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Impact Of Surface Treatment And Geometrical Characteristics On The Condensate Retention And Frost Formation On Metal Foams, Kashif Nawaz, Anthony M. Jacobi, Ahmed Elatar, Brian Fricke Jan 2018

Impact Of Surface Treatment And Geometrical Characteristics On The Condensate Retention And Frost Formation On Metal Foams, Kashif Nawaz, Anthony M. Jacobi, Ahmed Elatar, Brian Fricke

International Refrigeration and Air Conditioning Conference

Metal foams has been considered as promising materials for multiple thermal applications including air-cooling. Their use in such an application requires a detailed analysis of the condensate retention and frost accumulation in the metal foam pores. The current study is focused on the impact of surface treatment on the performance of metal foams when they are deployed in dehumidifying and frosting environment. Aluminum and cooper foam samples have been treated to achieve hydrophilic, hydrophobic and super hydrophobic characteristics and associated condensate retention and frost accumulation on the surface has been measured at various relative humidity and base temperature conditions. High …

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Effect Of Insulation On The Performance Of Wrapped-Coil-Tank Heat Pump Water Heater Deploying Low Gwp Refrigerants., Ahmed Elatar, Kashif Nawaz, Bo Shen, Van Baxter Jan 2018

Effect Of Insulation On The Performance Of Wrapped-Coil-Tank Heat Pump Water Heater Deploying Low Gwp Refrigerants., Ahmed Elatar, Kashif Nawaz, Bo Shen, Van Baxter

International Refrigeration and Air Conditioning Conference

Domestic water heating accounts for 18% of all residential and commercial building site energy used in the United States. Heat pump water heater is one of the most efficient water heating technologies compared to other conventional electric resistance or gas based water heating technologies. For heat pump water heaters, the water in the storage tank absorbs heat rejected by the condenser of the heat pump system. To accomplish this indirect heat transfer, condenser in form of a coil is wrapped around the water tank and the whole assembly is covered with thermal insulation. Tank insulation plays an important role in …

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Experimental Investigation Of Relative Humidity Effect On The Thermal Conductivity Of Desiccant Material, Shazia Hanif, Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama Jan 2018

Experimental Investigation Of Relative Humidity Effect On The Thermal Conductivity Of Desiccant Material, Shazia Hanif, Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama

International Refrigeration and Air Conditioning Conference

Study on effective thermal conductivity (ETC) of desiccant materials is getting attention in the literature in order to optimize the operating parameters of close and open cycle adsorption cooling systems. In addition, it is an important parameter to enhance the performance of adsorption heat pump and adsorption cooling systems (AHP/ACS). Most of the desiccant materials are porous in nature, therefore, results in different ETC at different operating conditions i.e. temperature and humidity. In order to find the more precise performance expression, the combined effect of desiccant porosity, temperature and relative humidity (RH) should be considered. In this regard, many empirical …

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Tube-Fin Heat Exchanger Circuitry Optimization For Multiple Airflow Maldistribution Profiles, Zhenning Li, Jiazhen Ling, Vikrant Chandramohan Aute Jan 2018

Tube-Fin Heat Exchanger Circuitry Optimization For Multiple Airflow Maldistribution Profiles, Zhenning Li, Jiazhen Ling, Vikrant Chandramohan Aute

International Refrigeration and Air Conditioning Conference

Tube-fin heat exchangers(HXs) are widely used in the HVAC&R industry. Studies have proved that by optimizing the refrigerant circuitry, heat exchanger performance can be significantly improved. Since air-to-refrigerant heat exchangers are typically confined in packaged units along with a fan, the airflow distribution on the face of the HXs is a dominant factor influencing its performance. During the operation of a heat exchanger as a part of the system, the air flow distribution changes continuously, especially as the fan speed changes during startup and shutdown cycles. This poses a design challenge as typically heat exchangers are designed using the assumption …

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Numerically Predicted Burning Velocities Of C1 And C2 Hydrofluorocarbon Refrigerant Flames With Air, Greg Linteris, Valeri Babushok Jan 2018

