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.

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 Performance Evaluation of a CO2 Refrigeration System Enhanced with a Dew Point Cooler

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1079 ◽  
Author(s):  
Martin Belusko ◽  
Raymond Liddle ◽  
Alemu Alemu ◽  
Edward Halawa ◽  
Frank Bruno
Keyword(s):  
Weather Conditions ◽  
Dew Point ◽  
Coefficient Of Performance ◽  
Experimental Program ◽  
Refrigeration System ◽  
Conventional System ◽  
Ambient Temperatures ◽  
Air Temperatures ◽  
Condenser Temperature

Dew point cooling (DPC) is a novel indirect evaporative cooling concept capable of delivering air temperatures approaching the dew point. Coupling this technology with CO2 refrigeration is well suited to minimising transcritical operation when the coefficient of performance (COP) is dramatically reduced in hot climates. A substantial experimental program was conducted to characterise this combination by testing a 20 kW CO2 refrigeration system subject to ambient temperatures above 40 °C. It was demonstrated that DPC operation not only avoided transcritical operation during such weather conditions, but also increased the COP by up to 140% compared to the conventional system. The combination of these technologies was successfully mathematically modelled, from which the optimum condenser inlet air temperature was identified for each condenser temperature. Using this optimum condition, it was possible to maximise the COP for a range of conditions applicable to the psychometric chart. An annual case study for Adelaide, Australia was conducted which demonstrated that optimally coupling DPC with CO2 refrigeration can reduce the annual energy consumption and peak demand by 16% and 47%, respectively, compared to a conventional CO2 booster system. Furthermore, the number of hours of transcritical operation was reduced from 3278 to 27.

Waste-Heat Driven Miniature Absorption Refrigeration System Using Ionic-Liquid as a Working Fluid

2011 ◽  
Author(s):  
Yoon Jo Kim ◽  
Sarah Kim ◽  
Yogendra K. Joshi ◽  
Andrei G. Fedorov ◽  
Paul A. Kohl
Keyword(s):  
Ionic Liquid ◽  
Waste Heat ◽  
Coefficient Of Performance ◽  
System Level ◽  
Working Fluid ◽  
Operating Efficiency ◽  
Outlet Temperature ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Absorption Refrigeration System

An ionic-liquid (IL) is a salt in a liquid state usually with an organic cation and inorganic anion. ILs provide an alternative to the normally toxic working fluids in absorption systems, such as the ammonia/water system. They also eliminate the problems of poor temperature match, crystallization and metal-compatibility problems of the water/LiBr system. In the present study, an IL is explored the working fluid of a miniature absorption refrigeration system so as to utilize waste-heat within the system for low-cost, high-power electronics cooling. To determine performance benchmarks for the refrigerant/IL (e.g. [bmim][PF6]) pairs, system-level simulations have been carried out. An NRTL model was built and used to predict the solubility of the mixture as well as the mixture properties such as enthalpy and entropy. The properties of the refrigerants were determined using REFPROP 6.0. Saturation temperatures at the evaporator and condenser were 25°C and 50°C, respectively. Chip power was fixed at 100 W with the operating temperature set at 85°C. R32 gave the highest operating efficiency with the maximum coefficient of performance (COP) of ca. 0.55 while R134a and R152a showed comparable performance with the maximum COP of ca. 0.4 at the desorber outlet temperature of 80°C. When waste-heat is available for the system operation, R134a and R152a COPs were comparable or better than that of R32.

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 Exergetic performance analysis of low GWP alternative refrigerants for R404A in a refrigeration system

2021 ◽  
Author(s):  
Mehmet Altinkaynak
Keyword(s):  
Cooling System ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration System ◽  
Alternative Refrigerants ◽  
Condenser Temperature ◽  
Parametric Analyses ◽  
Low Global Warming Potential ◽  
Very High

Abstract According to the regulation of European Union laws in 2014, it was inevitable to switch to low global warming potential (GWP) fluids in the refrigeration systems where the R404A working fluid is currently used. The GWP of R404A is very high, and the potential for ozone depletion is zero. In this study, energetic and exergetic performance assessment of a theoretical refrigeration system was carried out for R404 refrigerant and its alternatives, comparatively. The analyses were made for R448A, R449A, R452A and R404A. The results of the analysis were presented separately in the tables and graphs. According to the results, the cooling system working with R448A exhibited the best performance with a coefficient of performance (COP) value of 2.467 within the alternatives of R404A followed by R449A and R452A, where the COP values were calculated as 2.419 and 2.313, respectively. In addition, the exergy efficiencies of the system were calculated as 20.62%, 20.22% and 19.33% for R448A, R449A and R452A, respectively. For the base calculations made for R404A, the COP of the system was estimated as 2.477, where the exergy efficiency was 20.71%. Under the same operating conditions, the total exergy destruction rates for R404A, R448A, R449A and R452A working fluids were found to be 3.201 kW, 3.217 kW, 3.298 kW and 3.488 kW, respectively. Furthermore, parametric analyses were carried out in order to investigate the effects of different system parameters such as evaporator and condenser temperature.

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 THEORETIC-EXPERIMENTAL EVALUATION OF A CASCADE REFRIGERATION SYSTEM FOR LOW TEMPERATURE APPLICATIONS USING THE PAIR R22/R404A

2012 ◽  
Vol 11 (1-2) ◽  
pp. 07
Author(s):  
J. J. Fiori ◽  
C. U. S. Lima ◽  
V. Silveira Jr
Keyword(s):  
Low Temperature ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration System ◽  
Evaporation Temperature ◽  
Optimal Value ◽  
Cascade Refrigeration System ◽  
The Difference ◽  
Cascade Refrigeration ◽  
Good Agreement

This paper presents a thermodynamic analysis of a cascade refrigeration system using the refrigerant R22 as the working fluid in the high temperature circuit (HT) and the refrigerant R404a as the working fluid in the low temperature circuit (LT). The present analysis aimed to obtain the condensing temperature of the LT that provides an optimal value for the coefficient of performance (COP) of the cycle. Parameters involved in the analysis included the evaporation temperature, the condensing temperature and the difference between the condensing temperature of the LT (TC_LT) and evaporation temperature of the HT (TE_HT) – ΔTCAS. Simulations were performed using the software EES (Engineering Equation Solver). In addition to the analysis, experimental data obtained from a prototype was compared with the simulated results which showed good agreement. The COP varies with the increase in the intermediate temperature; however this variation does not exceed 1%.

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

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