This paper deals with the effects of equipment reliability consideration to thermoeconomic analysis of a
combined power and multi stage flash water desalination plant. Exergy and thermoeconomic models of the
considered process units are developed and presented in this work. An economic model of the system is
developed according to the Total Revenue Requirement (TRR) method. This application can be very useful, either
for the plant management in order to achieve a cost-effective operation, or for a better plant design. Equipment
reliability using the state-space and the continuous Markov method is incorporated in thermoeconomic analysis
to improve the cost values. The results show that the power and water costs with reliability consideration
increased 4.1% and 6.4%, respectively. Additionally, the sensitivity analysis shows the relationship between the
production cost and the system availability which can help the designer to decide how to improve the profit or
competitiveness.