每 text Heat exchangers are equipment primarily for transferring heat between hot and cold streams.They have separate passages for the two streams and operate continuously.The most versatile and widely used exchangers are the shell-and tube types,but various plate and other types are valuable and economically or superior in some applications. 3 3 text 1-1 Heat exchangers are equipment primarily for transferring heat between hot and cold streams. They have separate passages for the two streams and operate continuously. The most versatile and widely used exchangers are the shell-and￾tube types, but various plate and other types are valuable and economically or superior in some applications