Abstract
The multieffect desalination (MED) process is one of the most efficient thermal desalination processes due to its low energy consumption. Due to the recent developments in the desalination industry, latest desalination plants are more cost effective than the older technology-based plants. The primary goal of this paper is to investigate a mathematical model of an MED system in such a way that, it is able to predict the optimum number of effects. The number of effects for a specific plant is a major factor in determining thermal economy and capital amortization. Also the gain output ratio of an MED unit is totally dependent on steam economy and is directly proportional to the number of effects. The total cost of water is dependent on two chief costs: steam cost and capital cost. In this paper, a compromise has been made between these two costs to find optimum number of effects that would produce the minimum sum of the two cost components.