TY - JOUR AU - Dózsa, Levente AU - Groniewsky, Axel TI - Értékelőmátrix kidolgozása kistelepülési távhőrendszer megvalósíthatóságának vizsgálatázhoz JF - ENERGIAGAZDÁLKODÁS J2 - ENGA VL - 67 PY - 2026 IS - KLENEN'26 különszám SP - 23 EP - 25 PG - 3 SN - 0021-0757 UR - https://m2.mtmt.hu/api/publication/37069462 ID - 37069462 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Illés, Dávid AU - Hégely, László TI - Estimation of internal energy, enthalpy, and entropy, based on group contribution method and cubic equation of states JF - MATERIALS CHEMISTRY AND PHYSICS J2 - MATER CHEM PHYS VL - 348 PY - 2026 PG - 12 SN - 0254-0584 DO - 10.1016/j.matchemphys.2025.131605 UR - https://m2.mtmt.hu/api/publication/36372316 ID - 36372316 N1 - This work was funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA). The work was also supported by the ÚNKP-22-5 New National Excellence Program of the Ministry for Innovation and Technology and also in the form of grant FK-143059 from the source of the National Research, Development and Innovation Fund and by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. AB - By utilizing a group contribution method (GCM) by specifying the number of functional groups forming the molecules, estimation of some of the pivotal properties of substances becomes feasible. To broaden the scope of the predictable properties and to expand the applicability of the GCM procedure, it may be required to combine it with an equation of state. In this work, the internal energy, enthalpy, and entropy in 2000 states per material of 69 compounds from the NIST database were compared with the results of 25 different GCM-based cubic equations of state and analyzed by classes of compounds to identify the limitations of the method and to suggest the use of an equation of state for each type of compounds. Interestingly, equations that depend on fewer material properties tend to yield better results, especially when those properties can be estimated with high precision. In contrast, equations that rely on more parameters may be more sensitive to inaccuracies in property estimates, making them less reliable. LA - English DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Hégely, László TI - Prediction of temperature-entropy diagram classes for pure fluids in organic Rankine cycles using group contribution methods JF - FLUID PHASE EQUILIBRIA J2 - FLUID PHASE EQUILIBR VL - 607 PY - 2026 PG - 9 SN - 0378-3812 DO - 10.1016/j.fluid.2026.114705 UR - https://m2.mtmt.hu/api/publication/37020322 ID - 37020322 N1 - This work was funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA). The work was also supported by the ÚNKP-22–5 New National Excellence Program of the Ministry for Innovation and Technology and also in the form of grant FK-143059 from the source of the National Research, Development and Innovation Fund and by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. Project no TKP-6–6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. AB - The organic Rankine cycle is an indispensable technology in low-temperature heat recovery, where the working fluid is a critical element. It influences not only the type and design parameters of the equipment but, via the shape of the saturated liquid and vapor line, the configuration as well. Besides thermophysical and chemical properties, the selection of the ideal working fluid is also affected by the ever-growing stringency of environmental regulations. Hence, there is a growing demand to create unique, ecologically sound media. Addressing this challenge involves simultaneously optimizing molecular structure and process parameters —an endeavor often facilitated by computer-aided molecular design, applying group contribution methods. Given the frequent application of cubic equations of state (EoS) in this method, the present study investigates which of the 23 common cubic EoS should be chosen when the class of the shape of the newly designed phase curve is to be determined. The grouping is examined for the traditional 3-element and the more sensitive Györke classification. Interestingly, the findings indicate that the fewer material properties an EoS relies on, the more accurate the classification becomes, provided these properties are accurately estimated. Complex EoSs, however, may exhibit higher parameter sensitivity and, similarly to model validation, can become overfitted. Moreover, results show that achieving high accuracy in phase curve design does not necessarily equate to high classification ability, which may require the introduction of distinct indicators for classification and determining the precision of the temperature-entropy phase curve. LA - English DB - MTMT ER - TY - JOUR AU - Mayer, Martin János AU - Kun-Balog, Attila AU - Groniewsky, Axel TI - Effects of the electricity consumption profile on the optimal renewable energy supply JF - ENERGY CONVERSION AND MANAGEMENT J2 - ENERG CONVERS MANAGE VL - 348 PY - 2026 IS - C PG - 18 SN - 0196-8904 DO - 10.1016/j.enconman.2025.120797 UR - https://m2.mtmt.hu/api/publication/36462534 ID - 36462534 N1 - This paper is supported by the National Research, Development and Innovation Fund, project no. OTKA-FK 142702, and in the frame of the 2021-2.1.1-EK-00002 project, and the RRF-2.3.1-21-2022-00009 project titled National Laboratory for Renewable Energy implemented with the support provided by the Recovery and Resilience Facility of the European Union within the framework of Program Széchenyi Plan Plus, and by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. AB - The transition to weather-dependent renewable energy sources makes managing the temporal distribution of energy demand pivotal. This paper examines how the distinct characteristics of load profiles affect the levelized cost of electricity (LCOE) and the optimal technology mix of a hybrid renewable energy system (HRES) covering a pre-defined ratio of the electricity consumption. The proposed method involves the physical modeling of photovoltaic (PV) and wind turbine (WT) power production