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Wyszukujesz frazę "cycle efficiency" wg kryterium: Temat


Tytuł:
Late intake valve closing as a way of the throttleless control of SI engine load
Autorzy:
Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:
https://bibliotekanauki.pl/articles/247952.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spark-ignition engine
variable valve actuation
late intake valve closing
open Atkinson-Miller cycle
charge exchange process
cycle efficiency
Opis:
The paper tackles the problems connected with the charge exchange in internal combustion engines. The theoretical analysis of the charge exchange process in the SI engine has been presented. The realization of the charge exchange process is connected with the necessity of overcoming the flow resistances, then with the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by throttling valve is especially high at the partial load running of an engine. A system with independent, late intake valve closing has been analysed. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine. The open, theoretical Atkinson-Miller cycle has been assumed as a model of processes proceeding in the engine with variable intake valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle, which is theoretical cycle for the classic throttle governing of engine load. Benefits resulting from application of the system with late intake valve closing have been assessed on the basis of the selected parameters: a fuel dose, a cycle work, relative charge exchange work and cycle efficiency.
Źródło:
Journal of KONES; 2012, 19, 1; 491-499
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Throttleless control of SI engine load by fully flexible inlet valve actuation system
Autorzy:
Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:
https://bibliotekanauki.pl/articles/133835.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
spark-ignition engine
variable valve actuation
early inlet valve closure
theoretical cycle
charge exchange process
cycle efficiency
silnik o zapłonie iskrowym
cykl teoretyczny
wydajność cyklu
Opis:
A system with independent, early inlet valve closure (EIVC) has been analysed. The open, theoretical cycle has been assumed as a model of processes proceeding in the engine with variable inlet valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle which is theoretical cycle for the classic throttle governing of engine load. The influence of EIVC on fuel economy, cycle work, relative charge exchange work and cycle efficiency has been theoretically investigated. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine.
Źródło:
Combustion Engines; 2016, 55, 1; 44-48
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena sprawności cyklu roboczego pojazdu do usuwania odpadów z pojemników na podstawie danych eksploatacyjnych
Working cycle efficiency evaluation of Refuse Collection Vehicle based on exploitation data
Autorzy:
Wysocki, O.
Zajdziński, T.
Czyżewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/309906.pdf
Data publikacji:
2018
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
śmieciarka
zużycie energii
zużycie paliwa
efektywność cyklu roboczego
pojazd do usuwania odpadów z pojemników
energy consumption
fuel consumption
working cycle efficiency
waste collection vehicle
refuse collection vehicle
Opis:
W artykule przedstawiona została metoda oceny sprawności cyklu roboczego śmieciarki. Wykorzystując dane eksploatacyjne wyznaczono dwa reprezentatywne cykle i na ich podstawie obliczono zarówno sprawność całego cyklu, jak i jego poszczególnych faz. Porównano wartości energii potrzebnej do opróżniania pojemników, energii do zagęszczania odpadów oraz energii z paliwa. Przedstawiono przebiegi mierzonych i obliczonych wartości w czasie obrazując w ten sposób rzeczywiste przebieg parametrów układu hydraulicznego i obciążenia silnika spalinowego poczas rzeczywistej pracy pojazdu.
In this paper a method of efficiency evaluation of working cycle of Refuse Collection Vehicle is presented. Using real world data, two representative working cycles were analyzed. Total cycle efficiency was calculated, as well as the efficiency of particular cycle phases. Then, energy needed to collect, energy needed to compact the waste and energy from fuel were compared. Measured and calculated values vs time were shown on the diagrams illustrating hydraulic system parameters and the real load applied to the chassis combustion engine.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2018, 19, 9; 188-192
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The energy - efficient two - phase driving cycle (eta n greather than 1) can efficiency eta n in vehicles be higher than 1.0 ?
Autorzy:
Ubysz, A.