Numerically Predicted Burning Velocities Of C1 And C2 Hydrofluorocarbon Refrigerant Flames With Air, Greg Linteris, Valeri Babushok

International Refrigeration and Air Conditioning Conference

Due to their high global warming potentials, many existing working fluids for heating, cooling and refrigeration equipment are being phased out. Their replacements will often be flammable or slightly flammable, and the burning velocity of refrigerant-air mixtures is being used as a metric to rank their flammability. To allow industry to estimate the flammability of new blends of agents, predictive tools for the burning velocity of refrigerants are being developed, and calculating burning velocity requires a kinetic mechanism. The National Institute of Standards and Technology hydrofluorocarbon (HFC) mechanism was developed 20 years ago to describe hydrocarbon-air flames with added trace …

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Improving Refrigerant Flammability Limit Test Methods Based On Astm E681, Dennis K. Kim, Alexandra E. Klieger, Peter Q. Lomax, Conor G. Mccoy, Jonathan Y. Reymann, Peter B. Sunderland Jan 2018

Improving Refrigerant Flammability Limit Test Methods Based On Astm E681, Dennis K. Kim, Alexandra E. Klieger, Peter Q. Lomax, Conor G. Mccoy, Jonathan Y. Reymann, Peter B. Sunderland

International Refrigeration and Air Conditioning Conference

An improved test method for refrigerant flammability limit measurements is presented. Such measurements are essential for determining the lower flammability limits of refrigerants, and thus their safety classifications. Predicated on expert interviews and experiments, several changes to ASTM E681 and related standards are recommended, as follows. The 12 L glass vessel should be replaced with transparent polycarbonate (or other transparent plastic) to eliminate etching by HF and to facilitate vessel penetrations. The orientation of the electrode supports and the temperature probe should be changed from vertical to horizontal to prevent flame quenching. Venting should not occur before the flame stops …

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A Low Emission, Electrified Solution For Refrigerated Trucking, Shawn Wilfred Vehr Jan 2018

A Low Emission, Electrified Solution For Refrigerated Trucking, Shawn Wilfred Vehr

International Refrigeration and Air Conditioning Conference

Multiple Factors Are Driving Commercial Trucking Toward Electrified Solutions Which Will Lower Harmful Greenhouse Gas Emissions, Improve Efficiency And Reduce Fuel Consumption. As Part Of This, The Refrigerated Trucking Industry Is Searching For Methods To Meet These New Requirements. Today Most Refrigerated Truck Solutions Use A Diesel Engine To Provide Power For The Refrigeration System. This Diesel Engine Is A Source Of Pollutants Which Are Beginning To Be Federally Regulated By The EPA And State Regulated By Groups Such As The California Air Resource Board (CARB). In Addition, This Diesel Engine Is A Source Of Noise And Excessive Fuel Consumption. …

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A Simplified Model For Assessing Improvement Potential Of Air-To-Air Conditioners And Heat Pumps, Hassane Asloune, Philippe Riviere Jan 2018

A Simplified Model For Assessing Improvement Potential Of Air-To-Air Conditioners And Heat Pumps, Hassane Asloune, Philippe Riviere

International Refrigeration and Air Conditioning Conference

Many countries have adopted energy efficiency regulations for mini-split type air conditioners in the world. For these products, energy efficiency metrics is moving to seasonal performance evaluation. Many countries have already changed their metrics and many others are planning to customize the ISO 16358:2013 CSPF (Cooling Seasonal Performance Factor) and HSPF (Heating Seasonal Performance Factor) indicators to their own climate and use of air conditioners. To build policies to justify the need for implementing MEPS (Minimum Energy Performance Standard) and energy label programs, technico-economic model is required. A standard product is to be modeled as well as potential improvement options. …

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Flow Visualization Of R134a, R1234ze(E), And R1234yf In Microchannel Tube, Houpei Li, Predrag S. Hrnjak Jan 2018

Flow Visualization Of R134a, R1234ze(E), And R1234yf In Microchannel Tube, Houpei Li, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

