A new method for online measurement of the concentration of working fluids in absorption refrigeration systems

Accepted Manuscript Title: A new method for online measuring the concentration of working fluids in absorption refrigeration systems Author: Jingkai Jiang, Guogeng He, Yilin Liu, Keqiao Li, Dehua Cai PII: DOI: Reference:

S0140-7007(17)30107-X http://dx.doi.org/doi: 10.1016/j.ijrefrig.2017.03.012 JIJR 3587

To appear in:

International Journal of Refrigeration

Received date: Revised date: Accepted date:

11-7-2016 13-1-2017 11-3-2017

Please cite this article as: Jingkai Jiang, Guogeng He, Yilin Liu, Keqiao Li, Dehua Cai, A new method for online measuring the concentration of working fluids in absorption refrigeration systems, International Journal of Refrigeration (2017), http://dx.doi.org/doi: 10.1016/j.ijrefrig.2017.03.012. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

A new method for online measuring the concentration of working fluids in absorption refrigeration systems Jingkai Jianga, Guogeng Hea, Yilin Liub, Keqiao Lia, Dehua Caia,* a

School of Energy and Power Engineering, Huazhong University of Science and

Technology, Wuhan 430074, China b

State Key Laboratory of Coal Combustion, Huazhong University of Science and

Technology, Wuhan 430074, China *

Corresponding author: Tel: +86 27 87542718

E-mail address: [email protected] Highlights  A new method for concentration measuring of absorption working pair is present.  Electrical conductivity with different temperatures and concentrations is obtained. 

A new correlation for solution concentration calculation is provided.

Abstract: This paper proposes a new method for online measuring the concentration of working fluids in absorption refrigeration systems: electrical conductivity is measured to determine the concentration of the solution. Compared with the common density-concentration method, electrical conductivity-concentration method has the similar accuracy but helps to save the cost when applied in absorption systems with ammonia-salt solutions. This novel method is also suitable for systems with traditional working fluids like water-lithium bromide solution. Electrical conductivities of ammonia-lithium nitrate, ammonia-sodium thiocyanate and water-lithium bromide solutions were measured between (293.15 and 333.15) K, using an Industrial Conductivity Meter. The ammonia mass fraction varied from 0.35 1

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to 0.48 for ammonia-lithium nitrate solution and from 0.35 to 0.50 for ammonia-sodium thiocyanate solution. For water-lithium bromide solution, the mass fraction of lithium bromide was within the range of 40%-60%. The experimental data were correlated as a function of temperature and composition using the extended Casteel-Amis equation. In addition, correlations of refrigerant mass concentration as a function of electrical conductivity and temperature of the solution are proposed. Keywords: Absorption refrigeration, Concentration measurement, Electrical conductivity, Ammonia-lithium nitrate, Ammonia-sodium thiocyanate, Water-lithium bromide 1. Introduction Nowadays, there is a growing worldwide concern over the adverse environmental impacts of refrigerants [1]. Compared with vapour compression refrigeration systems, refrigerants used by absorption systems tend to be environment-friendly and cause no ozone depletion [2]. Simultaneously, absorption refrigeration systems can harness low-quality heat energy for cooling and reduce demand on electricity supply [3]. Therefore, absorption refrigeration cycle is gaining more and more attention. The most common absorption refrigeration systems are H2O-LiBr and NH3-H2O cycles. In recent decades, several new working fluids have been proposed, showing good performance such as ammonia-lithium nitrate and ammonia-sodium thiocyanate mixtures [4-6]. Compared with traditional absorption refrigeration systems, ammonia-based working fluid absorption refrigeration attracts increasingly worldwide interest due to its low evaporating temperature and the lack of problems under 2