Powiązania:
https://bibliotekanauki.pl/articles/242928.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
efficiency
driving cycle
overall engine efficiency
Opis:
The study presents an important part of fourth chapter of the monograph 'Energy Consumption in Relation to Fuel Efficiency Under Complex Driving Conditions' (2003) concerning opportunities to improve vehicle drive efficiency through application, during one phase of driving in neutral in two-phase driving cycle. Theoretical simulation of total energy consumption in vehicles with SI engine provided explanation of a relatively low fuel efficiency observed under real driving conditions in serial cars [1]. The study cites the original method of calculations developed by the author in order to calculate the efficiency of vehicle power unit in two-phase driving cycle assuming that one of the phases might be non-driving. The calculations were made for complex driving conditions, i.e. simulated changes with predefined steps for road slope (-3.5o to 3.5o), acceleration (-0.36-0.36 m/s2) and average speed (60-140 kmph) for a distance of 2x500 m. The results of calculation variants for each type of a drive system of a car proved that there are significant limitations of optimising the fuel consumption of cars. The first one is conditioned by the fact that the engine works at full dynamic load and the second one by the fact that idle running is against the 'Highway Code'.
Źródło:
Journal of KONES; 2012, 19, 4; 633-642
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Do institutional and political factors matter for the efficiency of banking sectors?
Autorzy:
Olszak, Małgorzata Anna
Chodnicka, Patrycja
Powiązania:
https://bibliotekanauki.pl/articles/2054545.pdf
Data publikacji:
2014-05-19
Wydawca:
Uniwersytet Warszawski. Wydawnictwo Naukowe Wydziału Zarządzania
Tematy:
banking sector
efficiency
business cycle
risk
Opis:
This paper investigates the relevance of banking- sector- specific and macroeconomic determinants of profitability of 21 banking sectors over the years 1995-2009. In the analysis we apply the Arellano and Bond GMM-estimator to aggregated data collected in a harmonized way by the OECD, to find out whether banking-sector-specific and macroeconomic determinants which significantly affect the efficiency of individual banks, are also of great importance to the profitability (proxied by ROA and ROE ratios) of banking sectors. Our results suggest that banking-sector-specific determinants affect the efficiency of banks in the anticipated way. Macroeconomic variables have a statistically-significant impact on both ROA and ROE. The sensitivity of efficiency to both groups of determinants depends on institutional and political criteria.
Źródło:
Journal of Banking and Financial Economics; 2014, 1(1); 40-58
2353-6845
Pojawia się w:
Journal of Banking and Financial Economics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic analysis of a combined cycle power plant located in Jordan: A case study
Autorzy:
Bataineh, Khaled
Khaleel, Bara A.
Powiązania:
https://bibliotekanauki.pl/articles/240565.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
combined cycle power plant
energy efficiency
exergy efficiency
exergy destruction
exergy losses
Opis:
Efficiency and electrical power output of combined cycle power plants vary according to the ambient conditions. The amount of these variations greatly affects electricity production, fuel consumption, and plant incomes. Obviously, many world countries have a wide range of climatic conditions, which impact the performance of power plants. In this paper, a thermodynamic analysis of an operating power plant located in Jordan is performed with actual operating data acquired from the power plant control unit. The analysis is performed by using first and second laws of thermodynamics. Energy and exergy efficiencies of each component of the power plant system are calculated and the effect of ambient temperature on the components performance is studied. The effects of gas turbine pressure ratio, gas turbine inlet temperature, load and ambient conditions on the combined cycle efficiency, power outputs and exergy destruction are investigated. Energy and exergy efficiencies of the combined cycle power plant are found as 45.29%, and 42.73% respectively when the ambient temperature is 34°C. Furthermore, it is found that the combustion chamber has the largest exergy destruction rate among the system components. The results showed that 73% of the total exergy destruction occurs in the combustion chamber when the ambient temperature is 34°C. Moreover, the results show that the second major exergy loss is in HRSC. The results show that the energy and exergy efficiency of the combined cycle power plant decreases as the ambient temperature increases. According to the calculation results, improvement and modification suggestions are presented.
