Journal of Selected Topics in Energy

Distribution feeder reconfiguration for loss reduction with new fuzzy adaptive PSO and DE algorithms

Samad Nejatian

Distribution feeder reconfiguration for loss reduction is a very important way to save the electrical energy. This paper proposes a new hybrid evolutionary algorithm to solve the Distribution Feeder Reconfiguration problem (DFR) .The algorithm is based on combination of a New Fuzzy Adaptive Particle Swarm Optimization (NFAPSO) and differential evolution algorithm (DE) called NFAPSO-DE. To exploit the advantages of the exploration ability of DE and the high speed search system and the ability to control and adjust the parameters of PSO algorithm, a hybrid PSO-DE method is proposed. The hybrid method uses the PSO to find the region of optimal solution, and then a combination of PSO and DE to find the optimal solution. In other hand, due to the results of PSO algorithm highly depends on the values of their parameters such as the inertia weight and learning factors, a fuzzy system is employed to adaptively adjust the parameters during the search process. Finally, the proposed algorithm is tested on 33 bus and 69 bus distribution test systems. The results of simulation shows that the proposed method is very powerful and effective to obtain the global optimization.

Experimental investigation on pool boiling heat transfer in binary mixture of Water and Ethanol

In this study, heat transfer coefficient and the bubble diameter during pool boiling of pure water, pure ethanol and water-ethanol solutions on a horizontal tube in an atmospheric pressure is examined. Experiments are accomplished for different mole fraction of ethanol in water and in heat flux of 5-103 .The results reveal that heat transfer coefficient increases by increasing heat flux for pure water and pure ethanol and the combination of these two liquids. The heat transfer coefficient in the solution except for ethanol molar concentration of 0.04 is less than those in single component substances at the same heat flux. Also the heat transfer coefficient for azeotrope molar concentration y an error about 6% is almost equal to ideal heat transfer coefficient. Finally, the results are analyzed by Genetic Algorithm and a new model is presented to calculate the heat transfer coefficient of the water-ethanol solution.

Thermodynamic modeling and performance analysis of a novel and modified Organic Rankine Cycle(ORC) equiped with ejector and regenerator

Due to pollution and limited fossil fuels, renewable sources can be considered the main alternative of these resources. Generally, the organic Rankine Cycle(ORC) uses renewable Low Grade Heat Source(LGHS) such as solar, geothermal and etc. In this study a novel configuration of ORC has been proposed to improve the efficiency and power generation using both of an ejector and a regenerator. In this cycle an ejector with a regenerator have been integrated in ORC. Also a dual-stage evaporator has been used. Steam from the second stage evaporator is entered to ejector as the primary fluid and after the pressure decrement tends to increase of the suction of the secondary fluid from the steam turbine outlet. This modification tends to the higher power generation. Also steam enters to the regenerator prior to the ejector and in this way a part of energy of needed for the first stage evaporator is supplied and the efficiency is increased. For thermodynamic modeling a code was developed in the Engineering Equation Solver(EES) software. In addition different working fluids were examined to evaluate of the thermodynamic performance of the proposed cycle. The results show that the efficiency of the cycle increased 17.5% compared to the ORC in the best case(depending on the working fluid). To evaluate of the thermodynamic parameters on the efficiency and output power, parametric study was done. The fluid with the highest efficiency was R245fa.