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Tytuł:
Thermal performance of energy storage vessel
Autorzy:
Jurigova, M.
Minarova, M.
Chmurny, I.
Powiązania:
https://bibliotekanauki.pl/articles/131595.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Komisja Inżynierii Budowlanej PAN Oddział w Katowicach
Tematy:
thermal energy storage
hot water
mathematical model
magazynowanie energii cieplnej
woda ciepła
model matematyczny
Opis:
This paper is focused on an analysis of thermal energy performance of storage vessel[4]. This storage system consists of two concentric cylindrical containers made of concrete, between these two layers there is a thermal insulation layer – the vacuum-like one. The inner container is filled by water intended to operate as a heat accumulation medium and temperature of the water is assumed as 90ºC. The cooling process was simulated for a period of 30 days in the ANSYS software environment. The simulation showed that the analyzed type of heat storage vessel is able to keep the thermal Energy relatively efficiently.
Źródło:
Roczniki Inżynierii Budowlanej; 2015, 15; 11-16
1505-8425
Pojawia się w:
Roczniki Inżynierii Budowlanej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance of novel indirect passive solar dryer
Autorzy:
Al-Jethelah, Manar
Deyab, Hussam
Yaseen, Tadahmun
Powiązania:
https://bibliotekanauki.pl/articles/35534092.pdf
Data publikacji:
2021
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
solar dryer
passive
flat collector
efficiency
Opis:
An experimental investigation was conducted to study the performance of a novel indirect type free convection solar dryer. The novel and a conventional indirect passive solar dryer were built. Solar irradiation and temperature of different locations were recorded. The air at the drying chamber entrance, lower space, and upper space temperatures besides the thermal efficiency of the novel dryer were 68, 39, 49 and 85%, respectively, higher than the conventional one.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2021, 30, 2; 293-303
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance of the thermal storage energy with phase change material
Autorzy:
Bałon, Paweł
Kiełbasa, Bartłomiej
Kowalski, Łukasz
Smusz, Robert
Powiązania:
https://bibliotekanauki.pl/articles/2204648.pdf
Data publikacji:
2023
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
energy storage
phase change material
PCM
heat accumulation
Opis:
Values of energy supply and demand vary within the same timeframe and are not equal. Consequently, to minimise the amount of energy wasted, there is a need to use various types of energy storing systems. Recently, one can observe a trend in which phase change materials (PCM) have gained popularity as materials that can store an excess of heat energy. In this research, the authors ana-lysed paraffin wax (cheese wax)’s capability as a PCM energy storing material for a low temperature energy-storage device. Due to the relatively low thermal conductivity of wax, the authors also analysed open-cell ceramic Al2O3/SiC composite foams’ (in which the PCM was dispersed) influence on heat exchange process. Thermal analysis on paraffin wax was performed, determining its specific heat in liquid and solid state, latent heat (LH) of melting, melting temperature and thermal conductivity. Thermal tests were also performed on thermal energy container (with built-in PCM and ceramic foams) for transient heat transfer. Heat transfer coefficient and value of accumulated energy amount were determined.
Źródło:
Acta Mechanica et Automatica; 2023, 17, 1; 76--84
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance analysis of manned airships in a thermally variable environment
Autorzy:
Shi, Hong
Liu, Meinan
Chen, Jiamin
Zou, Yitao
Powiązania:
https://bibliotekanauki.pl/articles/2173708.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
manned airship
thermal performance
nacelle
temperature difference
flight position
sterowiec załogowy
wydajność cieplna
gondola
różnica temperatur
pozycja lotu
Opis:
The safety and reliability of the manned airship depend to a considerable extent on its thermal performance. In this paper, heat balance equations are developed and solved in the C++ programming language. The temperature variation of the enclosure, gasbag, and nacelles of the manned airship is investigated. In addition, the effects of season, latitude, and orientation on the thermal performance of the manned airship and the airship nacelle are investigated. The results show that: (1) The average temperature difference of the nacelle surface at the same time is 25 K, while the maximum temperature difference in the nacelle is 29 K during the day, (2) the temperature distribution in the nacelle is similar in spring and autumn, with maximum temperature between 306 K and 309 K. The maximum temperature in the nacelle is between 300 K and 303 K in winter while the maximum temperature in the nacelles is between 309 K and 315 K in summer, (3) as the flight position of the manned airship changes from 20°N to 60°N, the average nacelle temperature varies slightly by about 1 K. However, as the latitude increases, the high- temperature region shifts from the bottom of the nacelle to the side of the nacelle, and (4) the temperature distribution of the upper envelope of the airship varies considerably with orientation. However, the average temperature of the nacelle is less impacted by orientation. These results are useful for understanding the thermal performance of manned airships.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 5; art. no. e143105
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of filling ratio on thermal performance and thermal parameters of closed loop pulsating heat pipes
Autorzy:
Kolková, Z.
