A Study on the Combined Driven Refrigeration Cycle Using Ejector

2021 ◽  
pp. 2150004
Author(s):  
Waseem Raza ◽  
Gwang Soo Ko ◽  
Youn Cheol Park
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Primary Source ◽  
Mechanical Efficiency ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Working Fluid ◽  
Low Grade ◽  
Refrigeration Cycle ◽  
R 134A

The rising need for thermal comfort has resulted in a rapid increase in refrigeration systems’ usage and, subsequently, the need for electricity for air-conditioning systems. The ejector system can be driven by a free or affordable low-temperature heat source such as waste heat as the primary source of energy instead of electricity. Heat-driven ejector refrigeration systems become a promising solution for reducing energy consumption to conventional compressor-based refrigeration technologies. An air-conditioning system that uses the ejector achieves better performance in terms of energy-saving. This paper presents a study on the combined driven refrigeration cycle based on ejectors to maximize cycle performance. The experimental setup is designed to determine the coefficient of performance (COP) with ejector nozzle sizes 1.8, 3.6, and 5.4[Formula: see text]mm, respectively. In this system, the R-134a refrigerant is considered as a working fluid. The results depict that the efficiency is higher than that of the conventional refrigeration method due to comparing the performance of the conventional refrigeration cycle and the combined driven refrigeration cycle. The modified cycle efficiency is better than the vapor compression cycle below 0∘C, which implies sustainability at low temperatures by using low-grade thermal energy. For the improvement of mechanical efficiency, proposed cycle can be easily used.

scholarly journals Investigation on the improvement of car air conditioning system performance using an ejector

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq
Keyword(s):  
System Performance ◽  
Test Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Compressor Work ◽  
R 134A

The purpose of this research is to know the improvement of car air conditioner system performance using an ejector. The study was conducted on a car engine with power 100 PS (74 kW) @ 5000 rpm. The test procedure is carried out under two conditions: the normal refrigeration cycle mode and the refrigeration cycle mode with the ejector. The working fluid used in the refrigeration cycle is R-134a. Performance data was measured on engine revolutions ranging from 1500 - 3000 rpm. Finally, the results showed that ejector usage on AC system generates an increase in the refrigeration effect and coefficient of performance (COP) of 25% and 22%, respectively. This has implications to better cooling capacity and compressor work that is lighter.

Instrumented Air Conditioning Bench Experimental Apparatus

2003 ◽  
Author(s):  
Amanie N. Abdelmessih ◽  
Dan Dye ◽  
Greg Holtcamp ◽  
Chet Doughty ◽  
Eric Heitzmannp ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Engineering Students ◽  
Working Fluid ◽  
Thermal Engineering ◽  
Refrigeration Cycle ◽  
Data Logging ◽  
Laboratory Equipment ◽  
Experimental Apparatus ◽  
Fluid Properties ◽  
R 134A

The Senior Mechanical Engineering students at Saint Martin’s College designed and built a unique, safe air conditioning/refrigeration bench experimentation apparatus. The apparatus is currently used as laboratory equipment to support instruction in four thermal engineering courses. This system demonstrates the fundamentals of the refrigeration cycle and psychrometric properties of air, as well as some fundamental concepts in heat transfer, heat exchangers, and thermodynamics. The refrigeration cycle working fluid is R-134a. The cycle operates with pressures between 760 kPa and 210 kPa, and with temperatures between 44 °C and −7 °C with flow rate of 6.8 kg/h. The apparatus is equipped with an instrumentation package to monitor the psychrometric properties of the effected air inside the ductwork. In addition the instrumentation package contains instrumentation to monitor the working fluid properties via computerized data logging equipment. Technical details about the uniqueness of this design and operation are given in the article.

scholarly journals A Comprehensive Energy and Exergoeconomic Analysis of a Novel Transcritical Refrigeration Cycle

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 758
Author(s):  
Bourhan Tashtoush ◽  
Karima Megdouli ◽  
Mouna Elakhdar ◽  
Ezzedine Nehdi ◽  
Lakdar Kairouani
Keyword(s):  
Waste Heat ◽  
Fortran Program ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Governing Equations ◽  
Working Pressure ◽  
Destruction Rate ◽  
Comprehensive Comparison ◽  
Exergoeconomic Analysis