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vacuum conditions. These advantages help to simplify the structure of the system and improve the reliability. In an absorption refrigeration system, the absorber is the key component which largely determines the performance of the whole system. To evaluate the absorber, absorption efficiency or absorbance is a critical parameter which is calculated by the inlet and outlet solution concentration of the absorber. Hence, measuring concentration of the working fluid is of great significance for the evaluation of absorption refrigeration system. Up to now, many thermodynamic and physical properties of the ammonia-salt mixtures have been presented in the open literature, including vapor-liquid equilibrium [7, 8], density [8, 9], viscosity [8, 9], heat capacity [8, 9] and thermal conductivity [10, 11], and some of which could be used to detect the concentration of the solution. For instance, density measurement method has been reported to determine the concentration of solution in the literature [12]. According to the experimental data, several researchers have regressed the density correlation for absorption working pairs as a function of temperature and composition [8, 9, 13]. Concise and straightforward as it is, this method has some disadvantages in practical application for absorption refrigeration systems with ammonia-salt mixtures. In the running system, it is impossible to directly measure the density of the ammonia-salt solution by static weighing due to the special properties of ammonia. Thus an online density meter is needed, such as vibrating-tube density meter or ionizing-radiation density meter. But the cost of these instruments is also the limitation of this method to be applied in real absorption refrigeration systems. Additionally, the density of 3

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ammonia-salt solution has little change with variable temperature, which may cause relatively large uncertainties to experimental results. Based on the above points, for ammonia-salt absorption refrigeration systems, we propose a new method of concentration measurement with lower cost than density-concentration method. Electrical conductivity is measured to determine the concentration of solution. According to our previous study [14-16], the ranges of ammonia concentration in air-cooled absorption refrigeration cycles with ammonia-lithium nitrate and ammonia-sodium thiocyanate mixtures were about 36-47 wt. % and 36-45 wt. %, respectively. So we mainly focus on the concentration and temperature ranges which can be used to evaluate our absorption refrigeration systems. For traditional absorption refrigeration systems, this novel method can also be adopted for online measurement and evaluation. In this paper, the electrical conductivities of several binary liquid mixtures, including ammonia-lithium nitrate, ammonia-sodium thiocyanate and water-lithium bromide mixtures, were measured in the temperature range between (293.15 and 333.15) K for various compositions. For ammonia-salt solution, the mass fraction of ammonia was within the range of 35%-50%. For water-lithium bromide solution, the mass fraction of lithium bromide was within the range of 40%-60%, which is wide enough for absorption system [17]. The experimental data were correlated with temperature and concentration using the extended Casteel-Amis equation. Hitherto, there is no data available about the electrical conductivity of absorption working fluids in the open literature. 2. Experimental section 4

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2.1. Material Ammonia (Niu Ruide, 99.9%), lithium nitrate (Aladdin, ≥99.9%), sodium thiocyanate (Olbase, ≥98%), lithium bromide (Aladdin, ≥99%), standard KCl solution (Aladdin, 0.1000 mol·dm-3). All chemicals were used without further purification. 2.2. Apparatus and experimental procedure All the devices were calibrated before the experiment. The electrical conductivity was measured by an Industrial Conductivity Meter (BOQU DDG-3080), which has been calibrated with standard 0.1000 mol∙dm-3 KCl solution. The measure range of the conductivity meter was 0-600

and the estimated uncertainty for electrical

conductivity was ±1.0%. Several pressure vessels made of stainless steel were used to contain solution samples, with a volume of 1.8L. An ammonia pressure gauge was installed on the vessel and two Pt100 thermometers were placed at the bottle of the vessel to measure the temperature of the solution sample. The measurements were made in the temperature range between (293.15 and 333.15) K. The standard uncertainty of the temperature measured was ±0.1 K. In order to adjust the temperature of solution samples, the vessel was immersed in a thermostat water bath of 0.2 m3 capacity, whose temperature was measured with a precision PT100 thermometer and controlled by a PID controller. The components were weighted on an electronic balance with a resolution of ±0.1g. The data acquisition system consisted of an Agilent model 34970A data logger and a computer. Figure 1 shows the scheme of the whole system. 5

