IMPORTANT POINTS 1 The First law says that the heat transferred from the hot stream must equal that transferred to the cold stream Therefore, of the six process variables (two flow rates and four temperatures), only five can be specified independently 2) The second law says that heat can only be transferred from a hotter fluid to a colder one. Therefore, the temperature of the cold fluid must be less than that of the hot fluid at all points along the leng th of the exchanger 2/21/99 HENS 1: Targeting2/21/99 HENS 1: Targeting 4 IMPORTANT POINTS 1) The First Law says that the heat transferred from the hot stream must equal that transferred to the cold stream. Therefore, of the six process variables (two flow rates and four temperatures), only five can be specified independently. 2) The Second Law says that heat can only be transferred from a hotter fluid to a colder one. Therefore, the temperature of the cold fluid must be less than that of the hot fluid at all points along the length of the exchanger