here a regeneration heat exchanger 170 may be additionally installed to enhance thermal efficiency by allowing heat exchange to be performed between the circulating liquid desiccants that is heat exchange is performed between the liquid desiccant moving from the first heat and mass exchange module to the second heat and mass exchange module and the liquid desiccant moving in the opposite direction in the regeneration heat exchanger 170 thereby reducing energy required to cool or heat the liquid desiccants fig3 shows a structure of the first heat exchanger 124 since the second heat exchanger 134 has the same structure as the first heat exchanger 124 its detailed explanations will be omitted the first heat exchanger 124 comprises a plurality of heat exchanger bodies 200 arranged in parallel cooling water supplied from the outside flows into the heat exchanger bodies 200 in a length direction of the heat exchanger bodies 200 the cooling water is heat exchanged with the liquid desiccant or air disposed on the surfaces of the heat exchanger bodies 200 thereby cooling the liquid desiccant or the air the heat exchanger bodies 200 are formed of a corrosion resistance material capable of enduring high corrosion of the liquid desiccant in the preferred embodiment the heat exchanger bodies 200 are formed of polypropylene pp plastic a folded plate 210 is arranged between the heat exchanger bodies 200 so as to extend a heat exchange area the folded plate 210 is configured by folding one plate in a zigzag form and.