An Experimental Investigation of Steam Ejector Refrigeration Systems

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Jingming Dong ◽  
D. A. Pounds ◽  
P. Cheng ◽  
H. B. Ma
Keyword(s):  
Operating Temperature ◽  
Back Pressure ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Nozzle Throat ◽  
Steam Ejector ◽  
Mixing Chamber ◽  
Ejector System ◽  
Throat Diameter ◽  
Temperature And Pressure

A steam ejector refrigeration system with a movable primary nozzle was developed in order to determine the nozzle exit position (NXP) effect on the coefficient of performance (COP). Experimental results show that there exists an optimum NXP for the ejector system investigated herein. The effects of the operating temperature, diffuser size, nozzle throat diameter, and mixing chamber configuration on the COP and critical back pressure were investigated experimentally. It is found that the critical back pressure and COP can be increased by increasing the low temperature evaporator (LTE) temperature and pressure. Although an increase of the high temperature evaporator (HTE) temperature can increase the critical condenser pressure, the system COP does not increase as the HTE temperature increases. The diffuser size significantly affects the critical back pressure but had almost no effect on the system COP. A finned mixing chamber was tested at NXP = 0 mm and NXP = 36 mm. Compared with the regular mixing chamber, the finned mixing chamber can increase the critical back pressure.

An Experimental Investigation of Steam Ejector Refrigeration Systems

2011 ◽  
Author(s):  
J. M. Dong ◽  
D. A. Pounds ◽  
P. Cheng ◽  
H. B. Ma ◽  
X. X. Pan
Keyword(s):  
Cooling Capacity ◽  
Back Pressure ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Operation Temperature ◽  
Steam Ejector ◽  
Mixing Chamber ◽  
Flow Mechanisms ◽  
Ejector System ◽  
Temperature And Pressure

A steam ejector refrigeration system with a movable primary nozzle was developed in order to determine the nozzle exit position (NXP) effect on the coefficient of performance (COP). Experimental results show that an optimum NXP exists for the ejector system investigated herein. In addition, the effects of the operation temperature, diffuser size, nozzle throat diameter, and structure of mixing chamber on the COP and cooling capacity were conducted experimentally. It was found that the critical condenser pressure and COP can be increased by increasing the low-temperature-evaporator (LTE) temperature and pressure. Although an increase of the high-temperature-evaporator (HTE) can increase the critical condenser pressure, the system COP did not increase as the HTE temperature increased. While the diffuser size significantly affected the critical back pressure, it had almost no effect on the system COP. A finned mixing chamber was tested at NXP = 0mm and NXP = 36mm. Compared with the regular mixing chamber, the finned mixing chamber can increase the critical back pressure. The results provide a better understanding of heat transfer and fluid flow mechanisms occurring in a steam ejector refrigeration system.

scholarly journals A Steam Ejector Refrigeration System Powered by Engine Combustion Waste Heat: Part 2. Understanding the Nature of the Shock Wave Structure

2019 ◽  
Vol 9 (20) ◽  
pp. 4435 ◽  
Author(s):  
Yu Han ◽  
Xiaodong Wang ◽  
Lixin Guo ◽  
Anthony Chun Yin Yuen ◽  
Hengrui Liu ◽  
...  
Keyword(s):  
Shock Wave ◽  
Waste Heat ◽  
Wave Structure ◽  
Back Pressure ◽  
Normal Shock ◽  
Engine Fuel ◽  
Refrigeration System ◽  
Shock Wave Structure ◽  
Steam Ejector ◽  
Shock Region

In general, engine fuel combustion generates 30% waste heat, which is disposed to the environment. The use of the steam ejector refrigeration to recycle the waste heat and transfer them to useful energy source could be an environmentally friendly solution to such an issue. The steam ejector is the main component of the ejector refrigeration system, which can operate at a low-temperature range. In this article, the internal shock wave structure of the ejector is comprehensively studied through the computation fluid dynamics (CFD) approach. The shock wave structure can be subdivided into two regions: firstly the pseudo-shock region consisting of shock train and co-velocity region; secondly the oblique-shock region composed of a single normal shock and a series of oblique shocks. The effect of the shock wave structure on both pumping performance and the critical back pressure were investigated. Numerical predictions indicated that the entrainment ratio is enhanced under two conditions including (i) a longer pseudo-shock region and (ii) when the normal shock wave occurs near the outlet. Furthermore, the system is stabilized as the back pressure and its disturbance is reduced. A critical range of the primary fluid pressure is investigated such that the pumping is effectively optimized.