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To prepare ammonia-lithium nitrate and ammonia-sodium thiocyanate solutions, the first step was to load the pressure vessel with lithium nitrate or sodium thiocyanate and then dry it in the oven for 24h at 373.15K. Then, it was degassed by vacuum extraction and ammonia was introduced into the vessel from the auxiliary stainless steel vessel. The exact quantity of ammonia introduced was determined by weighting the auxiliary stainless steel vessel. During the filling process, the pressure vessel was put into an ice bath and shaken slightly to help dissolve the salt in the liquid ammonia. In the end, the solution achieved a complete mixing. Considering the vaporization of the liquid ammonia, the initial solution sample occupied about 80% volume of the vessel. Thus the change of the concentration caused by the vaporization

of the liquid

ammonia was relatively small. The concentration of the solution can be determined by:

where

is the mass of salt added to the vessel,

added to the vessel and

is the mass of ammonia

is the mass of vapor phase of ammonia in the vessel.

The mass of ammonia vapor was calculated from obtained data for the volume of vapor phase and from information about the density of saturated vapor for ammonia at the parameters of the experiment [18]. The absolute error in determination of mass concentration of the solution was less than 0.06%. The sample composition was changed by release the gaseous ammonia into the water. The ammonia mass fraction varied from 0.35 to 0.48 for the ammonia-lithium nitrate mixture and from 0.35 to 0.50 for the ammonia-sodium thiocyanate mixture. 6

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The preparing process of the water-lithium bromide solution was similar to the above, except that the sample composition was changed by adding deionized water into the vessel. The lithium bromide mass fraction varied from 0.40 to 0.60. 3. Results and discussion The electrical conductivity of three solution samples were all measured at 2K intervals between (293.15 and 333.15) K. The ammonia mass fraction of the samples, ammonia-lithium nitrate and ammonia-sodium thiocyanate mixtures, were between 0.35 and 0.48 and between 0.35 and 0.50, respectively. Another, the electrical conductivity of water-lithium bromide solution was measured within the range of salt concentration 0.40-0.60. The experimental results are presented in Tables 1-3. The aim of measuring the electrical conductivity is to find: (2) But in the sample preparation and experimental stage, it is not possible to use electrical conductivity as a variable factor. Hence, electrical conductivity was used as the response while concentration was modified as a variable factor [19]:

Casteel and Amis [20] proposed a four-parameter equation to describe the electrolytic conductivity of an electrolyte as a function of its salt concentration. Diego et al. [21] successfully extended the Casteel-Amis equation from a univariate κ (m) function to a bivariate function κ (m,T). Similarly, the following equation is proposed to incorporate the effect of the temperature upon the electrical conductivity to the Casteel-Amis equation [22, 23]. 7

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where

is the electrical conductivity and

is the salt concentration (Casteel

and Amis used molarity C for the unit of salt concentration in their original paper, the use of

in place of C in the equation can be proved to be equal.); and A,B,C,D

are temperature-dependent parameters according to eqs 4a-4d.

Although the Casteel-Amis equation is not usually used in the field of absorption refrigeration, but may be helpful in other related fields. The present study regresses the experimental data and provides

correlation. The coefficient of Eq. 4

obtained are showed in Table 4-6. The root mean square deviations (RMSD) and the goodness of fit (R2) between the experimental and calculated electrical conductivity of the NH3-LiNO3 solutions were 0.17% and 0.9998, respectively; for NH3-NaSCN solutions, it was 0.21% and 0.9988, respectively; and for H2O-LiBr solutions, it was 0.17% and 0.9958, respectively. Figs 2 to 4 show the comparison of experimental and calculated data with eq 4 for different solutions. Experimental data and calculated results are all in agreement at different compositions.

