Optimization of Solar Terrestrial Power Production Using Heat Engines

1970 ◽  
Vol 92 (2) ◽  
pp. 173-181 ◽  
Author(s):  
M. K. Selc¸uk ◽  
G. T. Ward

Mathematical model and computer programs have been developed for the analysis of the economic performance of a terrestrial solar power system using heat engines. Various combinations of cycle, collector, engine, storage system, and sink have been studied and the influence of design parameters on power costs examined for both the steady and unsteady state cases. Typical minimum power costs under central Australian conditions for units of 12 kw capacity at current levels of materials and labor costs range from 7 to 47 U. S. cents per kwh, according to the specific design of installation.

2021 ◽  
pp. 3-11
Author(s):  
О.О. Osetrov ◽  
B. S. Chuchumenko

The throttle response of a vehicle determines its dynamic properties and is characterized by an acceleration time from 0 to 100 km/h. An experimental study of the influence of vehicle parameters on its throttle response is associated with significant material and labor costs. At the stage of sketching the design of the vehicle, preliminary determination of design parameters and settings, it is rational to use mathematical models. In the existing models of the vehicles movement dynamics, the engine power, as a rule, is set by empirical dependencies and does not take into account the possibility of changing its parameters and characteristics. The paper proposes a mathematical model that combines models of the engine workflow and the dynamics of vehicle acceleration. The mathematical model of the engine workflow is a quasi-stationary thermodynamic model, in which combustion is described by the Vibe equation, and heat transfer with the walls is described by the Woschni equation. To check its adequacy, an experimental study of the VAZ-2108 engine was carried out to obtain external speed, load and control characteristics. Good agreement between the calculated and experimental data is shown. Vehicle acceleration simulation was carried out according to the method of E.A. Chudakov. The parameters of the VAZ-2108 car and the resistance forces during acceleration from 0 to 100 km / h have been determined. It is shown that the car accelerates from 0 to 100 km / h in 18.3 s, which corresponds to the experimental data and indicates the adequacy of the chosen techniques. The influence of changing the parameters and settings of the engine on the dynamics of vehicle acceleration has been investigated. It is shown that in order to achieve better dynamics of motion, the cylinder diameter and compression ratio must be maximized. The ignition timing, intake valve closing angle and excess air ratio have extremes. The efficiency of using a 16-valve cylinder head instead of an 8-valve one is shown. Based on the results of the studies, it was proposed to apply a set of engine parameters, which made it possible to reduce the acceleration time of the VAZ-2108 from 18.3 s to 13.2 s. Thus, the developed mathematical model makes it possible to quantitatively evaluate the influence of engine parameters on the dynamics of vehicle acceleration, to optimize the parameters and settings of the power plant and the vehicle as a whole.


2011 ◽  
Vol 3 (8) ◽  
pp. 503-505
Author(s):  
Jaipal Jaipal ◽  
◽  
Rakesh Chandra Bhadula ◽  
V. N Kala V. N Kala

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 419
Author(s):  
Congzheng Qi ◽  
Zemin Ding ◽  
Lingen Chen ◽  
Yanlin Ge ◽  
Huijun Feng

Based on finite time thermodynamics, an irreversible combined thermal Brownian heat engine model is established in this paper. The model consists of two thermal Brownian heat engines which are operating in tandem with thermal contact with three heat reservoirs. The rates of heat transfer are finite between the heat engine and the reservoir. Considering the heat leakage and the losses caused by kinetic energy change of particles, the formulas of steady current, power output and efficiency are derived. The power output and efficiency of combined heat engine are smaller than that of single heat engine operating between reservoirs with same temperatures. When the potential filed is free from external load, the effects of asymmetry of the potential, barrier height and heat leakage on the performance of the combined heat engine are analyzed. When the potential field is free from external load, the effects of basic design parameters on the performance of the combined heat engine are analyzed. The optimal power and efficiency are obtained by optimizing the barrier heights of two heat engines. The optimal working regions are obtained. There is optimal temperature ratio which maximize the overall power output or efficiency. When the potential filed is subjected to external load, effect of external load is analyzed. The steady current decreases versus external load; the power output and efficiency are monotonically increasing versus external load.


