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Impact Of Suction And Injection Gas Superheat Degrees On The Performance Of A Residential Heat Pump With Vapor Injection And Variable Speed Scroll Compressor, Bertrand Dechesne, Lemort Vincent, Madiha Nadri, Pascal Dufour Jan 2018

Impact Of Suction And Injection Gas Superheat Degrees On The Performance Of A Residential Heat Pump With Vapor Injection And Variable Speed Scroll Compressor, Bertrand Dechesne, Lemort Vincent, Madiha Nadri, Pascal Dufour

International Refrigeration and Air Conditioning Conference

The market share of heat pump systems has grown significantly in Europe in the past decades and, in residential applications, air-source heat pumps (ASHP) are usually considered due to their relatively low cost. In the literature, it has been widely demonstrated that injection cycle can improve the system performance and operating range. This paper presents experimental results of an air-to-water residential heat pump using a variable speed scroll compressor with vapor injection. The first part of the paper focuses on the experimental results collected from a vapor injection and variable speed scroll compressor air-to-water residential heat pump. The unit is …

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Theoretical Development Of Thermodynamic Properties Of Environmental Friendly Refrigerant Re170 By Using Martin Hou Equation Of State, Ashok Babu Puttaranga Setty Talanki, Sharmas Vali Shaik Jan 2018

Theoretical Development Of Thermodynamic Properties Of Environmental Friendly Refrigerant Re170 By Using Martin Hou Equation Of State, Ashok Babu Puttaranga Setty Talanki, Sharmas Vali Shaik

International Refrigeration and Air Conditioning Conference

This paper deals with the theoretical development of thermodynamic properties of an environmental friendly refrigerant dimethylether (RE170). Since hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are going to be phase out and phase down as per Montreal and Kyoto protocol respectively. Refrigerant RE170 has zero ozone depletion potential (ODP) and very low global warming potential (GWP) which is less than two. Hence RE170 is considered as a viable option to replace for the refrigerants with high global warming potential (GWP) like HCFCs and HFCs. RE170 can be used as blend component with other ecofriendly refrigerant. The main objective of the present study …

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Tube-Fin Heat Exchanger Circuitry Optimization Using Integer Permutation Based Genetic Algorithm, Zhenning Li, Jiazhen Ling, Vikrant Chandramohan Aute Jan 2018

Tube-Fin Heat Exchanger Circuitry Optimization Using Integer Permutation Based Genetic Algorithm, Zhenning Li, Jiazhen Ling, Vikrant Chandramohan Aute

International Refrigeration and Air Conditioning Conference

Tube-fin heat exchangers (HXs) are widely used in air-conditioning and heat pumping applications. The performance of these heat exchangers is strongly influenced by the refrigerant circuitry, i.e. the refrigerant flow path along the different tubes in the HX core. Since for a given number of tubes, the number of possible circuitries is exponentially large, neither the exhaustive search nor traditional optimization algorithms can be used to optimize the circuitry for a given application. Researchers have previously used Genetic algorithms (GA) coupled with a learning module to solve this problem, but there is no guarantee that the resulting circuitry can be …

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Investigations Of Heat Transfer And Components Efficiencies In Two-Phase Isobutane Injector, Kamil Smierciew, Dariusz Butrymowicz, Mark Bergander, Tomasz Przybylinski Jan 2018

Investigations Of Heat Transfer And Components Efficiencies In Two-Phase Isobutane Injector, Kamil Smierciew, Dariusz Butrymowicz, Mark Bergander, Tomasz Przybylinski

International Refrigeration and Air Conditioning Conference

Renewable energy sources may be applied to drive refrigeration and air-conditioning systems, e.g. solar radiation, geothermal resources, heat derived from biomass or waste heat rejected form various thermal processes. In this case absorption refrigeration systems and ejection systems may be used for cooling applications. In both these systems the crucial problem is the development of a suitable liquid pump. Energy consumption to drive these systems is not a major problem here as in most cases amount of energy required to drive a mechanical pump is a contribution of at most a few percent of the overall energy balance of the …

