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Tytuł:
Comparative analysis of effeciency of waste heat conversion in low-temperature Brayton cycle
Autorzy:
Borsukiewicz, A.
Stawicki, P.
Powiązania:
https://bibliotekanauki.pl/articles/185192.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Brayton cycle
working fluid
low temperature source
low temperature power plant
Cykl Braytona
temperatura
elektrownia o niskiej temperaturze
Opis:
The paper discusses the feasibility, effectiveness and validity of a gas turbine power plant, operated according to the Brayton comparative cycle in order to develop low-potential waste heat (160◦C) and convert it into electricity. Fourteen working fluids, mainly with organic origin have been examined. It can be concluded that low molecular weight working fluids allow to obtain higher power efficiency of Brayton cycle only if conversions without taking into account internal losses are considered. For the cycle that takes into account the compression conversion efficiency in the compressor and expansion in the gas turbine, the highest efficiency was obtained for the perfluoropentane working medium and other substances with relatively high molecular weight values. However, even for the cycle using internal heat recovery, the thermal efficiency of the Brayton cycle did not exceed 7%.
Źródło:
Chemical and Process Engineering; 2018, 39, 1; 103--112
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Repair Welding of SQV2A Pressure Vessel Steel by Temper Bead Techniques Without Post Welding Heat Treatment
Spawanie remontowe stali SQV2A na zbiorniki ciśnieniowe z użyciem techniki ściegów odpuszczających bez obróbki cieplnej złącza po spawaniu
Autorzy:
Brziak, P.
Łomozik, M.
Mizuno, R.
Matsuda, F.
Powiązania:
https://bibliotekanauki.pl/articles/351100.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
termiczny cykl spawania
HAZ
technika ściegów odpuszczających
obróbka cieplna
thermal welding cycle
heat treatment
temper bead welding
Opis:
SQV2A Manganese-Molybdenum-Nickel ferritic steel has been developed for pressure vessel fabrication. Due to its chemical composition and carefully controlled heat treatment the SQV2A steel consists of fine-grained tempered martensite/lower bainite microstructure, which exhibits well-balanced combination of strength and low temperature toughness. However, this balance is disturbed by the thermal cycles experienced during welding, producing areas of unaccepted mechanical behaviors. Generally, a decrease in toughness of some regions of BM Heat Affected Zone is the most critical aspect of multi-layer (repair) welding. A full scale Post Welding Heat Treatment (PWHT) usually restores the mechanical behaviors to requested levels. Additionally, PWHT removes hydrogen trapped in the microstructure during welding. A situation becomes critical, when on-site local (repair) welding takes place. Harsh environment, difficult access and a presence other facilities make the in-situ PWHT almost inapplicable. In term of cold cracking prevention, a Gas Tungsten arc Welding (GTAW) gives acceptable hydrogen levels in the weld region; and full scale PWHT is unnecessary. This is the main reason why the GTAW has become a leading process for on-site (repair) welding of heavy section components. Moreover, a automatic GTAW process offers better weld geometry controlling which has become out of importance for welding not followed by PWHT. A precisely controlled multiple weld thermal cycles of predefined peak temperatures in particular weld regions can be employed for restoring the mechanical behavior of critical weld areas instead of full scale PWHT.