Malcho, M.
Powiązania:
https://bibliotekanauki.pl/articles/402056.pdf
Data publikacji:
2013
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
closed loop pulsating heat pipe
thermal performance
evaporation
condensation
filling ratio
thermal resistance
temperature
Opis:
Improving the performance of electrical components needs higher heat removal from these systems. One of the solutions available is to use a sealed heat pipe with a throbbing filling, where development meets the current requirements for intensification of heat removal and elimination of moving parts cooling systems. Heat pipes operate using phase change working fluid, and it is evaporation and condensation. They have a meandering shape and are characterized by high intensity of heat transfer, high durability and reliability. Advantage of these tubes is that it is not necessary to create the internal capillary structure for transporting liquid and they need no pump to the working fluid circulation. They have a simple structure, low cost, high performance, and they can be used for various structural applications. The choice of working fluid volume and performance affects thermal performance. Distilled water, ethanol and acetone were used in the performance ranges of 0-80%.
Źródło:
Structure and Environment; 2013, 5, 4; 37-40
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of working position for thermal performance of the capillary heat pipe
Autorzy:
Kosa, L.
Jobb, M.
Nemec, P.
Malcho, M.
Powiązania:
https://bibliotekanauki.pl/articles/402189.pdf
Data publikacji:
2014
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
capillary heat pipe
thermal performance
working position
Opis:
This experiment is concentrated on working position for optimization of capillary heat pipe. The main objective was to find optimal working position for capillary heat pipe. Working position is an important part for function of the heat pipe. A change in working position should change thermal performance of capillary heat pipe.
Źródło:
Structure and Environment; 2014, 6, 1; 46-48
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Obliczenia energetyczne budynków - dyskusja założeń
Thermal performance of buildings - discussion of assumptions
Autorzy:
Panek, A
Rucińska, J
Powiązania:
https://bibliotekanauki.pl/articles/362744.pdf
Data publikacji:
2010
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
zużycie energii
ocena energetyczna
energy use
energy performance of buildings
Opis:
Artykuł zawiera opis metody godzinowej obliczania zapotrzebowania energii do ogrzewania i chłodzenia. Wyniki zapotrzebowania na energię do ogrzewania i chłodzenia siedmiu budynków testowych uzyskane przy jej pomocy porównano z wynikami otrzymanymi z metody bilansowej, programu Audytor OZC oraz TRNSYS.
The paper presents description of the hourly method used for calculation of required energy usage for heating and cooling. The comparison of results of calculation was done with TRNSYS, Audytor OZC, hourly and seasonal method for seven buildings.
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2010, T. 5, nr 4, 4; 35-41
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of thermal performance factor for solar air heaters with artificially roughened channels
Autorzy:
Siddique, Waseem
Raheem, Aneeq
Aqeel, Muhammad
Qayyum, Sualeh
Salamen, Tareq
Waheed, Khalid
Qureshi, Kamran
Powiązania:
https://bibliotekanauki.pl/articles/1845043.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
turbulence promoter
solar air heater
heat transfer enhancement
thermal performance factor
słoneczny grzejnik powietrzny
intensyfikacja wymiany ciepła
współczynnik wydajności cieplnej
Opis:
Heat transfer augmentation has become the utmost industrial desire. Turbulence promoters seems to be a better option for better heat transfer but at the expense of enormous pressure drop. In the current study, experimental optimization of heat transfer and pressure drop in various configurations of ribbed and corrugated surfaces on the bottom wall of the Solar Air Heater channel, having aspect ratio of 26:5 was performed. The results were evaluated in terms of enhancement in heat transfer (Nu/Nu s), friction factor ratio (f/f s) and thermal performance factor ( η). Three different cases and nine configurations with a pitch to rib/corrugation height ratio of 4.0 were studied. Case A consists of a smooth, continuous square rib, inline and staggered broken ribs. Case B comprises 30°, 45°, 60° and 90° trapezoidal corrugated geometries while Case C is the comparison of smooth, wavy corrugated and the best configurations of cases A and B. The results show that rectangular duct with staggered broken ribs and trapezoidal corrugation at 45° are the best configurations for case A and B, respectively. The 45° corrugated configuration is the best one amongst all, with values of 1.53, 1.5 and 1.33% for Nu/Nu s, f/f s and η respectively.
