In this paper, a Polymer Electrolyte Membrane (PEM) fuel cell power system including burner, steam reformer, heat exchanger, and water heater has been considered. A PEM fuel cell system is designed to meet the electrical, domestic hot water, heating, and cooling loads of a residential building located in Tehran. Operating conditions of the system with consideration of the electricity cost has been studied. The cost includes social cost of the environmental pollutants (e.g. CO2, CO and NO). The results show that the maximum energy needs of the building can be met by 12 fuel cell stacks with nominal capacity of 8.5 kW. Annual average electricity cost of thissystem is equal to 0.39 US$/kWh and entropy generation of this system through a year is equal to 1004.54 GJ/K1. It is also concluded that increase in ambient temperature from 1 °C to 40 °C increases the entropy generation by 5.73%, carbon monoxide by 14.56%, and nitrogen monoxide by 8.9%, but decreases carbon dioxide by 0.47%.

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Solution precursor and suspension plasma spraying are emerging technologies to produce functional nanostructured coatings at moderate cost. In general, in these techniques, liquid is injected radially into a high-velocity high-temperature plasma flow. After liquid breakup and evaporation, solid particles remain in the field and impact the substrate. Preliminary studies have shown that liquid jet atomization is the main phenomenon that controls the coating quality. However, due to the complex thermophysical properties of plasma and its intricate flow physics, the breakup processes of liquid jets in plasma crossflows have not been investigated comprehensively yet. In general, the gaseous Reynolds number and the liquidto-gas density ratio in this process is around 50 and 10,000, respectively, which are far outside the limits normally observed in engines and wind tunnels. In the present work, detailed features of breakup phenomena of liquid jets in an argon plasma crossflow is provided. The finite volume scheme is used to solve the incompressible variable-density Navier-Stokes equations. In addition, volume of fluid (VOF) approach is utilized to track the gas-liquid interfaces. Overall, two different cases are simulated and different characteristics such as spray trajectory and droplet size distributions are investigated.