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001-es BibID:	BIBFORM111577
035-os BibID:	(cikkazonosító)101906 (Scopus)85159334693
Első szerző:	Kovács Zsolt
Cím:	Thermal stability investigations of different aerogel insulation materials at elevated temperature / Kovács Zsolt, Csík Attila, Lakatos Ákos
Dátum:	2023
ISSN:	2451-9049
Megjegyzések:	Super thermal insulation materials with low thermal conductivities, such as aerogels and vacuum insulation panels, are increasingly pushing conventional thermal insulations out of the market. Super insulation materials such as aerogels can be used easily on both vehicles and buildings. Nowadays, their usage by pipes transporting hot medium is also widespread. In these environments where elevated temperatures (100-250 ?C) are applied, it is a basic requirement that they should keep their excellent thermal insulating capability. In this study, a comprehensive examination performed on two new silica-aerogel type insulations is presented. We investigated the change in the thermal performance of different types of aerogel insulations (Slentex and Pyrogel) after thermal annealing, ageing them at 150 and 250 ?C temperatures for 1 day. After these thermal treatments, their thermal parameters such as thermal conductivities and specific heat capacities were measured. We revealed that both the thermal conductivity and the specific heat capacity for the Pyrogel changed considerably after annealing, while for Slentex the thermal conductivity remained constant and the specific heat capacity changed. To understand these changes we executed calorimetry tests and microscopic inspections with different methods. These experiments were completed with X-ray diffractometry to analyze the possible structural changes in the samples. From an application point of view, we consider the importance of these results, since they predict the lifetime of the used insulating material during their industrial use.
Tárgyszavak:	Műszaki tudományok Anyagtudományok és technológiák idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Super thermal insulations Aerogels XRD DSC Thermal conductivity Specific heat capacity Microscopy
Megjelenés:	Thermal Science and Engineering Progress. - 42 (2023), p. 1-12. -
További szerzők:	Csik Attila (1975-) (fizikus) Lakatos Ákos (1983-) (fizikus, környezetmérnök, létesítménymérnök)
Pályázati támogatás:	TKP2021-NKTA-34 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM104618
035-os BibID:	(cikkazonosító)101525 (WoS)000879878900003 (Scopus)85140972892
Első szerző:	L. Szabó Gábor (épületgépész)
Cím:	Energetic and exergetic study of a potential interconnection of a natural gas engine, heat pumps with a thermal and a mechanical compressor / Gábor L. Szabó
Dátum:	2022
ISSN:	2451-9049
Megjegyzések:	HVAC systems in buildings are significant energy consumers. It is proposed to utilize energy production systems that allow the generation of several types of energy from the same primary energy source. A solution of a CCHP, which consists of two types of heat pumps and a gas engine, was analysed in this article. The analysed solution can work in three operating modes, which allows the operators to avoid running both heat pumps, e.g., in the case of reduced demand or maintenance problems. These three operating modes are compared from energetical and exergetical. For a qualitative comparison of the operating modes, PXR is defined, and COP of heat pumps with a mechanical compressor is specified in an alternative way. Simplified equations are developed to determine PER and PXR to facilitate comparison. These equations can also be used to calculate the cases where the energy produced by the gas engine is not necessarily fully utilized by the heat pumps. The comparisons are also made via a case study. It is concluded that operating both heat pumps is the best option from energetical, but from exergetical, it is the worst. From the exergetical, if the required chilled water temperature is higher than 15.67 oC, or if the external air temperature is lower than 32.22 ?C, then it is advisable to operate only the absorption heat pump from the gas engine. From the energetical, this can only be the second-best option if the generator temperature is above 85.02 oC.
Tárgyszavak:	Műszaki tudományok Gépészeti tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Heat pump Absorption chiller Gas engine Exergy CCHP system
Megjelenés:	Thermal Science and Engineering Progress. - 36 (2022), p. 1-14. -
Pályázati támogatás:	TKP2021-NKTA-34 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: