Water is available in large quantities on earth but only a small
fraction has a low enough salinity to be fit for drinking and irrigation
[1]. Desalination is one of the most important processes to provide
water to population in water scarcity areas, especially in the Gulf Area.
But desalination processes consume a lot of energy; unfortunately the
majority of the energy currently used for desalination is obtained
from oil or natural gas [2].
Large dual-purpose plants are built to reduce the cost of electricity
production and freshwater. The dual purpose power desalination plants
make use of thermal energy extracted or exhausted from power plants
in form of low-pressure steam to provide heat input to thermal
desalinations, like multi-stage flash (MSF) or multi-effect distillation
(MED) systems.
Energy systems involve a large number and various types of
interactions with systems outside their physical boundaries. Engineers
must therefore face many issues, which involve with the energetic,
economic and so on. Thermoeconomic approach is used to distribute the
cost of the whole process on the internal streams based on exergy not
energy [3]. The stream-cost equations are arranged in a matrix form and
solved to calculate the monetary cost of the process streams.
The first published work in Thermo-Economic was by Tribus and
Evans [4] and dealt in fact with a seawater desalination process. Additional
progress by El-Sayed and Evans followed later [5]. Many other studies