at Temperatures from 313 to 393 K and Pressures up to 10 MPa

Article pubs.acs.org/jced

Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Heat Capacity of R1234ze(E) at Temperatures from 313 to 393 K and Pressures up to 10 MPa Yu Liu, Xiaoming Zhao,* Hanwei He, and Rui Wang MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China ABSTRACT: Isobaric heat capacities of R1234ze(E) were investigated by using a modified flow calorimeter covering a temperature range from 313 to 393 K and pressures up to 10 MPa. The uncertainties in measurement of the heat capacity were estimated to be less than 0.01 at temperatures below 373 K, rising to 0.02 in the near critical region (373 and 393 K). An empirical equation was developed for correlation on the basis of the experimental data. In addition, a comparison was made between the present data and literature values.

1. INTRODUCTION European Union’s fluorine gas regulation has established a schedule to restrict the use of high Global Warming Potential (GWP) fluorinated gases.1,2 Therefore, searching for new promising substitutes is necessary. Recently, great attention has been paid to trans-1,3,3,3-tetrafluoropropene (R1234ze(E)). It has zero ozone depletion potential (ODP) and a very low GWP. In addition, thermodynamic performance of R1234ze(E) is similar to that of R134a.2,3 These advantages make it a promising alternative refrigerant. Thermophysical properties of R1234ze(E) are required in chemical-process and product design. Tanaka et al. measured the vapor pressure and PVT properties of R1234ze(E).4 Higashi et al. reported the critical parameters and saturated liquid density data near the critical point.5 Lago et al. investigated its speed of sound.6 McLinden et al. measured the PVT properties of R1234ze( E) in the temperature range from 240 to 420 K and pressures up to 15 MPa as well as its vapor pressures from 261 to 380 K.7 Qiu et al. measured the densities of R1234ze(E) in the compressed liquid phase.8 Perkins et al. studied its thermal conductivities in the liquid and vapor phases at pressures up to 23 MPa.9 Brown et al. investigated its compressed liquid densities and PVT properties in vapor phase.10 Meng et al. measured its viscosities in the temperature range from 243 to 373 K from saturation to 30 MPa by means of a vibrating-wire viscometer.11 Liquid viscosity and surface tension data were also reported by researchers.12−14 Although many papers have been published concerning its thermophysical properties, little research has been done on the heat capacities. To the author’s knowledge, only two sets of data have been published on the isobaric heat capacity of R1234ze(E) in liquid phase. Tanaka et al. measured the isobaric heat capacity of liquid R1234ze(E) covering a temperature range from 310 to 370 K and pressures up to 5 MPa.15 Gao et © XXXX American Chemical Society

al. reported heat capacity data in liquid phase at temperatures from 310.15 to 365.15 K and pressures up to 5.5 MPa.16 However, its isobaric heat capacities at pressures above 5.5 MPa have not been published yet. For this reason, isobaric heat capacities of R1234ze(E) were studied in compressed liquid and supercritical phases by using a modified flow calorimeter. The isobaric heat capacities were acquired covering a temperature range of 313 to 393 K and pressures up to 10 MPa. The uncertainties of the capacity were estimated to be less than 0.01 at temperatures below 373 K and 0.02 in the near critical region (373 and 393 K).

2. EXPERIMENTAL SECTION 2.1. Chemicals. Chemicals used in present work were provided by Zhejiang Sinoloong refrigerant Co. Ltd. The declared mass fraction purity was larger than 99.95%. No further purification was performed before the experiment. The detailed description of the chemicals is summarized in Table 1. 2.2. Experimental Method. The isobaric heat capacity can be derived by the following equation:17−19 Table 1. Sample Used in This Paper

chemical name R1234ze(E) (trans1,3,3,3tetrafluoropropene)

source Zhejiang Lantian Environment Protection Hi-Tech Co.Ltd.

