The traditional design method for plate heat exchangers(PHEs), either epsilon-number of transfer units (epsilon-NTU) or logarithmic mean temperature difference method, involves many trials in order to meet the pressure drop constraints. This can be avoided through the developed design method, which takes the full utilization of the allowable pressure drops as a design objective. The proposed method is valid for the design situations with and without pressure drop specifications. In the case of the design with pressure drop specification, only one stream can fully utilize the allowable pressure drop. In the case of no pressure drop specification, allowable pressure drops can be determined through economical optimization. Compared to the previous design method, the proposed method does not require many trial iterations. Instead, all heat exchanger parameters, including plate size, number of passes, path, fluid velocity, etc., are determined in a straightforward way. Moreover, the suggested method can guarantee that the optimized values of allowable pressure drops can be fully utilized simultaneously by the two streams. In addition, the optimal corrugation angle is discussed for the most common chevron-type PHEs. (C) 2002 Elsevier Science Ltd. All rights reserved.