Źródło:
Archives of Thermodynamics; 2020, 41, 1; 95-123
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigating the Efficiency of Combined Cycle Power Plants with the Data Envelopment Analysis Process (with an Emphasis on Air Pollution)
Autorzy:
Sanjaranipour, Noushin
Atabi, Farideh
Momeni, Mansour
Ghodousi, Jamal
Lahijanian, Akramolmolok
Powiązania:
https://bibliotekanauki.pl/articles/2055783.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
efficiency
Combined Cycle Power Plants
DEA
air pollution
Opis:
Performance management is one of the most significant strategies in promoting the efficiency of organizations and is highly sensitive. It is important to check the efficiency of combined cycle power plants because of their major contribution to power generation and air pollution. This study was conducted to evaluate the economic and environmental efficiency of Combined Cycle Power Plants (CCPPs). The inputs and outputs required to evaluate the performance of the power plants were determined according to expert opinions. Then, the 7-year statistics and information of the Qom, Neishabour, Shahid Rajaee, Yazd and Kerman power plants were collected as the desired CCPPs in Iran. The Window Data Envelopment Analysis (WDEA) method was used for evaluating the efficiency of the power plants. The 3-year window length showed that most of the power plants were efficient. Only the Rajaee, Neishabour and Yazd power plants were ineffective in some years. The mean efficiency of the power plants in the 4-year window length showed that the plants were efficient from 2008 to 2010.
Źródło:
Geomatics and Environmental Engineering; 2022, 16, 2; 111--125
1898-1135
Pojawia się w:
Geomatics and Environmental Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On board LNG reliquefaction technology: a comparative study
Autorzy:
Gómez, J.
Gómez, M.
Garcia, R.
Catoira, A.
Powiązania:
https://bibliotekanauki.pl/articles/963412.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
reliquefaction
boil-off gas
vessel
Brayton Cycle
efficiency
Opis:
Reliquefaction technologies are being currently applied on board liquefied natural gas (LNG) carriers on the basis of economic criteria and energy efficiency. A variety of reliquefaction techniques have been developed so far during the last decade. Nevertheless, technology enhancement continues being a research area of interest. In this article the different technologies applied to the reliquefaction of the boil-off gas (BOG) on LNG carriers have been described, analysed and discussed, contributing to highlight the process and operation characteristics as well as selection plant criteria. Finally, a comparison of the different reliquefaction plants, considering their capacities and efficiencies as well as other technical data of interest has been carried out.
Źródło:
Polish Maritime Research; 2014, 1; 77-88
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using LCA method to describe logistic system of fuel
Autorzy:
Haller, P.
Jankowski, A.
Jaworska, E.
Kardasz, P.
Markowska, K.
Wróbel, R.
Powiązania:
https://bibliotekanauki.pl/articles/245154.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
logistic system
LCA method
fuel efficiency
life cycle
Opis:
This paper presents the life cycle of the fuel with the use of LCA. This method is taken from the management theory allows to describe and predict the impact of production processes, transport and use of fuels on the environment. The aim of the study is to compare the energy consumption of the test fuels (diesel, a blend of rapeseed oil and butyl alcohol) in the process of their production. The results indicate that most energy is consumed during the processing of crude oil. This process produced a large quantity of sulphur oxides. Very energy intensive (53,859 GJ per 10 k litres of fuel produced) part of the production is rape culture. This is due to the long working hours of agricultural tractors and combines. In this process, are secreted large amounts of exhaust gas: CO (2.664 kg), NOx (23.31 kg). Inter alia, environmental life cycle assessment, schematic structure of the LCA, the energy balance of the life cycle of diesel oil, the energy balance of the life cycle of rape oil mixed with butyl alcohol, the balance of raw material sourcing, the balance of the materials necessary to production of a mixture of rape oil and butanol alcohol are presented in the paper.
Źródło:
Journal of KONES; 2015, 22, 3; 293-299
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective efficiency in car engine as a function of reduction ratio during energy-aying speed control
Autorzy:
Ubysz, A.
Powiązania:
https://bibliotekanauki.pl/articles/246247.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
power efficiency
driving cycle
effective engine efficiency
B. S. F. C.
load torque
Opis:
The study examines the effect of transformation ratio in power transmission system on engine efficiency as a function of passenger vehicle velocity (m = 1400 kg) with energy-saving vehicle drive. The study also presents working range in driving phases for energy-saving speed control up to 120 km/h for a simplified overall engine performance map for SI engine. Understanding of the presented considerations can be facilitated through relating with advantages of application of non-driving phases in low engine load phases (field 4 in overall engine performance map). Working points of SI engines in engine performance maps were divided in terms of energy-saving vehicle speed control into 4 ranges. Zone l is the most economic whereas zones 3 and 4 are the least energy-saving, which was also discussed by the author in other works. The study presents the location of engine working points in overall engine performance map during energy-saving vehicle speed control within the range of 30-120 km/h using two different 6-gear gearboxes. Working range for CI engine in simplified overall characteristics in truck, the impact of speed control upon fuel consumption in real traffic conditions, sum and difference characteristics of components of drive engine unitary power, area of maximal rise in overall engine efficiency after reduction of rotational speed, simplified SI engine performance maps, covering with economic zone of working point in energy-saving drive of vehicles are presented in the paper.
