Prediction of Performance Equations for Household Compressors Depending on Manufacturing Data for Refrigerators and Freezers

2016 ◽  
Vol 818 ◽  
pp. 184-209
Author(s):  
Louay Abdalazez Mahdi ◽  
Emad Esmaael Habib ◽  
Laith Abdalmunam
Keyword(s):  
Power Consumption ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cooling Capacity ◽  
Surface Fitting ◽  
Temperature Cycle ◽  
Evaporator Temperature ◽  
Base Points ◽  
Swept Volume

A semi-empirical model has been investigated to represent household compressors. The model based on calorimeter data for two distinguished brand (Danfoss and Electrolux CUBIGEL) and compared with eight brands consisting of ninety compressors model. The calorimeter data are correlated (according to ARI standard 540-90 [1] and working refrigeration temperature cycle for ASHRAE Technical Committee 8.9[2]) as a function of refrigerant saturated evaporating temperatures from (-35 to 10) °C and swept volume range (2.24-11.15) cm3 keeping of the refrigerant saturated condensing temperature constant at 54.5 °C. The correlations were found with ten-coefficient polynomial by using Matlab software – surface fitting method for cooling capacity, power consumption, and refrigerant mass flow rate.In addition, other equations for cooling capacity, power consumption, and refrigerant mass flow rate at-23.3 °C evaporator temperature, 54.4 °C condenser temperature, and 32 °C temperature for liquid line which is the base points of the refrigerator cycle according to ASHRAE[2] , cover the range (2.42-11.15) cm3 swept volume which are created to quick choose the proper compressor.The result indicated that the surface fitting models are accurate within ± 15% deviation of compressors data of seventy-two models for cooling capacity, fifty models for power, and twenty-five models for refrigerant mass flow rate.

Experimental Investigation of a Pilot Compression Chiller With Alternatives Refrigerants R401a and R134a

2005 ◽  
Author(s):  
M. Fatouh
Keyword(s):  
Experimental Investigation ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Water Mass ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Inlet Temperature ◽  
Chilled Water ◽  
Water Mass Flow Rate

This paper reports the results of an experimental investigation on a pilot compression chiller (4 kW cooling capacity) working with R401a and R134a as R12 alternatives. Experiments are conducted on a single-stage vapor compression refrigeration system using water as a secondary working fluid through both evaporator and condenser. Influences of cooling water mass flow rate (170–1900 kg/h), cooling water inlet temperature (27–43°C) and chilled water mass flow rate (240–1150 kg/h) on performance characteristics of chillers are evaluated for R401a, R134a and R12. Increasing cooling water mass flow rate or decreasing its inlet temperature causes the operating pressures and electric input power to reduce while the cooling capacity and coefficient of performance (COP) to increase. Pressure ratio is inversely proportional while actual loads and COP are directly proportional to chilled water mass flow rate. The effect of cooling water inlet temperature, on the system performance, is more significant than the effects of cooling and chilled water mass flow rates. Comparison between R12, R134a and R401a under identical operating conditions revealed that R401a can be used as a drop-in refrigerant to replace R12 in water-cooled chillers.

Flashing Flow Mechanisms of HFC-134a and HFC-410a Through Short-Tube Orifices

2011 ◽  
Author(s):  
Kitti Nilpueng ◽  
Somchai Wongwises
Keyword(s):  
Temperature Distribution ◽  
Pressure Distribution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Operating Conditions ◽  
Evaporator Temperature ◽  
Hfc 134A ◽  
Flow Mechanisms ◽  
Short Tube

