Fatih Aksoy

Construction and testing of a dish/Stirling solar energy unit

AbstractThis study is concerned with the construction of a simple solar energy conversion system consisting of a parabolic dish concentrator and a Stirling engine. For this purpose, a parabolic dish concentrator consisting of planar mirror segments was built and coupled with a Stirling engine recently developed by the authors for solar energy conversion and domestic cogeneration. By mounting the engine to the bottom of the dish concentrator, the solar rays were directly reflected onto the hot end of the displacer cylinder. For the design of an appropriate parabolic dish concentrator reflecting solar rays onto the hot zone of a displacer cylinder and satisfying their uniform distribution, an equation was derived. The energy conversion unit constructed was tested under 820 W m−2 solar radiation. The engine started to run at 93°C hot end temperature. At steady running conditions, the hot end temperature of the displacer cylinder became stable at ∼156°C. The variation of shaft power with engine speed and char...

The Viscosity at Different Temperatures of Soybean and Sunflower Biodiesels and Diesel Fuel Blends

Abstract In order to obtain viscosities of biodiesel fuels at a temperature range from 0 to 100°C in the steps of 10°C, DV-II+ Pro rotary viscosimeter from Brookfield Engineering Co., USA, was used and tests were performed at 20°C ambient temperature. The viscosity measurements were made on a viscosimeter at a 100 rpm constant speed with PC control. The data with the Wingather VII software from Brookfield Engineering Co., USA, were recorded in the computer at 5 second intervals. It is observed that biodiesels are similar to diesel fuels in view of the viscosity properties when the diesel fuel concentration in which biodiesel and the temperature is increased.

Estimating the Dynamic Viscosity of Vegetable Oils Using Artificial Neural Networks

In this study, dynamic viscosities of poppy and hazelnut oils were measured at 30–100°C interval with 1°C increments by using a Brookfield Engineering Co. DV-II+ Pro rotary viscometer. Viscosity measurements were realized at 100 rpm constant speed and by using a RVII spindle. Three equations were used to estimate the viscosities of poppy and hazelnut oils. Regression analyses were conducted in MATLAB® program and R2 (coefficient of determination), correlation constants, and root mean squared error were determined. The best coefficients of determination obtained by using μ = e(A+B/T–C)) relation were 0.99983 and 0.99989 for poppy and hazelnut oils, respectively. In analyses conducted by using artificial neural networks, the coefficients of determination were obtained to be 0.999937 and 0.999960 for poppy and hazelnut oils, respectively. Although coefficients of determination obtained in two methods were close to each other, the root mean squared error obtained by using artificial neural networks was smaller for both two oils.

An Investigation on the Effect in the Viscosity of Canola and Corn Oil Biodiesels at a Temperature Range of 0 to 100°C

Abstract In this study, biodiesels were produced from canola and corn oil by using a methyl transesterification method. The viscosity values of canola and corn biodiesels and their blends were measured at the temperature range from 0 to 100°C in the steps of 10°C. In the same conditions, viscosities of diesel fuels were compared to viscosity values of biodiesels and the effects on viscosity of temperature were investigated. Viscosities of biodiesels are prominently decreased with increasing of their temperature, and thus, they are similar to diesel fuels in point of viscosity properties.

Analyzing the Effects of Methyl Esters Produced from Raw Soybean and Waste Frying Oil on Engine Performance and NOx Emission

Abstract In this study, biodiesel is produced from waste frying oil and raw soybean oil by using a transesterification method. The effects of waste frying and raw soybean methyl esters on engine performance and NOx emissions are investigated. By using waste frying and raw soybean methyl esters, a decrease in engine torque and power and an increase in specific fuel consumption due to low heating values of methyl esters are observed. Since the oxygen content of methyl esters affects NOx development, an increase in NOx emissions is also observed.

Alkaline catalyzed biodiesel production from safflower (Carthamus tinctorius L.) oil: Optimization of parameters and determination of fuel properties

ABSTRACT In this study, the process of biodiesel production from safflower oil was optimized using a single-stage alkaline catalyst (NaOH). The optimization process was carried out depending on parameters, such as catalyst concentration, methanol-oil ratio, reaction temperature, and reaction time. The optimum biodiesel conversion efficiency was obtained to be 93.4% at 0.5% catalyst concentration, 20% methanol-oil ratio, 60 min reaction time, and 60°C reaction temperature. The fuel properties of biodiesel obtained under optimal conditions were determined.