Manganowo - molibdenowo - niklowa ferrytyczna stal w gatunku SQV2A została opracowana do wytwarzania zbiorników ciśnieniowych w przemyśle energetycznym. Dzięki składowi chemicznemu oraz kontrolowanej obróbce cieplnej mikrostruktura stali SQV2A składa się z drobnoziarnistego odpuszczonego martenzytu / dolnego bainitu, która wykazuje dobre połączenie właściwości wytrzymałościowych i ciągliwości przy niskich temperaturach. Jednakże te dobre zależności pomiędzy właściwościami wytrzymałościowymi a ciągliwością zostają zakłócone przez cykle cieplne, które oddziałują podczas spawania i prowadzą do powstania w złączu spawanym obszarów o niekorzystnych właściwościach mechanicznych. Obniżenie właściwości plastycznych (ciągliwości) niektórych obszarów SWC spawanej stali stanowi najbardziej krytyczny aspekt wielowarstwowego spawania remontowego. Typowa obróbka cieplna złącza spawanego po spawaniu PWHT zwykle przywraca właściwości mechaniczne do wymaganego poziomu. Ponadto obróbka cieplna PWHT złącza spawanego powoduje usunięcie z mikrostruktury wodoru uwięzionego podczas procesu spawania. Sytuacja bardzo komplikuje się w przypadku konieczności spawania remontowego na ograniczonym obszarze na dużym elemencie. Trudne warunki otoczenia, ograniczony dostęp do miejsca naprawy oraz obecność innych niedogodności sprawiają, że poprawne przeprowadzenie obróbki cieplnej złącza po spawaniu PWHT staje się bardzo utrudnione. W warunkach zapobiegania pęknięciom zimnym, spawanie metodą TIG (GTAW) daje zadawalająco niskie ilości wodoru w obszarach złącza a obróbka cieplna po spawaniu, w pełnym zakresie, nie jest wymagana. To stanowi główną przyczynę dlaczego metoda spawania TIG jest najczęściej stosowanym sposobem lokalnego spawania remontowego dużych elementów konstrukcyjnych. Ponadto, automatyczne spawanie metodą TIG umożliwia lepszą kontrolę geometrii spawanego złącza zwłaszcza w przypadku kiedy obróbka cieplna złącza po spawaniu nie jest wykonywana. Precyzyjnie kontrolowane cykle cieplne, o zdefiniowanych temperaturach maksymalnych w szczególnych obszarach złącza, mogą być stosowane, podczas spawania wielowarstwowego, do przywrócenia własności mechanicznych w krytycznych rejonach SWC zamiast typowej obróbki cieplnej po spawaniu (PWHT).
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 2; 205-216
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of a combined gas-steam system with flue gas recirculation
Autorzy:
Chmielniak, T.
Mońka, P.
Pilarz, P.
Powiązania:
https://bibliotekanauki.pl/articles/185708.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CCS
combined cycle
rise in CO2
content in flue gases
flue gas recirculation
modelling
cykl mieszany
wzrost CO2
spaliny
recyrkulacja gazów
modelowanie
Opis:
This article presents changes in the operating parameters of a combined gas-steam cycle with a CO2 capture installation and flue gas recirculation. Parametric equations are solved in a purpose-built mathematical model of the system using the Ebsilon Professional code. Recirculated flue gases from the heat recovery boiler outlet, after being cooled and dried, are fed together with primary air into the mixer and then into the gas turbine compressor. This leads to an increase in carbon dioxide concentration in the flue gases fed into the CO2 capture installation from 7.12 to 15.7%. As a consequence, there is a reduction in the demand for heat in the form of steam extracted from the turbine for the amine solution regeneration in the CO2 capture reactor. In addition, the flue gas recirculation involves a rise in the flue gas temperature (by 18 K) at the heat recovery boiler inlet and makes it possible to produce more steam. These changes ontribute to an increase in net electricity generation efficiency by 1%. The proposed model and the obtained results of numerical simulations are useful in the analysis of combined gas-steam cycles integrated with carbon dioxide separation from flue gases.
Źródło:
Chemical and Process Engineering; 2016, 37, 2; 305-316
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of air-bottoming cycle as a heat source for the carbon dioxide capture installation of a coal-fired power unit
Autorzy:
Chmielniak, T.
Lepszy, S.
Czaja, D.
Powiązania:
https://bibliotekanauki.pl/articles/240691.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
absorpcja chemiczna
cykl powietrza
system gazowo-powietrzny
turbina gazowa
air bottoming cycle
CCS
chemical absorption
gas-air systems
gas turbine
Opis:
The installations of CO2 capture from flue gases using chemical absorption require a supply of large amounts of heat into the system. The most common heating medium is steam extracted from the cycle, which results in a decrease in the power unit efficiency. The use of heat needed for the desorption process from another source could be an option for this configuration. The paper presents an application of gas-air systems for the generation of extra amounts of energy and heat. Gas-air systems, referred to as the air bottoming cycle (ABC), are composed of a gas turbine powered by natural gas, air compressor and air turbine coupled to the system by means of a heat exchanger. Example configurations of gas-air systems are presented. The efficiency and power values, as well as heat fluxes of the systems under consideration are determined. For comparison purposes, the results of modelling a system consisting of a gas turbine and a regenerative exchanger are presented.