In this study, the flow mechanisms of HFC-134a and HFC-410A, including flow pattern, pressure distribution, temperature distribution, and mass flow rate inside short-tube orifice are presented and compared under the same working temperature. The test runs are performed at condenser temperature ranging between 35 and 45°C, evaporator temperature ranging between 2 and 12°C, and degree of subcooling ranging between 1 and 12 °C. The results show that the temperature distribution along the short-tube orifice obtained from HFC-410A is slightly higher than that obtained from HFC-134a. On the other hand, the pressure distribution between both refrigerants shows the large difference. It is also found that the tendency of mass flow rate obtained from HFC-134a almost coincides with those obtained HFC-410A as the operating conditions and short-tube orifice size are varied. However, the average mass flow rate of HFC-134a is slightly lower than that of HFC-410A.

scholarly journals Impacts of Room Temperature on the Performance of a Portable Propane Air Conditioner

2015 ◽  
Vol 23 (02) ◽  
pp. 1550015 ◽  
Author(s):  
Ahmad Sharifian ◽  
Jeri Tangalajuk Siang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Room Temperature ◽  
Capillary Tube ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Charge Condition ◽  
Full Charge

The performance of a portable propane air conditioner system, in which the temperatures of the air passing over the condenser and evaporator are equal, has been experimentally investigated under different room temperatures and refrigerant charge levels. The research has been carried out in a range of room temperatures from 20°C to 35°C and in undercharge, standard charge and overcharge conditions. The results show that, at higher room temperatures, the refrigerant temperature in all parts of the system, the density of the refrigerant at the inlet and outlet of the condenser, mass of the refrigerant in the compressor, the mass flow rate of the refrigerant and the cooling capacity of the system in either the undercharge or full charge condition, the specific cooling capacity of the undercharge system, the useful work of the compressor, and the maximum pressure of the refrigerant increase. The increase in room temperature decreases the density of the refrigerant at the inlet and outlet of the capillary tube, the mass of the refrigerant in the capillary tube, the refrigerant subcooling at the inlet of the capillary tube, the maximum velocity of the refrigerant and the coefficient of performance. In addition, the increase in room temperature at overcharge condition causes an increase in the mass flow rate, cooling capacity and specific cooling capacity to a maximum value followed by their decrease. The most important difference between a portable air conditioner and a nonportable system is the increase in cooling capacity with an increase in room temperature in full charge condition.

A Study on Anasysis and Fabrication of an Ice Plant Model

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
J. P. Yadav ◽  
Bharat Raj Singh
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Unit Mass ◽  
Ice Plant ◽  
Plant Model ◽  
Compression Cycle ◽  
Vapour Compression

Refrigeration may be defined as the process of achieving and maintaining a temperature below that of the surroundings, the aim being to freeze ice, cool some product, or space to the required temperature. The basis of modern refrigeration is the ability of liquids to absorb enormous quantities of heat as they boil and evaporate. One of the important applications of refrigeration is in ice plant. Ice plant is used for producing refrigeration effect to freeze potable water in standard cans placed in rectangular tank which is filled by brine. Our project based on simple refrigeration system which uses the vapour compression cycle. The vapour compression cycle comprises four process compression, condensing, and expansion and evaporation process. Our ice plant model contains various parts such as- Compressor, condenser, filter drier, Expansion valve, Evaporator coil, chilling tank and various measuring equipments like digital temperature indicator, pressure gauges, energy meter etc. The conventional ice plant has been studied and a prototype model of an ice plant has been fabricated with above said accessories. The model is analyzed for its cooling capacity assumed per unit mass flow rate of refrigerant. Its COP is also calculated. The model is compared for its coefficient of performance (COP) and cooling capacity by using R-134 a refrigerant with a theoretical COP and cooling capacity obtained using refrigerant R-22. The variations found in COP and cooling capacity are 0.12 and 0.042 TR respectively for unit mass flow rate of the refrigerant.

