Cooling load and coefficient of performance of thermoacoustic refrigerators: the role of the working fluid

2008 ◽  
Vol 123 (5) ◽  
pp. 3547-3547 ◽  
Author(s):  
Cila Herman
Keyword(s):  
Coefficient Of Performance ◽  
Working Fluid ◽  
Cooling Load ◽  
Thermoacoustic Refrigerators

Performance of Thermoacoustic Refrigerators: Cooling Load and Coefficient of Performance

2008 ◽  
Author(s):  
Cila Herman ◽  
Christopher Lavin ◽  
Zdeneˇk Tra´vni´cˇek
Keyword(s):  
Coefficient Of Performance ◽  
Working Fluid ◽  
Cooling Load ◽  
Working Fluids ◽  
Half Wavelength ◽  
Environmentally Safe ◽  
Pure Helium ◽  
Limiting Case ◽  
Load Behavior ◽  
Thermoacoustic Refrigeration

Thermoacoustic refrigeration is an environmentally safe refrigeration technology that has evolved over the past three decades [1–5]. The influence of working fluid on the performance of the thermoacoustic refrigerator (TAR) expressed in terms of the cooling load and the coefficient of performance is discussed in the paper. The calculations rely on the short stack boundary layer approximation. A simple model of a one-dimensional half wavelength resonance tube equipped with stack plates and a pair of heat exchangers was used as the physical model. It is known that a TAR with noble gases and their mixtures as working fluids can achieve high values of the coefficient of performance (COP) because of small Prandtl number values. The present study revealed and quantified that cooling load behavior is quite different from the performance in terms of the COP: the highest cooling load is achieved with pure Helium as the working fluid. A reason is the very high sound speed in Helium. TARs with Helium as the working fluids deliver the highest cooling load of all gases and their mixtures examined here, therefore it has been suggested as a limiting case of the most powerful TAR. The influence of geometry and thermophysical parameters of the device on TAR performance was studied systematically and a performance sensitiviy analysis was presented with particular emphasis on TAR cooling load.

Performance of a Residential-Sized GAX Absorption Chiller

2001 ◽  
Vol 123 (3) ◽  
pp. 236-241 ◽  
Author(s):  
Douglas K. Priedeman ◽  
Michael A. Garrabrant ◽  
James A. Mathias ◽  
Roger E. Stout ◽  
Richard N. Christensen
Keyword(s):  
Market Research ◽  
Experimental Testing ◽  
Research Effort ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Cooling Load ◽  
Absorption Chiller ◽  
Flow Meters ◽  
Pressure Transducers

This research effort involved experimentally testing an advanced-cycle, ammonia-water absorption chiller with a cooling capacity of 17.6 kW (5 refrigeration tons (RT)). The system was a generator-absorber heat exchange (GAX) cycle and was sized for residential and light commercial use, where very little absorption equipment is currently used. The components of the cycle were assembled with instrumentation, including flow meters, pressure transducers, and thermocouples. The findings of the research were cycle cooling load and coefficient of performance (COP), as well as many component heat duties and working fluid state points throughout the cycle. The COP of the chiller at essentially full load was measured at 0.68. A simulation of the GAX cycle was performed with a computer program that predicted the heat duties of each component and the cooling load of the cycle. The simulation of the GAX cycle and experimental testing compared closely. Existing market research shows that significant business opportunities exist for a GAX heat pump or chiller with a cooling COP of 0.70 or greater. The work performed in this study consisted of testing a GAX cycle with a COP that approached the target value of 0.70 and identified improvements that must be made to reach the target COP value.

scholarly journals Impact of Working Fluids and Performance of Isobutane in the Refrigeration System

2021 ◽  
Author(s):  
Solomon O. Banjo ◽  
Bukola O. Bolaji ◽  
Oluseyi O. Ajayi ◽  
Olatunde A. Oyelaran
Keyword(s):  
Global Warming ◽  
Air Conditioning ◽  
Energy Reduction ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration System ◽  
Compressor Work ◽  
And Performance

The effect of heat transfer medium (HTM) on the environment is associated with ozone layer depletion and global warming. The role of HTM (working fluid) in the heating and air conditioning industries is paramount, which cannot be underestimated. The conventional refrigerant has been predominantly used over decades due to their thermodynamic properties. However, hydrocarbon refrigerants such as isobutane are considered substitutes because they have negligible global warming potential and zero ozone depletion. That makes it eco-friendly among other existing refrigerants. The investigation of the refrigeration system’s performance characteristics required consideration for the coefficient of performance, refrigerating effect, and the compressor work; this enables the determination of the system’s efficiency without any assumption. Another factor that suggests a better absorption of refrigerant (working fluid) into a refrigeration system is an increase in the coefficient of performance (COP). The effect will cause a reduction in the rate of energy consumption by the compressor. The result shows that the system’s coefficient of performance when using R600a was 27.1% higher than when working with R134a, with an energy reduction of 23.3%.

Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

scholarly journals Numerical Modeling and Performance Evaluation of Standing Wave Thermoacoustic Refrigerators with a Multi-Layered Stack

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4360
Author(s):  
Umar Nawaz Bhatti ◽  
Salem Bashmal ◽  
Sikandar Khan ◽  
Rached Ben-Mansour
Keyword(s):  
Standing Wave ◽  
Numerical Study ◽  
Temperature Drop ◽  
Acoustic Power ◽  
Heat Energy ◽  
Coefficient Of Performance ◽  
Material Layer ◽  
And Performance ◽  
Stacked Material ◽  
Thermoacoustic Refrigerators

Thermoacoustic refrigerators have huge potential to replace conventional refrigeration systems as an alternative clean refrigeration technology. These devices utilize conversion of acoustic power and heat energy to generate the desired cooling. The stack plays a pivotal role in the performance of Standing Wave Thermoacoustic Refrigerators (SWTARs), as the heat transfer takes place across it. Performance of stacks can be significantly improved by making an arrangement of different materials inside the stack, resulting in anisotropic thermal properties along the length. In the present numerical study, the effect of multi-layered stack on the refrigeration performance of a SWTAR has been evaluated in terms of temperature drop across the stack, acoustic power consumed and device Coefficient of Performance (COP). Two different aspects of multi-layered stack, namely, different material combinations and different lengths of stacked layers, have been investigated. The combinations of four stack materials and length ratios have been investigated. The numerical results showed that multi-layered stacks produce lower refrigeration temperatures, consume less energy and have higher COP value than their homogeneous counterparts. Among all the material combinations of multi-layered stack investigated, stacks composed of a material layer with low thermal conductivity at the ends, i.e., RVC, produced the best performance with an increase of 26.14% in temperature drop value, reduction in the acoustic power consumption by 4.55% and COP enhancement of 5.12%. The results also showed that, for a constant overall length, an increase in length of side stacked material layer results in an increase in values of both temperature drop and COP.

Thermodynamic Performance of an Actual Thermo-Acoustic Refrigeration Micro-Cycle

2012 ◽  
Vol 614-615 ◽  
pp. 64-68
Author(s):  
Tuo Wang ◽  
Feng Wu ◽  
Jin Hua Fei ◽  
Ming Fang Liu
Keyword(s):  
Coefficient Of Performance ◽  
Pressure Amplitude ◽  
Cooling Load ◽  
Acoustic Effect ◽  
Thermodynamic Performance ◽  
Monotonically Increasing Function ◽  
Analytic Expressions ◽  
New Type ◽  
The Relationship ◽  
Increasing Function

Thermo-acoustic refrigerator is a new type of engine, which is based on the thermo-acoustic effect. A new model which expresses as an ellipse in pressure-volume diagram is established to investigate the thermodynamic performance of an actual thermo-acoustic refrigeration micro-cycle. The demarcation points of endothermic processes and exothermic processes in the actual micro-cycle are found. The analytic expressions of the dimensionless cooling load and the coefficient of performance (COP) are deduced. The relationship between the dimensionless cooling load and the COP are investigated by numerical examples. The results show that the dimensionless cooling load is a monotonically increasing function of the COP and the pressure amplitude.

Increase of energy efficiency ratio of a direct evaporative cooler by dynamic behavior with energy and exergy analysis

2021 ◽  
pp. 095440622110420
Author(s):  
Behzad Omidi Kashani
Keyword(s):  
Energy Efficiency ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Dynamic State ◽  
Circulation Rate ◽  
Cooling Load ◽  
Efficiency Ratio ◽  
Static State ◽  
Circulation Pump ◽  
Water Rate

