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Feasibility of Advanced Water Purification Processes
Published in Frank R. Spellman, Land Subsidence Mitigation, 2017
The heat transfer surface area for each effect is inversely proportional to the net temperature difference available for that effect. Increasing the number of effects reduces the temperature difference and evaporation duty per effect, which increases the total area of the evaporator in rough proportion to the number of effects. The temperature difference available to each effect is reduced by boiling point elevation and by the decrease in vapor saturation temperature due to pressure drop. The boiling point elevation of a solution is the increase in boiling point of the solution compared to the boiling point of pure water at the same pressure; it depends on the nature of the solute and increases with increasing solute concentration. In a multiple-effect evapo- rator, the boiling point elevation and vapor pressure drop losses for all the effects must be summed and subtracted from the overall temperature difference between the heat source and sink to determine the net driving force available for heat transfer.
A review of desiccant evaporative cooling systems in hot and humid climates
Published in Advances in Building Energy Research, 2021
Ismanizam Abd Manaf, Faisal Durrani, Mahroo Eftekhari
Other parameters indicated desiccant materials performance are (Shukla & Modi, 2017): (i) availability and cost, (ii) energy storage density, (iii) regenerating temperature, and (iv) Boiling Point Elevation (BPE). Shukla and Modi (2017) also listed a selection of an ideal liquid desiccant commonly based on following characteristic of: non-toxic, non-flammable, non-volatile, non-corrosive and chemically stable, large saturation absorption capacity, high heat and mass transfer coefficients, less power required for the blower/fan, odourless, less expensive, low viscosity, continues absorption-desorption process, low regeneration temperature, and air sterilization is possible as required in hospitals. However, all these requirements are not fully covered by a single desiccant. The drawback, the high cost of lithium-based solutions represents an obstacle to their use in solar liquid desiccant cooling systems, where large solution storage capacities are needed for providing cooling during the hours with low solar radiation (Gómez-castro et al., 2018).