Źródło:
Archives of Thermodynamics; 2011, 32, 3; 89-101
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual ORC-Brayton power system for waste heat recovery in heavy-duty vehicles
Autorzy:
Cholewiński, M.
Pospolita, W.
Błoński, D.
Powiązania:
https://bibliotekanauki.pl/articles/224018.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
organic Rankine cycle
Brayton cycle
energy efficiency
road transport
waste heat utilization
cykl Rankina
cykl Braytona
efektywność energetyczna
transport drogowy
wykorzystanie ciepła odpadowego
Opis:
Reducing the amount of energy required in industrial activities is one of the proven ways to achieve major cost savings, especially in the face of soaring energy prices. In the transport sector, besides the financial benefits, low energy consumption leads to the significant reduction of emissions of many pollutants. In this paper the new concept of dual power technology, dedicated to heavy road transport, was modelled and analysed by computer simulations. The combination of organic Rankine cycle and Brayton cycle was proposed, where the waste heat of fumes was recognized as a upper heat source, whereas the surrounding was adopted to be the lower one. Improvement of total energy conversion efficiency of the truck was the key success factor. Environmental friendly fluids (air and R123) were utilised. The operating parameters, power characteristics and energy streams (i.e. dispersion) of the system were evaluated, calculated and commented from the perspective of its theoretical profitability. The calculated net power capacity of analysed dual system was around 50 hp for 100% load. However, when the engine load is below 50% of nominal capacity, the power generation of combined system might be lower than in the case of single ORC system.
Źródło:
Archives of Transport; 2016, 39, 3; 7-19
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An innovative ecological hybrid refrigeration cycle for high power refrigeration facility
Autorzy:
Cyklis, P.
Janisz, K.
Powiązania:
https://bibliotekanauki.pl/articles/185060.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid ecological refrigeration cycle
adsorption
compression
hybrydowy ekologiczny cykl chłodniczy
adsorpcja
kompresja
Opis:
Searching for new refrigerants is one of the most significant scientific problems in refrigeration. There are ecological refrigerants commonly known: H2O and CO2. H2O and CO2 known as natural refrigerants, but they have problems:a high freezing point of H2O and a low triple point of CO2. These problems can be solved by the application of a hybrid sorption-compression refrigeration cycle. The cycle combines the application possibility of H2O in the high temperature sorption stage and the low temperature application of CO2 in the compression stage. This solution gives significant energy savings in comparison with the two-stage compressor cycle and with the one-stage transcritical CO2 cycle. Besides, the sorption cycle may be powered by low temperature waste heat or renewable heat. This is an original idea of the authors. In the paper an analysis of the possible extension of this solution for high capacity industrial refrigeration is presented. The estimated energy savings as well as TEWI (Total Equivalent Warming Impact) index for ecological gains are calculated.
Źródło:
Chemical and Process Engineering; 2015, 36, 3; 321-330
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of the ecological hybrid refrigeration cycle
Autorzy:
Cyklis, P.
Kantor, R.
Ryncarz, T.
Górski, B.
Duda, R.
Powiązania:
https://bibliotekanauki.pl/articles/240899.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid refrigerating cycle
adsorption
two stage refrigerating
hybrydowy cykl chłodniczy
adsorpcja
dwustopniowe chłodzenie
Opis:
The requirements for environmentally friendly refrigerants promote application of CO2 and water as working fluids. However there are two problems related to that, namely high temperature limit for CO2 in condenser due to the low critical temperature, and low temperature limit for water being the result of high triple point temperature. This can be avoided by application of the hybrid adsorption-compression system, where water is the working fluid in the adsorption high temperature cycle used to cool down the CO2 compression cycle condenser. The adsorption process is powered with a low temperature renewable heat source as solar collectors or other waste heat source. The refrigeration system integrating adsorption and compression system has been designed and constructed in the Laboratory of Thermodynamics and Thermal Machine Measurements of Cracow University of Technology. The heat source for adsorption system consists of 16 tube tulbular collectors. The CO2 compression low temperature cycle is based on two parallel compressors with frequency inverter. Energy efficiency and TEWI of this hybrid system is quite promising in comparison with the compression only systems.