Author(s):  
Oluwole K. Bowoto ◽  
Omonigho P. Emenuvwe ◽  
Meysam N. Azadani

AbstractThis study proposes a design model for conserving and utilizing energy affordably and intermittently considering the wind rush experienced in the patronage of renewable energy sources for cheaper generation of electricity and the solar energy potential especially in continents of Africa and Asia. Essentially, the global quest for sustainable development across every sector is on the rise; hence, the need for a sustainable method of extracting energy cheaply with less wastage and pollution is on the priority list. This research, integrates and formulates different ideologies, factors and variables that have been adopted in previous research studies to create an efficient system. Some of the aforementioned researches includes pumped hydro gravity storage system, Compressed air gravity storage system, suspended weight in abandoned mine shaft, dynamic modelling of gravity energy storage coupled with a PV energy plant and deep ocean gravity energy storage. As an alternative and a modification to these systems, this research is proposing a Combined solar and gravity energy storage system. The design synthesis and computational modelling of the proposed system model were investigated using a constant height and but varying mass. Efficiencies reaching up to 62% was achieved using the chosen design experimental parameters adopted in this work. However, this efficiency can be tremendously improved upon if the design parameters are modified putting certain key factors which are highlighted in the limitation aspect of this research into consideration. Also, it was observed that for a test load of 50 × 103 mA running for 10 h (3600 s), the proposed system will only need to provide a torque of 3.27Nm and a height range of 66.1 × 104 m when a mass of 10 kg is lifted to give out power of 48 kwh. Since gravity storage requires intermittent actions and structured motions, mathematical models were used to analyse the system performance characteristics amongst other important parameters using tools like MATLAB Simscape modelling toolbox, Microsoft excel and Sysml Model software.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1358
Author(s):  
Ewa Golisz ◽  
Adam Kupczyk ◽  
Maria Majkowska ◽  
Jędrzej Trajer

The objective of this paper was to create a mathematical model of vacuum drops in a form that enables the testing of the impact of design parameters of a milking cluster on the values of vacuum drops in the claw. Simulation tests of the milking cluster were conducted, with the use of a simplified model of vacuum drops in the form of a fourth-degree polynomial. Sensitivity analysis and a simulation of a model with a simplified structure of vacuum drops in the claw were carried out. As a result, the impact of the milking machine’s design parameters on the milking process could be analysed. The results showed that a change in the local loss and linear drag coefficient in the long milk duct will have a lower impact on vacuum drops if a smaller flux of inlet air, a higher head of the air/liquid mix, and a higher diameter of the long milk tube are used.


Author(s):  
Gennadiy Kryzhevich ◽  
Anatoliy Filatov

This paper studies marine structures made of steels and light alloys and exposed to cyclic operational loads. Stress-strain parameters of their joints were taken from mathematical simulations of loads and strains or from actual strain gauging data. The aim of this study is to develop recommendations on fatigue strength calculations: specifically, how to quite the complex mathematical model of multi-axial loading at critical structural points with fast fatigue wear in favour of a simplified stressstrain state description based on optimal assignment of design parameters (stresses) in fatigue failure criteria. Preferability of this approach depends on case-specific requirements to calculation accuracy and timeframes. Uniaxial description of stressed state instead of the three-axial one enables much faster calculation with acceptable drop in accuracy.


Author(s):  
Hee-Dong Chae ◽  
Seung-bok Choi ◽  
Jong-Seok Oh

This paper proposes a new bed stage for patients in ambulance vehicle in order to improve ride quality in term of vibration control. The vibration of patient compartment in ambulance can cause a secondary damage to a patient and a difficulty for a doctor to perform emergency care. The bed stage is to solve vertical, rolling, and pitching vibration in patient compartment of ambulance. Four MR (magneto-rheological) dampers are equipped for vibration isolation of the stage. Firstly, a mathematical model of stage is derived followed by the measurement of vibration level of patient compartment of real ambulance vehicle. Then, the design parameters of bed stage is undertaken via computer simulation. Skyhook, PID and LQR controllers are used for vibration control and their control performances are compared.


2011 ◽  
Vol 317-319 ◽  
pp. 1999-2006
Author(s):  
Yu Wan ◽  
Ai Min Du ◽  
Da Shao ◽  
Guo Qiang Li

According to the boost mathematical model verified by experiments, the valve train of traditional gasoline engine is optimized and improved to achieve extended expansion cycle. The simulation results of extended expansion gasoline engine shows that the extended expansion gasoline engine has a better economic performance, compared to traditional gasoline engines. The average brake special fuel consumption (BSFC) can reduce 22.78 g / kW•h by LIVC, but the negative impacts of extended expansion gasoline engine restrict the potential of extended expansion gasoline engine. This paper analyzes the extended expansion gasoline engine performance under the influence of LIVC, discusses the way to further improve extended expansion gasoline engine performance.


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