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Fig.5 shows the variations of electrical conductivity and density as a function of ammonia mass fraction for ammonia-lithium nitrate mixture. It can be seen that both density and electrical conductivity change obviously with concentration, and that the change of electrical conductivity with temperature is much more obvious than that of density. From this point, the electrical conductivity-concentration method is as effective as the density-concentration method. Considering the cost of measuring equipment and the special properties of ammonia-salt solution, conductivity-concentration method proposed in this paper is more appropriate for practical application. Finally, the

correlation provides a more convenient approach to

the solution concentration calculation for absorption refrigeration cycles. The following formula is used to determine the refrigerant concentration as an explicit expression of the electrical conductivity and temperature of the solution.  a 0  a1T  a 2T 2  a 3  a 4 2  a 5T   w1    2 2  b0  b1T  b2T  b3  b4  b5T  

(5)

The coefficients of Eq. (5) are summarized in Table 7. The

- -

plots are shown

in Fig. 6. It is observed that the refrigerant mass concentration varies significantly with electrical conductivity under given temperature. It is feasible to measure the solution concentration through the “ - - ” method. 4. Conclusion A new method of concentration measurement with lower cost was proposed in this paper compared with density-concentration method. For practical application, the electrical conductivities of ammonia-lithium nitrate, ammonia-sodium thiocyanate 9

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mixtures were measured in the temperature range between (293.15 and 333.15) K, with ammonia mass fractions between 0.35-0.48 and 0.35-0.50 respectively. The electrical conductivity of water-lithium bromide solution was measured in the temperature range between (293.15 and 333.15) K within the salt concentration range of 0.40-0.60. The experimental data were regressed with temperature and composition using the extended Casteel-Aims equations. The novel measurement method and the results presented in this paper will be useful for measuring the concentration of working fluids and evaluating the absorption efficiency in the absorption systems with ammonia-lithium nitrate, ammonia-sodium thiocyanate and water-lithium bromide solutions. Acknowledgements This present study was supported by the National Natural Science Foundation of China (No. 51176054).

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References [1] M. Mortazavi, R. Nasr Isfahani, S. Bigham, S. Moghaddam. Absorption characteristics of falling film LiBr (lithium bromide) solution over a finned structure. Energy. 87 (2015) 270-8. [2] F. Asfand, M. Bourouis. A review of membrane contactors applied in absorption refrigeration systems. Renewable and Sustainable Energy Reviews. 45 (2015) 173-91. [3] R.N. Isfahani, K. Sampath, S. Moghaddam. Nanofibrous membrane-based absorption refrigeration system. International Journal of Refrigeration. 36 (2013) 2297-307. [4] M. Zamora, M. Bourouis, A. Coronas, M. Vallès. Part-load characteristics of a new ammonia/lithium nitrate absorption chiller. International Journal of Refrigeration. 56 (2015) 43-51. [5] M.U. Siddiqui, S.A.M. Said. A review of solar powered absorption systems. Renewable and Sustainable Energy Reviews. 42 (2015) 93-115. [6] A. Lecuona, R. Ventas, C. Vereda, R. López. Absorption solar cooling systems using optimal driving temperatures. Applied Thermal Engineering. 79 (2015) 140-8. [7] S. Libotean, D. Salavera, M. Valles, X. Esteve, A. Coronas. Vapor-liquid equilibrium of ammonia+ lithium nitrate+ water and ammonia+ lithium nitrate solutions from (293.15 to 353.15) K. Journal of Chemical & Engineering Data. 52 (2007) 1050-5. [8] S.K. Chaudhari, D. Salavera, A. Coronas. Densities, Viscosities, Heat Capacities, and Vapor–Liquid Equilibria of Ammonia+ Sodium Thiocyanate Solutions at Several 11

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Temperatures. Journal of Chemical & Engineering Data. 56 (2011) 2861-9. . i otean

.

