Guest editorial for the topical collection: sustainable development and utilization of geothermal systems

--Abstract Not Available-

Improvement of Quality in Publication of Experimental Thermophysical Property Data: Challenges, Assessment Tools, Global Implementation, and Online Support

Article on the improvement of quality in the publication of experimental thermophysical property data

DOI:10.1068/htrt203 Effect of temperature and pressure on the thermal conductivity of aqueous CaI2 solutions

Abstract. Measurements of the thermal conductivity of aqueous CaI2 solutions in the temperature range 293 ^ 473 K and pressures up to 100 MPa for concentrations between 0 and 25 wt % are described. The accuracy of the derived data is estimated to be within 1.6%. A guarded parallelplate apparatus with a cylindrical thermal conductivity cell was used, with a gap of 301:0 0:1 mm between the plates and temperature differences of 0.9 ^ 1.2 K. The effect of temperature, pressure, and concentration on the thermal conductivity behaviour was studied. The pressure and temperature coefficients of the behaviour of the thermal conductivity have been studied with the use of derived experimental thermal conductivity data. A new correlation for thermal conductivity of H2O ‡ CaI2 solutions was developed which incorporates the correct temperature, pressure, and concentration behaviour. The data obtained have been used to test the prediction and estimation techniques developed by other authors. The thermal conductivity shows an almost linear dependence on pressure at all measured isotherms for each concentration. Along each isobar a given concentration shows the thermal conductivity maximum at temperatures between 405 K and 417 K. The effects of pressure and concentration on the thermal conductivity maximum temperatures have been studied.

High Temperatures ^ High Pressures, 2003/2004, volume 35/36, pages 149 ^ 168 DOI:10.1068/htjr097 Thermal conductivity of pure water and aqueous SrBr 2 solutions at high temperatures and high pressures

Abstract. Accurate thermal conductivity measurements were made on pure water and H2O ‡ SrBr2 solutions at pressures up to 100 MPa over the temperature range 293 ^ 473 K with a parallel-plate apparatus. The concentrations studied were between 2.5 and 20 mass%. The estimated accuracy of the method is about 1.6%. The pressure, temperature, and concentration dependences of the thermal conductivity have been studied. The thermal conductivity shows an almost linear dependence on pressure and concentration. Along each isobar, at a given concentration, the lsol ^ T curves show a thermal conductivity maximum at temperatures between 405 K and 420 K depending on pressure and concentration. The measured values of thermal conductivity at atmospheric pressure were compared with values reported by other authors and values calculated with the use of various correlation equations and prediction techniques. The experimental and calculated values from IAPWS formulation of thermal conductivity for pure water show excellent agreement within their experimental uncertainties (AAD ˆ 0:38%). The experimental results have been correlated in terms of the polynomials of x, T, P for practical use. The concentration dependence of the relative thermal conductivity lsol=lH2O was studied. The values of apparent and partial molar thermal conductivity were derived from the measured values of thermal conductivity for solutions lsol and pure water lH2O. Derived apparent molar thermal conductivities were extrapolated to zero concentration (x! 0) to yield partial molar thermal conductivity values f 1 l of electrolyte (SrBr2) at infinite dilution.

High-temperature and high-pressure (p, rho, T) measurements and derived thermodynamic properties of 1-octyl-3-methylimidazolium hexafluorophosphate

Densities of ionic liquid (IL) 1-octyl-3-methylimidazolium hexafluorophosphate [OMIM][PF6] at high temperatures and high pressures were measured. The measurements were made along 10 isotherms over a temperature range T = 278.15 to 413.15 K, at pressures up to 140 MPa by means of an Anton Paar DMA HPM vibration tube densimeter (VTD). The combined expanded relative uncertainties of the density, pressure and temperature measurements at the 95 % confidence level with a coverage factor of k = 2 are estimated to be 0.03 to 0.08 % (depending on temperature and pressure ranges), 0.1 %, and 0.015 K, respectively. We have critically assessed all of the reported high-pressure densities for [OMIM][PF6], together with the presented results, in order to carefully select primary data for development of a reference wide-ranging equation of state. Values of rho-T isobars curvatures, (partial derivative(2)rho/partial derivative T-2)(n), were estimated using the present high-pressure.-T measurements and they were pretty low (0.78x10(-7) to 1.50.x10(-7) m(3) kg(-1) K-1), indicating that the heat capacity of [OMIM][PF6] very weakly depends on pressure, since (partial derivative C-P/partial derivative P)(T) approximate to approximate to (partial derivative(2)rho/partial derivative T-2)(n). Density data were fitted to the modified Tammann-Tait equation and the multiparametric polynomial-type equation of state (EOS) for the IL was developed using the measured high-pressure and high-temperature (p, rho, T) data. This EOS, together with our previous measured heat capacity data at atmospheric pressure, was used to calculate high-pressure and high-temperature derived thermodynamic properties, such as isothermal compressibility