Experimental study of an ultrasonic regenerative evaporative cooler for a desiccant cooling system

2018 ◽  
Vol 40 (2) ◽  
pp. 151-175 ◽  
Author(s):  
BS Arun ◽  
V Mariappan
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cooling System ◽  
Cooling Capacity ◽  
Water Mist ◽  
Extraction Ratio ◽  
Feed Water ◽  
Airflow Rate ◽  
Evaporative Cooler

This paper presents fabrication of an ultrasonic regenerative evaporative cooler, coupled with a desiccant dehumidifier. Ultrasonic regenerative evaporative cooler consists of several sets of a dry channel and a wet channel. A part of the air from the dry channel is redirected into the wet channel where it is cooled by evaporation of water mist from an ultrasonic atomiser. Air flowing through dry channels is pre-cooled by heat transfer between wet and dry channels, without changing its humidity. In this cooler, the conventional hygroscopic layer for wetting the plate surface is replaced with the water mist. It is observed that the performance of the cooling system significantly depends on the channel spacing, channel length, inlet airflow rate and extraction ratio, and marginally depends upon feed water temperature. The room cooling capacity is eminently responsive to both air mass flow rate and extraction ratio. The maximum available room cooling capacity of 339.8 W is obtained for the optimal values of 0.0488 kg/s mass flow rate of air and 0.37 extraction ratio. The prototype achieved wet-bulb effectiveness values as high as 1.15 and delivered more than 10℃ temperature drop. Practical application: An ultrasonic regenerative evaporative cooler can be coupled with a desiccant dehumidification unit for use in hot and humid climate to achieve comfort condition utilising less energy and feed water when compared to the vapour compression refrigeration system. From this prototype researchers and engineers can develop, by combining desiccant regenerators and evaporative coolers which use ultrasonic method for low-temperature dehydration of desiccant substance. Solar thermal energy can also be directly utilised for marginally heating the desiccant substance during the regeneration process. Overall, this system can contribute to the development of energy efficient buildings.

Theoretical and Numerical Analysis on the Temperature Drop and Power Consumption of a Pre-Swirl System

2016 ◽  
Author(s):  
Gaowen Liu ◽  
Heng Wu ◽  
Qing Feng ◽  
Songling Liu
Keyword(s):  
Theoretical Analysis ◽  
Power Consumption ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Drop ◽  
Cover Plate ◽  
Radial Location ◽  
Total Temperature ◽  
Cooling Air

As a component of delivering cooling air to turbine rotor blade at appropriate pressure, temperature and mass flow rate, pre-swirl system is very important to the cooling of turbine blades. It is attractive to the designers and scholars for its potential ability to reduce relative total temperature of cooling air as large as 100K. A pre-swirl system is actually an aero-thermodynamic system with energy transformation between work and heat. Theoretical analysis was carried out on an isentropic pre-swirl system to deduce equations for ideal temperature drop and power consumption. For an actual pre-swirl system, correlation between the actual temperature drop and power consumption was deduced, and a temperature drop effectiveness was defined also. Theoretical analysis shows that the system’s temperature drop increases linearly with the reduction of the power consumption. Numerical models were derived from a real engine pre-swirl system with small simplification. Standard k-ε turbulence model and Frozen-Rotor approach were applied in the three dimensional steady simulations. Inlet total pressure and total temperature, outlet static pressure, mass flow rate delivered to the blade and rotating speed of rotor were kept to be fixed for all the models. The influences of heat transfer and sealing flow coming from the inner seal were ignored in the simulations. Section averaged parameters like pressure, swirl ratio and total enthalpy were presented at each typical station throughout the flow path. The relationship between the temperature drop and the power consumption of all the models has been verified to be consistent with the deduced formula. For the pre-swirl system with low radial location of nozzle, these measures, such as adding impellers in the cover-plate cavity and inclining the receiver hole, were taken to reduce the power consumption and enlarge the temperature drop obviously. For this specific pre-swirl system, models with high radial location of nozzle are more recommended to decrease the loss caused by the large circumferential velocity difference between the airflow and the rotor.

