Solar Thermal Power Plants: Progress and Prospects in Iran

AbstractOne of the most promising paths towards the sustainable development is utilizing solar energy, especially in oil-dependent economy nations like Iran. Electricity production in Iran is mainly dominated by its fossil fuel resources. High solar insolation and available desert lands in Iran are two main factors to encourage the full development of solar power plants for thermal and electrical energy productions. Herein, the solar thermal power plants have the priorities of consistent power output and the ability to incorporate storage. In the present study, a brief description and working principles of the solar thermal power plants are given. Besides, the paper points out the solar energy potential, the current state of electricity generation and the future of solar thermal power projects in the country. Special attention is drawn to the Iranian government initiatives and support for the use of solar energy. In the end, the future prospects of solar projects development with the worldwide competitive technologies by considering the existing obstacles that should be removed by the Iranian governments and energy planners in the future of energy production are presented

Combustion analysis of a CI engine performance using waste cooking biodiesel fuel with an artificial neural network aid

[Abstract]: A comprehensive combustion analysis has been conducted to evaluate the performance of a commercial DI engine, water cooled two cylinders, in-line, naturally aspirated, RD270 Ruggerini diesel engine using waste vegetable cooking oil as an alternative fuel. In order to compare the brake power and the torques values of the engine, it has been tested under same operating conditions with diesel fuel and waste cooking biodiesel fuel blends. The results were found to be very comparable. The properties of biodiesel produced from waste vegetable oil was measured based on ASTM standards. The total sulfur content of the produced biodiesel fuel was 18 ppm which is 28 times lesser than the existing diesel fuel sulfur content used in the diesel vehicles operating in Tehran city (500 ppm). The maximum power and torque produced using diesel fuel was 18.2 kW and 64.2 Nm at 3200 and 2400 rpm respectively. By adding 20% of waste vegetable oil methyl ester, it was noticed that the maximum power and torque increased by 2.7 and 2.9% respectively, also the concentration of the CO and HC emissions have significantly decreased when biodiesel was used. An artificial neural network (ANN) was developed based on the collected data of this work. Multi layer perceptron network (MLP) was used for nonlinear mapping between the input and the output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted values. The results showed that the training algorithm of Back Propagation was sufficient enough in predicting the engine torque, specific fuel consumption and exhaust gas components for different engine speeds and different fuel blends ratios. It was found that the R2 (R: the coefficient of determination) values are 0.99994, 1, 1 and 0.99998 for the engine torque, specific fuel consumption,CO and HC emissions, respectively

Investigating a Power tiller Handle and Seat Vibration on Transportation mode

In this paper, vibration a power tiller vibration was investigated at handle position as well as seat position of a trailer pulled by the power tiller. The experiments were conducted at five levels of engine speed, four levels of transmission gear ratio during transportation, and in three directions. Then the weighted 1/3rd octave spectrum was calculated from the narrow band vibration acceleration signals. The amount of vibration damage on operator's body and allowable exposure limits were calculated based on ISO standards. The results showed that the vibration increased with increasing the engine speed for all the gear ratios and directions. The magnitude of vibration was the greatest at vertical direction in all the experiments. The vibration allowable exposure time was in the range of 2.32-5.7 years at the power tiller handle for the different engine speeds and gear ratios. The total equivalent vibration, A (8), at the trailer seat was in the range of 0.5 to 0.87 m/s2 and it exceeded the allowable limits for the reduced comfort boundary, fatigue-decreased boundary and exposure limit for 8 hours/day. So, it is necessary to reduce the vibration transmitted to the operator’s hand and body by designing and developing adequate insulating systems