art n, D. Salavera, M. Valles, X. Esteve, A. Coronas. Densities,

viscosities, and heat capacities of ammonia+ lithium nitrate and ammonia+ lithium nitrate+ water solutions between (293.15 and 353.15) K. Journal of Chemical & Engineering Data. 53 (2008) 2383-8. [10] Y. Cuenca, D. Salavera, A. Vernet, A.S. Teja, M. Vallès. Thermal conductivity of ammonia + lithium nitrate and ammonia + lithium nitrate + water solutions over a wide range of concentrations and temperatures. International Journal of Refrigeration. 38 (2014) 333-40. [11] C. Infante Ferreira. Thermodynamic and physical property data equations for ammonia-lithium nitrate and ammonia-sodium thiocyanate solutions. Solar Energy. 32 (1984) 231-6. [12] M. Medrano, M. Bourouis, A. Coronas. Absorption of water vapour in the falling film of water–lithium bromide inside a vertical tube at air-cooling thermal conditions. International journal of thermal sciences. 41 (2002) 891-8. [13] R. Lee, R. DiGuilio, S. Jeter, A. Teja. Properties of lithium bromide-water solutions at high temperatures and concentrations-II: Density and Viscosity. ASHRAE Trans. 96 (1990) 709-28. [14] D. Cai, G. He, Q. Tian, Y. Bian, R. Xiao, A. Zhang. First law analysis of a novel double effect air-cooled non-adiabatic ammonia/salt absorption refrigeration cycle. Energy Conversion and Management. 98 (2015) 1-14. [15] D. Cai, G. He, Q. Tian, W. Tang. Thermodynamic analysis of a novel air-cooled 12

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non-adiabatic absorption refrigeration cycle driven by low grade energy. Energy Conversion and Management. 86 (2014) 537-47. [16] D. Cai, J. Jiang, G. He, K. Li, L. Niu, R. Xiao. Experimental evaluation on thermal performance of an air-cooled absorption refrigeration cycle with NH 3–LiNO 3 and NH 3–NaSCN refrigerant solutions. Energy Conversion and Management. 120 (2016) 32-43. [17] Y. Kaita. Thermodynamic properties of lithium bromide–water solutions at high temperatures. International Journal of Refrigeration. 24 (2001) 374-90. [18] E.W. Lemmon, M.L. Huber, M.O. McLinden. NIST Standard Reference Database 23. NIST Reference Fluid Thermodynamic and Transport Properties—REFPROP, version. 9 (2010) 55. [19] M. Sharifi, B. Young. Towards an online milk concentration sensor using ERT: Correlation of conductivity, temperature and composition. Journal of Food Engineering. 116 (2013) 86-96. [20] J.F. Casteel, E.S. Amis. Specific conductance of concentrated solutions of magnesium salts in water-ethanol system. Journal of Chemical and Engineering Data. 17 (1972) 55-9. [21] A. De Diego, J. Madariaga, E. Chapela. Empirical model of general application to fit (k, c, T) experimental data from concentrated aqueous electrolyte solutions. Electrochimica acta. 42 (1997) 1449-56. [22] S. Gadzuric, M. Vranes, S. Dozic. Electrical conductivity and density of ammonium nitrate+ formamide mixtures. Journal of Chemical & Engineering Data. 13

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56 (2011) 2914-8. [23] M.S. Ding. Casteel-Amis equation: Its extension from univariate to multivariate and its use as a two-parameter function. Journal of Chemical & Engineering Data. 49 (2004) 1469-74.

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Figure 1. Scheme of the electrical conductivity test system.

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Figure 2. Electrical conductivity for NH3-LiNO3 solutions, for several ammonia mass fractions (w1). Experimental values: ▲, w1=0.3538; ●, w1=0.3900; ■, w1=0.4454; ◆, w1=0.4770; —, calculated values.

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Figure 3. Electrical conductivity for NH3-NaSCN solutions, for several ammonia mass fractions (w1). Experimental values: ▲, w1=0.3550; ●, w1=0.4013; ■, w1=0.4691; ◆, w1=0.5060; —, calculated values.

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Figure 4. Electrical conductivity for H2O-LiBr solutions, for several lithium bromide mass fractions (w2). Experimental values: ▲, w2=0.6000; ●, w2=0.5503; ■, w2=0.4997; ◆, w2=0.4500; ★, w2=0.4003; —, calculated values.

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Fig.5 Variations of electrical conductivity and density as a function of ammonia mass fraction for ammonia-lithium nitrate mixture.

