Temat: exchanger - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Temperature efficiency of heat exchangers in air handling units
Autorzy:: Michalak, Piotr
Grygierczyk, Stanisław
Powiązania:: https://bibliotekanauki.pl/articles/95368.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: ventilation
heat recovery
rotary heat exchanger
cross-flow heat exchanger
temperature efficiency
PN-EN 308
wentylacja
odzysk ciepła
obrotowy wymiennik ciepła
krzyżowy wymiennik ciepła
sprawność temperaturowa
Opis:: In order to reduce ventilation heat loss and improve energy efficiency of low-energy buildings air-handling units (AHUs) with heat recovery are used. The article presents results of surveys performed in a passive building located in Katowice concerning the temperature efficiency of heat and cold recovery of two selected AHUs, with different heat exchangers. For this purpose the measurement data from the Building Management System (BMS) for the period 1.08.2015-31.07.2016 were used. The first unit was equipped with a rotary heat exchanger. Its average annual temperature efficiency of heat recovery was 47.2% annually. The efficiency of cold recovery amounted 52.9% on average for the warm half year. The second unit had a cross-flow exchanger. The average annual temperature efficiency of heat recovery in this device was 80.1%. The efficiency of cold recovery amounted 57.2% on average for the warm half year. Additional remarks concerning the temperature measurement in analysed units were also given.
Źródło:: Journal of Mechanical and Energy Engineering; 2019, 3, 3; 267-272
2544-0780
2544-1671
Pojawia się w:: Journal of Mechanical and Energy Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Maximum entropy generation rate in a heat exchanger at constant inlet parameters
Autorzy:: Laskowski, R.
Jaworski, M.
Powiązania:: https://bibliotekanauki.pl/articles/95303.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: maximum entropy generation rate
entropy
heat exchanger
maksymalna szybkość generowania entropii
entropia
wymiennik ciepła
Opis:: The main goal of the paper is to provide a condition for which a maximum entropy generation occurs in a heat exchanger at constant inlet parameters (temperatures and mass flow rates). Knowing this condition is essential during the design of the heat exchanger as it allows designers to avoid one of its most unfavourable operating conditions in terms of thermodynamics. Entropy generation resulting from the resistance of heat-transferring fluids to flow was not taken into account. Entropy generation was analysed as a function of a heat flow rate at constant parameters at the inlet of a condenser and a counter-flow double-pipe heat exchanger. The analysis showed that for the condenser the entropy generation rate increases with the increase in the heat flow rate. The maximum entropy generation rate occurs for the maximum flow rate of the heat that can be transferred according to the definition of heat transfer effectiveness. For the counter-flow heat exchanger, the entropy generation as a function of the heat flow rate reaches maximum at constant inlet parameters (temperatures and mass flow rates). It appeared that the peak entropy generation, or the largest exergy loss, occurs when the outlet temperatures of the fluids are equal. This assertion was verified against data obtained from a simulator of the counter-flow heat exchanger for two different relations between heat capacity rates.
Źródło:: Journal of Mechanical and Energy Engineering; 2017, 1, 1; 79-86
2544-0780
2544-1671
Pojawia się w:: Journal of Mechanical and Energy Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Effect of some parameters on the thermohydraulic characteristics of a channel heat exchanger with corrugated walls
Autorzy:: Ameur, Houari
Sahel, Djamel
Powiązania:: https://bibliotekanauki.pl/articles/95233.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: heat exchanger
corrugated walls
laminar flow
complex fluids
wymiennik ciepła
ściany pofalowane
przepływ laminarny
płyny złożone
Opis:: The present work is a numerical modeling of the flow of a viscous fluid provided with convective heat transfer in a rectangular channel. We focus on the influence of the shape of corrugations which are present on the channel walls. Three shapes of corrugations are studied and which are: the rectangular, triangular and semi-circular shape. Also, effects of the height and number of corrugations on the fluid dynamics and thermal characteristics of the exchanger are highlighted. The working fluid is non-Newtonian (having a shear thinning behavior modeled by the Otswald law). The obtained results reveal that the presence of corrugations yields a major change in the heat exchange execution. In terms of superiority of heat transfer ratio, the cases under investigation can be classified as follows: rectangular > triangular > semi-circular. However and in terms of low pressure drop, this ranking is reversed. Furthermore, the triangular and semicircular shapes were found to have almost similar effects.
Źródło:: Journal of Mechanical and Energy Engineering; 2019, 3, 1; 53-60
2544-0780
2544-1671
Pojawia się w:: Journal of Mechanical and Energy Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

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

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Skocz do pozycji: 5.

Tytuł:: Ground as a source of heat for heat pumps
Autorzy:: Matysko, R.
Powiązania:: https://bibliotekanauki.pl/articles/95309.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: heat pump
ground heat exchanger
transient behavior
ground regeneration
pompa ciepła
wymiennik ciepła gruntowy
stan nieustalony
regeneracja gruntu
Opis:: Heat pumps are an ideal solution for use in newly built passive and energy-plus buildings. One of the many problems present in such construction is the choice of the operational parameters of the lower heat source and the selection of a ground regeneration system which would enable effective regeneration in a short period of time and at a minimal cost. This article presents the heat analysis of the ground from which heat is obtained for heating purposes. The author also analyses ground heating, as the heat is delivered to it via regeneration systems. The presented in article results allow us to estimate the ground's thermal states based on lowered ambient temperature and the possible use of a lower heat pump source regeneration process. The original contribution in article is the calculation results of the ground behavior at the transient regeneration and heat consumption realized by the heat pump system.
Źródło:: Journal of Mechanical and Energy Engineering; 2018, 2, 2; 131-137
2544-0780
2544-1671
Pojawia się w:: Journal of Mechanical and Energy Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Identification of the flow pattern of liquid streams in the shell-side of a segmental-baffled shell-and-tube heat exchanger
Autorzy:: Ligus, G.
Zając, D.
Kołodziej, S.
Powiązania:: https://bibliotekanauki.pl/articles/95380.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: PIV
particle image velocimetry
shell and tube heat exchanger
tube bundles
leakage stream
bypass stream
anemometria obrazowa
wymiennik płaszczowo-rurowy
wiązki rur
strumień wycieku
strumień obejściowy
Opis:: Shell-and-tube heat exchangers are widely used in chemical and process engineering. Assessing hydrodynamics of fluid flow in their shell-side is a highly complex task. This results from the complex geometry of the shell-side itself, defined by such parameters as the tubesheet layout, tube diameter, baffle spacing or baffle cut. Shell-and-tube heat exchangers are the subject of many studies in which design and flow parameters are analysed. However, only a few studies concentrate on issues strictly related to the identification of streams of the liquid flowing in the shell-side of apparatus on an industrial scale. In this article, the authors present the results of an experimental visualization study, utilizing Particle Image Velocimetry (PIV). The experiment used a laser sheet technique along and across a tube bundle. The main results of the measurements and analyses concentrate on identifying the flow pattern of streams in the shell-side and assessing stagnation vortices and their consequences. Finally, detecting bypass streams and leakage streams flowing through design gaps between the shell and the tube bundle as well as between the baffles and the tubes in the bundle are presented.
Źródło:: Journal of Mechanical and Energy Engineering; 2018, 2, 3; 245-256
2544-0780
2544-1671
Pojawia się w:: Journal of Mechanical and Energy Engineering
Dostawca treści:: Biblioteka Nauki

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