Numerical Simulation of Performance of Steam Ejector Influenced by the Distance between Nozzle Outlet and Mixing Chamber Inlet

2011 ◽  
Vol 299-300 ◽  
pp. 970-973
Author(s):  
Xiao Chun Dai ◽  
Guo Jin Liao
Keyword(s):  
Numerical Simulation ◽  
Geometric Parameters ◽  
Experimental Results ◽  
Nozzle Outlet ◽  
Entrainment Ratio ◽  
Optimum Range ◽  
Steam Ejector ◽  
Mixing Chamber ◽  
Throat Diameter

The performance of a steam ejector was simulated using FLUENT. The performance of steam ejector was studied by changing the distance between primary nozzle outlet and mixing chamber inlet (DPM) while operating pressures and other geometric parameters were not varied. The entrainment ratios of the steam ejector with different values of DPM were calculated. The optimum range of DPM was given, which is changed from 1.8 to 2 times of the throat diameter of hybrid diffuser pipe. The errors of the CFD results to the experimental results of the entrainment ratio are not more than 15%.

scholarly journals Exergy and Exergoeconomic Analysis of a Cogeneration Hybrid Solar Organic Rankine Cycle with Ejector

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 702
Author(s):  
Bourhan Tashtoush ◽  
Tatiana Morosuk ◽  
Jigar Chudasama
Keyword(s):  
Electrical Power ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Temperature And Pressure

Solar energy is utilized in a combined ejector refrigeration system with an organic Rankine cycle (ORC) to produce a cooling effect and generate electrical power. This study aims at increasing the utilized share of the collected solar thermal energy by inserting an ORC into the system. As the ejector refrigeration cycle reaches its maximum coefficient of performance (COP), the ORC starts working and generating electrical power. This electricity is used to run the circulating pumps and the control system, which makes the system autonomous. For the ejector refrigeration system, R134a refrigerant is selected as the working fluid for its performance characteristics and environmentally friendly nature. The COP of 0.53 was obtained for the ejector refrigeration cycle. The combined cycle of the solar ejector refrigeration and ORC is modeled in EBSILON Professional. Different parameters like generator temperature and pressure, condenser temperature and pressure, and entrainment ratio are studied, and the effect of these parameters on the cycle COP is investigated. Exergy, economic, and exergoeconomic analyses of the hybrid system are carried out to identify the thermodynamic and cost inefficiencies present in various components of the system.

scholarly journals EFEK VARIASI BEBAN PENDINGINAN TERHADAP COEFFICIENT OF PERFORMANCE (COP) MESIN PENDINGIN PADA BOX COOLER ALAT DISTILASI

2021 ◽  
Vol 8 (2) ◽  
pp. 110
Author(s):  
Ahmad Akromul Huda ◽  
Karyanik Karyanik ◽  
Earlyna Sinthia Dewi
Keyword(s):  
Capillary Tube ◽  
Engine Performance ◽  
Study Data ◽  
Office Building ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Refrigeration System ◽  
Pressure Data ◽  
Load Variations ◽  
Temperature And Pressure

Refrigerator has been widely used by the community and can be found in almost every shop, office building and household. The application of refrigeration machines can also be developed in many other equipment and machines, one of which is in the distillation apparatus. Distillation is a method of separating two substances. A distillation machine using a cooling machine in the condenser will be very helpful, especially for distillation. This study aims to determine the effect of cooling on the performance of the cooling machine. Cooling engine performance coefficient of achievement (COP). Load variations are carried out by adjusting the boiler temperature using a thermostat. In this study, data on the temperature and pressure of the refrigerant flowing in the refrigeration system were taken at four points, namely before entering the compressor, before entering the capillary tube and before entering the evaporator . In this study also used four variations of the cooling load given to the box cooler of 110 °C, 125 °C, 140 °C, and 155 °C. Then the temperature and pressure data is processed to get the COP value every time from all variations of the cooling load. The results showed that the increaseing in the cooling load, the smaller the COP value of the cooling machine. In its effect on the length of time the COP value of each variation of the cooling load increases. The highest COP value in this study was obtained at a cooling load temperature of 110 ºC of 10.69 and the lowest was obtained at a temperature of 155 ºC of 9.38.

scholarly journals Simulation and Analysis of Biogas operated Double Effect GAX Absorption Refrigeration System

2011 ◽  
pp. 14-19
Author(s):  
G. Subba Rao ◽  
Vemuri Lakshminarayana
Keyword(s):  
High Temperature ◽  
Thermodynamic Simulation ◽  
Double Effect ◽  
Coefficient Of Performance ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Basic Parameters ◽  
Temperature And Pressure ◽  
Absorption Refrigeration System ◽  
Effect Generator

