Condensation heat transfer and pressure drop characteristics of R134a, R1234ze(E), R245fa and R1233zd(E) in a plate heat exchanger

Zhang, J.; Kærn, Martin Ryhl; Ommen, Torben Schmidt; Elmegaard, Brian; Haglind, Fredrik

doi:10.1016/j.ijheatmasstransfer.2018.08.124

Cited by 70 publications

(38 citation statements)

References 40 publications

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“…The more active turbulent can be connected to the higher heat transfer performance. The same approach in analysis of effect of vapor quality and mass flux can be found in Zhang et al [28], Goss Jr and Passos [29]. 𝜌 l and 𝜌 g are liquid and gas density, respectively.…”

Section: Condensation Heat Transfer In Two-stream Pfhe 41 Analysis Methodologymentioning

confidence: 95%

Effects of Experimental Parameters on Condensation Heat Transfer in Plate Fin Heat Exchanger

et al. 2021

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This study aims to provide an experimental investigation and comparison of the condensation heat transfer characteristics in a plate–fin heat exchanger (PFHE). The heat flux, mass flux, and saturation pressure were adjusted as experimental parameters to verify the effects on the condensation heat transfer. In addition, condensation heat transfer correlation of two-stream PFHEs was provided based on the experimental data for utilization as a design reference for the heat exchanger. The turbulence is the most influential in heat transfer. One of the ways to foster turbulence is to increase shear stress. The higher flow velocity results in the higher shear stress. That was why increasing mass flux or the flow with higher vapor quality showed the higher heat transfer coefficient (HTC). Refrigerant properties such as viscosity and specific volume of vapor changed according to the saturation pressure. It is expected they affect the degree of turbulence too in similar manners. The mass flux was more influential than the heat flux and saturation pressure. Thus, the equivalent mass flux of the refrigerant is dominant in the derived correlation model. The average difference between experimental and calculated HTC from correlations was about 6.5%. Multi-stream PFHE comprises an additional heat transfer surface, which implies a more active droplet formation. The average pressure drop in the multi-stream is 15% larger than that of the two-stream.

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Section: Condensation Heat Transfer In Two-stream Pfhe 41 Analysis Methodologymentioning

confidence: 95%

Effects of Experimental Parameters on Condensation Heat Transfer in Plate Fin Heat Exchanger

et al. 2021

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“…where T 13 , T 14 , T 15 , T 16 represent the corresponding temperature of cooling water during the condensation process of the working fluid, T 3 represents the condensing temperature. The actual process of working fluid being pumped into the evaporator is 5-6 and the isentropic compression process is 5-6 s. The pump power is calculated by Equation (17).…”

Section: Thermodynamic Analysis Methodsmentioning

confidence: 99%

“…Numerous scholars have studied the boiling heat transfer mechanism of heat exchangers, [16][17][18][19][20] which provides the foundations of improving the system performance. Lee et al 21 carried out the experiments in the brazed plate evaporator, and the heat transfer coefficient and pressure drop were measured.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the characteristics of heat exchangers based on organic Rankine cycle system under different operating conditions

Meng

Lian

et al. 2021

Int J Energy Res

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Heat exchangers are crucial equipment, and the research related to organic Rankine cycle system is also of paramount importance. Experiments were carried out in a self-built test rig with the radial inflow turbine as the expander under three operating conditions. By analyzing UA values, the heat transfer area in different stages of evaporation or condensation was roughly calculated, so as to understand the operation performance of heat exchangers and its influence on system. Experimental results show that the heat transfer area in gas-phase region accounts for a great proportion of evaporator at the beginning with the rising flow rate of R245fa, and finally insufficient heat transfer area is preferentially provided for the preheating and superheating sections. The turning point occurs when the flow rate of R245fa is 800 kg/h, where the distribution of heat transfer area is relatively balanced with optimum system performance. Excessive heat transfer oil flow rate also results in disequilibrium distribution of heat transfer area in the evaporation process. Meanwhile, the optimal flow rate of heat transfer oil is 4 m 3 /h with maximum thermal efficiencies. Besides, through the comparative analysis of the UA values, the stability of the condenser in the ORC system is better than that of the evaporator under different operating conditions. Highlights 1. The characteristics of the heat exchangers based on ORC system are investigated.2. The distribution of heat transfer area in each stage of evaporation is analyzed.3. The stability of the condenser is better than that of evaporator in experiments.4. The performance of the system is optimal under suitable operating conditions.

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“…This led, for the case of propane, to have a dominant effect of gravity pressure recovery. However, it is again stressed that the conclusion on the dominating effect of gravity pressure recovery is strictly related to the chosen prediction method for frictional pressure drop, and using correlations recently published by Tao & Ferreira (2019) or Zhang et al (2019) could lead to opposite results. However, Mancini et al (2019) showed that the influence of condenser pressure drop is not relevant for the heat pump COP of the same case study and fluids considered in the present paper.…”

Section: Economic Analysismentioning

confidence: 99%

Performance of heat pumps using pure and mixed refrigerants with maldistribution effects in plate heat exchanger evaporators

Mancini

Zühlsdorf

Aute

et al. 2019

International Journal of Refrigeration

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This paper presents a combined plate heat exchanger (PHE) -heat pump simulation framework for the evaluation of flow maldistribution in PHE evaporators and its effect on the cycle thermodynamic and economic performance. A case study of heat pump integration for waste heat recovery purposes in data centres was chosen to demonstrate the utilization of the simulation tool. The analyses were made for the pure fluids butane and propane, and for the zeotropic mixtures propylene/butane at (0.5,0.5) mass composition and CO 2 /dimethyl ether (DME) (0.2,0.8) as refrigerants. Both liquid/vapour maldistribution and the effect of end plates were considered in the heat exchanger models. Results show that butane is most sensitive to maldistribution, with a maximum Coefficient of Performance (COP) reduction of 5.9 %, while propane experiences the lowest reduction of 2.5 %. The different sensitivity of the working fluids to maldistribution was found to be related to the evaporator design, refrigerant pressure drop, and fluid properties. Last, the results of the economic analysis show that a higher specific cost of heat is obtained when considering maldistribution effects.

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Condensation heat transfer and pressure drop characteristics of R134a, R1234ze(E), R245fa and R1233zd(E) in a plate heat exchanger

Cited by 70 publications

References 40 publications

Effects of Experimental Parameters on Condensation Heat Transfer in Plate Fin Heat Exchanger

Effects of Experimental Parameters on Condensation Heat Transfer in Plate Fin Heat Exchanger

Experimental investigation on the characteristics of heat exchangers based on organic Rankine cycle system under different operating conditions

Performance of heat pumps using pure and mixed refrigerants with maldistribution effects in plate heat exchanger evaporators

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