.Unit 19 Types of Heat ExchangersHeat 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 competitive or superior in some applications.These other types will be discussed briefly but most of the space following will be devoted to the shell-and-tube t