Źródło:
Archives of Thermodynamics; 2014, 35, 3; 145-154
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Freeze-proof durability of concrete incorporating recycled coarse aggregate
Autorzy:
Deng, Xianghui
Xue, Liyuan
Wang, Rui
Gao, Xiaoyue
Powiązania:
https://bibliotekanauki.pl/articles/231420.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kruszywo recyklingowe
kruszywo gruboziarniste
beton
cykl zamrażanie-odmrażanie
mrozoodporność
recycled aggregate
coarse aggregate
concrete
freeze-thaw cycle
freeze-proof durability
Opis:
The recycle of the building and demolition waste could reduce project expenses and save natural resources as well as solve problem about environmental risks incurred during the disposal of building waste. In this study, waste C30 concrete is taken an experimental material. The mass loss, ultrasonic velocity, dynamic modulus of elasticity and cubic compressive strength of recycled coarse aggregate concrete whose coarse aggregate replacement percentage is 25%, 50%, 75%, and 100% are tested and compared with NAC when the cycles of freezing and thawing are 0, 25, 50, 75, 100, 125, 150, 175, and 200 times. The results show: (1) Generally, the loss of mass, ultrasonic velocity, dynamic modulus of elasticity and cubic compressive strength constantly increase with the growth of freezing and thawing cycles. (2) Compared with the recycled concrete of other replacement percentages, the RAC50 shows relatively close performance to NAC in mass loss, the change of dynamic modulus of elasticity and cubic compressive strength. (3) Performances of RAC25 specimens are better than the other RAC specimens for the ultrasonic wave velocity.
Źródło:
Archives of Civil Engineering; 2019, 65, 4; 63-80
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigating freeze-proof durability of air-entrained C30 recycled coarse aggregate concrete
Autorzy:
Deng, Xianghui
Liu, Yiyuan
Wang, Rui
Powiązania:
https://bibliotekanauki.pl/articles/1852544.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
domieszka napowietrzająca
kruszywo gruboziarniste
kruszywo z recyklingu
cykl zamrażanie-odmrażanie
mrozoodporność betonu
air-entraining admixture
recycled aggregate
coarse aggregate
concrete
freeze-thaw cycle
freeze-proof durability
Opis:
Incorporation of air-entraining agent has improved recycled concrete freeze-proof durability. However, it is very lacking to study the role of the entraining agent. In this paper, the influence of an air-entraining agent on freeze-proof durability for the ordinary C30 recycled coarse aggregate (RCA) concrete and air-entrained C30 RCA concrete was investigated with the laboratory comparative tests. The mass loss, the dynamic modulus of elasticity, ultrasonic wave velocity and cubic compressive strength were measured during freeze-thaw cycles. The test result showed the concrete’s performance was similar to the ordinary concrete and was better than that of other recycled concretes when the content of RCA was 50% and 0.03% of air-entraining agent was added for C30 RCA concrete. Meanwhile, the addition of air-entraining agent has an improved effect on the performance of recycled concrete, but the effect was limited.
Źródło:
Archives of Civil Engineering; 2021, 67, 2; 507-524
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The rationalization of automatic units for HPDC technology
Autorzy:
Herman, A.
Powiązania:
https://bibliotekanauki.pl/articles/382755.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
automatyka w odlewnictwie
robotyka w odlewnictwie
zarządzanie jakością
odlewanie wysokociśnieniowe
cykl pracy
automation in foundry
robotics in foundry
quality management
high pressure die casting (HPDC)
work cycle
rationalization of automatic unit
Opis:
The paper deals with problem of optimal used automatic workplace for HPDC technology - mainly from aspects of operations sequence, efficiency of work cycle and planning of using and servicing of HPDC casting machine. Presented are possible ways to analyse automatic units for HPDC. The experimental part was focused on the rationalization of the current work cycle time for die casting of aluminium alloy. The working place was described in detail in the project. The measurements were carried out in detail with the help of charts and graphs mapped cycle of casting workplace. Other parameters and settings have been identified. The proposals for improvements were made after the first measurements and these improvements were subsequently verified. The main actions were mainly software modifications of casting center. It is for the reason that today's sophisticated workplaces have the option of a relatively wide range of modifications without any physical harm to machines themselves. It is possible to change settings or unlock some unsatisfactory parameters.
