MODELING OF A VAPOR-COMPRESSION CHILLER FOR PERFORMANCE STUDY

2013 ◽  
Vol 21 (04) ◽  
pp. 1350025
Author(s):  
MENGWEI HUANG ◽  
YE YAO
Keyword(s):  
Experimental Data ◽  
Electronic Devices ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Performance Study ◽  
The Mean ◽  
Simulation Results

A variable speed refrigeration system was designed to supply chilled liquid for cooling high-power electronic devices to maintain the temperature at an acceptable level. Fin-plate heat exchangers were adopted to save space. The paper presents the simulation of the refrigeration system to study its steady performance. The simulation model was developed by using a detailed thermodynamic model and containing a series of heat transfer correlations for specific parameters. The cooling capacity of the refrigeration system under different working conditions is investigated. The simulation results keep in agreement with experimental data. The cooling capacity increases with the rise of cooled oil inlet temperature. Besides, condenser cooling liquid inlet temperature affects the cooling capacity greatly. The cooling capacity and the coefficient of performance (COP) of the system under different motor speeds are studied subsequently. The simulation results have been validated by experiments. The mean relative error of the cooling capacity and the COP between simulation results and experimental data is 12.6% and 4.8%, respectively. The results can be used to develop control strategy for regulating refrigeration flow rate to offer adequate cooling capacity and supply cooled oil of constant temperature.

Properties and Performance of Eco-Friendly Hydro-Fluoro-Olefin (HFO) Refrigerant-R1234yf: Part I

2021 ◽  
pp. 2130005
Author(s):  
B. S. Bibin ◽  
Edison Gundabattini
Keyword(s):  
Ozone Depletion ◽  
Past Research ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
General Effect ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Vapor Compression Refrigeration ◽  
Principal Points ◽  
And Performance

The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.

Effect of Gas Blockage on the Theoretical Performance of Thermoacoustic Refrigerators

2021 ◽  
Author(s):  
B. G. Prashantha ◽  
G. S. V. L. Narasimham ◽  
S. Seetharamu ◽  
K. Manjunatha
Keyword(s):  
Heat Exchanger ◽  
Cooling Capacity ◽  
Inert Gases ◽  
Environmentally Benign ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Simulation Results ◽  
The One ◽  
Thermoacoustic Refrigeration ◽  
Theoretical Performance

Thermoacoustic refrigeration is an emerging green, novel and promising alternate technology compared to vapor compression refrigerator systems for domestic cooling. It uses environmentally benign gases like air or helium or the mixture of inert gases as working substances and has no moving parts, no lubrication and no vibration. The cooler is designed and optimized with helium and air as refrigerants operating at 10[Formula: see text]bar with 3% drive ratio for the temperature difference of 28[Formula: see text]K and stack diameter of 200[Formula: see text]mm using linear thermoacoustic theory. In this paper, the effect of gas blockage (porosity) of the spiral-stack heat exchanger system ranging from 45% to 85% on the theoretical performance of the cooler is discussed. The one-third and one-fourth wavelength convergent–divergent resonator designs are optimized with air and helium as working substances, respectively, to improve performance and power density. The optimized coolers show best performance with 85% porosity. The theoretical results are validated with DeltaEC software simulation results. The simulation results show the coefficient of performance and cooling capacity of 0.93 and 219[Formula: see text]W for helium and of 0.50 and 139[Formula: see text]W for air, respectively, at the cold heat exchanger temperature of 0∘C.

Ejector Profile Modelling for Heat-Driven Ejector Refrigeration System Without Involving Shock

2015 ◽  
Author(s):  
Binoe E. Abuan ◽  
Menandro S. Berana
Keyword(s):  
Waste Heat ◽  
Fluid Dynamic ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Evaporator Temperature ◽  
Major Disadvantage ◽  
And Performance