Źródło:
Archive of Mechanical Engineering; 2021, LXVIII, 2; 195-225
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An effect of binary fluid on the thermal performance of pulsation heat pipe
Autorzy:
Barrak, Anwar S.
Ali, Nawfal M
Ali, Hussein Hayder Mohammed
Powiązania:
https://bibliotekanauki.pl/articles/2174164.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
rura cieplna
przepływ dwufazowy
przepływ ciepła
binary fluid
oscillation heat pipe
two phase flow
thermal resistance
heat transfer
Opis:
A pulsation heat pipe is an efficient heat pipe used in many engineering applications. This study aims to test the effect of working fluids on the thermal performance of pulsation heat pipe. Seven turned pulsation heat pipes were designed and manufactured from a copper pipe with a 3.5 mm inner diameter. The lengths of an evaporation part, an adiabatic passage, and a condenser part were 300 mm, 210 mm, and 300 mm, respectively. In this study, three different fluids were used as the working fluid: distilled water, methanol, and binary fluid (a mixture of water and methanol) with a 50% filling ratio. Compared to water, the experimental results suggested that methanol had a better thermal performance when used as a working fluid in the PHP. On the other hand, a binary fluid enhanced the lower thermal performance of water (29% reduction in the thermal resistance and a 20% increase in the effective thermal conductivity of the PHP).
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 1; 21--34
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance of corrugated plate heat exchanger using ethylene glycol as test fluid
Autorzy:
Sreedhar Rao, Battula
Keerthana Reddy, Chittireddy
Meena, Pullurwar
Kishore Kumar, Sriramoju
Powiązania:
https://bibliotekanauki.pl/articles/1819182.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
corrugated plate heat exchanger
overall heat transfer coefficient
effectiveness
Reynolds number
współczynnik przenikania ciepła
efektywność
liczba Reynoldsa
Opis:
This paper reports an experimental comparative thermal analysis of a flat plate heat exchanger and corrugated plate heat exchanger (CPHE) of different corrugation angles using ethylene glycol as test fluid. The experiments were carried out in counter current mode using water as hot fluid at 75°C. Design of each plate provided with eleven thermocouple sensors to determine the temperatures, in which seven were used to measure the surface temperature of plate and four were used to measure the inlet and outlet bulk temperature of cold and hot fluids. The mass flow rate of test fluid, varied between 0.5 to 4 liters per minute and corresponding steady state temperatures is measured. Using experimental readings, temperature difference between the inlet and outlet streams (∆T), logarithmic mean temperature difference (LMTD) and overall heat transfer coefficient (U) are determined. The obtained ∆T and U values of corrugation angles (30°, 50°) of CPHE were compared with those of flat plate heat exchangers. For corrugation angle of 30° and 50°, the ∆T and U values increases with increase of mass flow rate of the fluid. The turbulence in the flow increases due to increase in the corrugation angle, which results in the enhancement of heat transfer. Moreover, thermal effectiveness (ε) is estimated using NTU method and compared for all the plates. As the NRe values gradually increases, ε decreases for flat plate and CPHE (θ = 30° and θ= 50°). At low NRe value of 114, observed a maximum ε (≅0.998) value for corrugated angle of 50°. There is adequate contact time between the cold and hot fluids at low Reynolds number, so maximum rate of heat transfer is possible, as a result ε values are high.
Źródło:
Journal of Mechanical and Energy Engineering; 2020, 4, 2; 167--172
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena izolacyjności cieplnej metalowo-szklanych ścian osłonowych
Assessment of thermal performance of curtain walling
Autorzy:
Zacharski, A.
Firkowicz-Pogorzelska, K.