Power tiller vibration acceleration envelope curves on transportation mode

Application of power tillers are being increased as a main source of power supply for agricultural equipment due to their economic benefits. Beside on field applications, they are also engaged on transportation of agricultural products and human beings on rural roads. In spite of these advantages, power tillers are a big source of vibration generation too. Therefore, their operators have to work in a harsh environment. Single cylinder diesel engine used in power tillers and lack of suspension system are the main cause for generating high levels of vibration. The present research work was conducted on a 13-hp power tiller to determine the maximum and minimum vibration acceleration envelope curves on transportation mode. The power tiller vibration acceleration signals were measured for four transmission ratios and five engine speeds at positions of the power tiller handle and trailer seat to be pulled by the power tiller as well as wrist, arm, chest and head of the power tiller operator’s. The recorded time domain signals were converted to frequency domain signals using Fast Fourier Transform (FFT) algorithm. The 1/3rd octave frequency band was determined from the frequency domain signals. The maximum and minimum envelope curves were determined from the 1/3rd octave bands. The envelope curves at the handle position showed that the root mean square (RMS) values of vibration acceleration for frequencies of 8 to 80 Hz were exceeded 2 m/s2 (hand-arm exposure limit for 8 hours working per day) and at 31.5 Hz it reached to 11 m/s2. At the trailer seat position, the RMS values of vibration acceleration were exceeded the standard limits for comfortable operation in the frequency ranges of 3.15 to 6.3 and 25 to 40 Hz. Furthermore, the derived envelope curves seem to be suitable guidelines for designing and developing vibration control systems in the power tiller

Acoustic Analysis of a Single Cylinder Diesel Engine Using Biodiesel Fuel Blends

AbstractFuel type has a direct effect on the quality of IC engine's combustion phenomenon. One of the most important quality parameters that can be fluctuated by fuel type is engine noise. The purpose of this study is to analyze the noise parameter of a diesel engine using B0, B5 (5% vol., biodiesel and 95% vol., diesel blends), B10, B15, B20, B25 and B30 biodiesel–diesel blends. This study was carried out at stationary position and at three positions such driver's left ear position (Drivers Left Ear Position-DLEP), 1.5 meter (1.5 meter Away From Exhaust-MAFE) and 7.5 meters (7.5 meter Away From Exhaust-MAFE) away from exhaust at 6 engine speeds (1200, 1400, 1600, 1800, 2000 & 2200 RPM). The results proved that the lowest and highest Sound Pressure Level (SPL) of power tiller takes place at B10, and B30 respectively. The SPL increased by 7.8dB for increasing engine speed from 1200 to 2200 RPM. The test results showed that the average SPL at DLEP was 4.3dB higher than 7.5 MAFE position. The dominant frequency of engine noise was315Hz that exhaust structure is the source of it. In this frequency SPL of B10 was, 23%lower than thefuelB30 (a mixture of 30percentbiodiesel and70percentdieselfuel, respectively). The slightest and strongest sound by using theB10, B30 fuel mixture was produced respectively

Parametric comparison of different lobe rotor geometry for positive displacement turbine in water distribution network

The application of hydro turbines for harnessing water energy within distribution networks, as an alternative to pressure relief valves, is steadily increasing. These turbines are particularly suitable for recovering energy from incompressible subsonic fluid flows. In this research paper, three models of positive displacement lobe machine designed to function as water turbines were extensively examined and compared. The three selected turbine types included the circular lobe turbine, the cycloidal arc lobe turbine and the epicycloid arc lobe turbine. These turbines were meticulously designed and developed for their respective applications. Under identical operational conditions, optimization processes were applied to enhance volumetric efficiency and power efficiency for all three turbine variants, each having a different number of blades. A computer program was devised to facilitate the optimization and calculation of blade geometries under various operating conditions. This research delved into the impact of blade geometry type and the number of blades on turbine efficiency and size. The data obtained from the present investigation were systematically analyzed, and the performance of the different turbines were compared. Notably, the circular lobe turbine was found to be the largest among the three, occupying more space. The cycloidal arc requiring a greater amount of material resulting in rotor volume, which subsequently resulted in a higher overall cost. In contrast, the cycloidal arc lobe turbine emerged as the smallest variant, demanding less space for operation. Efficiency-wise, the cycloidal arc lobe turbine exhibited the highest efficiency with two blades, while the circular lobe turbine displayed the lowest efficiency with six blades. Moreover, among the turbines with the same number of lobes, the cycloidal arc lobe turbine consistently demonstrated superior efficiency compared to the circular lobe turbine

TOPSIS multi-criteria decision modeling approach for biolubricant selection for two-stroke petrol engines

Exhaust pollutants from two-stroke petrol engines are a problem for the environment. Biolubricants are a new generation of renewable and eco-friendly vegetable-based lubricants, which have attracted a lot of attention in recent years. In this paper, the applicability of the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method to support the process of building the scoring system for selecting an appropriate two-stroke lubricant has been analyzed. For this purpose, biolubricants (TMP-triesters) based on castor oil, palm oil, and waste cooking oil were produced and then utilized in a 200 cc two-stroke gasoline engine to investigate their effects on its performance and exhaust emissions. The results obtained from the use of the entropy technique in the TOPSIS algorithm showed that palm oil-based lubricant took up the greatest distance from the Negative Ideal Solution (NIS) and was selected as the most optimal lubricant for these types of engines

