A novel integrated system for fresh water production in greenhouse: Dynamic simulation

• A new design for fresh water production from seawater in greenhouse is purposed.
• Application of direct contact dehumidification instead of indirect condensers.
• An economical solar water heater purposed to increase fresh water production rate
• Estimation of fresh water production in any time of the year by dynamic simulation
• Water production rate can be reached 6 to 22 (m3/day/ha) with this method.

Solar humidification–dehumidification (HD) desalination can be used for fresh water production from seawater in greenhouse. In this paper, a new design for an integrated system is proposed and evaluated to improve performance of fresh water production from seawater in greenhouse by two major changes: first, using a direct contact dehumidifier (DCD) instead of common indirect condensers and second, applying a more efficient and economical solar water heater (SWH) system. DCD can solve many problems of indirect condensers that are reported in previous studies. Also, for increasing driving force of mass transfer in DCD, an efficient SWHS increases the hot water temperature in the humidifier. Humidifier and dehumidifier were modeled and solved based on finite deference method. SWH system was dynamically modeled to predict the storage tank temperature at any time of the day and for various months of the year. The completed model, including the SWH system and the desalination unit, solved to estimate the fresh water production of the system. Results show that the proposed system can produce 6–22 (m3/day/ha) fresh water in various days of the year. Also it can solve many operational problems of the indirect condensers that can help the commercialization of this technology.