Thermal investigation and performance analysis of a novel evaporation system based on a humidification-dehumidification process

A novel humidification-dehumidification (HDH) system is designed to enhance the evaporation capacity. A more rigorous mathematical model of humidifier is proposed. A simulation programme of the whole system is built. Theoretical investigation is performed to investigate the effect of various parameters on the evaporation capacity and gained input ratio. The results demonstrate that the reflux ratio and inlet solution temperature of the humidifier are proportional to the evaporation capacity. An optimum mass flow rate of air exists for which the evaporation capacity is maximized. The gained input ratio (GIR), defined as the ratio between the total latent heat of evaporated water and the external heat input, decreases with the increase in air mass flow rate and increases with the increase in the reflux ratio. The optimum value of the gas-liquid ratio for maximum evaporation capacity is near 1.17, regardless of conditions. A multi-index comprehensive evaluation is introduced to assess the overall performance of the system. And a practical case is carried out to illustrate how to select the optimum operational parameters under different circumstances.