Źródło:
Journal of KONES; 2010, 17, 4; 547-552
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of environmentally-friendly technologies based on the Double-ECO model – an evaluation platform
Autorzy:
Pena-Gonzalez, L. E.
Da Silva, P.
Tanabe, I.
Powiązania:
https://bibliotekanauki.pl/articles/100204.pdf
Data publikacji:
2018
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
eco-efficiency
lubrication
life cycle assessment (LCA)
Mahalanobis-Taguchi system
Opis:
In recent years, the urgency to create environmentally-friendly technologies has dramatically increased. However, these technologies are usually not adopted due to their large cost and low profit. Previously the “Double-ECO model” has been proposed as a methodology that reconciles both “Economy” and “Ecology”, which relies on the exploration of technology alternatives that offer an improved mechanical performance. Here, as mechanical performance, cost and environmental impact were meant to be approached under the same degree of priority, this model was thought to offer the basis for a broader technology development framework. The current research initiates said framework by proposing an evaluation platform, which through a transition from a focus on environmental-friendliness towards an improved eco-efficiency definition lays groundwork for an automated evaluation. This was done by defining a dimensionless evaluation parameter based on existing methodologies and referred as the “DE Index”. This paper applied the proposed evaluation method into a machine tool lubrication technology example. It was concluded that, (1) the platform was able to effectively compare technologies under the proposed eco-efficiency parameter, (2) the developed technology possessed improvements in the environmental pollution output, mechanical performance and cost when compared to conventional technologies.
Źródło:
Journal of Machine Engineering; 2018, 18, 1; 18-31
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increase of efficiency of SI engine through the implementation of thermodynamic cycle with additional expansion
Autorzy:
Noga, M.
Sendyka, B.
Powiązania:
https://bibliotekanauki.pl/articles/200877.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
innovative five-stroke engine cycle
Carnot cycle
Otto cycle
five-stroke engine
additional expansion
increase of thermal efficiency of the five-stroke engine cycle
Opis:
The paper presents the theoretical basis and practical implementation of the concept of a five-stroke cycle where an additional expansion of the working medium is achieved in a separate cylinder. The work, carried out at the Cracow University of Technology, constitutes a development of the idea of five-stroke engine. This paper proposes a new theoretical thermodynamic cycle that describes the processes occurring in a five-stroke engine. It has been taken into consideration that the expansion ratio of the engine is twice the compression ratio. At the next step an analysis of the thermodynamic cycle with particular emphasis on its thermal efficiency compared to efficiency of four-stroke engine has been shown. In the second part of the article selected research results of the five-stroke engine built based on the existing four-cylinder spark ignition engine have been presented. A comparison of the total efficiency obtained by the engine in the four- and five-stroke version has been provided. Similar comparisons for specific emission of the selected exhaust components have also been given.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 2; 349-355
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test bed studies of an engine with combustion initiation from ignition dose of fuel
Autorzy:
Sendyka, B.
Noga, M.