initial mass fraction purity

purification method

0.9995

none

Received: August 6, 2017 Accepted: December 8, 2017

A

DOI: 10.1021/acs.jced.7b00713 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

c p,app =

Q mΔT

Article

(1)

where Q is the heat flux. m represents the mass flow rate of the sample. ΔT refers to the temperature difference of the fluid between the inlet and outlet of the calorimeter. We note that not all the energy generated by the heater is received by the sample. Although insulating materials are installed to reduce the heat loss, some of the heat still transfers to the surroundings. Then eq 1 can be rewritten, c p,app =

Q + QL QL Q = F = cp + mΔT ΔT mΔT

(2)

where cp,app is the observed heat capacity, and QL is the heat loss released from the sample to the surroundings. To determine the heat loss QL, more than four measurements are conducted with different mass flow rate under the same temperature increment and pressure. As shown in eq 2, cp can be acquired by replacing 1/m in eq 2 with zero (see Figure 1).

Figure 2. Schematic diagram of the experimental system. TB, thermostatic bath; EC, experimental cell; TS, thermometer; HC, heater; TC, high accuracy temperature controller; DMM, Keithley 2700 data acquisition system; PC, computer; PS1, and PS2, pressure sensors; MF, Siemens mass flowmeter; VP, vacuum pump; SB, sample bottle; V1−V7, needle valve; PR, pressure reducing valve; PB, back pressure valve; P, constant-flux pump.

while the voltage and the current could be obtained with a multimeter. When the fluid left the thermostatic bath, its mass flow rate (about 294−411 mg/s) was measured by a commercial mass flowmeter (SIEMENS MASS2100 DI1.5). In addition, its pressure was acquired at the same time by a pressure sensor with the uncertainty of 15 kPa (supplied by Beijing Leaf-Stone Technology & Development Co. Ltd.). The isobaric heat capacity value can be determined by measuring the temperature increase, heat flux, and mass flow rate. Regarding to the uncertainty assessment, the standard uncertainties of measured properties are listed in Table 2. Table 2. Standard Uncertainties of Measured Properties Figure 1. Relation between cp,app, cp, and 1/m, ■, cp,app; solid line, fitted curve.

In this work, the isobaric heat capacity is considered the value at the pressure P and the average temperature, T = (T1+ T2)/2. Here, T1 and T2 are temperatures of the inlet and outlet sample, respectively. 2.3. Apparatus. The detailed information about the present experimental system was described in our previous papers.20,21 Because there are many descriptions about the reliability of the experimental apparatus in our earlier work,20 we do not describe the experimental system in detail in this study. As illustrated in Figure 2, the measurement system consists of a modified flow calorimeter, a thermostatic bath, and the temperature and pressure measuring systems. Among those parts, the calorimeter is the core component, and it includes a special designed heater and two standard platinum resistance thermometers. The experimental procedures are as follows: the fluid passed through a long stainless steel tube inside the thermostatic bath so that the fluid could reach the bath temperature. When the thermal equilibrium between the sample and the bath was attained, the fluid flowed into the calorimeter and was heated by the microheater. Then, the sample temperatures in the inlet and outlet of the calorimeter were simultaneously measured by two thermometers. Note that the heater was powered by a high-precision DC power supply,

measured properties

uncertainty

temperature mass flow rate heat flux pressure isobaric heat capacity

10 mK 0.05% 0.01% 15 kPa 0.5% (at temperatures below 373 K) 1.0% (at 373−392 K)

The uncertainty of the flow rate m is 0.05%. Additionally, the uncertainties of the heat input and the temperature are less than 0.01% and 10 mK, respectively. Then, the expanded relative uncertainty can be estimated according to the following equation, ⎛ δQ ⎞2 ⎛ δT ⎞2 ⎛ δm ⎞2 ⎟ + ⎜ ⎟ Uc,c p = k ⎜ ⎟ + ⎜ ⎝ ΔT ⎠ ⎝m⎠ ⎝Q ⎠

(3)

The combined expanded uncertainty Uc,r(cp,exp) is 0.01 (0.95 level of confidence, k = 2) at temperatures below 373 K, rising to 0.02 in the near critical region (373 and 393 K).

