To improve a heat exchange efficiency of a circulating cooling water by enabling heat exchanging elements to be simply assembled in a little steps only by inserting and assembling the predetermined number of closed heat exchangers previously molded in a zigzag manner between a pair of supporting side plates, by preparing the predetermined number of the closed exchanges, and assembling the elements so as to apply scattering water even to bent parts.

A method for assembling the heat exchanging elements comprises the steps of preparing the predetermined number of the closed heat exchanges B each made of a heat exchanger coil formed by previously connecting a pipe 11 with a U-bent tube 12 and molding one pipe in the zigzag manner, inserting the outside of the bent part 12a of each of the U-bent tubes 12 of the closed heat exchangers B from the inside of a long lateral groove 16 of the support 14, and supporting a plurality of the exchangers B between the pair of the support side plates 13. Thus, the heat exchanging elements T are simply assembled.