and the joint optimization of the operation of three energy storage technologies, namely lithium iron phosphate (LFP) and sodium-sulfur (NaS) batteries and hydrogen, and the installed capacities of all components with linear programming. All results are presented as a function of the renewable coverage ratio, enabling analysis across the entire pathway of a renewable energy transition. Nine measurement-based load profiles are considered, representing all combinations of three daily and three seasonal consumption trends. The LCOE of supplying the least favorable load profile is up to 88% higher than that of the most favorable one for small-scale systems consisting of four households supplied by only PV and LFP. This difference reduces to 42% if all five technologies are included in a town-sized community, which highlights the benefits of larger-scale energy communities with a diverse technology mix. The seasonal consumption habits are found to have a greater impact on the optimal cost and sizing than daily usage behaviors. Renewable energy production has largely different costs at different parts of the year, calling for a shift in the paradigm that energy efficiency is judged based on the amount of consumed or saved energy, since changes in the temporal distributions are becoming equally important. LA - English DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Hégely, László TI - Extension of the Constantinou and Gani group contribution method with the Tochigi method through an automatic conversion procedure JF - FLUID PHASE EQUILIBRIA J2 - FLUID PHASE EQUILIBR VL - 584 PY - 2024 PG - 16 SN - 0378-3812 DO - 10.1016/j.fluid.2024.114148 UR - https://m2.mtmt.hu/api/publication/34889882 ID - 34889882 N1 - Export Date: 10 June 2024 CODEN: FPEQD Correspondence Address: Groniewsky, A.; Department of Energy Engineering, Műegyetem rkp. 3, Hungary; email: groniewsky@energia.bme.hu Funding details: Magyar Tudományos Akadémia, MTA Funding details: Innovációs és Technológiai Minisztérium, FK-143059 Funding details: Innovációs és Technológiai Minisztérium Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA, TKP-6-6/PALY-2021 Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding text 1: Axel Groniewsky reports financial support was provided by Hungarian Academy of Sciences. Axel Groniewsky reports financial support was provided by Ministry for Innovation and Technology Hungary. Laszlo Hegely reports financial support was provided by Ministry of Culture and Innovation of Hungary. Axel Groniewsky reports a relationship with Hungarian Academy of Sciences that includes: funding grants. Axel Groniewsky reports a relationship with Ministry for Innovation and Technology Hungary that includes: funding grants. Laszlo Hegely reports a relationship with Ministry of Culture and Innovation of Hungary that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.This work was funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA). The work was also supported by the \\u00DANKP-22\\u20135 New National Excellence Program of the Ministry for Innovation and Technology and also in the form of grant FK-143059 from the source of the National Research, Development and Innovation Fund and by the J\\u00E1nos Bolyai Research Scholarship of the Hungarian Academy of Sciences. Project no. TKP-6\\u20136/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. The authors would like to thank Tam\\u00E1s Fleiner for highlighting the problem of ring perception in chemical graphs. Funding text 2: This work was funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA) . The work was also supported by the \\u00DANKP-22-5 New National Excellence Program of the Ministry for Innovation and Technology and also in the form of grant FK-143059 from the source of the National Research, Development and Innovation Fund and by the J\\u00E1nos Bolyai Research Scholarship of the Hungarian Academy of Sciences . Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund , financed under the TKP2021-NVA funding scheme. The authors would like to thank Tam\\u00E1s Fleiner for highlighting the problem of ring perception in chemical graphs. LA - English DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Kun-Balog, Attila TI - NaS akkumulátorok alkalmazása a lakossági villamosenergia-szektorban JF - ENERGIAGAZDÁLKODÁS J2 - ENGA VL - 65 PY - 2024 IS - 4 SP - 2 EP - 6 PG - 5 SN - 0021-0757 UR - https://m2.mtmt.hu/api/publication/35457635 ID - 35457635 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Kustán, Réka AU - Imre, Attila TI - Simultaneous working fluid and expander selection method for reaching low-threshold technology organic Rankine cycle (ORC) design JF - ENERGY SCIENCE & ENGINEERING J2 - ENERGY SCI ENG VL - 11 PY - 2023 IS - 7 SP - 2330 EP - 2350 PG - 21 SN - 2050-0505 DO - 10.1002/ese3.1457 UR - https://m2.mtmt.hu/api/publication/33879854 ID - 33879854 LA - English DB - MTMT ER - TY - JOUR AU - Sztankó, Krisztián Endre AU - Lezsovits, Ferenc AU - Groniewsky, Axel TI - Ipari projektek az Energetikai Gépek és Rendszerek Tanszéken JF - ENERGIAGAZDÁLKODÁS J2 - ENGA VL - 64 PY - 2023 IS - különszám SP - 35 EP - 41 PG - 7 SN - 0021-0757 UR - https://m2.mtmt.hu/api/publication/34023973 ID - 34023973 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Kustán, Réka AU - Imre, Attila TI - Efficiency Increase of Biological Methanation based Power-toMethane Technology Using Waste Heat Recovery with Organic Rankine Cycle JF - PERIODICA POLYTECHNICA-CHEMICAL ENGINEERING J2 - PERIOD POLYTECH CHEM ENG VL - 66 PY - 2022 IS - 4 SP - 596 EP - 608 PG - 13 SN - 0324-5853 DO - 10.3311/PPch.20428 UR - https://m2.mtmt.hu/api/publication/33599677 ID - 33599677 LA - English DB - MTMT ER - TY - JOUR AU - Groniewsky, Axel AU - Kustán, Réka AU - Imre, Attila TI - Power-to-Methane technológia: műszaki összegzés és esettanulmány JF - ENERGIAGAZDÁLKODÁS J2 - ENGA VL - 63 PY - 2022 IS - különszám SP - 2 EP - 12 PG - 11 SN - 0021-0757 UR - https://m2.mtmt.hu/api/publication/33105827 ID - 33105827 LA - Hungarian DB - MTMT ER -