Intercooling between compressors and the magnitude of compression are issues. In this paper the use of a two-compressor system without intercooling is developed and applied to Miami, FL, during the summer. Output power calculations are modeled as an improved Rankine-cycle with reheaters, regenerators, and feedwater heating to improve overall cycle efficiency. The net power output for a water-vapor throughput of 1 kg/s (2.204 lbm/s) is +151.1 kW (+515.5 kBtu/hr) with the water discharged from the system as a liquid. A turbine-based power extraction system is described that uses the warmed cooling fluid flowing from the steam condenser following the main turbine for power production. This system converts approximately 1% of the heat from the condenser into power. System calculations are specific to humid coastal areas, such as Miami, FL.
Improvements to Converting Moist Air Into Water and Power
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Vidmar, RJ. "Improvements to Converting Moist Air Into Water and Power." Proceedings of the ASME 2009 Power Conference. ASME 2009 Power Conference. Albuquerque, New Mexico, USA. July 21–23, 2009. pp. 551-560. ASME. https://doi.org/10.1115/POWER2009-81023
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