scholarly journals Endoreversible Modeling of a Hydraulic Recuperation System

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 383 ◽  
Author(s):  
Robin Masser ◽  
Karl Heinz Hoffmann
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Energy Savings ◽  
Dynamical Behavior ◽  
Real Data ◽  
Pipe Diameter ◽  
Transfer Coefficients ◽  
Hydraulic Unit ◽  
Energy Saving Potential ◽  
Heat Transfer Coefficients

Hybrid drive systems able to recover and reuse braking energy of the vehicle can reduce fuel consumption, air pollution and operating costs. Among them, hydraulic recuperation systems are particularly suitable for commercial vehicles, especially if they are already equipped with a hydraulic system. Thus far, the investigation of such systems has been limited to individual components or optimizing their control. In this paper, we focus on thermodynamic effects and their impact on the overall systems energy saving potential using endoreversible thermodynamics as the ideal framework for modeling. The dynamical behavior of the hydraulic recuperation system as well as energy savings are estimated using real data of a vehicle suitable for application. Here, energy savings accelerating the vehicle around 10% and a reduction in energy transferred to the conventional disc brakes around 58% are predicted. We further vary certain design and loss parameters—such as accumulator volume, displacement of the hydraulic unit, heat transfer coefficients or pipe diameter—and discuss their influence on the energy saving potential of the system. It turns out that heat transfer coefficients and pipe diameter are of less importance than accumulator volume and displacement of the hydraulic unit.

Development of a chemical simplex of deposit formationon the walls of the fuel supply channels of engines and power plants

2021 ◽  
Author(s):  
K.V. Altunin
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Real Data ◽  
Similarity Criteria ◽  
Theoretical Research ◽  
Transfer Coefficients ◽  
Fuel Supply ◽  
Heat Transfer Coefficients ◽  
Mass Fractions ◽  
Number Of Cycles

The article describes a theoretical research related to development of a new simplex of deposit formation. This simplex differs from the existing similarity criteria and heat transfer simplices in that it is chemical and consists of the mass fractions of some fuel components, a metal wall and deposits. The problem of the formation of carbon-containing deposits on the heated walls of the fuel supply channels of power plants and engines is considered in detail. The main conditions for the occurrence of carbon-containing deposit and its properties, as well as its dependence on many factors, including temperature, number of cycles, the presence of additives in fuel, etc., are shown. For some thermophysical properties of deposits in different engines real data are given, as well as data on metals-catalysts and metals-inhibitors of oxidation and sedimentation. The obtained chemical simplex can be successfully used when creating new heat transfer criterion equations that would be much more accurate and applied for the following determination of heat transfer coefficients in fuel supply channels of engines and power plants.

Influences of External Windows on Energy Consumption of Industrial Buildings in Cold Areas

2011 ◽  
Vol 250-253 ◽  
pp. 3055-3058 ◽  
Author(s):  
Hong Wei Wang ◽  
Ya Dong Zheng ◽  
Fang Wen Tu
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Energy Saving ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Industrial Buildings ◽  
Different Types ◽  
Insulation Performance ◽  
The Heat Transfer Coefficient ◽  
Plastic Steel

Shenyang is located in the cold areas and main industy city in China. The most current industrial buildings can’t meet the demand of energy-saving standard because of the thermal insulation performance of the windows.This paper aims at using DeST software to analyze industrial workshop energy consumption, according to different types of external windows and window-wall ratio of buildings to provide reference for energy saving design of industrial buildings in Shenyang area.The thermal performance of the windows has great effect on the heat load. The lower the heat transfer coefficient of windows is, the more beneficial for energy saving of the buildings. The window-wall ratio has great effect on the energy consumption, and different heat-transfer coefficients possess various sensitivity for window-wall ratio, and reflective glass varis smaller than the others.It is better for energy saving to replace the conventional windows with plastic-steel reflective glass windows.

scholarly journals The modifications to the requirements on energy savings and thermal insulation of buildings in Poland in the years 1974-2021

2015 ◽  
Vol 14 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Anna Życzyńska ◽  
Tomasz Cholewa
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Energy Demand ◽  
Energy Savings ◽  
Building Energy ◽  
The European Union ◽  
Transfer Coefficients ◽  
Total Energy Consumption ◽  
Heat Transfer Coefficients ◽  
Technical Requirements

Residential and public buildings use for heating more than 40% of the total energy consumption in the European Union. Therefore, this paper discusses the modifications to the building energy standard, which is currently in force. It is based on the requirements included in the Polish technical building regulations and standards. The proper energy-saving police have been implemented to this kind of consumers to diminish the energy consumption. The analysis pertains to the values of heat transfer coefficients of building partitions as well as the indexes of the energy demand for various types of buildings. The analysis was conducted between 1974 and 2013. Moreover; the changes within this range, which will come into force in 2014 and will continue to 2021, which act in accordance with the technical requirements suitable for buildings, were also discussed. Furthermore, minimal thicknesses of insulation materials which enable meeting this requirements of a heat transfer coefficient for building partitions, were examined in the article.

Exergy and sensibility analysis of each individual effect in a kraft multiple effect evaporator

TAPPI Journal ◽  
2019 ◽  
Vol 18 (10) ◽  
pp. 607-618
Author(s):  
JÉSSICA MOREIRA ◽  
BRUNO LACERDA DE OLIVEIRA CAMPOS ◽  
ESLY FERREIRA DA COSTA JUNIOR ◽  
ANDRÉA OLIVEIRA SOUZA DA COSTA
Keyword(s):  
Optimization Problem ◽  
Real Data ◽  
Kraft Pulping ◽  
Steam Temperature ◽  
Input Flow ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Multiple Effect ◽  
Sensibility Analysis ◽  
Exergetic Analysis

The multiple effect evaporator (MEE) is an energy intensive step in the kraft pulping process. The exergetic analysis can be useful for locating irreversibilities in the process and pointing out which equipment is less efficient, and it could also be the object of optimization studies. In the present work, each evaporator of a real kraft system has been individually described using mass balance and thermodynamics principles (the first and the second laws). Real data from a kraft MEE were collected from a Brazilian plant and were used for the estimation of heat transfer coefficients in a nonlinear optimization problem, as well as for the validation of the model. An exergetic analysis was made for each effect individually, which resulted in effects 1A and 1B being the least efficient, and therefore having the greatest potential for improvement. A sensibility analysis was also performed, showing that steam temperature and liquor input flow rate are sensible parameters.

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