Powiązania:
https://bibliotekanauki.pl/articles/245825.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
two-cycle engine
compression ignition
spark ignition
total efficiency of engine
Opis:
Results of test bed studies of combustion engine with work possibility with application of spark ignition and combustion from ignition dose injected directly into the combustion chamber were described in this article. In engine working according to the patent solution of Prof. B. Sendyka, during start and work at low rotational speed and low load a system realizing spark ignition of homogenous mixture formed in classical way in the intake manifold is active. For higher rotational speeds and heavy load the ignition system is switched off whereas, injectors of ignition dose injecting fuel by the end of the compression stroke directly into the working space of the engine are activated. The fuel dose injected into the combustion chamber undergoes auto-ignition and in this way the combustion process in the whole volume of the homogenous combustion charge accumulated in the cylinder is initiated. The mass of ignition dose of fuel constitutes about 5 – 10% of the whole fuel mass per working cycle what differs decisively the presented solution from other known engines working according to similar principles. Application of two combustion system in four stroke combustion engine aims at combining the advantages of spark ignition a compression ignition engines. The engine is characterized by easy starting and during work at higher rotational speed and higher load in the mode of ignition from pilot dose exploitation efficiency of energy contained in fuel is higher than for spark ignition engine, this finds direct reflection in increase in total efficiency by over 9% as related to the base value.
Źródło:
Journal of KONES; 2011, 18, 4; 427-509
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibility of the charge exchange work diminishing of an internal combustion engine in part load
Autorzy:
Postrzednik, S.
Żmudka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/247156.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
engine efficiency
charge exchange work
engine load
valve actuating
thermodynamic cycle
Opis:
Internal combustion engines, used for driving of different cars, occur not only at the full load, but mostly at the part load. The relative load exchange work at the full (nominal) engine load is significant low. At the part load of the IC engine his energy efficiency r)e is significantly lower than in the optimal (nominal field) range of the performance parameters. One of the numerous reasons of this effect is regular growing of the relative load exchange work of the IC engine. The load exchange work of IC engine essentially determines the effective engine efficiency. It is directly connected with the quantitative regulation method common used in the IC engines. From the thermodynamic point of view - the main reason of this effect is the throttling process (causing exergy losses) occurring in the inlet and outlet channels. The known proposals for solving of this problem are based on applying of the fully electronic control of the motion of inlet, outlet valves and new reference cycles. The independent actuating (steerage) procedures of the ICE inlet valves should assure the adequate mass of the fresh charge, while procedures of the outlet valves are focused on the optimal exhaust gas recirculation rate, according to the engine load. The idea presented in the paper leads to diminishing the charge exchange work of the IC engines. The mentioned above problem can be solved using presented in the paper a new concept of the reference cycle (called as eco-cycle) of IC engine.
Źródło:
Journal of KONES; 2011, 18, 4; 377-387
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple tank-to-wheels analysis tool for future vehicle powertrains
Autorzy:
Vavra, J.
Macek, J.
Takats, M.
Cerovsky, Z.
Powiązania:
https://bibliotekanauki.pl/articles/243520.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vehicle powertrain efficiency
internal combustion engine
fuel cells
simulation
driving cycle
Opis:
The future powertrains have to be properly assessed in early stages of vehicle design using simple and fast but reliable tools. The aim of the paper is to develop a simulation tool suitable for any of current transient cycles for finding of upper limits of tank-to-wheel efficiencies of recent or future vehicle powertrains in different concepts of vehicles to assess their potential, to find gaps between the state-of-the-art and to find ways to bridge them. The simulation philosophy and procedure may be described in the following steps. The testing cycle power demands on vehicle movement are analyzed and the optimum operation efficiency of a primary mover (engine, fuel cell, electric motor) is assigned to them. Dynamic torques at powertrain are accounted for. Speed, speed slip (driving machine/wheels) and load dependencies of transmission efficiency are simulated by simple models. In the case of a hybrid solution, charging and discharging efficiencies of energy accumulators and additional losses (e.g., in converters and inverters) are considered. The clear modular structure of the simulation tool enables the researcher to amend new features of powertrain components. The links to more detailed simulation tools are prepared. The simulation tool is described by regression and algebraic models (based on the results of higher level simulation tools) in a way giving immediate response during sensitivity analysis. The examples of tool calibration for different powertrains and results comparing powertrain potential are presented for lower medium class passenger car. The current simulation tool creates a useful link between detailed and accurate but CPU time demanding 1-D tools, based on partial differential equations, and rules-of-thumb, used sometimes for initial potential assessments. Moreover, the described tool does not require detailed data on the powertrain during early stage of design but it shows its potential for further development.
Źródło:
Journal of KONES; 2008, 15, 3; 525-534
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approaches to Teaching Building Materials and Technologies for Energy-Efficient Sustainable Construction
Autorzy:
Lushnikova, N.
