Characteristics of R718 refrigeration/heat pump systems with two-phase ejectors

Šarevski, Milan N.; Šarevski, Vasko N.

doi:10.1016/j.ijrefrig.2016.07.007

Cited by 21 publications

(10 citation statements)

References 55 publications

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“…Similar to [27], the exergy efficiency for the vacuum unit system can be written as (Figure 5): After exergy transformations of Equation ( 14), taking into account formula (11), there is…”

Section: Exergy Methods For Analyzing a Vacuum Unit Based On A Liquid...mentioning

confidence: 99%

“…Recent European and world studies have been devoted to exploring the operation of two-phase jet devices on different refrigerants or carbon dioxide [6][7][8][9]. Although they have significant advantages over single-phase devices, they have been studied due to their complex working process [10,11]. The main disadvantage of two-phase jet devices is the cost of the working medium (refrigerant) and issues of safety and environmental friendliness.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

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Vapor Overproduction Condition Monitoring in a Liquid–Vapor Ejector

et al. 2022

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We consider the influence of vapor content in the mixed flow leaving a liquid-vapor ejector on the energy efficiency of a vacuum unit. As shown by numerical studies of liquid-vapor ejectors, this issue is important as vapor overproduction, which accompanies the process of secondary flow ejection, directly impacts the efficiency of the working process of both the liquid-vapor ejector and the vacuum unit as a whole. The greater the degree of vapor overproduction, the greater the load on the vapor phase of the separator, which is part of the vacuum unit. In addition, the liquid phase must be returned to the cycle to ensure the constancy of the mass flow rate of the working fluid of the primary flow. Our numerical study results revealed the rational value of the degree of vapor overproduction at which the efficiency of the liquid–vapor ejector was maximized, and the amount of additional working fluid that needed to enter the cycle of the vacuum unit was minimal. Experimental condition monitoring studies on the liquid–vapor ejector were carried out on plane-parallel transparent models with different flow path geometries. Through experimental studies, we confirmed and adjusted the values of the achievable efficiency of the working process of a liquid–vapor ejector, depending on the degree of vapor overproduction. Using a comparative analysis of liquid–vapor ejectors with different flow path geometries, differences were revealed in their working processes, which consisted of the degree of completion of the mixing of the working media of primary and secondary flows. To determine the feasibility of using liquid–vapor ejectors with different flow path geometries, exergy analysis was performed, resulting in achievable efficiency indicators.

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“…Similar to [27], the exergy efficiency for the vacuum unit system can be written as (Figure 5): After exergy transformations of Equation ( 14), taking into account formula (11), there is…”

Section: Exergy Methods For Analyzing a Vacuum Unit Based On A Liquid...mentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Vapor Overproduction Condition Monitoring in a Liquid–Vapor Ejector

et al. 2022

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“…Šarevski [60] Theoretical investigations of R718 refrigeration cycles with two-phase ejector as a compression device.…”

Section: šArevski Andmentioning

confidence: 99%

Mechanical Vapour Compression Refrigeration System: Review Part 1: Environment Challenge

Mahmood

Ali

Noor

2020

International Journal of Applied Mechanics and Engineering

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In Australia and others developed countries, concerns about global warming have increased, and these concerns influence the use of refrigerants as working fluids in mechanical vapour compression refrigeration systems. One of the most important aspects of refrigerant selection is to reduce its impact on the environment and the ozone layer. This paper provides a comprehensive review of various theoretical and experimental studies which have been carried out on air conditioning and refrigeration applications to investigate the effect of refrigerants on the environment. The analysis in this paper reveals that alternative refrigerants are the most suitable working fluids that can be used in refrigeration systems to meet the needs of the environment. This study also suggests that natural types of refrigerants such as water, carbon dioxide, and hydrocarbon will play a significant role in protecting the environment and providing alternative friendly refrigerants to be used in refrigeration and air conditioning systems.

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“…If on the contrary, the liquid is the moving agent of the vapor, then the device is simply called two-phase ejector [16][17][18].…”

Section: Two-phase Ejector Characteristicsmentioning

confidence: 99%

“…Some work was also devoted to demonstrate that it is still possible to consider using water as refrigerant. To this end, Sarevski and Sarevski [17,183] analyzed several cases of refrigeration configurations relying only on two-phase ejector to operate as water-chillers for air-conditioning and other cooling applications. Shen et al [184] proposed to replace the feed pump in supersonic ejector cooling cycle powered by solar energy to form a bi-ejector setup.…”

Section: Theoretical Studiesmentioning

confidence: 99%

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 2: Two-Phase Ejectors

et al. 2019

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Two-phase ejectors play a major role as refrigerant expansion devices in vapor compression systems and can find potential applications in many other industrial processes. As a result, they have become a focus of attention for the last few decades from the scientific community, not only for the expansion work recovery in a wide range of refrigeration and heat pump cycles but also in industrial processes as entrainment and mixing enhancement agents. This review provides relevant findings and trends, characterizing the design, operation and performance of the two-phase ejector as a component. Effects of geometry, operating conditions and the main developments in terms of theoretical and experimental approaches, rating methods and applications are discussed in detail. Ejector expansion refrigeration cycles (EERC) as well as the related theoretical and experimental research are reported. New and other relevant cycle combinations proposed in the recent literature are organized under theoretical and experimental headings by refrigerant types and/or by chronology whenever appropriate and systematically commented. This review brings out the fact that theoretical ejector and cycle studies outnumber experimental investigations and data generation. More emerging numerical studies of two-phase ejectors are a positive step, which has to be further supported by more validation work.

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Characteristics of R718 refrigeration/heat pump systems with two-phase ejectors

Cited by 21 publications

References 55 publications

Vapor Overproduction Condition Monitoring in a Liquid–Vapor Ejector

Vapor Overproduction Condition Monitoring in a Liquid–Vapor Ejector

Mechanical Vapour Compression Refrigeration System: Review Part 1: Environment Challenge

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 2: Two-Phase Ejectors

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