Capacity Control for Refrigeration and Air-Conditioning Systems: A Comparative Study

2000 ◽  
Vol 123 (1) ◽  
pp. 92-99 ◽  
Author(s):  
Mohammad Yaqub ◽  
Syed M. Zubair
Keyword(s):  
Comparative Study ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Finite Size ◽  
Cooling Capacity ◽  
System Capacity ◽  
Coefficient Of Performance ◽  
Capacity Control ◽  
Hfc 134A

The capacity control of a vapor-compression refrigeration system is investigated for three different capacity control schemes. In a hot-gas by-pass control scheme, the refrigerant is by-passed from the compressor and injected back into the suction line to decrease the cooling capacity, whereas in cylinder-unloading scheme, one or more cylinders are unloaded to decrease the refrigerant mass flow rate in the system, which decreases the cooling capacity. However, in suction gas throttling, the suction gas throttled at the inlet of the compressor, decreases the refrigerant mass flow rate, and hence a corresponding decrease in the system capacity. These schemes are investigated for HFC-134a by considering finite size of the components that are used in the refrigeration systems. The models consider the finite-temperature difference in the heat exchangers, thus allowing the variations in the condenser and evaporator temperatures with respect to capacity and external fluid inlet temperatures. A comparative study is performed among these schemes in terms of the system coefficient of performance (COP), the operating temperatures, and percentage of refrigerant mass fraction as a function of the percentage of full-load system capacity.

scholarly journals Mathematical Modelling of Active Magnetic Regenerator Refrigeration System for Design Considerations

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6301
Author(s):  
Aref Effatpisheh ◽  
Amir Vadiee ◽  
Behzad A. Monfared
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Single Layer ◽  
Cooling Capacity ◽  
Magnetic Refrigeration ◽  
Maximum Pressure ◽  
Refrigeration System ◽  
Design Considerations ◽  
Active Magnetic Regenerator

A magnetic refrigeration system has the potential to alternate the compression system with respect to environmental compatibility. Refrigeration systems currently operate on the basis of the expansion and compression processes, while active magnetic refrigeration systems operate based on the magnetocaloric effect. In this study, a single layer of Gd was used as the magnetocaloric material for six-packed-sphere regenerators. A one-dimensional numerical model was utilized to simulate the magnetic refrigeration system and determine the optimum parameters. The optimum mass flow rate and maximum cooling capacity at frequency of 4 Hz are 3 L·min−1 and 580 W, respectively. The results show that the maximum pressure drop increased by 1400 W at a frequency of 4 Hz and mass flow rate of 5 L·min−1. In this study, we consider the refrigeration system in terms of the design considerations, conduct a parametric study, and determine the effect of various parameters on the performance of the system.

Performance Comparison of Automotive Air Conditioner Using Various Refrigerants

2015 ◽  
Vol 1125 ◽  
pp. 561-565
Author(s):  
Vina Serevina ◽  
Sumeru ◽  
Azhar Abdul Aziz ◽  
Henry Nasution
Keyword(s):  
Global Warming ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Compression Ratio ◽  
Cooling Capacity ◽  
Performance Comparison ◽  
Working Fluid ◽  
Air Conditioner ◽  
Ambient Temperatures

Working fluid of R134a is widely used as a refrigerant in automotive air conditioner. This refrigerant has a good performance on the automotive air conditioner. However, because R134a still has a high global warming potential, this refrigerant must be reduced and replaced by environmentally friendly refrigerants. Hydrocarbons of R600a, R290 and their mixtures are widely used as substitute refrigerant. These refrigerants are natural fluids, no effect on the climate, inexpensive and readily available. There are three performances will be discussed in the present study, namely COP, mass flow rate and compression ratio. The present study investigates the effect of three refrigerants, i.e. R134a, R600a and R290 on the performance of automotive air conditioner. The results show that the COP of R600a is higher than those R134a and R290. For the same cooling capacity, the mass flow rate of R600a is approximately 50% of R134a for all ambient temperatures. In addition, the compression ratio of R600a is lower than that of R134a.

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