Źródło:
Archives of Foundry Engineering; 2012, 12, 2; 29-34
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of selected water disinfection technologies with the use of life cycle assessment
Porównawcza analiza wybranych technologii dezynfekcji wody przy wykorzystaniu środowiskowej analizy cyklu życia
Autorzy:
Jachimowski, Artur
Nitkiewicz, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/205450.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LCA
life cycle assessment
drinking water
sodium hypochlorite
chlorination
water disinfection
UV disinfection
cykl życia
woda pitna
podchloryn sodu
chlorowanie
dezynfekcja wody
dezynfekcja UV
Opis:
The objective of the paper is to use life cycle assessment to compare environmental impact of different technologies used in the process of water disinfection. Two scenarios are developed for water disinfection life cycle at ZUW Raba water treatment plant: (1) historical, in which gaseous chlorine is used as a disinfectant and (2) actual, in which UV radiation and electrolytically generated sodium hypochlorite are used for that purpose. Primary data is supplemented with ecoinvent 3 database records. Environmental impact is assessed by IMPACT2002+ method and its midpoint and endpoint indicators that are calculated with the use of SimaPro 8.4 software. The focus of the assessment is on selected life cycle phases: disinfection process itself and the water distribution process that follows. The assessment uses the data on flows and emissions streams as observed in the Raba plant. As the results of primal analysis show, a change of disinfectant results in quantitative changes in THMs and free chlorine in water supplied to the water supply network. The results of analysis confirm the higher potential of THMs formation and higher environmental impact of the combined method of UV/NaClO disinfection in distribution phase and in whole life cycle, mainly due to the increase of human toxicity factors. However, during the disinfection phase, gaseous chlorine use is more harmful for environment. But the final conclusion states that water quality indicators are not significant in the context of LCA, while both disinfection and distribution phases are concerned.
Celem artykułu było pokazanie wykorzystania środowiskowej oceny cyklu życia (LCA) do porównania wpływu na środowisko różnych technologii stosowanych w procesie dezynfekcji wody. Dla cyklu życia procesu dezynfekcji wody w zakładzie uzdatniania wody Raba Miejskiego Przedsiębiorstwa Wodociągów i Kanalizacji (MPWiK) w Krakowie w niniejszej pracy zostały sformułowane dwa scenariusze: (1) historyczny, w którym dezynfektantem jest chlor gazowy oraz (2) bieżący, w którym tę rolę spełnia układ dwustopniowy z promieniowaniem UV i podchlorynem sodu. Podstawowe dane były uzupełniane rekordami bazy danych ecoinvent 3. Oddziaływanie środowiskowe poddano ocenie przy wykorzystaniu metody IMPACT2002+. Pośrednie i końcowe wskaźniki kategorii wpływu wyliczono przy wykorzystaniu oprogramowania SimPro 8. Analiza obejmowała wybrane fazy cyklu życia: sam proces dezynfekcji i następujący po nim proces dystrybucji wody. W ocenie wykorzystano dane ilościowe o przepływach i emisjach w procesie dezynfekcji wody z wybranego zakładu uzdatniania wody. Wyniki wstępnych analiz pokazują, że zmiana dezynfektanta powoduje zmiany ilościowe trihalometanów (THM) i chloru wolnego w wodzie dostarczanej do sieci wodociągowej. Analiza wskazuje, że w fazie dezynfekcji użycie chloru gazowego jest bardziej szkodliwe dla środowiska. Natomiast wyniki analizy potwierdzają wyższy potencjał tworzenia się THM i większy wpływ na środowisko połączonej metody dezynfekcji UV/NaClO w fazie dystrybucji wody.