3. RESULTS AND DISCUSSION The heat capacity data were obtained in the temperature range from 313 to 392 K with pressures from 1.0 to 10 MPa. The experimental results were listed in Table 3. As shown in Figure 3, the isobaric heat capacity of R1234ze(E) rises with B



Article

Table 3. Experimental Heat Capacity of R1234ze(E)

a

T/K

P/MPa

cp,exp/kJ·kg−1·K−1

T/K

P/MPa


313.487 313.495 313.508 313.520 313.465 313.482 313.470 313.470 313.480 313.492 313.491 313.506 313.489 313.488 313.499 313.510 313.518 313.516 313.531 323.328 323.330 323.333 323.321 323.278 323.279 323.287 323.290 323.309 323.317 323.328 323.307 323.294 323.294 323.294 323.291 323.344 323.363 333.077 333.076 333.105 333.130 333.106 333.153 333.188 333.183 333.180 333.164 333.148 333.146 333.133 333.141 333.163 333.187 333.208 333.196 343.533 343.568 343.575 343.588 343.601 343.610

1.04 1.51 2.01 2.48 3.00 3.49 3.98 4.49 5.01 5.49 6.01 6.51 6.99 7.47 7.99 8.50 8.99 9.51 10.00 1.51 2.01 2.50 3.01 3.52 4.03 4.53 4.99 5.49 6.01 6.48 7.03 7.49 8.01 8.52 9.04 9.49 10.01 1.55 2.06 2.51 3.03 3.50 4.00 4.50 4.98 5.50 6.01 6.52 7.02 7.49 8.04 8.50 9.02 9.51 10.08 2.04 2.55 3.00 3.54 4.04 4.54

1.450 1.440 1.430 1.424 1.410 1.402 1.394 1.385 1.377 1.373 1.365 1.355 1.347 1.341 1.336 1.331 1.324 1.321 1.315 1.481 1.468 1.455 1.444 1.436 1.424 1.414 1.407 1.400 1.391 1.384 1.376 1.367 1.357 1.352 1.342 1.339 1.331 1.562 1.540 1.523 1.509 1.493 1.482 1.471 1.458 1.443 1.434 1.424 1.415 1.410 1.397 1.392 1.386 1.380 1.367 1.629 1.605 1.581 1.564 1.541 1.519

343.641 343.639 343.637 343.651 343.627 343.627 343.619 353.552 353.584 353.553 353.656 353.644 353.614 353.606 353.619 353.639 353.644 353.655 353.647 353.668 353.681 353.680 353.682 363.570 363.557 363.563 363.605 363.620 363.614 363.629 363.638 363.639 363.644 363.641 363.646 363.654 363.656 363.663 373.345 373.415 373.423 373.429 373.445 373.474 373.485 373.482 373.493 373.503 373.515 373.557 373.571 373.586 391.655 392.199 392.375 392.456 392.521 392.572 392.595 392.633 392.673

7.07 7.51 8.09 8.48 9.08 9.53 10.07 2.55 3.04 3.51 4.05 4.52 5.01 5.51 6.04 6.53 7.05 7.50 7.97 8.48 9.03 9.51 10.09 3.00 3.50 4.00 4.51 4.99 5.52 6.02 6.52 6.99 7.53 8.01 8.53 9.05 9.45 9.99 3.54 4.03 4.51 5.01 5.54 6.02 6.53 7.01 7.50 8.03 8.51 9.05 9.43 9.99 4.52 5.02 5.47 6.01 6.54 7.06 7.56 8.03 8.51

1.449 1.437 1.422 1.411 1.403 1.395 1.382 1.723 1.684 1.652 1.618 1.591 1.564 1.548 1.536 1.523 1.513 1.505 1.497 1.491 1.479 1.475 1.464 1.925 1.821 1.754 1.708 1.669 1.635 1.603 1.580 1.555 1.535 1.518 1.503 1.492 1.482 1.471 2.275 2.032 1.902 1.810 1.747 1.702 1.662 1.628 1.605 1.575 1.556 1.538 1.530 1.514 4.608 2.727 2.260 1.985 1.842 1.759 1.706 1.675 1.665

C



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Table 3. continued T/K

P/MPa


T/K

P/MPa


343.623 343.621 343.640 343.642

5.04 5.51 6.05 6.59

1.506 1.488 1.477 1.461

392.717 392.767 392.769 392.753

9.07 9.52 10.01 10.00

1.649 1.653 1.644 1.640

a

Standard uncertainty u is u(T)= 10 mK, u(P)= 15 kPa, and the combined expanded uncertainty Uc,r(cp,exp) is 0.01 (0.95 level of confidence, k = 2) at temperatures below 373 K, rising to 0.02 in the near critical region (373 and 393 K).