Powiązania:
https://bibliotekanauki.pl/articles/390582.pdf
Data publikacji:
2016
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
building material
energy efficiency
sustainability
construction technology
life cycle assessment (LCA)
Opis:
There are highlighted the peculiarities of teaching subjects “Building Materials in Energy-efficient Construction” and “Technologies in Sustainable Construction” developed in English within the scope of Civil Engineering Master Studies curricula „Building ecological Europe”. Basic objectives, teaching methods, content of the lectures and course project, and course results are considered.
Źródło:
Budownictwo i Architektura; 2016, 15, 3; 53-62
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the use of waste heat from a glass melting furnace for electricity production in the organic Rankine cycle system
Autorzy:
Musiał, Arkadiusz Mateusz
Antczak, Łukasz
Jędrzejewski, Łukasz
Klonowicz, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1845495.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
energy efficiency
distributed generation
organic rankine cycle
ORC
industrial waste heat
Opis:
In most production plants, waste heat is usually discharged into the environment, contributing to a reduction in the energy efficiency of industrial processes. This is often due to the low thermal parameters of the carriers in which this energy is contained, such as oils, water, exhaust gases or other post-process gases, which means that their use for electricity production in a conventional Rankine cycle may prove to be economically unprofitable. One of the technologies enabling the use of lowand medium-temperature waste heat carriers is the organic Rankine cycle (ORC) technology. The paper present results of calculations performed to evaluate potential electricity production in ORC using waste heat from a natural gas-fired glass melting furnace. The analysis was carried out assuming the use of a single-stage axial turbine, whose efficiency was estimated using correlations available in the literature. The calculations were carried out for three working fluids, namely hexamethyldisiloxane, dimethyl carbonate, and toluene for two scenarios, i.e. ORC system dedicated only to electricity production and ORC system working in cogeneration mode, where heat is obtain from cooling the condenser. In each of the considered cases, the ORC system achieves the net power output exceeding 300 kW (309 kW for megawatts in the cogenerative mode to 367 kW for toluene in the non-cogenerative mode), with an estimated turbine efficiency above 80%, in range of 80,75 to 83,78%. The efficiency of the ORC system, depending on the used working fluid and the adopted scenario, is in the range from 14.85 to 16.68%, achieving higher efficiency for the non-cogenerative work scenario.
Źródło:
Archives of Thermodynamics; 2021, 42, 1; 15-33
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the operating parameters of steam jet injectors for a main boiler’s regenerative feedwater system
Autorzy:
Adamkiewicz, Andrzej
Grzesiak, Szymon
Powiązania:
https://bibliotekanauki.pl/articles/135226.pdf
Data publikacji:
2019
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
steam jet injector
steam cycle
steam turbine
propulsion plant
thermal efficiency
determination
Opis:
Due to the development of alternative propulsion systems, there is a need for LNG tanker turbine propulsion plants to regain their competitiveness. Previous research revealed effective methods to increase the thermal efficiency of the steam cycle based on quality assessment, and it was proposed that the latent heat of the main turbine exhaust steam could be recovered. Research was carried out for the steam cycle using regenerative heat exchangers fed by steam jet injectors. In this paper, an algorithm to determine the operating parameters of steam jet injectors, and the calculation results for different drive steam parameters are presented. The obtained results will be used as input parameters for further heat balance calculations of the proposed regenerative steam cycles.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2019, 60 (132); 171-176
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conditions of economic efficiency of industrial enterprises in the enterprise life cycle stages
Uwarunkowania efektywności ekonomicznej przedsiębiorstw przemysłowych w fazach cyklu życia przedsiębiorstwa
Autorzy:
Żurakowska-Sawa, J.