A thermodynamic simulation of a double effect generator heat exchanger absorption refrigeration cycle using biogas as source of energy has been carried out. The binary mixture considered in the present investigation was NH3 – H2O (Ammonia - Water). This simulation was performed in order to investigate the effect of the temperature and pressure of the high temperature generator and the pressure of evaporator have over the Coefficient of Performance (COP) for a constant condenser and absorber temperatures. The basic parameters at various state points of the cycle was computed using standard correlations. The solution circulation rates and volume of biogas required for operation of the cycle are analysed for the variations in operating parameters at the high temperature generator and evaporator.

scholarly journals Energetic Optimization and Exergetic Performance Investigation of an Ejector System Using HCFO-1233zd(E) as a Refrigerant

2021 ◽  
Author(s):  
Aggrey Mwesigye ◽  
Amir Kiamari ◽  
Seth B. Dworkin
Keyword(s):  
Exergy Analysis ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Small Contribution ◽  
Analysis Method ◽  
Refrigeration System ◽  
Critical Mode ◽  
Mode Of Operation ◽  
Ejector System ◽  
Loss Coefficients

In this study, the performance of an ejector refrigeration system using HCFO-1233zd(E) as the working fluid is investigated and presented. A novel improved modeling approach that considers ejector loss coefficients as functions of the ejector pressure lift and area ratio has been used. The resulting mathematical model developed using the first and second laws of thermodynamics and gas dynamics is solved using Engineering Equation Solver. Different ejector geometries with area ratios of 6.44, 7.04, 7.51, 7.73, 8.28, 8.62, 9.13, 9.41 and 10.64 were used in this study. The evaporator temperatures were between 0 °C and 16 °C, the generator temperatures were between 75 °C and 120 °C and the condensing temperatures varied between 20 °C and 40 °C. For the range of parameters used, the optimal coefficient of performance (COP) is in the range 0.11 and 0.88 for evaporator temperatures between 4 °C and 16 °C. At the optimal working conditions, the COP improves with higher area ratios, lower condensing temperatures and requires increased generator temperatures. In the critical mode of operation, both the energetic and exegetic performance of the ejector are shown to decline as generator temperatures increase, evaporator temperatures reduce and as the area ratios decrease. Thermodynamic investigation using the exergy analysis method indicates that most of the exergetic losses come from the ejector (46-56%) followed by the condenser (18-29%), the generator (21-26%), the evaporator (0.8-3%), and the throttle valve (1- 1.6%), with the pump having a very small contribution. Moreover, correlations for the optimal generator and optimal COP were derived and presented. Keywords: Coefficient of performance, Critical mode, Ejector refrigeration system, Ejector loss coefficients, Exergetic performance, Hydroflouroolefins

scholarly journals Simulation of flow field in steam ejector and analysis of shock wave characteristics

2018 ◽  
Vol 198 ◽  
pp. 03001
Author(s):  
Yi Cui
Keyword(s):  
Shock Wave ◽  
Flow Field ◽  
Back Pressure ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Wave Characteristics ◽  
Steam Ejector ◽  
Two Dimensional Flow ◽  
Fluent Software ◽  
Throat Diameter

Fluent software is used to simulate the two-dimensional flow field in the steam ejector. The generation, development and end of shock in the flow field are analyzed. The influence of the shock wave characteristics on the ejector performance is discussed. The results show that the working back pressure in the steam ejector and the throat diameter of the nozzle all affect the position and intensity of the shock wave. When the shock wave ends prematurely or belatedly , it all affect the performance of the injector.

scholarly journals Performance of Commercially Open Refrigerated Showcases with and without Ice Storage—A Case Study

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 683
Author(s):  
Kai-Shing Yang ◽  
Yun-Sheng Chao ◽  
Chia-Hsing Hsieh ◽  
Min-Lun Chai ◽  
Chi-Chuan Wang
Keyword(s):  
Peak Power ◽  
Storage System ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Ice Storage ◽  
Air Cooling ◽  
Refrigeration System ◽  
Temperature And Pressure ◽  
Immersion Type

This study examines the applicability of the ice storage systems in the small commercial refrigerated showcases through experimental analysis. R-404A is used as the working fluid and various influence of parameter settings and improvements, are discussed in details. In the ice storage system, the condenser is changed from air-cooling (refrigeration mode) to an immersion type that is placed in an ice storage tank, the corresponding condensing temperature and pressure are reduced appreciably. This increased the efficiency and can effectively reduce the peak power consumption. The reduction of the condensing temperature and pressure increased the coefficient of performance (COP) from 3.6 (refrigeration mode) to 6.35 (melting mode), effectively enhancing the refrigeration efficiency. The results indicated that the ice storage system could effectively increase the coefficient of performance from 3.6 to 6.35 during ice melting when compared to the conventional refrigeration system. It also can shift approximately 35% of the power during peak hours and lower the energy cost by USD$ 17.13 per month.

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