in this paper, the nonlinear differential equation for the convection of the temperature distribution of a straight fin  with the thermal conductivity depends on the temperature is solved using adomian decomposition method and padé approximation(padm) for boundary problems. actual results are then compared with results obtained previously  using digital solution by runge–kuttamethod and a diffe...

A regenerative organic Rankine cycle (RORC) is modeled and optimized for the use of waste heat recovery from a prime mover (PM). Three PMs including, a diesel engine, a gas engine, and a microturbine are selected in this study. Four refrigerants including isobutane, R123, R134a, and R245fa are selected. The nominal capacity of the PM, PM operating partial load, turbine inlet pressure, condenser...

the main objectives of this paper are measuring the technical efficiency of iranian thermal power plants and investigating the determinants of technical efficiency levels in these plants. stochastic nonparametric envelopment data (stoned) method applied to plant-level data over a period of thirteen years from 1999 to 2011. this is the first comprehensive analysis (to our knowledge) of technical...

In addition to greenhouse gas emissions, coastal thermal power plants would gain further opposition due to their heat rejection distressing the local ecosystem. Therefore, these plants need to enhance their thermal efficiency while reducing their environmental offense. In this study, a hybrid plant based on the principle of Ocean Thermal Energy Conversion was coupled to a 740 MW coal-fired powe...

one of the effective methods to improve the thermal efficiency of solar collectors is using nanofluids as the coolant. the present study experimentally investigated the effect of sio2/water nanofluid with 1% mass fraction on the performance of a symmetric collector, i.e. conical solar collector. the conical solar collector with 1 m2 area and normal to the earth was tested in ahvaz, a city in th...

The objective of this study is to investigate the thermal efficiency and power production of typical models of endoreversible heat engines at the regime of minimum entropy generation rate. The study considers the Curzon-Ahlborn engine, the Novikov's engine, and the Carnot vapor cycle. The operational regimes at maximum thermal efficiency, maximum power output and minimum entropy production rate...

Heat and mass transfer, in this paper, is considered in one-row heat exchanger, that fins are hotter than air flow and water is added to fins. Related governing equations are derived by analyzing a two-dimension model in a unique cell of a heat exchange. These equations are numerically solved by finite difference method. Heat transfer and efficiency under partially wet surface are calculated by...

The effect of a regenerative heat exchanger in a gas turbine is analyzed using a regenerative Brayton cycle model, where all fluid friction losses in the compressor is quantified by an isentropic efficiency term and all global irreversibilities in the heat exchanger are taken into account by means of an effective efficiency. This analysis, which generalizes that reported by Gordon and Huleihil ...

The electrical and thermal performances of photovoltaic thermal (PVT) water collectors were determined under 500–800 W/m solar radiation levels. At each solar radiation level, mass flow rates ranging from 0.011 kg/s to 0.041 kg/s were introduced. The PVT collectors were tested with respect to PV efficiency, thermal efficiency, and a combination of both (PVT efficiency). The results show that th...