This paper presents visualization results of two-phase flow of R134a, R1234yf, and R1234ze(E) in microchannel tube with hydraulic diameter of 0.643 mm. Visualization section has been made to record the flow in the microchannel to study the flow characteristic. Flow pattern maps of R134a, R1234ze(E), R1234yf are reported in this paper. Flow pattern maps are presented in two ways: mass flux-quality as coordinates, and superficial velocities as coordinates. The quality range of experiment is from 0 to 1 thermally. Mass flux varies from 50 to 250 kgm-2s-1. Flow patterns are classified as: plug/slug flow, transitional flow, and annular flow. The …

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Non-Condensable Gases And Their Effect On The Dynamic Behavior Of Domestic Refrigerators, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Joel Boeng Jan 2018

Non-Condensable Gases And Their Effect On The Dynamic Behavior Of Domestic Refrigerators, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Joel Boeng

International Refrigeration and Air Conditioning Conference

The aim of this work was to experimentally investigate the effect of non-condensable gases on the thermal acoustic behavior of domestic refrigerators under dynamic conditions. To this end, an acrylic made filter dryer was installed in the system for a proper visualization of the refrigerant flow at the capillary inlet. An accelerometer was also installed at the evaporator inlet to capture vibrations/noise signals, caused by the refrigerant pattern at the inlet of the expansion device. During the experiments the energy consumption was measured with the system systematically doped with precise amounts of nitrogen. It has been found that the energy …

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Performance Evaluation Of Bubble Absorber Using R134a/Dmf In Vapour Absorption Refrigeration System With Swirl Injector, Santosh Kumar Panda, Mani Annamalai Jan 2018

Performance Evaluation Of Bubble Absorber Using R134a/Dmf In Vapour Absorption Refrigeration System With Swirl Injector, Santosh Kumar Panda, Mani Annamalai

International Refrigeration and Air Conditioning Conference

Vapour absorption refrigeration systems (VARS) importance has increased due to utilization of solar energy, waste heat, etc. To improve the efficiency of this system, it is necessary to increase the heat and mass transfer in the absorber with tangential injectors. Experiments were carried out to analyze a tubular heat exchanger used as an absorber with tangential injector. In this study, a vertical bubble absorber is considered for heat and mass transfer studies with refrigerant, R134a (1,1,1,2 –Tetrafluoroethane) and absorbent, DMF(dimethyl formamide). R134a vapour is injected into the absorber using two injectors of 4.8 mm inner diameter at an injection angle …

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Removal Effect Of Bio-Contaminants In A Packaged Liquid Desiccant-Assisted Air Conditioning Unit, Hye-Won Dong, Jae-Weon Jeong Jan 2018

Removal Effect Of Bio-Contaminants In A Packaged Liquid Desiccant-Assisted Air Conditioning Unit, Hye-Won Dong, Jae-Weon Jeong

International Refrigeration and Air Conditioning Conference

The purpose of the study is to evaluate the removal effects of microbial contamination, such as fungi and bacteria, on a packaged liquid desiccant-assisted air conditioning unit. Recently, a package unit of a liquid desiccant and indirect and direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS) was proposed. The LD-IDECOAS consists of a liquid desiccant system, an indirect evaporative cooler, and a direct evaporative cooler. The test was conducted under operating conditions during the cooling season when the LD-IDECOAS operates a liquid desiccant system, an indirect evaporative cooler, and a direct evaporative cooler. The sampling is performed at the inlet …

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Alternative Defrost Strategies For Residential Heat Pumps, Cara Martin, Paul Oppenheim, John Bush, Hal Stillman Jan 2018

Alternative Defrost Strategies For Residential Heat Pumps, Cara Martin, Paul Oppenheim, John Bush, Hal Stillman

International Refrigeration and Air Conditioning Conference

Heat pumps are an energy efficient way to provide adequate heating to an indoor space. In contrast to electric or gas heating, a heat pump works to draw the "free" heat from the cold outdoor ambient and transfer thermal energy to the heated space. When the outdoor ambient is cold and humidity conditions are right, however, frost will start to develop on the heat pump’s outdoor coil. Frost on the coil surface blocks air flow through the coil thus reducing the heat pump’s efficiency and overall performance. Control of frosting and defrosting is particularly important to the successful use of …

