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The aim of the present study is to evaluate the thermal behavior of cylindrical modules in a thermal energy storage unit as a combined sensible and latent heat. A thermal energy storage unit is designed, fabricated, and connected to a cold and hot water supply at constant temperatures to monitor the performance of the storage unit. The thermal energy storage unit contains the cylindrical microcapsules containing paraffin waxes as a phase change material which is located inside an insulating cylinder storage tank. Water is used as a heat transfer fluid to transfer heat from a hot water reservoir to the thermal energy storage unit during the phase change material charging process and also during the discharging process water receives heat from the thermal energy storage unit. Charge tests are carried out at the constant temperature. Moreover, the effect of different inlet flow on storage unit performance is investigated. Data were analyzed using Design Expert software and regression analysis which indicated that the increase of charge inlet temperature and charge inlet flow leads to the increase of heat power, thermal performance of thermal energy storage unit, and output variables. In comparison to the heat storage system without phase change material, microcapsules phase change material can improve the heat power of the heat storage system. Also, based on the optimization process, the maximum thermal performance of 96.4% and the maximum heat power level of 1.7 kW can be achieved in the optimized condition of the charging inlet temperature of 75 °C, charging inlet flow of 1.8−4 m3/s, and discharging inlet temperature of 35 °C.

Wet washing is the most common method for biodiesel purification, but higher water consumption, longer purification time, and high expenses bring limitations on the use of this process. One of the suitable methods to remove such limitations is to use new techniques for purification. In this study, biodiesel purification was evaluated in a novel continuous centrifugal contactor separator (CCCS) at 0.5:1, 1:1, and 1.5:1 (V/V%)water to biodiesel ratio; 10 Hz, 20 Hz, and 30 Hz device working frequency; and 25 °C, 40 °C, and 55 °C temperatures. A mathematical model for the wet-washing process of biodiesel and energy consumption of the CCCS device using the response surface method is proposed. A 0.8:1 (V/V%) water to biodiesel ratio, 10 Hz working frequency, and 35 °C temperature were found to be the optimal conditions in the experiment. At this point, the biodiesel yield and the amount of energy consumption were reported to be 96% and 17 kJ, respectively. The results showed that compared to the traditional wet washing method, the biodiesel purification method using CCCS is cost-effective and consumes more than 75% less of water.

Concerning the growing need for energy resources and reduction of fossil fuels, researchers seek for the use and development of biofuels. Among the biofuels, biodiesel has captured the attention of...

Given the energy crisis, fossil fuel reserves crisis, climate mitigation, and energy efficiency increase, scientists have embarked on producing alternative fuels such as the biodiesel. This study w...

Biodiesel is a green renewable energy source and an alternative for diesel fuel. The objective of this research was to study the feasibility of biodiesel production from Celtis australis L. oil usi...

In recent years, leveraging the amount of energy loss occurring in different fields of human activity has captured the attention of researchers. Harvesting and drying processes can be integrated in order to reduce energy losses. The present research work seeks to pinpoint the association between the harvesting and drying processes as well as to make optimal use of both processes so as to decrease the level of energy loss and apply the renewable energies to the food supply chain. The olive harvesting machine was designed and evaluated, and the olives harvested in the solar dryer were placed in the solar dryer as the input materials. To obtain the evaluation of the experimental tests’ purpose, Mari cultivar was used. Following this trend was the evaluation of the olive harvesting machine and its comparison with the manual harvesting method. Having separated the olives from the tree through use of the harvesting machine designed and made, a solar dryer was used to accommodate the olives in order to make the final examination concerning any damage to olives. Findings of the study indicated up to 92% separation of the olive fruits by the olive harvester. It was also found that there is a 29.47 harvest efficiency for the olive harvester. In addition, evaluation of the solar dryer emphasized that an increase in the temperature and velocity of the inlet air results in a rapid decrease in the olive moisture.

The Iranian energy sector has recently discovered a great interest in the concept of renewable and clean energy. The interest is motivated primarily by concerns about greenhouse gas (GHG) emissions and global climate change, as well as the desire to find alternative and sustainable energy sources and create potential job opportunities related to these new technologies for future generations of Iranians. This study supports the search for alternative, sustainable energy sources by assessing okra's usability as a biofuel. Okra is an annual, warm season crop that provides a rich source of industrial oil and protein. According to our investigation, the seeds of Iranian okra ecotypes that have an oil content of 20% could produce up to 325 kg/ha oil yield. Our study on Iranian okra seed oil showed that, the most dominant fatty acids of are linoleic acid (C18:2) (38–40%), Palmitic acid (C16:0) (29–30%), and Oleic acid (C18:1) (19–22%). The biodiesel derived from okra via a transesterification reaction using an ultrasonic system could meet ASTM D6751 standards with satisfactory results in methyl ester content (more than 96%), viscosity (2.3–2.4 mm−2/S, and flash point (155–158 °C)). Because of its high oil yield, quality, and large ecological adaptation window, okra is a strong contender to provide a new source of non-edible oil for biodiesel production in bioenergy farms.

Nowadays, Biodiesel as an alternative, sustainable and less toxic fuel has been accepted by both researchers and industry. Developing process intensification reactors with the aim of reaching more ...

