Journal of Renewable Energy and Environment
Volume:6 Issue: 3, Summer 2019

In this study, esterification reaction of different carboxylic acids (Acetic acid, Palmitic acid, Oleic acid) with ethanol was investigated by ZnO, Al2O3-ZnO mixed oxide and phosphotungestic acid (10 %wt) immobilized on the Al2O3-ZnO mixed oxide. The heterogeneous catalysts were characterized by XRD, BET, FE-SEM and EDX techniques. Optimum yield was achieved by using 10% HPW/Al2O3-ZnO as the best catalyst and the effect of amount of catalyst, molar ratio of acid to alcohol, reaction temperature and time was investigated to get the ideal yield of esterification reaction of acetic acid and ethanol. The results showed that the esterification of acetic acid to its ethyl ester was carried out in 3.5 hours, alcohol to acid molar ratio equal to 2 and temperature of 80˚C with yield 98%. Also, the 10% HPW/Al2O3-ZnO catalyst showed well activity in biodiesel production by esterification of palmitic and oleic acids and the reaction yield didn’t decrease with increasing of alkyl chain length in acid molecules, remarkably.

Fuel cells are potential candidates for storing energy in many applications; however, their implementation is limited due to poor efficiency and high initial and operating costs. The purpose of this research is to find the most influential fuel cell parameters by applying the adaptive neuro-fuzzy inference system (ANFIS). The ANFIS method is implemented to select highly influential parameters for proton exchange membrane (PEM) element of fuel cells. Seven effective input parameters are considered including four parameters of semi-empirical coefficients, parametric coefficient, equivalent contact resistance, and adjustable parameter. Parameters with higher influence are then identified. An optimal combination of the influential parameters is presented and discussed. The ANFIS models used for predicting the most influential parameters in the performance of fuel cells were performed by the well-known statistical indicators of the root-mean-squared error (RMSE) and coefficient of determination (R2). Conventional error statistical indicators, RMSE, r, and R2, were calculated. Values of R2 were calculated as of 1.000, 0.9769, and 0.9652 for three different scenarios, respectively. R2 values showed that the ANFIS could be properly used for yield prediction in this study

A considerable amount of waste heat is produced by internal combustion engines. Bottoming cycle application of Organic Rankine Cycles (ORC) is one of the promising technologies that recuperates the waste heat of engines. A lot of engine waste heat is released into the environment. There are a lot of working fluids that can be applied in these cycles. As the engine waste heat temperature is extremely high, finding a suitable working fluid, which operates properly in the combined cycle, is challenging. In this paper, the thermodynamic analysis of ten working fluids including cyclohexane, HFE7000, HFE7100, n-hexane, n-pentane, R11, R123, R134a, R141b, and R245fa is conducted to observe the influence of different parameters on the system performance and introduce the most appropriate working fluid. Results indicated that, in the studied ranges, R134a had the best performances since (a) its thermal and exergy efficiencies were 17.39 % and 17.34 %, respectively; (b) the thermal efficiency of the engine  increased by 9 %, and the net power of the system reached 7.5 kW. Furthermore, there was about 9 % reduction in fuel consumption. On the other hand, among the studied working fluids, cyclohexane operates as the least suitable one by possessing the minimum amounts.

To preserve fossil fuel sources and reduce environmental pollution, it is necessary to use higher quality and more efficient fuels that cause lower pollution and are recovered more easily. Therefore, this study will investigate the cycle of biodiesel production from chicken fat by life-cycle assessment (LCA). To achieve this purpose, information on the amount of inputs consumed and produced by some broiler-farming units was collected using questionnaire. The value of net energy in this cycle was assessed to be a large negative number, and the energy ratio lower than one indicates high energy consumption of the production of this fuel. The net yield of biodiesel production was 0.574 liter-biodiesel per kg of waste fat. In the cycle, the greatest impact of pollutants was exerted on the Marine aquatic ecotoxicity intoxication and the least effect on ozone depletion. According to the global warming index, production of 1 liter of biodiesel yielded 1.90 kg CO2, and the depletion rate of fossil fuel sources for the production of 1 liter of biodiesel was obtained 21.35 MJ. The production of biodiesel from chicken slaughterhouse waste fat is considered a kind of energy recycling and is an effort to reduce environmental pollution.

Water scarcity is a critical issue in Caspian Sea regions of Iran. Thus, people may use polluted water or saline brackish groundwater, estuarine water or seawater. This paper deals with the application of Low-Pressure reverse osmosis (RO) for removing salt and Total Organic Carbon (TOC) in synthetic and Caspian Sea waters. The study aims to achieve optimization at different pressures (30, 50, 70, and 90 PSI) with synthetic seawater at initial salt concentrations (5, 25, and 35 g/L TDS) at various retention time intervals (15, 30, 60, 90, and 120 minutes). The results showed that the low-pressure RO system was able to reject 95 %, 57 %, and 46 % of 5, 25, and 35 g/L of TDS from synthetic seawater. In addition, rejection efficiency was achieved at 86 % and    78 % for Caspian seawater and Tajan River, respectively. In addition, optimal conditions (pressure: 70 PSI, time: 120 min) for salt rejection included 16-23 %, 93-94, 52-56 %, 88-90, and 22 % for 35g/L TDS, Tajan River, 5g/L TDS, 25g/L TDS, and Caspian seawater, respectively. Moreover, TOC rejection was achieved at >95 % and >97 % of Tajan River and Caspian seawater, respectively, at an overall 120-minute interval. In the case of growing environmental pollution that is discharged into Caspian sea including industrial and agricultural effluents from rivers, this study proposed the suggested pilot as a simple design that will significantly reduce salt, TOC, and TDS.

The renewable energy can be utilized to satisfy the energy demand. Moreover, the solar energy as the most abundant energy resource among renewable energies plays a crucial role to provide the energy demand. The BIPV (building integrated photovoltaics) systems can be considered to supply the required energy demand from renewable sources. The essential advantage of BIPV systems is that they can be utilized as building component such as roof, window, shading systems and building façade and they can generate electricity simultaneously. Even though the photovoltaic technologies have been improved within past few years, however the utilization of the BIPV systems will be considered expensive. For this reason, the payback period calculation is considered a vital parameter in evaluating the BIPV systems. In this study, the overall energy consumption for producing one m2 of a mono-crystalline photovoltaic module is calculated 1334 kWh. Additionally, the photovoltaic module data for three companies were investigated and the annual energy productions for one m2 of each company’s product were obtained. The results showed that the average energy payback time for 270 and 280 watt modules are 5.565 and 5.254 respectively. Moreover, the energy payback time for 290, 325 and 340 watt modules were calculated 4.903, 5.437 and 4.965 respectively.