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Leakage Rate Measurement And Durability Testing Of Field-Made Mechanical Joints For Systems With Flammable Refrigerants (Ashrae Rp-1808), Stefan Elbel, Neal Lawrence, Sharat Raj Jan 2018

Leakage Rate Measurement And Durability Testing Of Field-Made Mechanical Joints For Systems With Flammable Refrigerants (Ashrae Rp-1808), Stefan Elbel, Neal Lawrence, Sharat Raj

International Refrigeration and Air Conditioning Conference

Much concern has been raised recently about the flammability of several low-GWP replacement refrigerant options, such as HFO’s, lower-GWP HFC’s, and flammable natural refrigerant options, regarding the potential leakage or failure of joints in systems using these refrigerants. This paper presents the results of a study investigating the assembly, durability, and leakage rate of different types of field-made joints used in refrigeration and air-conditioning systems. The focus of the project is on flame-free joining methods; in particular, three different types of joints were investigated: Press/crimp fittings, compression fittings, and flare fittings. For each type of joint, two different sizes were …

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Correction Of Log Mean Temperature Difference Method And Effectiveness-Ntu Relations For Two-Phase Heat Transfer With Pressure Drop And Temperature Glide, Hongtao Qiao Jan 2018

Correction Of Log Mean Temperature Difference Method And Effectiveness-Ntu Relations For Two-Phase Heat Transfer With Pressure Drop And Temperature Glide, Hongtao Qiao

International Refrigeration and Air Conditioning Conference

The Logarithmic Mean Temperature Difference (LMTD) method and the effectiveness-NTU method are the two important methods for design and analysis of heat exchangers. The derivation of these two methods relies on a critical assumption, i.e., the fluid specific heats are constant. Under special operating conditions where one fluid experiences condensation or evaporation at constant temperature, these two methods are still valid. In practice, however, the fluid temperature in heat exchangers will never remain constant during phase change because of pressure drop. Meanwhile, zeotropic refrigerant mixtures exhibit temperature variations even during a constant pressure phase change process. Therefore, both LMTD and …

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Integrated Thermal Energy Storage For Cooling Applications, Paul Kalinowski, Cara Martin, William L. Kopko Jan 2018

Integrated Thermal Energy Storage For Cooling Applications, Paul Kalinowski, Cara Martin, William L. Kopko

International Refrigeration and Air Conditioning Conference

Many commercial and industrial facilities are cooled using vapor compression cycles (VCC). The performance of such systems degrades with high outdoor temperatures causing high peak electric demand increase, reduced efficiency and lower cooling capacity. An Integrated Thermal Energy Storage System (ITESS) utilizing chilled water provides additional subcooling for a VCC condenser, thereby increasing the capacity of the entire system and providing significant reductions in electric demand and consumption. The ITESS uses a dedicated chiller to cool a thermal storage tank, typically at night when electricity demand and rates may be lower. This thermal reservoir is used during the following day …

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An Experimentally Validated Model For Microchannel Condensers With Separation Circuiting, Jun Li, Predrag S. Hrnjak Jan 2018

An Experimentally Validated Model For Microchannel Condensers With Separation Circuiting, Jun Li, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

The experimental study of an automotive microchannel condenser with separation circuiting was presented in the past by the same authors demonstrating the potential for performance improvement (lower refrigerant exit temperature or higher condensate flow rate). The condenser has an inlet in the middle of the height and vapor is expected to separate from liquid in the second header after de-superheating in the first pass. Upper path (for vapor) and lower path (for liquid) recombine upstream the exit of the condenser. This paper presents a mechanistic model developed to predict the phase separation efficiency in the second header that is incorporated …

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Expanded Hot Surface Ignition Testing Of A2l Refrigerants, Patrick Coughlan, Nina Gray, Mary Koban Jan 2018

Expanded Hot Surface Ignition Testing Of A2l Refrigerants, Patrick Coughlan, Nina Gray, Mary Koban