Powiązania:
https://bibliotekanauki.pl/articles/182970.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniki Budowlanej
Tematy:
ściana osłonowa
ściana metalowo-szklana
ściana słupowo-ryglowa
współczynnik przenikania ciepła
metoda obliczeń
metoda oceny składnikowa
metoda oceny zbiorcza
izolacyjność cieplna
złącze liniowe
norma
curtail wall
thermal transmittance
calculating method
single assessment method
component assessment method
thermal performance
Opis:
Przedstawiono metody obliczania współczynnika przenikania ciepła metalowo-szklanych ścian osłonowych składających się z przezroczystych i/lub nieprzezroczystych paneli włożonych w ramy lub z nimi połączonych. Opisano dwie metody: zbiorczą metodę oceny i składnikową metodę oceny. Podano ograniczenia obu metod oraz wskazówki przydatne przy ich stosowaniu.
The paper deals with the methods for calculating the thermal transmittance of curtain walls consisting of glazed and/or opaque panels fitted in, or connected to, frames. Two methods were described: single assessment method and component assessment method. The limitations of the methods and advices for their application were given.
Źródło:
Prace Instytutu Techniki Budowlanej; 2009, R. 38, nr 3, 3; 3-26
0138-0796
Pojawia się w:
Prace Instytutu Techniki Budowlanej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring thermal performance of gravitational heat pipes depending on the amount of working fluid
Autorzy:
Jobb, M.
Nemec, P.
Kosa, L.
Malcho, M.
Powiązania:
https://bibliotekanauki.pl/articles/402517.pdf
Data publikacji:
2014
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
gravity heat pipe
working substance ethanol
performance parameter
Opis:
This paper deals with an impact of working medium on the performance parameters of the heat pipe. The aim was to find the ideal amount of working fluid used in gravitational heat pipes. For the working medium 96% alcohol was selected.
Źródło:
Structure and Environment; 2014, 6, 1; 43-45
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study on thermal performance of water flow in a twisted duct heat exchanger
Autorzy:
Rashed, Musaab K.
Jehhef, Kadhum Audaa
Badawy, Faris Ali
Powiązania:
https://bibliotekanauki.pl/articles/2174205.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja mieszana
wymiennik ciepła
przepływ laminarny
mixed convection
twisted square duct
heat exchanger
laminar flow
Opis:
This paper presents a numerical study of heat transfer through a downstream annulus using water as the working fluid within the laminar flow region. The annulus consisted of an outer twisted square duct and an inner circular pipe. A three-dimensional formulation was used to solve the Navier-Stokes equations numerically for the laminar flow system with a low Reynolds number. Three parameters were used in the numerical simulation: the length of the twisted square [...] the inner diameter of the inner circular pipe [...] and 25 mm and the twist angle [...]. Numerical calculations were conducted on sixteen twisted square duct heat exchangers, with water flowing within a Reynolds number range of .220 1100− The results were illustrated as a profile of the thermal enhancement factor, the friction factor and the Nusselt number. The results show that the twisted outer duct of the heat exchanger can create a swirl flow along the length of the heat exchanger. It also caused a boundary layer separation-reattachment on the wall of the inner pipe. Moreover, an increase in the twist angle increased the Nusselt number by %,20 and the friction factor was also increased as the annular gap of the heat exchanger decreased.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 199--216
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance enhancement of the mixed convection between two parallel plates by using triangular ribs
Autorzy:
Jehhef, K. A.
Badawy, F. A.
Hussein, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/1839881.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
badanie numeryczne
konwekcja mieszana
równanie Naviera-Stokesa
numerical study
mixed convection
vertical channel
triangular rib
Opis:
This paper aims to investigate the mixed convection between two parallel plates of a vertical channel, in the presence of a triangular rib. The non-stationary Navier-Stokes equations were solved numerically in a two-dimensional formulation for the low Reynolds number for the laminar air flow regime. Six triangular ribs heat-generating elements were located equidistantly on the heated wall. The ratio of the ribs to the channel width is varied (h / H = 0.1, 0.2, 0.3 and 0.4) to study the effect of ribs height effects, the ratio of the channel width to the ribs height is fixed constant at (H / w = 2) and the ratio of the channel height to the ribs pitch is fixed at (W/p=10). The influence of the Reynolds number that ranged from 68 to 340 and the Grashof number that ranged from 6.6 ×103 to 2.6 ×104 as well as the Richardson number chosen (1.4, 0.7, 0.4 and 0.2) is studied. The numerical results are summarized and presented as the profile of the Nusselt number, the coefficient of friction, and the thermal enhancement factor. The contribution of forced and free convection to the total heat transfer is analyzed. Similar and distinctive features of the behavior of the local and averaged heat transfer with the variation of thermal gas dynamic and geometric parameters are investigated in this paper. The results showed that the Nusselt number and friction factor increased by using the attached triangular ribs, especially when using the downstream ribs. Also, the results revealed that the Nusselt number increased by increasing the ratio of the ribs to the channel width.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 2; 11-30
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of working fluid selection on thermal performance of heat exchanger filled by the porous material
Autorzy:
Szymański, P.