A comprehensive energy and exergoeconomic analysis of a novel transcritical refrigeration cycle (NTRC) is presented. A second ejector is introduced into the conventional refrigeration system for the utilization of the gas-cooler waste heat. The thermodynamic properties of the working fluid are estimated by the database of REFPROP 9, and a FORTRAN program is used to solve the system governing equations. Exergy, energy, and exergoeconomic analyses of the two cycles are carried out to predict the exergetic destruction rate and efficiency of the systems. The optimum gas cooler working pressure will be determined for both cycles. A comprehensive comparison is made between the obtained results of the conventional and the new cycles. An enhancement of approximately 30% in the coefficient of performance (COP) of the new cycle was found in comparison to the value of the conventional cycle. In addition, the results of the analysis indicated a reduction in the overall exergy destruction rate and the total cost of the final product by 22.25% and 6%, respectively. The final product cost of the proposed NTRC was found to be 6% less than that of the conventional ejector refrigeration cycle (CERC), whereas the optimum value of the gas cooler pressure was 10.8 MPa, and 11.4 MPa for the NTRC and CERC, respectively.

Performance investigation of a solar-driven ejector refrigeration cycle

2019 ◽  
Vol 16 (5) ◽  
pp. 625-635
Author(s):  
B. Saleh ◽  
Ayman A. Aly ◽  
M. Alsehli ◽  
M.M. Bassuoni ◽  
A. Elfasakhany
Keyword(s):  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Entrainment Ratio ◽  
Working Fluids ◽  
Content Type ◽  
Condenser Temperature ◽  
Working Parameters

Purpose This paper aims to investigate the performance and working fluids screening for an ejector refrigeration cycle (ERC) activated by solar energy. Several common and new hydrofluorocarbons, hydrocarbons, hydrofluoroolefins and hydrofluoroethers are proposed as refrigerants for the ERC to determine the most appropriate one. Design/methodology/approach The ejector performance is characterized by the ejector area ratio (EAR) and entrainment ratio (ω), while the cycle performance is described by the coefficient of performance (COP). The influences of many working parameters like the evaporator, condenser and generator temperatures on the ejector and cycle performances are investigated for all candidates as well. Findings The results indicate that the best ejector and cycle performances are attained with the highest critical temperature dry refrigerant, i.e. R601 under all studied working conditions. From the perspective of energy efficiency and environmental issues, R601 can be considered the most appropriate working fluid amongst all candidates. However, extra attention should be considered against its flammability. The maximum COP, the corresponding ω and the necessary EAR using R601 are 0.743, 1.02 and 15.5, respectively, with 25 ºC condenser temperature and the typical values for the rest operating conditions. Originality/value Many common and new hydrofluorocarbons, hydrocarbons, hydrofluoroolefins and hydrofluoroethers are suggested as working fluids for the ERC to determine the most appropriate one. The mixing process inside the ejector constant-area section is assumed constant-pressure process.

Analysis of a Reheat Carbon Dioxide Transcritical Power Cycle Using a Low Temperature Heat Source

2011 ◽  
Author(s):  
Hanfei Tuo
Keyword(s):  
Heat Source ◽  
Thermal Efficiency ◽  
Waste Heat ◽  
Cycle Performance ◽  
Working Fluid ◽  
Low Grade ◽  
Work Output ◽  
Environment Impact ◽  
Two Stage ◽  
Power Cycle

The CO2 transcritical Rankine power cycle has been widely investigated recently, because of its better temperature glide matching between sensible heat source and working fluid in vapor generator, and its desirable qualities, such as moderate critical point, little environment impact and low cost. A reheat CO2 transcritical power cycle with two stage expansion is presented to improve baseline cycle performance in this paper. Energy and exergy analysis are carried out to investigate parametric effects on cycle performance. The main results show that reheat cycle performance is sensitive to the medium pressures and the optimum pressures exist for maximizing net work output and thermal efficiency, respectively. Reheat cycle is compared to baseline cycle under the same conditions. More significant improvements by reheat are obtained at lower turbine inlet temperatures and/or larger high cycle pressure. Work output improvement is much higher than thermal efficiency improvement, because extra waste heat is required to reheat CO2. Based on second law analysis, exergy efficiency of reheat cycle is also higher than that of baseline cycle, because more useful work is converted from waste heat. Reheat with two stage expansion has great potential to improve thermal efficiency and especially net work output of a CO2 transcritical power cycle using a low-grade heat source.