International Refrigeration and Air Conditioning Conference

Transitioning to low global warming potential (GWP) refrigerants will be critical as the world rises to solve the issues of climate change. Finding low GWP alternatives for HVAC equipment which can be safely used and serviced in varying applications is the new challenge. An interesting class of low GWP alternatives are the “mildly flammable” or class 2L refrigerants. ISO 817 and ANSI/ASHRAE Standard 34 both employ the “mildly flammable” or “2L” refrigerant classification. Class 2L refrigerants are not easily ignited due to their relatively high minimum ignition energy (MIE) and high lower flammability level (LFL) compared to class 3 refrigerants. …

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Numerical Investigation On Effects Of Sub-Cooling Methods On Performance Of Multi-Split Variable Refrigerant Flow Systems With Bypass And Vapor Injection Techniques, Byung-Chae Min, Sang-Kyung Na, Hyeongjun Kim, G.M. Choi Jan 2018

Numerical Investigation On Effects Of Sub-Cooling Methods On Performance Of Multi-Split Variable Refrigerant Flow Systems With Bypass And Vapor Injection Techniques, Byung-Chae Min, Sang-Kyung Na, Hyeongjun Kim, G.M. Choi

International Refrigeration and Air Conditioning Conference

The pipeline connected between outdoor units and indoor units is lengthened in the VRF systems because the VRF systems are generally used in light commercial buildings. Therefore, a sub-cooler is installed in the VRF systems to avoid flash gas caused by pressure drop and heat transfer in the liquid pipeline. Usually, the liquid refrigerant in the pipeline can be cooled by bypass and refrigerant injection techniques with an internal heat exchanger (IHX) and electric expansion valve (EEV). In this study, the performance of the VRF systems using bypass and refrigerant injection cycles are compared by numerical method. The simulation for …

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Tomato Cultivar Evaluation In High Tunnels, Northern Indiana, 2017, Elizabeth Maynard, Erin A. Bluhm Jan 2018

Tomato Cultivar Evaluation In High Tunnels, Northern Indiana, 2017, Elizabeth Maynard, Erin A. Bluhm

Purdue Fruit and Vegetable Research Reports

Tomatoes are a common crop grown in unheated greenhouses, commonly called high tunnels. Production in these structures has increased in recent years. This trial was conducted to evaluate varieties for their performance as a summer-harvested crop in soil-based high tunnel production systems. Five hybrid determinate varieties or line, one hybrid indeterminate, and one open-pollinated indeterminate variety were compared for yield, earliness, fruit size, and quality.

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Exploring An Organizational Science View On Faculty Gender And Work-Life Inclusion: Conceptualization, Perspectives, And Interventions, Ellen Ernst Kossek Jan 2018

Exploring An Organizational Science View On Faculty Gender And Work-Life Inclusion: Conceptualization, Perspectives, And Interventions, Ellen Ernst Kossek

NSF Workshop Fostering Gender and Work-Life Inclusion for Faculty in Understudied Contexts: An Organizational Science Lens

No abstract provided.

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Proof Or Pedigree: Prestige Of Men’S But Not Women’S Phd Program Predicts Top Placements In Business Schools, Stefanie Johnson Jan 2018

Proof Or Pedigree: Prestige Of Men’S But Not Women’S Phd Program Predicts Top Placements In Business Schools, Stefanie Johnson

NSF Workshop Fostering Gender and Work-Life Inclusion for Faculty in Understudied Contexts: An Organizational Science Lens

No abstract provided.

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Faculty Time Allocation Across Work And Family Roles, Tammy Allen Jan 2018

Faculty Time Allocation Across Work And Family Roles, Tammy Allen

NSF Workshop Fostering Gender and Work-Life Inclusion for Faculty in Understudied Contexts: An Organizational Science Lens

No abstract provided.

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Can Work-Life Inclusion Reshape Gender And Ideal Worker Norms?, Eden King Jan 2018

Can Work-Life Inclusion Reshape Gender And Ideal Worker Norms?, Eden King

NSF Workshop Fostering Gender and Work-Life Inclusion for Faculty in Understudied Contexts: An Organizational Science Lens

No abstract provided.