Powiązania:
https://bibliotekanauki.pl/articles/2073660.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Capillary Pumped Loop
Loop Heat Pipes
Opis:
Thermal management of electronics semiconductor technologies that are located i.e. in a novel marine power plants or computer server rooms become very important issue for designers of such systems. Motivation and need for research in development of novel cooling strategies for modern electronics is of paramount importance. Heat exchangers filled by the porous material are a novel research topic in current heat pipe science. The design of such heat exchangers is rather complex with many things to consider. In this paper the focused is the get knowledge about who to select the working fluid to be used.
Źródło:
Journal of Polish CIMEEAC; 2015, 10, 1; 149--154
1231-3998
Pojawia się w:
Journal of Polish CIMEEAC
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of back propagation neural network to predict the thermal performance of porous bed solar air heater
Autorzy:
Ghritlahre, Harish Kumar
Prasad, Radha Krishna
Powiązania:
https://bibliotekanauki.pl/articles/240570.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solar air heater
porous bed
thermal performance
artificial neural network
Levenberg-Marquardt algorithm
Opis:
The objective of present work is to predict the thermal performance of wire screen porous bed solar air heater using artificial neural network (ANN) technique. This paper also describes the experimental study of porous bed solar air heaters (SAH). Analysis has been performed for two types of porous bed solar air heaters: unidirectional flow and cross flow. The actual experimental data for thermal efficiency of these solar air heaters have been used for developing ANN model and trained with Levenberg-Marquardt (LM) learning algorithm. For an optimal topology the number of neurons in hidden layer is found thirteen (LM-13).The actual experimental values of thermal efficiency of porous bed solar air heaters have been compared with the ANN predicted values. The value of coefficient of determination of proposed network is found as 0.9994 and 0.9964 for unidirectional flow and cross flow types of collector respectively at LM-13. For unidirectional flow SAH, the values of root mean square error, mean absolute error and mean relative percentage error are found to be 0.16359, 0.104235 and 0.24676 respectively, whereas, for cross flow SAH, these values are 0.27693, 0.03428, and 0.36213 respectively. It is concluded that the ANN can be used as an appropriate method for the prediction of thermal performance of porous bed solar air heaters.
Źródło:
Archives of Thermodynamics; 2019, 40, 4; 103-128
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Performance Assessment of Heat Resistant Fabrics Based on a New Thermal Wave Model of Skin Heat Transfer
Autorzy:
Zhu, F.
Zhang, W.
Song, G.
Powiązania:
https://bibliotekanauki.pl/articles/90033.pdf
Data publikacji:
2006
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
thermal performance
skin burn
skin simulant sensor
heat resistant fabrics
thermal wave skin model
ciepło
temperatura skóry
oparzenie
Opis:
A thermal wave skin model incorporating surface heat flux from a skin simulant sensor is developed to characterize the thermal performance of heat resistant fabrics covering the skin simulant sensor. Comparisons of time to 2nd-degree skin burn and temperature elevation of skin beneath a layer of fabric between the Pennes’ equation and the newly developed thermal wave skin model are performed in this research. Results of tolerance time from the Stoll criterion method are also compared with those from 2 skin models in a thermal protective performance calorimeter. It is concluded that the thermal properties of heat resistant fabrics can be characterized more precisely than previously.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2006, 12, 1; 43-51
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance of porous fins with temperature-dependent heat generation via the homotopy perturbation method and collocation method
Autorzy:
Hoshyar, H. A.
Rahimipetroudi, I.
Ganji, D. D.
Majidian, A. R.
