Integration of ground and ventilation air energy for heating buildings

Petrash, V. V.; Khomenko, Andrii; Polomannyy, Oleksiy; Visotska, Maria

doi:10.17512/bozpe.2021.1.01

Cited by 2 publications

(1 citation statement)

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“…Insulation increases the energy efficiency of various systems, including engineering networks of rural buildings and parts of agricultural devices and machines. Ideal insulation [7] is a very helpful concept in some theoretical cases but it cannot be achieved in practice. Analysis of heat insulation of buildings [8][9][10][11][12] can show very large external sizes of insulation.…”

Section: Introductionmentioning

confidence: 99%

Analysis of critical radius of insulation for horizontal pipes

Vakulenko

Mileikovskyi

Tkachenko

et al. 2023

22nd International Scientific Conference Engineering for Rural Development Proceedings

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Thermal insulation of pipelines is used in different industries including agricultural technologies. Energy efficiency depends on heat losses, which, in turn, are limited by heat insulation. Decentralized ventilation is effective in rural low-rise buildings. One such device used is a regenerative ventilator like Blauberg Vento or Vents TwinFresh. There is a task to improve the efficiency of its operation. Investigation of heat recovery processes in thin ducts is taking place. Experimental uncertainty decreases with better heat insulation of the experimental setup. But in heat transfer literature, there is a notion of the critical radius of insulation. More the insulation radius should decrease its effectiveness due to the development of the outer surface. In the theory, the heat transfer coefficient of the outer surface is assumed to be constant. In this study, laminar convective flow around the outer horizontal cylindrical insulation surface of a large thickness is considered. The formula of the average heat transfer coefficient is used that takes into account the Grashof number. While the insulation thickness is increased, the surface temperature and the heat transfer coefficient are decreased. The function of thermal resistance dependence on the outer diameter related to the inner one and its derivative have been analysed. As a result, an asymptotic increase of thermal resistance was observed without extremums. So, there are no critical diameters if the insulation is so large to obtain laminar convective flow. The maximum radius of thermal insulation should be determined not as critical, but as expedient. Thus, it can provide 5-20% lower heat transfer resistance than the asymptotic one. The radius of thermal pipe insulation of technological devices should be accepted based on technical and economic justification.

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Section: Introductionmentioning

confidence: 99%

Analysis of critical radius of insulation for horizontal pipes

Vakulenko

Mileikovskyi

Tkachenko

et al. 2023

22nd International Scientific Conference Engineering for Rural Development Proceedings

View full text Add to dashboard Cite

show abstract

Thermal comfort assessment in the modern passenger car under actual operational conditions

Dębska

Krawczyk

2023

Production Engineering Archives

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People’s ever-increasing needs encourage designers of various vehicles to search for solutions that will provide the most comfortable internal environment conditions. Currently, partly due to the COVID-19 threat, many people use their individual cars to travel to work, college, shops, trips, and holidays. Proper internal air parameters that need to be maintained in vehicles are critical in the summer. The article discusses the thermal comfort of four passengers of a modern car produced in 2017 to verify if contemporary production technology can successfully meet the thermal needs of people under actual conditions in the Polish climate. For this purpose, five temperature values were tested: 20°C, 22°C, 24°C, 26°C, and 28°C for the car located in the shade and sun. In addition, the Testo 400 meter was used to control and measure the internal parameters, and questionnaires were used to find out about the thermal impressions of the respondents. The research was carried out in July when the air temperature in Poland was high.

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Integration of ground and ventilation air energy for heating buildings

Cited by 2 publications

References 0 publications

Analysis of critical radius of insulation for horizontal pipes

Analysis of critical radius of insulation for horizontal pipes

Thermal comfort assessment in the modern passenger car under actual operational conditions

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