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(a)

(b)

(c) Fig. 6 Refrigerant concentration as a function of electrical conductivity and temperature; (a) NH3-LiNO3 solution; (b) NH3-NaSCN solution; (c) H2O-LiBr solution 20

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Table 1. Experimental Electrical conductivity κ (mS·cm-1) for NH3-LiNO3 solutions, For Several Temperatures T (K) and Ammonia Mass Fractions (w1) T (K) w1=0.3538 293.1 295.0 297.0 299.0 301.1 303.1 305.1 307.0 309.1 311.1 313.1 315.1 317.0 319.0 321.1 323.1 325.2 327.1 329.1 331.1 333.1 w1=0.3731 292.8 295.0 297.1 299.1 300.9 303.0 305.0 306.9 309.0 311.1 313.0 315.1 317.1 319.0 321.1 323.0

κ (mS·cm-1) 19.14 20.67 22.11 23.85 25.53 27.27 29.10 30.75 32.91 34.89 36.99 39.12 41.19 43.44 45.93 48.21 50.70 53.40 55.86 58.56 61.17 21.90 23.91 25.71 27.48 29.07 31.14 33.27 34.98 37.35 39.00 41.55 44.10 46.50 48.60 51.42 53.76

T (K) w1=0.4361 293.1 295.0 297.1 299.1 301.1 303.1 305.1 307.1 309.1 311.1 313.1 315.1 317.1 319.1 321.1 323.1 325.1 327.2 329.1 331.1 333.1 w1=0.4454 293.0 295.0 297.0 299.1 301.1 303.0 305.0 307.0 308.9 311.1 313.1 315.1 317.1 319.0 321.0 323.0

κ (mS·cm-1) 35.70 37.80 40.26 42.69 45.12 47.64 50.13 53.07 55.74 58.65 61.38 64.38 67.08 70.32 73.29 76.44 79.56 82.68 85.89 89.10 92.19 38.13 40.62 43.08 45.48 48.15 50.88 53.70 56.31 58.62 62.07 65.19 68.16 70.98 74.01 76.98 80.58

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325.1 327.1 329.1 331.1 333.1 w1=0.3900 293.1 295.1 297.0 299.2 301.1 303.2 305.1 307.1 309.1 311.1 313.1 315.1 317.1 319.1 321.0 323.1 325.0 327.1 329.1 331.1 333.1 w1=0.4087 293.2 295.1 297.1 299.1 301.1 303.1 305.0 307.1 309.1 311.1 313.1 315.1 317.2 319.1 321.1

56.67 59.31 61.98 64.74 67.32 25.26 26.94 28.68 30.87 32.67 34.95 37.08 39.24 41.47 43.86 46.23 48.57 51.18 53.67 56.13 58.92 61.53 64.62 67.50 70.32 72.93 29.04 30.90 32.79 35.01 37.20 39.45 41.46 44.13 46.53 48.96 51.33 54.33 57.03 59.52 62.52

325.0 327.0 329.0 331.0 332.8 w1=0.4555 293.1 295.1 297.0 299.0 301.0 303.1 305.1 307.1 309.0 311.1 313.0 315.0 317.0 319.0 321.0 323.0 325.1 327.1 329.1 331.0 333.0 w1=0.4770 295.3 298.0 299.3 301.4 303.3 305.2 307.1 309.0 310.9 313.2 315.3 317.2 319.1 321.0 323.1

83.58 86.82 89.76 93.27 95.82 41.73 44.16 46.62 49.29 51.99 54.96 57.81 60.63 63.57 66.63 69.60 72.60 75.81 78.78 82.17 85.38 88.80 92.04 95.43 98.85 102.1 49.44 55.86 58.29 60.78 63.68 66.48 69.39 72.57 75.60 79.44 82.68 85.74 88.62 92.85 96.48

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323.2 325.2 327.2 329.1 331.1 333.2 w1=0.4236 293.1 295.1 297.1 299.1 301.1 303.2 305.1 307.1 309.0 311.1 313.2 315.1 317.6 319.1 321.1 323.2 325.1 327.2 329.2 331.0 333.1