Heat-driven ejector refrigeration system is one of the fastest emerging technologies in cooling applications for years. This is due to the fact that it can harness cooling capacity from waste heat sources at above 80 °C. Low coefficient of performance (compared to commercial vapor compression systems) is the major disadvantage of the said system, and thus it became a topic of research studies in the field of cooling. The work required by the compressor in a vapor compression cycle (VCC) can be eliminated by using waste heat from any available heat source. Although a relatively lower COP was obtained, the savings using the ejector refrigeration system can cover all the disadvantages and proved that this system can be actually helpful if implemented in the real working systems with waste heat. In this study, a mathematical model for determining ejector parameters and performance was developed and applied to a system where shock was tried to be avoided. The model was coded into a computer program to allow easier computation of the ejector geometric and thermo-fluid dynamic parameters with varying input data such as the refrigerant to be used, evaporator and condensing temperatures, entrainment ratio, and velocity of the fluid flows. An ejector refrigeration system using ammonia, propane, R22, R134a, R1234yf, and R245fa as refrigerants was simulated using the said model. A boiler or generator temperature of 90 °C, a condenser temperature of 40 °C, and a refrigerating capacity of 35kW were maintained for all the refrigerants; however, the evaporator temperature was varied within the range of −10 °C to 10 °C, depending on the behavior of the system. A combination of a short straight section and then a converging-diverging profile was used for the combined mixing section and diffuser to smoothly decelerate the fully mixed supersonic flow exiting the short mixing section and thereby avoid shock waves in the section. The resulting parameters including the ejector dimensions, pressure and Mach number were determined along the length of the ejector. For all the simulation runs, the fluids respond as expected and the expansion energy was utilized from the high pressure side of the ejector as shown in the trend of pressure along the length of the ejector. Ejector size varies a little for different refrigerants; the calculated range of length is from 0.14 m to 0.36 m — this range shows the compactness of the resulting ejectors. The results show that a VCC refrigeration system can be replaced by a heat-driven ejector refrigeration system with the ejector that was designed from the simulations. Since the two systems are designed to have the same refrigerating capacity and working temperatures, it can be projected that savings can be made by using the ejector system. The compactness of the ejector produced in the simulations show a good potential for this kind of refrigerating system to be manufactured and mass produced.

Improved performance of a nanorefrigerant-based vapor compression refrigeration system: A new alternative

2020 ◽  
pp. 095765092090455
Author(s):  
Lal Kundan ◽  
Kuljeet Singh
Keyword(s):  
Temperature Drop ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Flow Rates ◽  
System A ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration ◽  
Improved Performance

An attempt has been made to improve the heat transfer characteristics of the vapor compression refrigeration cycle using nanorefrigerant (R134a and Al2O3, size 20 nm). The performance parameters such as, coefficient of performance, cooling capacity, energy consumption, and temperature drop across condenser and evaporator have been investigated and analyzed. This has been done by varying the mass fraction of nanoparticles of Al2O3 (0.5–1 wt%) and the flow rate of nanorefrigerant. The investigation has been carried out using three types of nanorefrigerants, i.e. pure R134a, R134a+Al2O3 (0.5 wt%), and R134a+Al2O3 (1 wt%) at flow rates of 6.5 L/h and 11 L/h, respectively. The coefficient of performance of the refrigeration system using 0.5% of Al2O3 (wt%) is found to be improving with volume flow rates of nanorefrigerant, i.e. 7.20% for 6.5 L/h and 16.34% for 11 L/h. The use of nanorefrigerant (R134a+Al2O3) has also resulted in a significant increase in the cooling capacity of the refrigeration system. A substantial drop in the temperature across the condenser (3.0–23.77%), and gain in temperature across the evaporator (4.69–39.30%) is also observed for the refrigeration system under investigation.

Performance Study of Activated Carbon – Hydrofluoro Olefin Based Adsorption Cooling System

2013 ◽  
Vol 465-466 ◽  
pp. 206-210
Author(s):  
Khairul Habib
Keyword(s):  
Activated Carbon ◽  
Waste Heat ◽  
Cooling System ◽  
Combustion Engine ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Performance Study ◽  
Adsorption Chiller

In this study, a dynamic behavior of a two bed adsorption chiller has been analyzed using highly porous activated carbon of type Maxsorb III as adsorbent and hydrofluoro olefin [R1234ze (E)] as refrigerant. R1234ze (E) has a low global warming potential (GWP) and zero ozone depletion potential (ODP). A parametric study has been presented where the effects of adsorption/desorption cycle time, cooling water inlet temperature and regeneration temperature on the performance are reported in terms of cooling capacity and coefficient of performance (COP). This chiller can be driven by the waste heat of internal combustion engine and hence it is applicable in automobile air conditioning.

scholarly journals KAJI PERFORMANSI REFRIGERAN R-290, R-32, DAN R-410A SEBAGAI ALTERNATIF PENGGANTI R-22

2021 ◽  
Vol 4 ◽  
pp. 133-139
Author(s):  
Rikhard Ufie ◽  
Cendy S. Tupamahu ◽  
Sefnath J. E. Sarwuna ◽  
Jufraet Frans
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Vapor Compression ◽  
Know How ◽  
Evaporation Temperature ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Refrigeration Capacity

