scholarly journals DETERMINATION OF MEANS OF CONTRAINDICATION OF OPERATIVE DAMAGE OF SUPERIOR WAGON-THERMAL SYSTEMS OF THE MODEL TN 4-201

2018 ◽  
Vol 32 (1) ◽  
pp. 135-146
Author(s):  
O. Fomin ◽  
A. Stetsko
Keyword(s):  
Thermal Systems ◽  
Tn 4

scholarly journals Reviewing the Exergy Analysis of Solar Thermal Systems Integrated with Phase Change Materials

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 724
Author(s):  
Macmanus Chinenye Ndukwu ◽  
Lyes Bennamoun ◽  
Merlin Simo-Tagne
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Second Law Of Thermodynamics ◽  
Heat Transfer Fluid ◽  
Solar Still ◽  
Thermal Systems ◽  
Solar Systems ◽  
Exergy Balance ◽  
Change Material

The application of thermal storage materials in solar systems involves materials that utilize sensible heat energy, thermo-chemical reactions or phase change materials, such as hydrated salts, fatty acids paraffin and non-paraffin like glycerol. This article reviews the various exergy approaches that were applied for several solar systems including hybrid solar water heating, solar still, solar space heating, solar dryers/heaters and solar cooking systems. In fact, exergy balance was applied for the different components of the studied system with a particular attention given to the determination of the exergy efficiency and the calculation of the exergy during charging and discharging periods. The influence of the system configuration and heat transfer fluid was also emphasized. This review shows that not always the second law of thermodynamics was applied appropriately during modeling, such as how to consider heat charging and discharging periods of the tested phase change material. Accordingly, the possibility of providing with inappropriate or not complete results, was pointed.

The Design and Performance Optimization of Thermal Systems

1990 ◽  
Vol 112 (1) ◽  
pp. 86-93 ◽  
Author(s):  
M. R. von Spakovsky ◽  
R. B. Evans
Keyword(s):  
Performance Optimization ◽  
Optimization Techniques ◽  
Operating Costs ◽  
Capital Expenditures ◽  
Analytical Determination ◽  
Second Law ◽  
Thermal Systems ◽  
Rules Of Thumb ◽  
And Performance

Optimization techniques are, in general, still not used today in the design and performance analysis of thermal systems and their components. The engineer’s search for the best system configuration is based solely on rules-of-thumb and not on a systematic, analytical determination of what the optimal design or performance should be. In addition, economic factors are not directly tied to thermodynamic ones; therefore, the economic ramifications of thermodynamic changes to the system are not usually, if ever, immediately apparent. A general analytical approach that directly determines the optimum thermodynamic and econmic behavior of thermal systems is discussed and illustrated using Rankine cycles. Utilizing the Second Law and typical Second Law costing techniques, this method provides for the creation of mathematical models that balance a cycle’s operating costs and capital expenditures. Such models can be solved numerically, subject to various constraints, for the optimum design and performance of thermal systems.

Characterization of the Thermal Behavior of the Materials Commonly Used in Colombia for the Construction of Building Envelopes

2014 ◽  
Author(s):  
Eduardo Vélez ◽  
Fabián Amaya ◽  
Antonio Olmos ◽  
Raúl Pérez ◽  
Antonio Bula ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Architectural Design ◽  
Building Materials ◽  
National Development ◽  
Relevant Information ◽  
Energy Performance ◽  
Thermal Systems ◽  
Sustainable Building ◽  
Materials Used

The thermal performance of building materials used in Colombia is not currently characterized, which is essential to obtain the necessary information for an architectural design based on energy efficiency. The determination of materials thermal properties, as well as thermal and energy performance of building materials commonly used in Colombia are the main challenges for this research. The proposed methodology implies the experimental determination of the different materials thermal properties through the design and construction of an experimental device capable to accommodate different materials configurations. This will allow us to obtain relevant information to develop the government’s energy standards for quality building materials and quality policies for private companies. Among others are included: the Environmental Seal for Sustainable Building, which is currently being developed by the Colombian Council of Sustainable Building (CCCS); the Colombian standard for thermal systems applications in buildings (RITE) currently being developed by the Colombian Association of Air Conditioning and Refrigeration (ACAIRE); and policies for national sustainable buildings that were included in the National Development Plan 2010–2014 and 2015–2019.

Optimal Synthesis and Operation of Thermal Systems by the Thermoeconomic Functional Approach

1992 ◽  
Vol 114 (4) ◽  
pp. 707-714 ◽  
Author(s):  
C. A. Frangopoulos
Keyword(s):  
Functional Analysis ◽  
Systems Approach ◽  
Optimization Method ◽  
Functional Approach ◽  
Thermal System ◽  
Thermal Systems ◽  
Process Plant ◽  
Cogeneration System ◽  
Economic Considerations

Methods developed for optimization of thermal systems usually work on a predetermined configuration of the system. Consequently, in order to select the best system, it is necessary to apply the method separately for each possible configuration and compare the results. The designer’s work would be significantly facilitated, if the optimization method could synthesize the optimal configuration of the system automatically. Such a method is presented here, based on the Thermoeconomic Functional Approach (TFA). TFA is a method developed for optimal design or improvement of complex thermal systems. It combines thermodynamic concepts with economic considerations in a systems approach. A thermal system is considered as a set of interrelated units; each unit has one particular function (purpose, or product). The documented determination of the function of the system as a whole and of each unit individually is achieved by functional analysis. The problem is mathematically formulated (objective function, constraints) at two levels: (A) optimization of operation, (B) optimization of the configuration and the design of the system. The solution is obtained by a two-level algorithm. As an example, the method is used to optimize a cogeneration system supplying a process plant with heat and electricity, which are known functions of time.

scholarly journals A Calorimetric Method for Determination of Heat Capacity of Ceramics for Concentrated Solar Thermal Systems / Skenējošās Kalorimetrijas Metode Siltumietilpības Noteikšanai Saules Kolektoru Keramikā

2013 ◽  
Vol 50 (5) ◽  
pp. 68-73 ◽  
Author(s):  
J. Kalnačs ◽  
V. Grehovs ◽  
G. Mežinskis ◽  
L. Bidermanis
Keyword(s):  
Heat Capacity ◽  
Protective Coatings ◽  
Thermal Contact ◽  
Ceramic Materials ◽  
Concentrated Solar Power ◽  
Scanning Calorimetry ◽  
Thermal Systems ◽  
Continuous Scanning ◽  
Resistant Ceramic

Abstract Differential scanning calorimetry was carried out to determine the heat capacity (Cp) of the high temperature resistant ceramic materials to be used as protective coatings for stainless steel tubes of parabolic trough solar collectors in concentrated solar power (CSP) systems. The Ср(Т) measurements and calculations were performed at continuous scanning in the temperature range 20-800 °С. In the work, calibration curves have been derived for conversion of measuring units from mcV into mW. To achieve a better repeatability of measurements, methods for stabilization of the thermal contact between the sample-containing vessel and the probe have been developed. The Ср(Т) dependence was obtained for different ceramic materials.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

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