Powiązania:
https://bibliotekanauki.pl/articles/122933.pdf
Data publikacji:
2015
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
collocation method
homotopy perturbation method
porous fin
temperature-dependent heat generation
Opis:
An analysis has been performed to study the problem of the thermal performance of a nonlinear problem of the porous fin with temperature-dependent internal heat generation. Highly accurate semi-analytical methods called the collocation method (CM) and the homotopy perturbation method (HPM) are introduced and then are used to obtain a nonlinear temperature distribution equation in a longitudinal porous fin. This study is performed using passage velocity from the Darcy’s model to formulate the heat transfer equation through porous media. The heat generation is assumed to be a function of temperature. The effects of the natural convection parameter Nc, internal heat generation εg, porosity Sh and generation number G parameter on the dimensionless temperature distribution are discussed. Also, numerical calculations called the fourth order Runge-Kutta method were carried out for the various parameters entering into the problem for validation. Results reveal that analytical approaches are very effective and convenient. Also it is found that these methods can achieve more suitable results compared to numerical methods.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2015, 14, 4; 53-65
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania eksperymentalne charakterystyk cieplnych radiatorów do chłodzenia mikroprocesorów
Experimental investigation of thermal performance of heat sinks for electronics cooling
Autorzy:
Jaworski, M.
Powiązania:
https://bibliotekanauki.pl/articles/271370.pdf
Data publikacji:
2012
Wydawca:
Centralny Ośrodek Badawczo-Rozwojowy Aparatury Badawczej i Dydaktycznej, COBRABiD
Tematy:
chłodzenie mikroprocesorów
radiatory
opór cieplny
materiały PCM
electronics cooling
heat spreaders
thermal resistance
phase change materials
Opis:
W pracy omówiono, istotne z punktu widzenia wymiany ciepła, parametry radiatorów wykorzystywanych do chłodzenia elementów elektronicznych, przede wszystkim mikroprocesorów. Przedstawiono proste stanowisko eksperymentalne pozwalające na pomiar oporu cieplnego radiatorów w warunkach konwekcji naturalnej i wymuszonej. Przybliżono zagadnienie zastosowania materiałów zmiennofazowych PCM (Phase Change Materials) w radiatorach do chłodzenia elektroniki. Zaprezentowano wyniki badań doświadczalnych charakterystyk pracy dwóch radiatorów z wbudowanymi zasobnikami z PCM. Przeprowadzone badania były symulacją awarii zasadniczego układu chłodzenia procesorów.
In the paper basic properties of heat sinks used in electronics cooling, important from the point of view of heat transfer phenomena, were presented. Simple experimental set-up for the measurement of thermal resistance of heat sinks was described. The unit allows to perform studies in both forced and free convective heat transfer conditions. The application of phase change materials (PCM) in the cooling of microprocessors was discussed. Two heat sinks with PCM incorporated in theirs structure were shown. Results of experimental investigation of thermal performance characteristics of these radiators were given and discussed in details. In the tests the thermal behavior of heat sinks with PCM in simulated failure of primary cooling system was analyzed.
Źródło:
Aparatura Badawcza i Dydaktyczna; 2012, 17, 4; 21-27
2392-1765
Pojawia się w:
Aparatura Badawcza i Dydaktyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performance evaluation of an earth-to-air heat exchanger for the heating mode applications using an experimental test rig
Autorzy:
Ahmad, Saif Nawaz
Prakash, Om
Powiązania:
https://bibliotekanauki.pl/articles/2091363.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer
earth-to-air heat exchanger
ground heat exchanger
geothermal energy
renewable energy
assive heating
assive cooling
effectiveness
Opis:
This paper presents the experimental investigation of an earth-to-air heat exchanger for heating purposes in the Patna region of India, using an experimental test rig. In the view of the author, real field experiments have several limitations such as lack of repeatability and uncontrolled conditions. It also takes more time for the response of parameters that depends on nature and climate. Moreover, earth-to-air heat exchangers may be expensive to fabricate and require more land area. Thus, in this work authors executed their experimental work in indoor controllable environments to investigate the thermal performance of an earth-to-air heat exchanger. The actual soil conditions were created and maintained the temperature at 26°C throughout the soil in the vicinity of pipes. Three horizontal PVC pipes of equal lengths and diameters of 0.0285 m, 0.038 m and 0.0485 m were installed in the test rig. The experiments were performed for different inlet air velocities at ambient air temperature. This study acknowledges that the maximum rise in outlet temperature occurs at a lower speed for smaller pipes. Also, the maximum effectiveness of 0.83 was observed at 2 m/s for the smallest diameter pipe.