Table 4. Parameters in Eq 4a R1234ze(E) a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 a10 AAD% MAD% no. of points

5.273404 −106.4602 −37.35996 4515.713 24.59900 384.5608 −21.92864 −2.527596 290.9454 1.335668 25.40251 0.55 1.93 117

AAD% = 100·(∑Ni=1|(cp,cal − cp,exp)/cp,exp)|)/N; MAD% = 100·MAX(| (cp,cal − cp,exp)/cp,exp)|)N.

a

Figure 3. Isobaric heat capacities of R1234ze(E) in compressed liquid and supercritical phases, ○, 313.68 K; △, 323.68 K; ▽, 333.7 K; ◁, 343.73 K; ▷, 353.75 K; ●,363.77 K; ×, 373.31 K; ■, 392.51 K; solid line, calculated from eq 4.

temperature and falls with pressure. According to Figure 3, the heat capacity value decreases slowly with pressure in the low temperature zone (at isotherms from 313 to 353 K). For instance, the heat capacity at 313 K falls from 1.394 kJ·kg−1·K−1 at 4.0 MPa to 1.315 kJ·kg−1·K−1 at 10 MPa. It is a gradual decline of about 6.0%. In the high temperature region (at temperatures higher than 353 K), the heat capacity decreases rapidly as pressure increases. For example, the isobaric heat capacity value at 363 K drops from 1.754 kJ·kg−1·K−1 at 4.0 MPa to 1.471 kJ·kg−1·K−1 at 10 MPa. That means a decrease around 19.2%. In the supercritical phase, this trend is more obvious. Along the isotherm of 392 K, a sharp decline in the heat capacity can be observed. The isobaric heat capacity goes down from 4.608 kJ·kg−1·K−1 at 4.5 MPa to 1.640 kJ·kg−1·K−1 at 10 MPa. There is a decline of 181.0%. An empirical equation was used to correlate the experimental data in the temperature range from 313 to 373 K, Mcp R

=

Figure 4. Deviations between experimental results and calculations by eq 4: ○, 313.68 K; △, 323.68 K; ▽, 333.7 K; ◁, 343.73 K; ▷, 353.75 K; ●, 363.77 K; ×, 373.31 K.

A comparison is conducted between experimental results and two sets of literature data and calculated data by McLinden et al. The results are shown in Figures 5−7. The present experimental data are close to the data by Tanaka et al. The average absolute deviation of our experimental data from the results by Tanaka et al. is 1.30%, while the maximum absolute deviation is 3.65% (see Figure 5). Figure 6 shows the comparison between the present results and data obtained by Gao et al. The AAD and MAD between the experimental data and those of Gao et al. are 1.45 and 3.88%. Figure 7 shows the deviations between the experimental results and calculated results by McLinden’s equation. It can be seen that the calculated data from McLinden et al. equation agree

a0 + a1(1 − Tr) + a 2Pr + a3(1 − Tr)2 + a4Pr 2 + a5(1 − Tr)Pr 1 + a6(1 − Tr) + a 7Pr + a8(1 − Tr)2 + a 9Pr 2 + a10(1 − Tr)Pr

(4)

where cp is the isobaric heat capacity (kJ·kg−1·K−1), Tc is the critical temperature (382.52 K), and Pc refers to the critical pressure (3.6363 MPa).7 R = 8.314 J·mol−1·K−1. M represents the molar mass (114.04 g·mol−1), Pr = P/Pc, Tr = T/Tc. a0−a10 are the dimensionless coefficients of eq 4 and can be obtained by a stepwise method; their values are shown in Table 4. The average absolute deviation (AAD) and maximum absolute deviation (MAD) of experimental results from eq 4 are 0.55 and 1.93% (see Figure 4). D



Article

Figure 5. Deviation between present experimental data and data reported by Tanaka et al.: ○, 320 K; △, 330 K; ▽, 340 K; ◁, 350 K; ▷, 360 K; ●, 370 K.