Powiązania:
https://bibliotekanauki.pl/articles/2051458.pdf
Data publikacji:
2019
Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Tematy:
industrial enterprise
enterprise condition
economic efficiency
enterprise
life cycle
conditioning
macroeconomic situation
Opis:
Subject and purpose of work: The purpose of the study is to determine the variables determining the level of synthetic measure of economic efficiency in listed companies of the industry sector as part of their enterprise life cycle. Materials and methods: The article uses data from annual unitary financial statements of industrial enterprises according to the classification of the Warsaw Stock Exchange and data describing the macroeconomic situation of the state economy. The research period covered the years 1999-2012. In order to examine which factors determine the level of economic efficiency at each stage of the life cycle of enterprises, estimation of econometric models was carried out. Results: In the models obtained for companies in the growth and maturity stage, statistically significant determinants were obtained only in the field of internal factors. In the models estimated for companies in the stages of launch, shake-out and decline, statistically significant conditions were identified, both in terms of external factors and in the area of internal factors. Conclusions: A comprehensive assessment of the conditions for the level of economic efficiency of enterprises should take into account both factors dependent on the enterprise (microeconomic) as well as those determined by the environment (macroeconomic) and beyond its control. It is therefore necessary for managers of enterprises to have extensive and up-todate knowledge of factors and conditions that are significant in shaping the level of economic efficiency.
Źródło:
Economic and Regional Studies; 2019, 12, 3; 287-301
2083-3725
2451-182X
Pojawia się w:
Economic and Regional Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Air bottoming combined cycle performance analyses by the combined effect of variable parameters
Autorzy:
Khan, Mohammad N
Alzafiri, Dhare
Powiązania:
https://bibliotekanauki.pl/articles/27309845.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
topping cycle
air bottoming cycle
net power output
thermal efficiency
total exergy
destruction
exergetic efficiency
cykl uzupełniania
cykl opadania powietrza
moc wyjściowa netto
wydajność termiczna
całkowita egzergia
zniszczenie
efektywność egzergetyczna
Opis:
To meet the continuous demand for energy of industrial as well as commercial sectors, researchers focus on increasing the power generating capacity of gas turbine power plants. In this regard, the combined cycle is a better solution in terms of environmental aspects and power generation as compared to a simple gas turbine power plant. The present study is the thermodynamic investigation of five possible air bottoming combined cycles in which the topping cycle is a simple gas turbine cycle, regenerative gas turbine cycle, inter-cool gas turbine cycle, reheat gas turbine cycle, and intercool-reheat gas turbine cycle. The effect of pressure ratio of the topping cycle, the turbine inlet temperature of topping cycle, and ambient temperature on net power output, thermal efficiency, total exergy destruction, and exergetic efficiency of the combined cycle have been analyzed. The ratio of the net power output of the combined cycle to that of the topping cycle is maximal in the case when the topping cycle is a simple gas turbine cycle. The ratio of net power output and the total exergy destruction of the combined cycle to those of the topping cycle decrease with pressure ratio for all the combinations under study except for the case when the topping cycle is the regenerative gas turbine cycle.
Źródło:
Archive of Mechanical Engineering; 2022, LXIX, 3; 497--517
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression of the transport sector operational efficiency evaluation methodology (trends) at different stages of the economic cycle
Autorzy:
Kiyak, D.
Župerkienė, E.
Powiązania:
https://bibliotekanauki.pl/articles/374297.pdf
Data publikacji:
2017
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
transport sector
operational efficiency indicators
economic cycle
sektor transportu
wskaźniki efektywności operacyjnej
cykl koniunkturalny
Opis:
It is important to evaluate the impact of economic fluctuations on the transport sector operational efficiency, since such an analysis is a source of economic information which contributes to the identification of the sector's potential and advantages, the establishment of the risky areas of activity, and the exploration of the opportunities to increase its effectiveness. The aim of the study was to apply mathematical evaluation methods to the exploration of the operational efficiency of the Lithuanian transport sector companies and, based on the outcomes, to validate the opportunity of predicting a potential change of the economic cycle. The operational efficiency of the Lithuanian transport sector was analysed in the context of the cyclical national economy, and not in individual economic boom or recession periods, as that allowed for more detailed evaluation of the specific activities of the sector and its impact on Lithuanian economy. To achieve the aim, three different stages of the economic cycle in Lithuania were identified, and calculations were made during them. Based on the aggregate financial data, four different economic efficiency indicators were developed that reflected the efficiency level of the entire transport sector, and the sensitivity of the transport sector to economic fluctuations was identified. The comparison of the changes in the transport sector and in Lithuanian economy made it obvious that the level of the sector's operational efficiency could be regarded as a leading indicator of the economic cycle.