The present research is about increasing the energy efficiency ratio (EER) in current direct evaporative coolers (DEC) in Iran. Increasing the cooling load and reducing the electrical energy consumption simultaneously (increasing the energy efficiency ratio (EER)) in DEC are the main goals of manufacturers and consumers of this device. When the circulation water pump runs continuously (static state), the circulation water rate is about 1.89 to 2.90 times of the amounts recommended in the reasonable standards. In order to adjust the circulation water rate to the recommended amount by standards, the present study has utilized repetitive cyclic scheduling programs to reduce the circulation rate to the optimal amount, (by turning the circulation pump on and off by dynamic pattern operation). In other words, the circulation pump stays on only for a certain period of a working cycle, and then the pump stays off for the rest of it. The cooling load and EER were measured based on ASHRAE 133 (2015). The results indicated that the cooling load in the dynamic state increased by 5.03 and 6.18 percent compared to the static state at low and high fan speeds, respectively. Moreover, in comparison with the static state, the amount of electrical energy consumed (kW-hr) in the dynamic state decreased by 8.8 and 4.2 percent at low and high fan speeds, respectively. Finally, the coefficient of performance (COP or EER) of the DEC in the dynamic state is increased by 15.16 and 10.78 in comparison with the static state at low and high fan speeds, respectively.

scholarly journals ENERGY IMPLEMENTATION OF SOLAR PANELS FOR REFRIGERATOR NEEDS LOAD FISHING RESULTS 80 WATT MAXIMUM CAPACITY 20 KG

2019 ◽  
Vol 4 (1) ◽  
pp. 19-31
Author(s):  
A. YUNUS NASUTION ◽  
ADITYA PRATAMA
Keyword(s):  
Power Consumption ◽  
Solar Panel ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Cooling Load ◽  
Solar Panels ◽  
Average Output ◽  
Average Value ◽  
Battery Capacity ◽  
Compressor Power

The initial problems of fishermen still use their semi-modern catches and still use ice cubes as a cooling medium, due to the lack of innovation in the development of the cooling media caught by fishermen. The implementation of solar panel energy is the beginning for the development of refrigerator power consumption caught by fishermen. The goal is to calculate the cooling load on the refrigerator, calculate the Coefficient of performance (COP) at the refrigerator and the loading factors at the refrigerator, where the average ambient temperature is 34 ℃ and the temperature to be achieved is 0℃, the fisherman results used in the study this is a shrimp with a capacity of 20 kg and the cooling time is 4 hours. Where the total cooling load value is 244.29 Watt, multiplied by 10% safety factor, so the overall cooling load is 268.72 Watts, refrigerant mass flow rate is 0.0012 Kg / s, the evaporator capacity is 261 Watt, compressor power is 15.6 Watt, The coefficient of performance (COP) value was 16.73 while for the refrigerant capacity was 0.074 Tons of refrigerant, the loading factors in the study were used to run a refrigerator with 80 Watt power for 4 hours, so that the total refrigerator load was 320 Wh (Watt hour) , to produce 320 Wh power is used 2 solar panel modules with a capacity of 50 Wp (Watt Peak), and uses a solar change controller (SCC) with a capacity of 10 A. The output power of the solar panel is influenced by the intensity of the sun's light emitted, from the test obtained an average value the average output of solar panels is 90.6 watts, while the total power generated in 11 test points is 536 watts, the type used is polycrystalline, solar panels battery and inverter capacity must be greater than the refrigerator power consumption, in this study used a 12V 35 Ah battery capacity and 500 Watt Inverter

Integrated Systems for Cogeneration and Absorption Chilling: Comparison for Varying Chiller COPs

1999 ◽  
Author(s):  
R. Tang ◽  
M. A. Rosen
Keyword(s):  
Steam Turbine ◽  
Integrated System ◽  
Coefficient Of Performance ◽  
Integrated Systems ◽  
Base Case ◽  
Cooling Load ◽  
Absorption Chillers ◽  
Multi Stage ◽  
Wide Range ◽  
Thermodynamic Effects

Abstract The thermodynamic effects are demonstrated of integrating steam turbine-based cogeneration systems with absorption chillers. A wide range of realistic extraction steam pressures and coefficient of performance (COP) values of absorption chillers are considered. A simple model of a steam turbine-based cogeneration plant is used for the evaluation of the integrated system. The integrated systems are evaluated based on the ratio of fuel consumption between a base case (one-stage absorption chiller with a COP value of 0.6) and several alternative cases (multi-stage absorption chillers with COP values ranging from 0.6 to 1.5). Two categories of scenarios are considered: (i) cases where the cooling load is fixed; and (ii) cases where the cooling load is fixed and the electrical output for the integrated system is set equal to that for the base case.

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.

Sign in / Sign up

Export Citation Format

Share Document