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• A MVCHP coupled HD desalination system with packed bed dehumidifier is proposed. • Energetic and entropic analysis is achieved with the modified effectiveness during humidification. • The top water production and GOR of the HD desalination system reach 71.56 kg h−1 and 5.28. • The cost of the produced water is obtained as 0.018 $ L−1 with a lifetime of 10 years. • Advantages of energy conservation for the HD desalination system are proved. In this paper, the humidification dehumidification (HD) desalination system, driven by a mechanical vapor compression heat pump (MVCHP), is proposed. The direct contact dehumidifier, with packings filled, is applied to condense the humid air for water producing. On the basis of the thermodynamic laws, the energetic and entropic analysis, with the modified effectiveness to describe the heat and mass transfer characteristics of humidification, are first achieved to assess the desalination performance of the combined system. The influence laws from the terminal temperature difference (TTD) of the evaporator, the pressure ratio (PR) during compression and pinch temperature difference (PTD) of the condenser on the desalination performance are also explored and presented. The research results presented that the top thermodynamic performance of the MVCHP coupled HD desalination system arises as 71.56 kg h−1 for the water production, 5.28 for the gained-output-ratio (GOR) and 1.73 kJ kg−1 K−1 for the specific entropy generation rate, while two fully coupled cases at 1.21 and 1.96 for the mass flow rate ratio will emerge. It is found that water production can be elevated effectively through increasing the pressure ratio, while the peak value of GOR keeps at the design conditions. Furthermore, the positive effects from lower values both for the TTD e and PTD con on the performance of the MVCHP coupled HD desalination system are proved. After the economic analysis, it is calculated that the cost of fresh water is about 0.018 $ L−1 with a lifetime of 10 years. According to the performance comparison, the great potential of energy conservation for the MVCHP coupled HD desalination system are validated, although the water production will be reduced after the integration of the MVCHP. [ABSTRACT FROM AUTHOR]

In this paper, a water-heated humidification dehumidification (HDH) desalination system, which is powered by the waste exhaust gas from a furnace, is applied to produce water. In order to overcome the corrosion from the seawater on the dehumidifier with a general heat exchanger, the packed bed is used to achieve the dehumidification process. Based on the mathematical models for the HDH desalination system, the relevant thermodynamic and economic performance are acquired. Furthermore, the influences from the effectiveness, top and ambient temperatures on the aforementioned performance are also investigated. The simulation results show that peak values of the water production and gained-output-ratio (GOR) are obtained as 84.60 kg h −1 and 1.44 at the balance condition of the dehumidifier. The total cost for all the heat and mass transfer areas rises from 470.81$ to 701.46$ when the mass flow rate of the dry air increases from 0.1 kg s −1 at to 0.5 kg s −1 , while the unit cost of water production (UCWP) ascends from 6.20$ kg −1  h to 13.41$ kg −1  h. Furthermore, raising the effectiveness, reducing the spraying temperature into the humidifier is always effective to cut the unit cost of water production, while it is only useful within a limited range of air mass flow rate for a higher ambient temperature. [ABSTRACT FROM AUTHOR]

Humidification dehumidification (HDH) processes have been proved to be efficient for producing freshwater from seawater or brackish water. In this paper, an HDH desalination system, in which the seawater is appointed to recover the waste heat, is suggested. Based on the principles of mass and energy conservation, mathematical models for all the contained components as well as the entire desalination system, are built, and then the relevant thermo-economic analysis is also accomplished. The simulation results show that peak values of water production with m w  = 99.05 kg h −1 and gained-output-ratio (GOR) with GOR  = 1.51 are obtained when the balance condition of the dehumidifier appears at the design conditions, while a bottom value of unit cost of water production (UCWP) is found as UCWP  = 37.68$ kg −1  h at the case of m da  = 0.14 kg s −1 . Hence, the great advantages at the aspect of cost for unit water production compared to the solar drive type is validated. It is also found that reducing the seawater spraying temperature and elevating the humidification effectiveness are beneficial to raise the relevant thermodynamic and economic performance of the desalination system. With respect to the variation for dehumidification effectiveness, the peak value of GOR rises from GOR  = 1.28 at ε d  = 0.8 to GOR  = 1.85 at ε d  = 0.9, while a peak value of UCWP is obtained as UCWP  = 50.12$ kg −1  h due to the substantial increase of the heat transfer area for the dehumidifier. [ABSTRACT FROM AUTHOR]

Humidification dehumidification (HDH) technology is efficient to evaporate freshwater from seawater or brackish water. In this paper, a water-heated HDH desalination system to recover waste heat through plate heat exchangers (PHEs) is proposed, and heat and mass coupled processes are both applied in the humidifier and dehumidifier. In view of the mathematical models based on energy equilibrium and entropy generation, characteristics of the advised desalination system at different appointed key parameters are calculated and analyzed. Surface areas involved in the PHEs, which contain the low grade heat collector (LGHC) and the hot water recuperator (HWR), are obtained. The simulation results show that the modified heat capacity ratio (HCR) of the humidifier, HCR h , is always at HCR h >1 for the prescribed operation conditions, while the balance condition of the dehumidifier, HCR d = 1, is available, which is significant for the performance of the HDH desalination system. A maximum value of GOR, GOR = 2.01, is attained corresponding to the minimum irreversible loss of the whole desalination system. Furthermore, in consideration both of the heat and mass transfer area as well as the water production, the unit cost is acquired as C u,c = 26.94￥t-1h and Cu,t = 68.13￥t-1h, which indicates a great superiority of the HDH desalination system using a direct-contact dehumidifier compared with the traditional type. [ABSTRACT FROM AUTHOR]

• Open-air, open-water configurations are introduced into the HD desalination method. • Energetic, entropic and economic analysis for the HD desalination system is conducted. • Influences from the effectiveness on the desalination performance are focused. • Performance comparison between the current and previous systems are collected. In the present paper, an open-air, open-water configuration is introduced into the humidification dehumidification desalination system, to recover the industrial waste heat. Thermodynamic performance, from the energetic and entropic standpoints, and the relevant economic performance of the desalination system are acquired. The theoretical analysis shows that top water production, gained-output-ratio and specific energy consumption reach 96.45 kg h−1, 1.70 and 0.38 kWh kg−1, respectively, while the lowest investment and cost of water production arrive at 848.86$ and 8.04 × 10−3$ kg−1. It is concluded that the thermodynamic performance and cost of water production for the desalination system will benefit, once the humidification and dehumidification effectiveness rise, while the bottom investment is found at a lower humidification effectiveness. Furthermore, the performance comparison between the newly proposed and previous solar and heat pump powered desalination systems confirms the economic advantages. [ABSTRACT FROM AUTHOR]