Źródło:
Transport Problems; 2017, 12, 4; 109-118
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy efficiency for the transcritical compression CO2 cycle with the use of the ejector as the first stage of the compression
Autorzy:
Kozioł, J.
Gazda, W.
Wilżyński, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/240536.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
efektywność energetyczna
eżektor
transkrytyczny cykl CO2
ejector
energy efficiency
transcritical CO2 cycle
Opis:
An analysis of energy efficiency for transcritical compression unit with CO2 (R744) as the refrigerant has been carried out using empirical operating characteristics for the two-phase ejector. The first stage of the refrigerant compression is carried out in the ejector. The criterion adopted for the estimation of energy efficiency for the cycle is the coefficient of performance COP. The analysis is performed for the heat pump and refrigeration systems. The results of COP for the systems with the ejector has been compared with the COP[L], values for the single stage Linde cycle.
Źródło:
Archives of Thermodynamics; 2010, 31, 4; 61-69
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efektywność wydobycia węgla kamiennego z perspektywy cyklu życia produktu
Efficiency of hard coal extraction from the perspective of product life cycle
Autorzy:
Jonek-Kowalska, I.
Turek, M.
Powiązania:
https://bibliotekanauki.pl/articles/322933.pdf
Data publikacji:
2016
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
efektywność
polskie górnictwo węgla kamiennego
optymali-zacja efektywności
cykl życia produktu
efficiency
Polish coal mining sector
efficiency optimizing
product life cycle
Opis:
Węgiel kamienny jest znanym i powszechnie wykorzystywanym surowcem energetycznym. Znajduje się w bilansach energetycznych wielu krajów europejskich. W Polsce jest kluczowym nieodnawialnym źródłem energii. Niemniej z uwagi na rosnącą presję dekarbonizacji rozwój alternatywnych nośników energetycznych oraz technologii energooszczędnych jego znaczenie systematycznie maleje. W fazie schyłkowej cyklu życia produktu z reguły maleją zyski, dlatego też głównym celem niniejszego artykułu jest analiza efektywności w polskim górnictwie węgla kamiennego z perspektywy cyklu życia produktu oraz wskazanie potencjalnych możliwości optymalizacji tej efektywności.
Hard coal is known and widely used energy resource. It is present in the energy balance in many European countries. In Poland hard coal is a key non-renewable source of energy. However, due to the growing pressure of decarbonization, development of alternative energy sources and energy saving technologies its importance has been steadily decreasing. In the declining phase of product life cycle the profit decreases and therefore the main aim of this article is to analyse the efficiency in Polish coal mining industry from product life cycle perspective and to identify the potential opportunities to optimize the efficiency.
Źródło:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska; 2016, 99; 157-168
1641-3466
Pojawia się w:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative investigation of working fluids for an organic Rankine cycle with geothermal water
Autorzy:
Liu, Y.-N.
Xiao, S.
Powiązania:
https://bibliotekanauki.pl/articles/240415.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
geothermal water
energy efficiency
organic Rankine cycle
wody geotermalne
efektywność energetyczna
organiczny obieg Rankine'a
Opis:
In this paper, the thermodynamic investigation on the use of geothermal water (130°C as maximum) for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a) were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.
Źródło:
Archives of Thermodynamics; 2015, 36, 2; 75-84
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of different organic fluids on performances of binary slag washing water power plants
Autorzy:
Li, Z.
Liu, Y.
Dong, P.
Zhang, Y.
Xiao, S.
Powiązania:
https://bibliotekanauki.pl/articles/240438.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
slag washing water
efficiency
organic fluids
binary power cycle
wydajność
płyn organiczny
podwójny cykl zasilania
Opis:
In this paper, 3 typical organic fluids were selected as working fluids for a sample slag washing water binary power plants. In this system, the working fluids obtain the thermal energy from slag washing water sources. Thus, it plays a significant role on the cycle performance to select the suitable working fluid. Energy and exergy efficiencies of 3 typical organic fluids were calculated. Dry type fluids (i.e., R227ea) showed higher energy and exergy efficiencies. Conversely, wet fluids (i.e., R143a and R290) indicated lower energy and exergy efficiencies, respectively.
Źródło:
Archives of Thermodynamics; 2017, 38, 3; 49-62
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł

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