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And They Were There- Reports Of Meetings - 37th Annual Charleston Conference, Ramue K. Kubilius, Sever Bordeianu Jan 2018

And They Were There- Reports Of Meetings - 37th Annual Charleston Conference, Ramue K. Kubilius, Sever Bordeianu

Against the Grain

No abstract provided.

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Measuring Religiosity In A Religiously Diverse Society: The China Case, L. Luke Chao, Fenggang Yang Jan 2018

Measuring Religiosity In A Religiously Diverse Society: The China Case, L. Luke Chao, Fenggang Yang

Department of Sociology Faculty Publications

No abstract provided.

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Religion In The Global East: Challenges And Opportunities For The Social Scientific Study Of Religion, Fenggang Yang Jan 2018

Religion In The Global East: Challenges And Opportunities For The Social Scientific Study Of Religion, Fenggang Yang

Department of Sociology Faculty Publications

This essay is based on the Presidential Address at the East Asian Society for the Scientific Study of Religion Inaugural Conference on 3–5 July 2018 in Singapore. It discusses some aspects of the key concepts, some of the distinct characteristics of religion in East Asia, and some implications for the social scientific study of religion in general.

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Shaping The Religiosity Of Chinese University Students: Science Education And Political Indoctrination, Miao Li, Yun Lu, Fenggang Yang Jan 2018

Shaping The Religiosity Of Chinese University Students: Science Education And Political Indoctrination, Miao Li, Yun Lu, Fenggang Yang

Department of Sociology Faculty Publications

Our study examined the respective relationships between two components of higher education in mainland China—science education and political indoctrination—and the religiosity of university students. Using a cross-sectional, representative sample of about 1700 college students in Beijing, we found first that students studying natural/applied sciences were less likely to perceive Protestantism, Catholicism, and Islam as plausible and less likely to have supernatural belief, relative to students in humanities/social sciences. In addition, the more students positively evaluated the political education courses—which indicates students’ acceptance of political indoctrination—the less likely they reported Protestantism and Catholicism as being plausible. Nevertheless, neither science education nor …

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Optimization Of Oil Separator For Variable Swash Plate Compressor In The Vehicle Air Conditioning System, Taejin Lee, Bongsub Lee, Geonho Lee Jan 2018

Optimization Of Oil Separator For Variable Swash Plate Compressor In The Vehicle Air Conditioning System, Taejin Lee, Bongsub Lee, Geonho Lee

International Compressor Engineering Conference

The air-conditioning system operated by the variable swash plate compressor which is used in most engine vehicle is a convenient device that allows the user to comfortably maintain the temperature inside the vehicle properly. However, since the compressor is operated by the engine, the high efficiency of air-conditioning system to reduce fuel consumption and the compressor durability improvement on the high speed and high load conditions has been becoming the important issue. In this paper, the research of the compressor oil separator has been carried out to improve the system efficiency and to guarantee the compressor durability. The compressor circulates …

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Modeling A Scroll Compressor Using A Cartesian Cut-Cell Based Cfd Methodology With Automatic Adaptive Meshing, Ha-Duong Pham, Thomas Brandt, David Henry Rowinski Jan 2018

Modeling A Scroll Compressor Using A Cartesian Cut-Cell Based Cfd Methodology With Automatic Adaptive Meshing, Ha-Duong Pham, Thomas Brandt, David Henry Rowinski

International Compressor Engineering Conference

The recent requirements on the scroll compressors used in air conditioning systems are focused on the reduction of the noise and the improvement of the efficiency. To achieve this, the complex fluid flow phenomenon taking place inside of the compressor must be better understood. Two modeling approaches for investigating this problem are one-dimensional multi-physics modeling and three-dimensional computational fluid dynamics (CFD) modeling. The one-dimensional multi-physics based models are available to perform these calculations with low computational cost, but the influence of detailed geometrical effects on the fluid flow behavior is not taken into account. This paper deals with the development …

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