The objective of this research was to study the feasibility of biodiesel production from Pistacia atlantica (Atlas pistache) oil using ultrasonic system. Results showed that the best models for both the yield and energy consumption were full quadric models with suitable coefficients of determination (0.98, 0.99) and least mean squared errors (MSE) (0.351, 17.14). With increasing the amplitude and pulse, the methyl ester content increased. When reaction time and molar ratio increased to range of 5–7 min and 5–6, respectively, methyl ester content increased; while when these parameters increased out of range, yield decreased. The major properties of Atlas pistache methyl ester met the requirements of EN 14214 biodiesel standard and consequently, Atlas pistache can be a potential substitute to petro diesel.

Solid calcium oxide (CaO) catalyst was prepared via the calcination of chicken eggshells as an environmentally friendly waste resource and incorporated in a continuous centrifugal contactor separator (CCCS) for intensified biodiesel synthesis. Biodiesel or fatty acid methyl esters (FAME) were produced via the transesterification of sunflower oil (containing 5 wt % tetrahydrofuran as a cosolvent) with methanol under 60 °C and separated from the glycerol and catalyst phases continuously in the CCCS. The influence of reaction parameters on biodiesel production was well modeled by response surface methodology. At an oil flow rate of 9 mL/min, an alcohol to oil molar ratio of 11:1, and a weight hourly space time (defined as the catalyst weight over the oil mass flow rate) of 0.050 h, an optimized FAME yield of 83.2% with a productivity of 638 kgFAME/(m3reactor·h) was achieved. CaO catalyst was reused without significant activity loss for at least four cycles.

Ultrasonic processing is an effective tool to attain required mixing while providing the necessary activation energy in the field of biofuels. In this regard, optimization of fast transesterification of waste cooking oil is very important. The goal of this research paper is therefore to determine the effect of important parameters such as methanol to oil molar ratio, catalyst concentration (potassium hydroxide), temperature, and horn position on oil conversion to methyl ester in ultrasonic mixing method. Result of experiments showed that the optimum conditions for the transesterification process have been obtained as molar ratio of alcohol to oil as 6:1, catalyst concentration of 1 wt.%, temperature as 45°C, and horn position at the interface of methanol to oil. The results show that the ultrasonic method decreases the reaction time as much as up to eight times compare to the conventional stirring. For practically evaluating the theoretical optimum point using genetic algorithm, the obtained values were verified experimentally. In order to perform this, the catalyst concentration, temperature, and the time of reaction were determined, and the values are 1%, 48°C, and 449s, respectively. For the obtained values, the biodiesel conversion was 93.2%, so that the experimental optimum value is closed to that of the theoretical values. As a result, experimental data confirmed the obtained values from optimization method in this research work.

Biodiesel is a green (clean), renewable energy source and is an alternative for diesel fuel. Biodiesel can be produced from vegetable oil, animal fat and waste cooking oil or fat. Fats and oils react with alcohol to produce methyl ester, which is generally known as biodiesel. Because vegetable oil and animal fat wastes are cheaper, the tendency to produce biodiesel from these materials is increasing. In this research, the effect of some parameters such as the alcohol-to-oil molar ratio (4:1, 6:1, 8:1), the catalyst concentration (0.75%, 1% and 1.25% w/w) and the time for the transesterification reaction using ultrasonication on the rate of the fatty acids-to-methyl ester (biodiesel) conversion percentage have been studied (3, 6 and 9 min). In biodiesel production from chicken fat, when increasing the catalyst concentration up to 1%, the oil-to-biodiesel conversion percentage was first increased and then decreased. Upon increasing the molar ratio from 4:1 to 6:1 and then to 8:1, the oil-to-biodiesel conversion percentage increased by 21.9% and then 22.8%, respectively. The optimal point is determined by response surface methodology (RSM) and genetic algorithms (GAs). The biodiesel production from chicken fat by ultrasonic waves with a 1% w/w catalyst percentage, 7:1 alcohol-to-oil molar ratio and 9 min reaction time was equal to 94.8%. For biodiesel that was produced by ultrasonic waves under a similar conversion percentage condition compared to the conventional method, the reaction time was decreased by approximately 87.5%. The time reduction for the ultrasonic method compared to the conventional method makes the ultrasonic method superior.

The issue of searching alternatives for diesel fuel in transport sector that is one of the largest diesel fuel consuming sectors in each country has become more attractive nowadays. In this study, the energy consumption and CO2 emissions of biodiesel production from rapeseed as an alternative for diesel fuel in transport sector was assessed in terms of three main stages including agricultural crop production, transport, and industrial conversion. The results revealed that the total fossil energy input cost was calculated as 28 122.16 MJ ha−1 and the renewable energy output content (biodiesel as the final outcome) was estimated as 31 802.06 MJ ha−1. The net energy returns and the fossil energy ratio were calculated as 3679.9 MJ ha−1 and 1.13, respectively. It shows rapeseed could be a suitable energy crop for biodiesel production. CO2 emissions assessment showed that the total greenhouse gas emissions over biodiesel production life cycle were 1054.98 kg CO2 eq ha−1 and the agricultural crop production stage ranks the first. In order to establish energy crops cultivation such as rapeseed and achieve the sustainable development, meteorological and water source availability data collected and analyzed for all the 31 provinces in Iran to generate a map of regions capable of rapeseed cultivation. The results revealed that 24 provinces among 31 provinces have a great potential for rapeseed cultivation.