Źródło:
Archives of Environmental Protection; 2019, 45, 3; 3-10
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A case study of working fluid selection for a small-scale waste heat recovery ORC system
Autorzy:
Klimaszewski, Piotr
Zaniewski, Dawid
Witanowski, Łukasz
Suchocki, Tomasz
Klonowicz, Piotr
Lampart, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/240748.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
waste heat recovery
organic Rankine cycle
ORC fluids
heat exchangers
turboexpander
ciepło odpadowe
odzysk ciepła
ORC
organiczny cykl Rankine'a
wymienniki ciepła
turboekspander
Opis:
The paper illustrates a case study of fluid selection for an internal combustion engine heat recovery organic Rankine cycle (ORC) system having the net power of about 30 kW. Various criteria of fluid selection are discussed. Particular attention is paid to thermodynamic performance of the system and human safety. The selection of working fluid for the ORC system has a large impact on the next steps of the design process, i.e., the working substance affects the turbine design and the size and type of heat exchangers. The final choice is usually a compromise between thermodynamic performance, safety and impact on natural environment. The most important parameters in thermodynamic analysis include calculations of net generated power and ORC cycle efficiency. Some level of toxicity and flammability can be accepted only if the leakages are very low. The fluid thermal stability level has to be taken into account too. The economy is a key aspect from the commercial point of view and that includes not only the fluid cost but also other costs which are the consequence of particular fluid selection. The paper discusses various configurations of the ORC system – with and without a regenerator and with direct or indirect evaporation. The selected working fluids for the considered particular power plant include toluene, DMC (dimethyl carbonate) and MM (hexamethyldisiloxane). Their advantages and disadvantages are outlined.
Źródło:
Archives of Thermodynamics; 2019, 40, 3; 159-180
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of a program for supercritical power plant calculations
Autorzy:
Kotowicz, J.
Łukowicz, H.
Bartela, Ł.
Michalski, S.
Powiązania:
https://bibliotekanauki.pl/articles/240731.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
blok nadkrytyczny
cykl parowy
walidacja
steam cycle
supercritical power plant
validation
Opis:
This article describes the validation of a supercritical steam cycle. The cycle model was created with the commercial program GateCycle and validated using in-house code of the Institute of Power Engineering and Turbomachinery. The Institute's in-house code has been used extensively for industrial power plants calculations with good results. In the first step of the validation process, assumptions were made about the live steam temperature and pressure, net power, characteristic quantities for high- and low-pressure regenerative heat exchangers and pressure losses in heat exchangers. These assumptions were then used to develop a steam cycle model in GateCycle and a model based on the code developed in-house at the Institute of Power Engineering and Turbomachinery. Properties, such as thermodynamic parameters at characteristic points of the steam cycle, net power values and efficiencies, heat provided to the steam cycle and heat taken from the steam cycle, were compared. The last step of the analysis was calculation of relative errors of compared values. The method used for relative error calculations is presented in the paper. The assigned relative errors are very slight, generally not exceeding 0.1%. Based on our analysis, it can be concluded that using the GateCycle software for calculations of supercritical power plants is possible.
Źródło:
Archives of Thermodynamics; 2011, 32, 4; 81-89
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of optimisation methods applied to thermal cycle of a coal fired power plant
Autorzy:
Kowalczyk, Ł.
Elsner, W.
Powiązania:
https://bibliotekanauki.pl/articles/240829.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermodynamic optimisation
Nelder-Mead method
thermal cycle
coal fired power plant
IPSEpro
optymalizacja termodynamiczna
metoda Neldera-Meada
cykl termiczny
elektrownia węglowa
Opis:
The paper presents a thermodynamic optimization of 900 MW power unit for ultra-supercritical parameters, modified according to AD700 concept. The aim of the study was to verify two optimisation methods, i.e., the finding the minimum of a constrained nonlinear multivariable function (fmincon) and the Nelder-Mead method with their own constrain functions. The analysis was carried out using IPSEpro software combined with MAT-LAB, where gross power generation efficiency was chosen as the objective function. In comparison with the Nelder-Mead method it was shown that using fmincon function gives reasonable results and a significant reduction of computational time. Unfortunately, with the increased number of decision parameters, the benefit measured by the increase in efficiency is becoming smaller. An important drawback of fmincon method is also a lack of repeatability by using different starting points. The obtained results led to the conclusion, that the Nelder-Mead method is a better tool for optimisation of thermal cycles with a high degree of complexity like the coal-fired power unit.
Źródło:
Archives of Thermodynamics; 2013, 34, 4; 175-186
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
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
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