Figure 7. Deviations between experimental results and calculations by McLinden et al. equation: ○, 313.68 K; △, 323.68 K; ▽, 333.7 K; ◁, 343.73 K; ▷, 353.75 K; ●, 363.77 K; ×, 373.31 K; ■, 392.51 K.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]; Tel.: +86-29-82665445; Fax: +86-29-82668789. ORCID

Xiaoming Zhao: 0000-0003-2938-8080 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS We acknowledge the support of the National Natural Science Foundation of China (Grant 51676160) and the 111 Project (Grant B16038).

■

Figure 6. Deviation between present experimental values and data obtained by Gao et al.: ■, 315.15 K; ○, 320.15 K; △, 325.15 K; ▽, 330.15 K; ◁, 335.15 K; ▷, 340.15 K; ●, 345.15 K; ×, 350.15 K; □, 355.15 K; ▲, 360.15 K; ▼, 365.15 K.

REFERENCES

(1) European Parliament and the Council. Regulation (EU) No 517/ 2014 of the European Parliament and the Council of 16 April 2014 on fluorinated greenhouse gases and repealing Regulation (EC) No 842/ 2006. Off. J. Eur. Union 2015, 150, 195−230. (2) Mota, B. A.; Navarro, E. J.; Barragán, C. A.; Molés, F.; Peris, B. Analysis based on EU Regulation No 517/2014 of new HFC/HFO mixtures as alternatives of high GWP refrigerants in refrigeration and HVAC systems. Int. J. Refrig. 2015, 52, 21−31. (3) Mota, B. A.; Navarro, E. J.; Molés, F.; Barragán, C. A.; Peris, B.; Verdú, G. A Review of Refrigerant R1234ze(E) Recent Investigations. Appl. Therm. Eng. 2016, 95, 211−222. (4) Tanaka, K.; Takahashi, G.; Higashi, Y. Measurements of the vapor pressures and pρT properties for trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)). J. Chem. Eng. Data 2010, 55, 2169−2072. (5) Higashi, Y.; Tanaka, K.; Ichikawa, T. Critical parameters and saturated densities in the critical region for trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)). J. Chem. Eng. Data 2010, 55, 1594− 1597. (6) Lago, S.; Albo, P. A. G.; Brignolo, S. Speed of sound results in 2,3,3,3-tetrafluoropropene (R-1234yf) and trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)) in the temperature range of (260−360) K. J. Chem. Eng. Data 2011, 56, 161−163. (7) Mclinden, M. O.; Thol, M.; Lemmon, E. W. Thermodynamic properties of trans-1,3,3,3-tetrafluoropropene(R1234ze(E)): measurements of density and vapor pressure and a comprehensive equation of state. International Refrigeration and Air Conditioning Conference, Purdue University, Indiana, United States; 12−15 July 2010.

with the experimental data in the compressed liquid state. The AAD and MAD of McLinden et al. calculated results from the present values are 1.75 and 4.96%, respectively. As illustrated in Figure 7, most deviations are negative; all deviations at temperatures lower than 373.31 K (including 373.31 K) are located within 3%, and the deviations reached a maximum in the near critical region.

4. CONCLUSIONS The heat capacity measurements of R1234ze(E) were carried out using a flow calorimeter in compressed liquid and supercritical phases. A total of 130 data points were obtained from 313 to 393 K at pressures up to 10 MPa. An empirical equation was correlated to represent the experimental data with an average absolute deviation of 0.55%. In addition, the available literature values are consistent with the present data. E



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at Temperatures from 313 to 393 K and Pressures up to 10 MPa

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