Thermodynamic modelling of a single-effect LiBr-H2O absorption refrigeration cycle

2005 ◽  
Vol 219 (3) ◽  
pp. 261-273 ◽  
Author(s):  
M A Mehrabian ◽  
A E Shahbeik
Keyword(s):  
Computer Program ◽  
Cooling Water ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Design Parameters ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Chilled Water ◽  
Single Effect

The objective of this paper is to develop a computer program for design and thermodynamic analysis of a single effect absorption chiller using LiBr-H2O solution as working fluid. The conditions of hot water entering and leaving the desorber, cooling water entering the absorber and leaving the condenser, chilled water entering and leaving the evaporator, as well as the approach temperatures in condenser, evaporator, desorber, and absorber, the effectiveness of solution heat exchanger, the chiller refrigeration power, and the ambient temperature are used as input data. The program then gives the thermodynamic properties of all state points, the design information of all heat exchangers in the cycle and the overall cycle performance. The results deduced from the computer program are used to study the effect of design parameters on cycle performance. For example, increasing the evaporator and generator temperatures or decreasing the condenser and desorber temperatures can improve the second-law efficiency of the cycle. It is also noticed that the temperatures of hot water, cooling water, and chilled water, respectively, at the inlet of the desorber, condenser, and evaporator have a great effect on cycle coefficient of performance. The results of this program can be used either for sizing a new refrigeration cycle or rating an existing system. It can also be used for optimization purposes. The predictions of the present program are compared with other simulating programs and qualitative agreement is achieved.

Performance of Ejector Refrigeration Cycle for Automotive Air Conditioning

2016 ◽  
Vol 819 ◽  
pp. 202-206
Author(s):  
Reza Maziar ◽  
Kasni Sumeru ◽  
M.Y. Senawi ◽  
Farid Nasir Ani
Keyword(s):  
Compression Ratio ◽  
Air Conditioning ◽  
The Other ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Entrainment Ratio ◽  
Automotive Air Conditioning ◽  
Average Improvement

In this study, two experiments were performed, one with the conventional compression refrigeration cycle (CRC) and the other with an ejector refrigeration cycle (ERC). The CRC system for automotive air conditioning was designed, fabricated and experiments were conducted. The system was then retrofitted with an ejector as the expansion device and experiments were repeated for the ERC system. Calculations of the entrainment ratio, compressor compression ratio and coefficient of performance (COP) were made for each cycle. The calculations showed that ERC has some advantages over the CRC. In this study, an average improvement of 5% in COP has been obtained for the ERC compared with the CRC.

A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

2021 ◽  
pp. 1-38
Author(s):  
Noman Yousuf ◽  
Timothy Anderson ◽  
Roy Nates
Keyword(s):  
Waste Heat ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Factors Affecting ◽  
Thermally Driven ◽  
Mass Flowrate ◽  
Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

Design and Analysis of a High Power Density, Low Temperature Waste Heat Recovery System Using an Oil-Free Turboalternator

2010 ◽  
Author(s):  
James F. Walton ◽  
Andrew Hunsberger ◽  
Hooshang Heshmat
Keyword(s):  
Output Power ◽  
Waste Heat ◽  
Maximum Output Power ◽  
Output Power Level ◽  
Working Fluid ◽  
Prototype System ◽  
Low Grade ◽  
Maximum Output ◽  
Test Results ◽  
Study Results

In this paper the authors will present the design and preliminary test results for a distributed electric generating system that uses renewable energy source for economical load-following and peak-shaving capability in an oil-free, high-speed micro-turboalternator system using compliant foil bearings and a permanent magnet alternator. Test results achieved with the prototype system operating to full speed and under power generating mode will be presented. A comparison between predicted and measured electrical output will also be presented up to a power generating level of 25 kWe at approximately 55,000 rpm. The excellent correlation between design and test provides the basis for scale up to larger power levels. Based upon the turboalternator test results a thermodynamic cycle analysis of a system using low grade waste heat water at approximately 100 C will be reviewed. The tradeoff study results for a series of environmentally friendly refrigerant working fluids will also be presented including sensitivity to vaporization and condensing temperatures. Based on the cycle and pinch point analyses predicted maximum output power was determined. Finally a preliminary turbine design for the selected R134a working fluid was completed. The results of this study show that a net output power level of greater than 40 kW is possible for approximately 240 l/m flow of water at 100C is possible.

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