ABSTRACT

In order to develop relationships between the heat transfer rate q, surface area A, uid terminal temperatures, and ow rates in a heat exchanger, the basic equations used for analysis are the energy conservation and heat transfer rate equations [1]. The energy conservation equation for an exchanger having an arbitrary ow arrangement is

q C t t C t t= − = −h h,i h,o c c,o c,i( ) ( ) (2.1)

and the heat transfer rate equation is

q UA t t

R = =∆ ∆m m

o (2.2)

where ∆tm is the true mean temperature difference (MTD), which depends upon the exchanger ow

arrangement and the degree of uid mixing within each uid stream Cc is the capacity rate of the cold uid, (Mcp)c Ch is the capacity rate of the hot uid, (Mcp)h tc,i and tc,o are cold uid terminal temperatures (inlet and outlet) th,i and th,o are hot uid terminal temperatures (inlet and outlet)

The heat exchanger thermal circuit variables and overall conduction described here are based on Refs. [1,2].