## 1 Introduction  
Hydrofluoroolefins (HFOs) are a class of synthetic refrigerants that are derived from propane. Due to their chemical structure, they are chemically unstable once released in the atmosphere; therefore, they rapidly decompose, lowering their global warming impact. In addition, since they are not made by chlorine, they do not contribute to the ozone layer depletion, having a null ozone depletion potential (ODP). Among the first published works related to HFOs, [PERSON] et al. [1] presented critical temperatures, critical pressures, critical densities, acentric factors, and ideal gas specific heats for eight fluorinated olefins: R225 ye(E), R225 ye(Z), R1225 zc, R1234 ye(E), R1234 yf, R1234 ze(E), R1234 ze(Z), andR1243. Thermodynamic properties for these refrigerants were also estimated with the Peng-Robinson equation of state. Later on, numerous studies have followed, measuring the thermodynamic and transport properties of R1234 ze(E). [PERSON] and [PERSON] [2] proposed an equation of state for the calculation of thermodynamic properties of R1234 ze(E). Correlations for the estimation of R1234 ze(E) liquid and vapor viscosities were validated by [PERSON] and [PERSON] [3], of thermal conductivity by [PERSON] and [PERSON] [4], and of surface tension by [PERSON] and [PERSON] [5]. All of the aforementioned models are implemented in REFPROP 10 [6] for the estimation of R1234 ze(E) properties. R1234 ze(E) is, among the proposed HFOs, one of the possible alternatives to R134a for medium/high temperature systems. Its major benefit, compared to R134a, is its extremely low global warming potential (GWP), which is below than 1, as stated by [PERSON] et al. [7]. Considering works related to R1234 ze(E) two-phase heat transfer inside tubes, one of the first experimental studies was conducted by [PERSON] et al. [8]. They studied R1234 ze(E)condensation heat transfer inside a multiport tube with a hydraulic diameter of 1.45 mm, for mass velocity from 50 to 260 kg m\({}^{-2}\) s\({}^{-1}\), at saturation temperature from 30 \({}^{\circ}\)C to 70 \({}^{\circ}\)C. The condensation heat transfer coefficient showed a decrease as vapor quality decreased, as mass velocity decreased and as saturation temperature increased. The heat transfer performance of R1234 ze(E) was about 15-25% lower than that of R134a and similar to that of R245 fa under the same working conditions. [PERSON] et al. [9] investigated the local heat transfer coefficient of R1234 ze(E) during condensation inside a single minichannel with a hydraulic diameter of 0.96 mm. Mass velocity was varied from 100 to 800 kg m\({}^{-2}\) s\({}^{-1}\), at saturation temperature between 38.6 \({}^{\circ}\)C and 40.9 \({}^{\circ}\)C. The condensation heat transfer coefficients for R1234 ze(E) resulted lower than those for R32, comparable to those for R134a and higher than those for R1234 yf, under the same saturation temperature and mass flux. The frictional pressure drops of R1234 ze(E) resulted higher than those of R134a and R1234 yf under the same working conditions. R1234 ze(E) condensation inside minichannels was also studied by [PERSON] et al. [10], whose minichannels had circular and squared section with hydraulic diameter of 1.085 mm and 0.952 mm, respectively. The saturation temperatures were 40 \({}^{\circ}\)C and 50 \({}^{\circ}\)C, mass velocities were from 200 to 800 kg m\({}^{-2}\) s\({}^{-1}\). The comparison against propane and R22 revealed that both the heat transfer coefficients and pressure drops of R1234 ze(E) were in between the other two fluids. Other experimental research aimed at studying condensation of R1234 ze(E) inside tubes can be found in [11; 12; 13]. Among the first works which studied flow boiling of R1234 ze(E), [PERSON] et al.