65.43 68.31 71.34 74.19 77.13 80.40

325.1 327.2 329.1 331.0 333.0

99.36 103.4 106.8 110.2 113.7

32.73 34.74 36.84 38.94 41.31 43.98 46.47 49.05 51.15 54.42 57.18 59.91 62.67 65.64 68.40 71.70 74.61 77.82 80.91 83.52 87.18

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Table 2. Experimental Electrical conductivity κ (mS·cm-1) for NH3-NaSCN solutions, For Several Temperatures T (K) and Ammonia Mass Fractions (w1) T (K)

κ (mS·cm-1)

w1=0.3550 299.4 301.4 303.4 305.3 307.2 309.1 311.2 313.2 315.3 317.1 319.2 321.2 323.2 325.2 327.2 329.2 331.1 333.0

76.87 82.88 89.60 95.08 101.1 106.5 111.4 117.0 122.3 128.0 132.9 138.2 143.8 148.8 156.0 162.2 167.0 172.2

w1=0.3786 298.9 301.2 303.2 305.1 307.1 309.2 311.2 313.2 315.2 317.3 319.1 321.0 323.0 325.0 326.9 329.0

99.24 104.1 109.6 115.0 121.1 126.6 132.0 137.7 142.8 148.6 154.2 159.3 164.9 170.6 176.3 181.1

T (K) w1=0.4461 297.6 299.5 301.5 303.5 305.5 307.5 309.5 311.6 313.5 315.5 317.5 319.5 321.5 323.6 325.5 327.4 329.3 331.3 333.1 w1=0.4691 299.2 301.1 303.1 305.1 307.1 309.1 311.0 313.1 315.0 317.1 319.0 321.0 323.0 324.9 327.0 329.1

κ (mS·cm-1) 155.3 160.4 165.2 170.3 176.5 182.6 187.8 192.8 197.9 203.2 208.5 214.5 219.9 226.3 231.1 235.7 240.4 244.6 249.2 185.5 191.2 196.3 202.2 207.0 212.8 218.5 224.3 228.8 234.5 239.8 245.0 250.4 255.2 259.2 264.2

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330.9 332.8 w1=0.4013 298.9 301.6 303.5 305.4 307.3 309.1 311.1 313.2 315.1 317.0 318.8 320.8 322.8 324.9 326.8 329.0 330.7 332.7 w1=0.4256 298.3 301.1 303.1 304.9 307.1 309.1 311.0 313.0 315.0 316.9 319.1 321.0 323.0 324.9 326.9 329.0 330.8 333.4

186.6 191.7

330.9 332.8 w1=0.4873 298.2 299.3 301.3 303.1 305.2 307.2 309.2 311.1 313.2 315.2 317.3 319.2 321.1 323.2 325.2 327.1 329.1 331.2 333.1 w1=0.5060 299.4 301.3 303.3 305.3 307.3 309.3 311.4 313.3 315.2 317.4 319.4 321.3 323.2 325.3 327.2 329.3 331.3 333.2

116.0 121.6 127.3 132.3 137.9 142.9 148.6 154.0 159.7 165.6 170.9 176.6 182.3 188.4 193.5 198.3 202.8 208.2

133.1 140.8 145.9 152.1 158.0 163.3 168.7 174.0 179.1 184.2 189.7 195.1 199.8 205.5 211.1 216.5 222.0 226.4

268.9 273.5 198.9 202.1 207.5 212.9 218.2 223.4 228.7 233.8 239.0 244.1 249.3 254.3 259.6 264.7 269.5 274.3 279.6 285.1 290.9 226.0 231.3 236.6 241.7 247.0 252.3 257.6 263.0 268.7 274.0 279.0 285.0 290.2 295.4 300.3 305.4 310.1 315.3

