Heat Exchanger Effectiveness (ε)

The heat exchanger effectiveness is defined as the ration of actual heat transfer to the maximum possible heat transfer.

ε=Actual heat transferMaximum possible heat transfer=QQmax

The actual heat transfer rate Q can be determined by writing an energy balance over either side of heat exchanger

Q = ṁh.Cph.(th1 - th2) = ṁc.Cpc.(tc2 - tc1)