This book deals with the modeling and simulation of multiple effect evaporators. A computer program for the optimum design of the above has been developed in C++. Two different methods are used for calculating number of effects. Once the number of effects are finalized the program proceeds to calculate heat transfer area of the short tube vertical (Calandria type) evaporator for different feeding arrangements.The program also gives detail of mechanical design of evaporator which includes thickness of tubes, tube sheet thickness, drum diameter and drum thickness etc.Finally the program is tested using published data with success.