Effect of temperature of working fluid on the performance of centrifugal thermal pumps

2021 ◽  
Author(s):  
Allu Ram Sundeep ◽  
S. G. Rakesh
Keyword(s):  
Effect Of Temperature ◽  
Working Fluid

Temperature Transformation for High-Temperature Heat Pumps

1988 ◽  
Vol 110 (4) ◽  
pp. 652-657 ◽  
Author(s):  
R. Radermacher ◽  
L. A. Howe
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
Heat Pumps ◽  
Pure Component ◽  
Effect Of Temperature ◽  
Working Fluid ◽  
Fluid Mixture ◽  
Temperature Transformation ◽  
Temperature Levels ◽  
Very High

A heat pump cycle is introduced that allows heat pumping between two very high temperature levels, while the suction temperature of the working fluid vapor passing through the compressor is considerably lower. This effect of “Temperature Transformation” is achieved by using a working fluid mixture instead of a single pure component and by employing an unconventional cycle design. The proposed cycle allows the extension of heat pump applications to high temperature levels without encountering operating problems for conventional compressors. This cycle and its features are explained. Its performance has been calculated and the results are presented and discussed.

scholarly journals Effect of Temperature Change on Geometric Structure of Isolated Mixing Regions in Stirred Vessel

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Nor Hanizah Shahirudin ◽  
Alatengtuya ◽  
Norihisa Kumagai ◽  
Takafumi Horie ◽  
Naoto Ohmura
Keyword(s):  
Temperature Change ◽  
Geometric Structure ◽  
Three Dimensional ◽  
Effect Of Temperature ◽  
Working Fluid ◽  
Initial State ◽  
Steady Temperature ◽  
Single Filament ◽  
Stirred Vessel ◽  
Rushton Turbine

The present work experimentally investigated the effect of temperature change on the geometric structure of isolated mixing regions (IMRs) in a stirred vessel by the decolorization of fluorescent green dye by acid-base neutralization. A four-bladed Rushton turbine was installed in an unbaffled stirred vessel filled with glycerin as a working fluid. The temperature of working fluid was changed in a stepwise manner from 30°C to a certain fixed value by changing the temperature of the water jacket that the vessel was equipped with. The step temperature change can dramatically reduce the elimination time of IMRs, as compared with a steady temperature operation. During the transient process from an initial state to disappearance of IMR, the IMR showed interesting three-dimensional geometrical changes, that are, simple torus with single filament, simple torus without filaments, a combination of crescent shape and circular tori, and doubly entangled torus.

Thermal Features of Compliant Foil Bearings—Theory and Experiments

2000 ◽  
Vol 123 (3) ◽  
pp. 566-571 ◽  
Author(s):  
Mohsen Salehi ◽  
Erik Swanson ◽  
Hooshang Heshmat
Keyword(s):  
Heat Dissipation ◽  
Thermal Characteristics ◽  
Heat Energy ◽  
Effect Of Temperature ◽  
Experimental Program ◽  
Working Fluid ◽  
Simplified Approach ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Cooling Air

The paper presents an analytical and experimental investigation aimed at eliciting the thermal characteristics of air lubricated compliant foil bearings. A Couette Approximation to the energy equation is used in conjunction with the compressible Reynolds equation to obtain a theoretical temperature distribution in the air used as a lubricant. The effect of temperature on the thermal properties of the working fluid is included. In parallel, an experimental program was run on a 100 mm diameter foil bearing operating at speeds up to 30,000 rpm employing cooling air across the bearing. The temperature rise of the cooling air provided an indication of the amount of heat energy conducted across the top foil of the bearing from the hydrodynamic film. The temperatures resulted from some tests are compared with the temperatures predicted by the analysis, and maximum over-prediction of about 19 percent was obtained. This simplified approach provides us with reasonably predicted temperatures. By comparing the theoretical heat dissipation obtained from the analytical predicted temperatures with the amount of heat carried away by the cooling air it was possible to arrive at the relative quantities of heat transferred from the bearing by convection via side leakage and by conduction via the top foil. From these comparisons it was deduced that about an average of 80 percent of the heat energy is carried away by conduction. The transient temperatures of the foil bearing in conducted tests for various speeds and loads are also presented.

Evaluation on the Performance of Photovoltaic–Thermal Hybrid System Using CO2 as a Working Fluid

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Chayadit Pumaneratkul ◽  
Haruhiko Yamasaki ◽  
Hiroshi Yamaguchi ◽  
Yuhiro Iwamoto
Keyword(s):  
Power Generation ◽  
Temperature Distribution ◽  
Hybrid System ◽  
Three Dimensional ◽  
Weather Conditions ◽  
Rankine Cycle ◽  
Solar Panel ◽  
Effect Of Temperature ◽  
Working Fluid ◽  
Generation Efficiency

In this study, the CO2-based photovoltaic–thermal hybrid system has been investigated with an objective to increase the power generation efficiency in photovoltaic solar panel and to improve the performance of supercritical CO2 solar Rankine cycle system (SRCS). From a previous study, an improvement of 2% of power generation efficiency was confirmed via experimental investigation. In this study, the temperature distribution on the CO2-based photovoltaic–thermal hybrid system has been numerically and experimentally investigated and confirmed with referenced experimental results. Particularly, in this study, the one-dimensional (1D) calculation of CO2 flow in the cooling tube and three-dimensional (3D) calculation of temperature distribution on the surface of the photovoltaic solar panel are conducted. The typical summer and winter weather conditions are used as the calculation references to investigate the effect of temperature distribution of the photovoltaic solar panel. The results show that the trend of temperature distribution from calculation was confirmed with the experimental data both in summer and winter conditions. Furthermore, in summer condition, the CO2 temperature was increased to a maximum of 28 °C.

Galvanic Corrosion Study in Ethylene Glycol

CORROSION ◽  
2011 ◽  
Vol 67 (8) ◽  
pp. 086001-1-086001-4 ◽  
Author(s):  
P. Rostron
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Ethylene Glycol ◽  
Temperature Dependence ◽  
Electrical Resistance ◽  
Galvanic Corrosion ◽  
Effect Of Temperature ◽  
Working Fluid ◽  
Corrosion Study ◽  
Actual Working

Abstract The potential for galvanic corrosion between carbon steel and duplex (22Cr) stainless steel in impure ethylene glycol (CH2OHCH2OH) is assessed. The temperature dependence of the corrosion is determined, as well as the effect of temperature on the conductivity of dry, wet, and impure wet ethylene glycol. The temperature dependence of the corrosion can be explained by the change in electrical resistance of the glycol with temperature. The authors also show the importance of testing corrosiveness by using the actual working fluid rather than a simulation fluid.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum
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