https://www.sfu.ca/~mbahrami/ENSC%20461/Project/Some%20papers%20for%20CO2%20Ref/Fundamental%20process%20and%20system%20design%20issues%20in%20CO2%20vapor%20compression%20systems.pdf

Fundamental process and system design issues in CO2 vapor compression systems

New functional forms have been developed for multiparameter equations of state for non- and weakly polar fluids and for polar fluids. The resulting functional forms, which were established with an optimization algorithm which considers data sets for different fluids simultaneously, are suitable as a basis for equations of state for a broad variety of fluids. The functional forms were designed to fulfil typical demands of advanced technical application with regard to the achieved accuracy. They are numerically very stable and their substance-specific coefficients can easily be fitted to restricted data sets. In this way, a fast extension of the group of fluids for which accurate empirical equations of state are available is now possible. This article deals with the results found for the polar fluids CFC-11 (trichlorofluoromethane), CFC-12 (dichlorodifluoromethane), HCFC-22 (chlorodifluoromethane), HFC-32 (difluoromethane), CFC-113 (1,1,2-trichlorotrifluoroethane), HCFC-123 (2,2-dichloro-1,1,1-trifluoroethane), HFC-125 (pentafluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HFC-143a (1,1,1-trifluoroethane), HFC-152a (1,1-difluoroethane), carbon dioxide, and ammonia. The substance-specific parameters of the new equations of state are given as well as statistical and graphical comparisons with experimental data. General features of the new class of equations of state such as their extrapolation behavior or their numerical stability and results for non- and weakly polar fluids have been discussed in preceding articles.

Equations of state for technical applications. III. Results for polar fluids

A recent argon–argon interatomic potential energy curve determined from quantum-mechanical ab initio calculations and described with an analytical representation [B. Jager, R. Hellmann, E. Bich, and E. Vogel, Mol. Phys. 107, 2181 (2009); 108, 105 (2010)] was used to calculate the most important thermophysical properties of argon governed by two-body interactions. Second pressure, acoustic, and dielectric virial coefficients as well as viscosity and thermal conductivity in the limit of zero density were computed for natural argon from 83 to 10,000 K. The calculated values for the different thermophysical properties are compared with available experimental data and values computed for other argon–argon potentials. This extensive analysis shows that the proposed potential is superior to all previous ones and that the calculated thermophysical property values are accurate enough to be applied as standard values for the complete temperature range of the calculations.

/pdf/ab-initio-potential-energy-curve-for-the-neon-atom-pair-and-5fykeq8bqn.pdf

Ab initio potential energy curve for the neon atom pair and thermophysical properties for the dilute neon gas. II. Thermophysical properties for low-density neon

Helix 4 of the Bacillus thuringiensis Cry1Aa toxin lines the lumen of the ion channel.

http://www.pvv.org/~stm/research/thermofluid.pdf

CO2 transport: Data and models – A review

The speed of sound in gaseous argon at temperatures between 110 K and 450 K and at pressures up to 19 MPa

The speed of sound and derived thermodynamic properties of ethane at temperatures between 220 K and 450 K and pressures up to 10.5 MPa

Speed of sound in carbon dioxide at temperatures between (220 and 450) K and pressures up to 14 MPa

Thermodynamic properties of gaseous argon have been determined from our recent highly accurate measurements of the speed of sound by means of a numerical integration of the differential equations which link the speed of sound and the equation of state. Compression factosr and both isochoric and isobaric heat capacities at temperatures between 110 and 450 K at densities up to either one-half of the critical (T ⩾ 150 K ) or 74 percent of the saturated-vapor density (T < 150 K ) are reported. To perform the integration, initial conditions were required along an isotherm close to the critical temperature. The method of integration is described in detail and the results are compared withpVT and calorimetric data from the literature.

Thermodynamic properties of gaseous argon at temperatures between 110 and 450 K and densities up to 6.8 mol · dm -3 determined from the speed of sound

We describe methods by which all of the observable thermodynamic properties of a compressed gas, including the compressibility factor and the isochoric heat capacity, may be determined from sound speed data by numerical integration of a pair of partial differential equations. The technique may be employed over a wide range of conditions. Initial values are required. but we demonstrate that values specified on an isotherm close to the critical temperature are sufficient for application of the method to the entire homogeneous fluid region at subcritical densities. The method may also be extended to higher densities at temperatures above the critical. The effects of errors in both the initial values and the speed of sound are examined in detail by means of analytic and numerical results. The results indicate that all of the observable thermodynamic properties may be obtained with an uncertainty equal to or less than that achievable by the best available alternative techniques.

A.F. Estrada-Alexanders

Papers

The speed of sound in gaseous argon at temperatures between 110 K and 450 K and at pressures up to 19 MPa

The speed of sound and derived thermodynamic properties of ethane at temperatures between 220 K and 450 K and pressures up to 10.5 MPa

Speed of sound in carbon dioxide at temperatures between (220 and 450) K and pressures up to 14 MPa

Thermodynamic properties of gaseous argon at temperatures between 110 and 450 K and densities up to 6.8 mol · dm -3 determined from the speed of sound

Determination of thermodynamic properties from the speed of sound