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    Wyświetlanie 1-8 z 8
    Tytuł:
    Efficiency optimization of a closed indirectly fired gas turbine cycle working under two variable-temperature heat reservoirs
    Autorzy:
    Ma, Z.
    Wu, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/240010.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    obieg
    technologie bioenergetyczne
    termodynamika
    turbina gazowa
    wymiennik ciepła
    Bioenergy technology
    Cycle performance
    finite time thermodynamics
    High temperature heat exchanger
    Indirectly fired gas turbine
    Opis:
    Indirectly or externally fired gas turbines (IFGT or EFGT) are interesting technologies under development for small and medium scale combined heat and power (CHP) supplies in combination with micro gas turbine technologies. The emphasis is primarily on the utilization of the waste heat from the turbine in a recuperative process and the possibility of burning biomass even "dirty" fuel by employing a high temperature heat exchanger (HTHE) to avoid the combustion gases passing through the turbine. In this paper, finite time thermodynamics is employed in the performance analysis of a class of irreversible closed IFGT cycles coupled to variable temperature heat reservoirs. Based on the derived analytical formulae for the dimensionless power output and efficiency, the efficiency optimization is performed in two aspects. The first is to search the optimum heat conductance distribution corresponding to the efficiency optimization among the hot- and cold-side of the heat reservoirs and the high temperature heat exchangers for a fixed total heat exchanger inventory. The second is to search the optimum thermal capacitance rate matching corresponding to the maximum efficiency between the working fluid and the high-temperature heat reservoir for a fixed ratio of the thermal capacitance rates of the two heat reservoirs. The influences of some design parameters on the optimum heat conductance distribution, the optimum thermal capacitance rate matching and the maximum power output, which include the inlet temperature ratio of the two heat reservoirs, the efficiencies of the compressor and the gas turbine, and the total pressure recovery coefficient, are provided by numerical examples. The power plant configuration under optimized operation condition leads to a smaller size, including the compressor, turbine, two heat reservoirs and the HTHE.
    Źródło:
    Archives of Thermodynamics; 2011, 32, 2; 3-20
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rotating combustion chambers as a key feature of effective timing of turbine engine working according to Humphrey cycle – CFD analysis
    Autorzy:
    Tarnawski, Piotr
    Ostapski, Wiesław
    Powiązania:
    https://bibliotekanauki.pl/articles/2173712.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pressure gain combustion
    Humphrey cycle
    turbine engine
    CFD analysis
    valve timing system
    isochoric combustion
    engine energy efficiency
    sealing system
    ciśnienie spalania
    cykl Humphreya
    silnik turbinowy
    analiza CFD
    układ rozrządu
    spalanie izochoryczne
    sprawność energetyczna silnika
    system uszczelniający
    Opis:
    The paper presents a concept of a new turbine engine with the use of rotating isochoric combustion chambers. In contrast to previously analyzed authors’ engine concepts, here rotating combustion chambers were used as a valve timing system. As a result, several practical challenges could be overcome. An effective ceramic sealing system could be applied to the rotating combustion chambers. It can assure full tightness regardless of thermal conditions and related deformations. The segment sealing elements working with ceramic counter-surface can work as self-alignment because of the centrifugal force acting on them. The isochoric combustion process, gas expansion, and moment generation were analyzed using the CFD tool (computational fluid dynamics). The investigated engine concept is characterized by big energy efficiency and simple construction. Finally, further improvements in engine performance are discussed.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 5; art. no. e143100
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of the type of working fluid in the lower cycle and superheated steam parameters in the upper cycle on effectiveness of operation of binary power plant
    Autorzy:
    Stachel, A. A.
    Wiśniewski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/240335.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    binary power plant
    ORC power plant
    elektrownia binarna
    siłownia ORC
    Opis:
    In the paper presented have been the results of the analysis of effectiveness of operation of binary power plant consisting of combined two Clausius-Rankine cycles, namely the binary cycle with water as a working fluid in the upper cycle and organic substance as a working fluid in the lower cycle, as well as a single fluid component power plant operating also in line with the C-R cycle for superheated steam, with water as a working fluid. The influence of the parameters of superheated steam in the upper cycle has been assessed as well as the type of working fluid in the lower cycle. The results of calculations have been referred to the single-cycle classical steam power plant operating at the same parameters of superheated steam and the same mass flow rate of water circulating in both cycles. On the basis of accomplished analysis it has been shown that the binary power plant shows a greater power with respect to the reference power plant.
    Źródło:
    Archives of Thermodynamics; 2015, 36, 1; 111-123
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental investigation on a rotodynamic pump operating in the cogeneration system with a low-boiling working medium
    Autorzy:
    Kaczmarczyk, T.
    Żywica, G.
    Ihnatowicz, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/175328.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    organic rankine cycle
    micro-CHP
    rotodynamic peripheral pump
    low-boiling medium
    HFE7100
    Opis:
    The article presents the research carried out on the circulating rotodynamic pump (peripheral pump) operating in the organic Rankine cycle with or without regeneration. The low-boiling solvent HFE7100 was used as the working fluid. Its boiling point is around 61 ◦C at atmospheric pressure. An expansion valve, which simulated the operation of an expansion machine, was used to load the tested pump. The flow characteristics were given for the working media: a solution of glycol and HFE7100 in the condenser, thermal oil and HFE7100 in the evaporator and HFE7100 in the regenerator. The research results concerning the PK70 pump operating in an ORC cycle are reported for the HFE7100 temperature range 15-60 ◦C and the dynamic viscosity range of 0.132 to 0.66 mPas. The maximum flow rate and pressure of the pump during its operation in the ORC system were assessed. The analysis of the results demonstrates that the maximum efficiencies of the pump operating with or without regeneration were 44% and slightly below 37%, respectively. The impact of the selected physicochemical parameters of the working mediums on the pressure drops occurring in the ORC cogeneration installation was discussed. Based on the research conducted and the measurement results, the possibility to apply a PK70 unit as a circulating pump for the working medium in an ORC cycle was checked.
    Źródło:
    Transactions of the Institute of Fluid-Flow Machinery; 2016, 134; 63-87
    0079-3205
    Pojawia się w:
    Transactions of the Institute of Fluid-Flow Machinery
    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:
    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:
    Criteria for selection of working fluid in low-temperature ORC
    Autorzy:
    Mikielewicz, D.
    Mikielewicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/185262.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    micro CHP
    organic Rankine cycle
    mikro CHP
    organiczny cykl Rankine'a
    Opis:
    The economics of an ORC system is strictly linked to thermodynamic properties of the working fluid. A bad choice of working fluid could lead to a less efficient and expensive plant/generation unit. Some selection criteria have been put forward by various authors, incorporating thermodynamic properties, provided in literature but these do not have a general character. In the paper a simple analysis has been carried out which resulted in development of thermodynamic criteria for selection of an appropriate working fluid for subcritical and supercritical cycles. The postulated criteria are expressed in terms of non-dimensional numbers, which are characteristic for different fluids. The efficiency of the cycle is in a close relation to these numbers. The criteria are suitable for initial fluid selection. Such criteria should be used with other ones related to environmental impact, economy, system size, etc. Examples of such criteria have been also presented which may be helpful in rating of heat exchangers, which takes into account both heat transfer and flow resistance of the working fluid.
    Źródło:
    Chemical and Process Engineering; 2016, 37, 3; 429-440
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    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
      Wyświetlanie 1-8 z 8

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