Development of micro-scale biomass-fuelled CHP system using stirling engine

In this research study, a Micro-scale Combined Heat and Power (MCHP) plant with a stirling engine for biomass fuels was developed and optimized. The nominal electric power output of the plant is 100 Watt. Currently this plant has run using wood powder as fuel. With consideration of the biomass energy potential, a gamma type Stirling engine with 220cc swept volume and 580cc total volume was designed, optimized and manufactured. The performance is investigated with regard to the operating conditions , the heat fluxes, temperatures and the type of biomass. Electrical energy produced from biomass sources. The results shows that the highest efficiency of the system is reached for moderate speed values of stirling engine approximately 500-600 rpm. Sugarcane bagasse, wood, wheat straw, poplar wood and sawdust as fuel system were selected. Most power be obtained from the sawdust (46 watt) and pruning of trees for wood for low power (21 watts), respectively. Minimum ignition time of the Sawdust (4 min) and the most time flammable wood from pruned trees (10 min) was measured. At maximum power, the internal thermal efficiency of the engine was measured as 16%. The test results confirm the fact that Stirling engines driven by temperature of biomass gases are able to achieve a valuable output power. Results of the present work encouraged initiating design of a MCHP system with 1 kWe capacity for rural electrification. So this operation can be considered as a breakthrough in the utilization of stirling engine for micro-scale CHP plants utilizing wood powder fuels

Experimental investigation of a diesel engine power, torque and noise emission using water-diesel emulsions

In the present study, the results of an investigation on a Perkins A63544 direct injection diesel engine using water-diesel emulsions (2%, 5%, 8% and 10% water by volume) are reported. The engine was run at different engine speeds ranging from 1400 to 1900 rpm, with steps of 100 rpm, for power and torque analysis. In order to evaluate noise emissions, four engine speeds (1600-1900 rpm with steps of 100 rpm) and four engine load conditions (25%, 50%, 75% and 100%) were selected. No change in engine components and fuel injection systems was made. The statistical analysis results showed that the engine speed and fuel type parameters had significant effects at 1% probability level (P < 0.01) on the average values of the engine power and torque. The engine noise emission was affected significantly (P < 0.01) by the engine speed, fuel type and engine load parameters. The results showed that adding small amounts of water, 2%, to neat diesel fuel produced a significant increase in the engine power. Furthermore, its engine torque and noise emission were comparable with those of neat diesel fuel. The higher water addition to diesel decreased the engine power and torque, however no such change was found for the engine noise emission. The significant increase in the engine power and comparable engine torque and noise emission for 2% water content showed a good potential for this emulsion to be considered as an appropriate alternative to neat diesel fuel

Investigating A Power Tiller Vibration Transmissibility Using Diesel-Biodiesel Fuel Blends On Stationary Conditions

The wide use of fossil fuel in internal combustion engine cause reduction in these fuel resources and also increase in greenhouse gasses and environmental pollution, for conquering these problems, so many researches have done for finding the renewable herbaceous fuel. Between these different kinds of fuel, biodiesel seems to be appropriate because of the nonexistence of air pollutions and the existence of similar trait with diesel fuel. In this research, vibration of 13hp power tiller in 5 levels of engine speed and 6 levels of consuming fuel blends for investigating the power tiller engine vibration behavior and the vibration transmissibility. Results showed that vibration transmissibility is decreased by increasing the engine speed. The maximum of the vibration transmissibility is happened in B20 and B5 and minimum of it is happened in B15 and D respectively. Also it is observed that the amount of vibration acceleration in longitudinal axis is much more than other two axes. The vibration acceleration value, in the frequency range of 8 to 100 Hz was higher than a dangerous frequency range of hand-arm vibration transmission and the total weighted acceleration has the maximum value at the frequency of 20, 31.5, 40 and 63 Hz with the vibration amplitude reach up to 20, 12.6, 18.6 and 40 m/s2 respectively. The best engine speed are 1400, 1600 and 2000 rpm, in this Engine speed using the B20 and B5 seems appropriate