Correlations for liquid thermal conductivity of low GWP refrigerants in the reduced temperature range 0.4 to 0.9 from saturation line to 70 MPa

2020 ◽  
Vol 117 ◽  
pp. 358-368
Author(s):  
Sebastiano Tomassetti ◽  
Gianluca Coccia ◽  
Mariano Pierantozzi ◽  
Giovanni Di Nicola
Keyword(s):  
Thermal Conductivity ◽  
Saturation Line ◽  
Temperature Range ◽  
Liquid Thermal Conductivity ◽  
Reduced Temperature

REFRIGERANTS OF THE METHANE, ETHANE AND PROPANE SERIES: THERMAL CONDUCTIVITY CALCULATION ALONG THE SATURATION LINE

2011 ◽  
Vol 19 (01) ◽  
pp. 37-43 ◽  
Author(s):  
GIOVANNI LATINI ◽  
MARCO SOTTE
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Organic Compounds ◽  
Saturation Line ◽  
Characteristic Parameters ◽  
Temperature Range ◽  
Almost All ◽  
Thermal Conductivity Calculation ◽  
Reduced Temperature

In this paper, a formula is presented for the calculation of thermal conductivity of liquids along the saturation line. The formula is valid for organic compounds in a wide reduced temperature range (0.30 to 0.95), but is proven to be particularly reliable for refrigerants by testing it on a database of more than 40 refrigerants of the methane, ethane and propane series that includes almost all those reported by ASHRAE in its 2007 revision of standard 34. The test on the indicated refrigerants shows a very satisfying performance: mean and maximum absolute deviations between calculated values and experimental data are generally less than 3% and 8% respectively. The proposed formula is very simple; three characteristic parameters express the thermal conductivity dependence on the reduced temperature: the constant Φ, a multiplying factor A, and an exponent a.

Organic Compounds Thermal Conductivity in the Liquid Phase: A Prediction Method in the Temperature Range From the Melting Point to Near the Critical Temperature

2010 ◽  
Author(s):  
Giovanni Latini ◽  
Marco Sotte
Keyword(s):  
Thermal Conductivity ◽  
Critical Temperature ◽  
Melting Point ◽  
Organic Compounds ◽  
Golden Ratio ◽  
Prediction Method ◽  
Temperature Range ◽  
Experimental Values ◽  
Two Parameters ◽  
Reduced Temperature

In this work a new equation for liquid thermal conductivity prediction is proposed; its goal is to overcome the existing relations’ limitations, being reliable for many compounds in a wide temperature range and requiring few parameters to be used. The equation allows thermal conductivity calculation along or near the saturation line by the knowledge of the reduced temperature and two parameters characteristic of the organic family and of the single investigated compound. Also the “golden ratio” appears in the formula and an investigation on this number is carried out, proposing it as a characteristic value of the liquid state. The results of the formula’s test on the best available experimental values of more than 120 organic compounds, belonging to 13 different families (including the most used refrigerants) are presented. In the investigated reduced temperature range (going from the melting point to close the critical temperature, Tr = 0.30 ÷ 0.95) mean absolute deviations between calculated and experimental thermal conductivity data are generally less than 3% and maximum ones usually close to 8%.

scholarly journals Silanes and Siloxanes Thermal Conductivity in the Liquid Phase: A Critical Review and an Improved Prediction Method

2021 ◽  
Vol 65 (2-4) ◽  
pp. 212-217
Author(s):  
Giovanni Latini ◽  
Giorgio Passerini
Keyword(s):  
Thermal Conductivity ◽  
Liquid Phase ◽  
Atmospheric Pressure ◽  
Empirical Equation ◽  
Scientific Literature ◽  
Prediction Method ◽  
Saturation Line ◽  
Prediction Methods ◽  
Reduced Temperature ◽  
Thermal Conductivity Λ

The thermal conductivity λ of the silanes and siloxanes families in the liquid phase at atmospheric pressure or along the saturation line is investigated as function of the reduced temperature. Because of the large scarcity or even of the lack of accurate experimental λ data an empirical equation is proposed as a generalization based on investigations presented in previous works [1, 2]. The families of silanes and siloxanes (21 chlorosilanes, 5 cyclosiloxanes, 10 linear siloxanes, 10 silanes and 19 other silanes) are taken into consideration using a large database [3] in order to extend the use of a general formula valid for organic compounds (alcohols, alkanes, ketones,….) and to improve preceeding results obtained in the case of the cited silanes and siloxanes, for which experimental thermal conductivity data at atmospheric pressure or along the saturation line in the liquid phase are available in very few cases. The equation is proposed as acceptable for engineering purposes and comparable with the existing prediction methods [3]. The database DIPPR [3] in the version 2020 containing a linear correlation with various parameters is taken into account, also considering the results of 7 other prediction methods existing in the technical and scientific literature. An extensive and critical comparison points out that the method proposed in this work can be considered valid with absolute errors usually not greater than 5%.

Effects of anisotropy and solid/liquid thermal conductivity ratio during inverted Bridgman growth

2002 ◽  
Author(s):  
Julaporn Kaenton ◽  
Victoria Timchenko ◽  
Mohammed El Ganaoui ◽  
Graham de Vahl Davis ◽  
Eddie Leonardi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Conductivity Ratio ◽  
Conductivity Ratio ◽  
Bridgman Growth ◽  
Liquid Thermal Conductivity ◽  
Solid Liquid

Measurement of apparent thermal conductivity of regenerator materials in 4-20 K temperature range

Cryogenics ◽  
2021 ◽  
pp. 103300
Author(s):  
Yang Biao ◽  
Xi Xiaotong ◽  
Liu Xuming ◽  
Xu Xiafan ◽  
Chen Liubiao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Temperature Range ◽  
Apparent Thermal Conductivity

Effects of Nb doping on thermoelectric properties of Zn4Sb3 at high temperatures

2009 ◽  
Vol 24 (2) ◽  
pp. 430-435 ◽  
Author(s):  
D. Li ◽  
H.H. Hng ◽  
J. Ma ◽  
X.Y. Qin
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Temperature Range ◽  
A Value ◽  
Nb Doping ◽  
Thermal Conductivities

The thermoelectric properties of Nb-doped Zn4Sb3 compounds, (Zn1–xNbx)4Sb3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn4Sb3. Among the compounds studied, the lightly substituted (Zn0.995Nb0.005)4Sb3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn4Sb3 compound for the temperature range investigated. In particular, the ZT of (Zn0.995Nb0.005)4Sb3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn4Sb3 obtained in this study.

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