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Table 3. Experimental Electrical conductivity κ (mS·cm-1) for H2O-LiBr solutions, For Several Temperatures T (K) and Lithium bromide Mass Fractions (w2) T (K) w2= 0.4003 297.7 298.5 300.8 302.7 304.7 306.9 308.7 310.8 313.0 314.9 317.0 319.0 320.7 322.8 325.0 326.8 329.0 331.0 333.0 w2= 0.4500 294.0 296.8 298.6 300.8 303.0 304.9 306.9 308.8 311.0 312.9 314.8 316.8 318.7 320.7 322.6 324.9

κ (mS·cm-1) 192.5 195.6 202.7 209.4 216.4 223.1 230.1 237.3 244.0 251.1 258.1 265.0 272.0 279.4 286.5 294.0 301.0 307.1 313.0 169.2 177.0 183.4 190.0 196.4 202.9 209.1 215.0 221.0 227.6 234.9 241.5 248.1 256.4 263.5 271.1

T (K) w2= 0.5503 296.3 299.5 301.4 303.3 305.2 307.2 309.1 311.5 313.1 315.3 317.4 319.2 321.3 323.2 325.1 327.3 329.4 331.2 333.4 w2= 0.6000 303.6 305.5 307.4 309.3 311.3 313.2 315.3 317.4 319.3 321.2 323.3 325.3 327.3 329.5 331.3 333.3

κ (mS·cm-1) 129.4 137.6 142.9 148.2 153.4 159.7 165.1 170.8 176.3 182.1 188.1 194.0 200.2 206.3 212.7 218.7 225.1 231.0 237.1 116.5 121.3 126.3 131.4 136.5 141.6 146.8 152.2 157.5 163.2 169.2 175.0 182.4 187.9 193.1 198.1

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327.0 329.2 331.3 332.8 w2= 0.4997 297.3 299.4 301.5 303.4 305.4 307.4 309.4 311.2 312.8 314.8 317.0 319.5 321.3 323.4 325.5 327.3 329.5 331.2 333.6

278.1 285.6 293.6 301.8 163.2 169.3 175.4 181.7 188.1 194.5 200.8 207.3 213.2 219.5 225.6 233.9 240.3 246.8 253.5 260.5 266.0 272.3 278.9

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Table 4. Coefficients of Equation 4 for electrical conductivity of NH3-LiNO3 solutions coefficient

value

coefficient

value

a0 a1 a2 b0 b1 b2

3.571·103 -2.222·101 3.460·10-2 4.961·103 -3.084·101 4.790·10-2

c0 c1 c2 d0 d1 d2

-1.197·104 7.433·101 -1.155·10-1 7.196·103 -4.471·101 6.950·10-2

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Table 5. Coefficients of Equation 4 for electrical conductivity of NH3-NaSCN solutions coefficient

value

coefficient

value

a0 a1 a2 b0 b1 b2

-7.565·103 4.770·101 -7.520·10-2 -1.264·104 7.933·101 -1.246·10-1

c0 c1 c2 d0 d1 d2

2.757·104 -1.736·102 2.732·10-1 -1.588·104 1.001·102 -1.577·10-1

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Table 6. Coefficients of Equation 4 for electrical conductivity of H2O-LiBr solutions coefficient

value

coefficient

value

a0 a1 a2 b0 b1 b2

1.047·103 -7.091·100 1.190·10-2 1.942·103 -1.345·101 2.290·10-2

c0 c1 c2 d0 d1 d2

-4.098·103 2.794·101 -4.710·102 2.277·103 -1.545·101 2.600·10-2

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Table 7. Coefficients for Eq. 5. Coefficients NH3-LiNO3 NH3-NaSCN H2O-LiBr a0 -44207.7 105996.3 -71674.9 a1 324.1258 -198.566 620.9895 a2 -0.58886 -0.36503 -1.3419 a3 250.9868 -342.572 -286.6 a4 0.354813 -0.41854 -0.1931 a5 -0.47015 1.443356 1.21821 b0 -99915.1 122187.3 -157502 b1 688.5363 36.67081 1419.224 b2 -1.15154 -0.83547 -3.15971 b3 179.004 -580.907 -779.778 b4 0.204459 -0.4056 -0.60294 b5 0.109856 1.7556 3.322487 Application range 293K
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