Refrigerant R-22 is a substance that destroys the ozone layer, so that in the field of air conditioning it has begun to be replaced, among others with refrigerants R-32 and R-410a, and also R-290. Through this research, we want to know how much Coefficient of Performance (COP) and Refrigeration Capacity (Qe) can be produced for the four types of refrigerants. The study was carried out theoretically for the working conditions of the vapor compression cycle with an evaporation temperature (Tevap) of 0, -5, and -10oC, a further heated refrigerant temperature (ΔTSH) of 5 oC, a condensation temperature (Tkond) of 45 oC and a low-cold refrigerant temperature. (ΔTSC) 10 oC and compression power of 1 PK . The results of the study show that the Coefficient of Performance (COP) in the use of R-22 and R-290 is higher than the use of R-32 and R-410a, which are 4,920 respectively; 4,891; 4.690 and 4.409 when working at an evaporation temperature of 0 oC; 4.260; 4,234; 4.060 and 3.812 when working at an evaporation temperature of -5 oC; and amounted to 3,730; 3,685; 3,550 and 3,324 if working at an evaporation temperature of -10 oC. Based on the size of the COP, if this installation works with a compression power of 1 PK, then the cooling capacity of the R-22 and R-290 is higher than the R-32 and R-410a, which are 3,617 respectively. kW; 3,597 kW; 3,449 kW and 3,243 kW. If working at an evaporation temperature of 0 oC; 3.133 kW; 3.114 kW; 2,986 kW and 2,804 kW if working at an evaporation temperature of -5 oC; and 2,741 kW; 2,710 kW; 2,611 kW and 2,445 kW if working at an evaporation temperature of -10oC.

Miniature Vapor Compression Refrigeration Systems for Active Cooling of High Performance Computers

2001 ◽  
Author(s):  
Ali Heydari ◽  
Kathy Russell
Keyword(s):  
Heat Exchanger ◽  
High Performance ◽  
Capillary Tube ◽  
New Technology ◽  
Mathematical Formulation ◽  
Coefficient Of Performance ◽  
Simulation Program ◽  
Vapor Compression ◽  
Refrigeration System ◽  
System Components

Abstract A small refrigeration system for cooling of computer system components is evaluated. A thermodynamic model describing the performance of the cycle along with a computer simulation program is developed to evaluate its performance. The refrigeration system makes use of a miniature reciprocating vapor compression compressor. Due to space limitations in some high performance computer servers, a miniature refrigeration system composed of a compressor, capillary tube, a compact condenser, and a cold-plate evaporator heat exchanger are used. Mathematical multi-zone formulation for modeling thermal-hydraulic performance of heat exchanger for the condenser and evaporator are presented. The throttling device is a capillary tube and there is presented a mathematical formulation for predicting refrigerant mass flow rate through the throttling device. A physically based efficiency formulation for simulating the performance of the miniature compressor is used. An efficient iterative numerical scheme with allowance for utilization of various refrigerants is developed to solve the governing system of equations. Using the simulation program, the effects of parameters such as the choice of working refrigerant, evaporating and condensing temperatures on system components and overall efficiency of system are studied. In addition, a RAS (reliability, availability and serviceability) discussion of the proposed CPU-cooling refrigeration solution is presented. The results of analysis show that the new technology not only overcomes many shortcomings of the traditional fan-cooled systems, but also has the capacity of increasing the cooling system’s coefficient of performance.

An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System

2021 ◽  
pp. 2150028
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain
Keyword(s):  
Experimental Investigation ◽  
Thermal Equilibrium ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Compression System ◽  
Vapor Compression System ◽  
Vapor Compression Refrigeration ◽  
Cascaded System

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.

Refrigeration Cooled Computers: Application and Review

2000 ◽  
Author(s):  
R. R. Schmidt ◽  
M. J. Ellsworth ◽  
R. C. Chu ◽  
D. Agonafer
Keyword(s):  
Temperature Stability ◽  
Continuous Operation ◽  
Coefficient Of Performance ◽  
System Level ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Maintenance System ◽  
Vapor Compression Refrigeration ◽  
Computer Processor ◽  
Heat Loads

Abstract This paper outlines and discusses the application conditions pertinent to refrigeration cooling a computer processor at both the module and system level. Amongst the issues that are addressed are total refrigeration heat load (comprised of active and parasitic heat loads), coefficient of performance (COP), continuous operation (reliability, concurrent maintenance), system heat rejection, condensation formation, and temperature stability. The paper will then examine how a vapor compression refrigeration system has been incorporated in IBM’s high end (Gx) servers. Finally, the paper will touch upon some of the additional complexities of operation at very low temperatures (less than −40 °C).

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