Źródło:
Archives of Thermodynamics; 2022, 43, 1; 185--207
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal efficiency and hydraulic performance evaluation on Ag–Al2O3 and SiC–Al2O3 hybrid nanofluid for circular jet impingement
Autorzy:
Datta, Abanti
Halder, Pabitra
Powiązania:
https://bibliotekanauki.pl/articles/1845498.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid nanofluid
thermal performance factor
pumping power
merit number
Opis:
Hybrid nanofluids is obtained by dispersing more than one nanoparticle into a base fluid. The work is concerned with a detailed numerical investigation of the thermal efficiency and hydraulic performance of hybrid nanofluids for circular jet impinges on a round plate. For this paper, a metal (Ag), a metal oxides (Al2O3) and a metal carbides (SiC) nanoparticle and their water based hybrid nanofluids are considered to analyse numerically with varying significant dimensionless parameters, i.e., the jet-to-plate spacing ratio, Reynolds number and volume fraction of nanoparticles. The results demonstrated that the efficiency of heat transfer of all nanofluids is increased by the addition of nanoparticle to the dispersed in water at constant Reynolds number. Moreover, the results illustrate that heat transfer efficacy and pumping power penalty both increased as jet-to-plate spacing ratio reduced. The jet-to-plate spacing ratio equal to 4 is the best as the percentage enhance heat transfer is maximum in this situation. Since both the heat transfer effect and pumping penalty increase using hybrid nanofluids, thermal performance factor increases or decreases depends on nanoparticles of nanofluids. It is evident that the analysis of these hybrid nanofluids will consider both the increase in heat efficiency and the pumping capacity. The best flow behaviour is achieved for SiC–Al2O3 hybrid nanofluids. New merit number is introduced for additional clarification.
Źródło:
Archives of Thermodynamics; 2021, 42, 1; 163-182
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Budynki z konstrukcją przysłupową. Termomodernizacja ścian zewnętrznych i dachu
Buildings with a corner timbered-framework. Thermal performance improvement of external walls and roof
Autorzy:
Chądzyński, A.
Piróg, M.
Powiązania:
https://bibliotekanauki.pl/articles/293668.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
konstrukcja przysłupowa
termomodernizacja
corner timbered-framework construction
thermal performance improvement
Opis:
Tematem artykułu jest termomodernizacja przegród zewnętrznych (dachu i ścian) budynków drewnianych o konstrukcji przysłupowej. Zagadnienie to dotyczy obiektów liczących w większości kilkadziesiąt i więcej lat. W artykule poruszono kwestię konieczności ich remontów i dostosowania przegród do współczesnych wymagań w zakresie izolacyjności termicznej. Na podstawie analizy formy budynków drewnianych z konstrukcją przysłupową zaproponowano sposoby wykonania docieplenia zewnętrznych ścian wieńcowych, ryglowych i połaci dachu. Przedstawiono kierunek postępowania w tym procesie, biorąc szczególnie pod uwagę rodzaj materiału, jakim jest drewno, wyjątkowy charakter budynków o konstrukcji przysłupowej oraz ich znaczenie dla krajobrazu kulturowego.
The subject of the article is thermal performance improvement of external partitions (roof and walls) of wooden buildings with a corner timbered-framework structure. This problem concerns objects which are several dozen and more years old. The article discusses the need of renovation and adapting partitions to modern requirements in the field of thermal insulation. Based on the analysis of the form of wooden buildings with a timbered structure, methods of thermal insulation of external corrugated walls, timbered walls and roof slopes have been proposed. The article presents the course of action in this process, taking into account in particular the type of material which is wood, the unique character of the buildings with a corner timbered-framework structure and their meaning for the cultural landscape.
