scholarly journals Experimental and Numerical Characterization of the Sliding Rotary Vane Expander Intake Pressure in Order to Develop a Novel Control-Diagnostic Procedure

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1970 ◽  
Author(s):  
Fabio Fatigati ◽  
Marco Di Bartolomeo ◽  
Davide Di Battista ◽  
Roberto Cipollone

Waste heat recovery via Organic Rankine Cycle (ORC)-based power units represents one of the most promising solutions to counteract the effects of CO2 emissions on climate change. Nevertheless, several aspects are still limiting its development on the on-the-road transportation sector. Among these aspects, the significant variations of the conditions of the hot source (exhaust gases) are a crucial point. Therefore, the components of the ORC-based unit operate far from the design point if the main operating parameters of the plant are not suitably controlled. The maximum pressure of the cycle is one of the most important variables to be controlled for the importance it has on the effectiveness of the recovery and on safety of operation. In this paper, a wide experimental and theoretical activity was performed in order to define the operating parameters that mostly affect the maximum pressure of the recovery unit. The results showed that the mass flow rate provided by the pump and the expander volumetric efficiency were the main drivers that affect the plant maximum pressure. Subsequently, through a validated model of the expander, a diagnostic map was outlined to evaluate if the expander and, consequently, the whole plant were properly working.

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Md. Zahurul Haq

Abstract Organic Rankine cycle (ORC)-based waste heat recovery (WHR) systems are simple, flexible, economical, and environment-friendly. Many working fluids and cycle configurations are available for WHR systems, and the diversity of working fluid properties complicates the synergistic integration of the efficient heat exchange in the evaporator and net output work. Unique guidelines to select a proper working fluid, cycle configuration and optimum operating parameters are not readily available. In the present study, a simple target-temperature-line approach is introduced to get the optimum operating parameters for the subcritical ORC system. The target-line is the locus of temperatures satisfying the pinch-point temperature difference along the length of the heat exchanger. Employing the approach, study is carried out with 38 pre-selected working fluids to get the optimum operating parameters and suitable fluid for heat source temperatures ranging from 100 °C to 300 °C. Results obtained are analyzed to get cross-correlations between key operating and performance parameters using a heat-map diagram. At the optimum condition, optimal working fluid’s critical temperature and pressure, evaporator saturation temperature, effectivenesses of the heat exchange in the evaporator, cycle, and overall WHR system exhibit strong linear correlations with the heat source temperature.


GIS Business ◽  
2019 ◽  
Vol 14 (6) ◽  
pp. 230-242
Author(s):  
M. Ganesan, K ◽  
K. Veerakumar ◽  
N. R Vembu ◽  
Dr. M. K Durgamani ◽  
Dr. Renuka

Job satisfaction is an important factor for employees working in formal and informal sector. The job is small or big, permanent or temporary, risky or non-risky, job satisfaction is important. It is the mental feeling which drives the employees to excel. Job satisfaction is a combination of psychological, physiological and environmental circumstances. A satisfied employee is a contented and happy human being. The labour turnover depends upon job satisfaction. Even highly paid employees quit the job when they are not satisfied with the job. Road transportation in Tamilnadu is growing day by day. Job stress in the road transportation is very high due to increase in number of vehicle playing on the road and heavy traffic. The drivers and conductors working in public transport corporation are suffering from high job stress. If drivers and conductors are not satisfied with their job which leads to mental stresses and affects the productivity and also creates accidents. In this present study the researchers made an attempt to study the level of job satisfaction among the drivers and conductors who are working in the Tamilnadu State Transport Corporation (TNSTC). The study reveals the expectations of drivers and conductors working in TNSTC with regards to the attributes like salary, promotion and fringe benefits etc., are satisfactory and not detrimental. 


2021 ◽  
Vol 11 (5) ◽  
pp. 1984
Author(s):  
Ramin Moradi ◽  
Emanuele Habib ◽  
Enrico Bocci ◽  
Luca Cioccolanti

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.


2021 ◽  
pp. 1-21
Author(s):  
G.E. Pateropoulos ◽  
T.G. Efstathiadis ◽  
A.I. Kalfas

ABSTRACT The potential to recover waste heat from the exhaust gases of a turboprop engine and produce useful work through an Organic Rankine Cycle (ORC) is investigated. A thermodynamic analysis of the engine’s Brayton cycle is derived to determine the heat source available for exploitation. The aim is to use the aircraft engine fuel as the working fluid of the organic Rankine cycle in order to reduce the extra weight of the waste heat recovery system and keep the thrust-to-weight ratio as high as possible. A surrogate fuel with thermophysical properties similar to aviation gas turbine fuel is used for the ORC simulation. The evaporator design as well as the weight minimisation and safety of the suggested application are the most crucial aspects determining the feasibility of the proposed concept. The results show that there is potential in the exhaust gases to produce up to 50kW of power, corresponding to a 10.1% improvement of the overall thermal efficiency of the engine.


2021 ◽  
Vol 13 (3) ◽  
pp. 1218
Author(s):  
Sharjeel Ashraf Ansari ◽  
Mustafa Khalid ◽  
Khurram Kamal ◽  
Tahir Abdul Hussain Ratlamwala ◽  
Ghulam Hussain ◽  
...  

The proton exchange membrane fuel cell (PEMFC) is the fastest growing fuel cell technology on the market. Due to their sustainable nature, PEMFCs are widely adopted as a renewable energy resource. Fabricating a PEMFC is a costly process; hence, mathematical modeling and simulations are necessary in order to fully optimize its performance. Alongside this, the feasibility of a waste heat recovery system based on the organic Rankine cycle is also studied and power generation for different operating conditions is presented. The fuel cell produces a power output of 1198 W at a current of 24A. It has 50% efficiency and hence produces an equal amount of waste heat. That waste heat is used to drive an organic Rankine cycle (ORC), which in turn produces an additional 428 W of power at 35% efficiency. The total extracted power hence stands at 1626 W. MATLAB/Simulink R2016a is used for modeling both the fuel cell and the organic Rankine cycle.


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