Źródło:
Architectus; 2018, 3 (55); 101-110
1429-7507
2084-5227
Pojawia się w:
Architectus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solar air heater performance prediction using artificial neural network technique with relevant input variables
Autorzy:
Ghritlahre, Harish Kumar
Chandrakar, Purvi
Ahmad, Ashfaque
Powiązania:
https://bibliotekanauki.pl/articles/240435.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
artificial neural network
solar air heater
thermal performance
multilayer perceptron
Opis:
Solar air heater (SAH) is an important device for solar energy utilization which is used for space heating, crop drying, timber seasoning etc. Its performance mainly depends on system parameters, operating parameters and meteorological parameters. Many researchers have been used these parameters to predict the performance of SAH by analytical or conventional approach and artificial neural network (ANN) technique, but performance prediction of SAH by using relevant input parameters has not been done so far. Therefore, relevant input parameters have been considered in this study. Total ten parameters were used such as mass flow rate, ambient temperature, wind speed, relative humidity, fluid inlet temperature, fluid mean temperature, plate temperature, wind direction, solar elevation and solar intensity to find out the relevant parameters for ANN prediction. Seven different neural models have been constructed using these parameters. In each model 10 to 20 neurons have been selected to find out the optimal model. The optimal neural models for ANN-I, ANN-II, ANN-III, ANN-IV, ANN-V, ANN-VI and ANN-VII were obtained as 10-17-1, 8-14-1, 6-16-1, 5- 14-1, 4-17-1, 3-16-1 and 2-14-1, respectively. It has been found that ANN-II model with 8-14-1 is the optimal model as compared to other neural models. Values of the sum of squared errors, mean relative error, and coefficient of determination were found to be 0.02138, 1.82% and 0.99387, respectively, which shows that the ANN-II developed with mass flow rate, ambient temperature, inlet and mean temperature of air, plate temperature, wind speed and direction, relative humidity, and relevant input parameters performed better. The above results show that these eight parameters are relevant for prediction.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 255-282
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comprehensive review on energy and exergy analysis of solar air heaters
Autorzy:
Ghritlahre, Harish Kumar
Sahu, Piyush Kumar
Powiązania:
https://bibliotekanauki.pl/articles/240351.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solar energy
energy
exergy analysis
solar air heater
thermal performance
Opis:
For economic growth of nation, the energy plays an important role. The excessive use of fossil fuels results the increase in global warming and depleting the resources. Due to this reason, the renewable energy sources are creating more attraction for researchers. In renewable energy sector, solar energy is the most abundant and clean source of energy. In solar thermal systems, solar air heater (SAH) is the main system which is used for heating of air. As it is simple in construction and cheaper in cost, it is of main interest for the researchers. The concept of first law and second law of thermodynamics is used for the study of the energy and exergy analysis respectively. The energy analysis is of great importance for the study of process effectiveness while the exergetic analysis is another significant concept to examine the actual behavior of process involving various energy losses and internal irreversibility. For efficient utilization of solar energy, the exergy analysis is very important tool for optimal design of solar air heaters. The aim of the present work is to review the works related to energy and exergy analysis of various types of solar air heaters and to find out the research gap for future work.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 183-222
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Further Study on Thermal Performance of Porous Fin with Temperature-Dependent Thermal Conductivity and Internal Heat Generation using Galerkin’s method of Weighted Residual
Autorzy:
Sobamowo, M. G.
Kamiyo, O. M.
Adeleye, O. A.
Powiązania:
https://bibliotekanauki.pl/articles/1046542.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Galerkin’s method of weighted residual
Porous Fin
Surface convective heat transfer
Temperature-Dependent Thermal Conductivity and Internal Heat Generation
Thermal performance
Opis:
This work is presented as a further study to our previous work, “Thermal performance analysis of a natural convection porous fin with temperature-dependent thermal conductivity and internal heat" published in "Thermal Science and Engineering Progress. 1 (2017) 39–52”, where it was assumed that the surface convection is negligible and heat is transferred only by natural convection in the porous fin. In this present study, such an assumption has been relaxed. Also, effects of surface convective heat transfer on the thermal performance of porous fin with temperature-dependent thermal conductivity and internal heat generation have been investigated using Galerkin’s method of weighted residual. The results of the Galerkin’s method of weighted residual show excellent agreement with the results of numerical method using shooting method coupled with Runge-Kutta method and also with the results of homotopy perturbation method. Thereafter, the developed analytical solutions are used to investigate the influences of the thermal model parameters on the thermal performance of the porous fin. It is found as the with the other model parameters that as the convective parameter increases, the rate of heat transfer from the base of the fin increases and consequently, the porous fin efficiency improves. However, increase in the nonlinear thermal conductivity parameter decreases the temperature distribution in the fin. Based on the high accuracy of the Galerkin’s method of weighted residual as displayed in this work, it is hoped that the simple analytical solutions given by the approximate analytical method will enhance the analysis of extended surfaces and also assist the designers.
Źródło:
World Scientific News; 2019, 138, 2; 167-191
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 125

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