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Hydrofluoroolefins As Refrigerants For Heat Pump Water Heating Applications, Kashif Nawaz, Bo Shen, Ahmed Elatar, Van Baxter Jan 2018

Hydrofluoroolefins As Refrigerants For Heat Pump Water Heating Applications, Kashif Nawaz, Bo Shen, Ahmed Elatar, Van Baxter

International Refrigeration and Air Conditioning Conference

Recently there has been a growing interest in utilization of alternative refrigerants for residential and commercial HVAC&R systems due to the potential environmental impacts of conventional fluids (CFCs and HFCs). Hydrofluoroolefins such as R1234yf and R1234ze(E) has shown promising performance and are being extensively considered for range of heat pump applications. This study illustrates the performance evaluation of R1234yf and R1234ze(E) as drop-in-replacement for R134a for heat pump water heating (HPWH). A component-based model is used to predict the performance. Key performance parameters such as unified energy factor, first hour rating and thermal stratification in the water tank are investigated. …

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An Axial Resistance-Varying Method For Improved Quantification Of Enhanced Surface Condenser Tube Performance, Cameron Stuart Nelson, Icksoo Kyung Jan 2018

An Axial Resistance-Varying Method For Improved Quantification Of Enhanced Surface Condenser Tube Performance, Cameron Stuart Nelson, Icksoo Kyung

International Refrigeration and Air Conditioning Conference

In shell-and-tube condensers, local heat flux and thermal resistance change along a tube’s length due to the rise in water temperature as heat is absorbed. In this study, the outside heat transfer coefficient for pure condensation on an enhanced surface condenser tube was developed as a function of local heat flux. The developed heat transfer coefficient correlation was then substituted into the energy equation and solved to obtain the local mean water temperature as a function of axial position. The developed axial resistance-varying method was compared to the conventional log mean temperature difference method and showed applicability for long tube …

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Comparing Maintenance Strategies For Rooftop Units Having Multiple Faults Through Simulation, Andrew L. Hjortland, James E. Braun Jan 2018

Comparing Maintenance Strategies For Rooftop Units Having Multiple Faults Through Simulation, Andrew L. Hjortland, James E. Braun

International Refrigeration and Air Conditioning Conference

Maintenance strategies currently used for commercial building rooftop units (RTU) can be classified into two categories: reactive strategies and proactive strategies. In reactive strategies, maintenance and service is performed only when needed, e.g. when a system is unable to maintain setpoint. In proactive strategies, maintenance is scheduled at routine intervals to avoid service interruptions regardless of whether the system actually needs it. While these strategies could not be more different, it is unclear which strategy is more optimal. Moreover, whether one strategy is more optimal than the other more than likely depends on the application – contributing to much uncertainty. …

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The Analysis Of Binary Fluid Ejector Assisted Solar Desalination System, Olexiy Buyadgie, Oleksii Drakhnia, Takahiko Miyazaki, Dmytro Buyadgie, Igor Vasil'ev, Shigeru Koyama Jan 2018

The Analysis Of Binary Fluid Ejector Assisted Solar Desalination System, Olexiy Buyadgie, Oleksii Drakhnia, Takahiko Miyazaki, Dmytro Buyadgie, Igor Vasil'ev, Shigeru Koyama

International Refrigeration and Air Conditioning Conference

The proposed desalination technology represents the combined processes of distillation and congelation of seawater. While distilling runs at two-stage, the condensation heat of the distillate vapors is utilized for cold generation in the Binary Fluid Ejector Refrigeration System (BERS). The congelation process is organized with continuous heat recuperation that enables to mark up about 80% of the fresh water, produced by BERS. The system tolerates any type of seawater (30k ≤ TDS ≤ 100k) and operates with solar thermal heat of 338-356F. The integrated binary fluid ejector heat pump doubles the input of thermal energy at 248F, so the overall …

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3d Direct Numerical Simulation Of Magneto-Caloric Regenerators, Ibai Mugica, Sebastien Poncet, Jonathan Bouchard Jan 2018

3d Direct Numerical Simulation Of Magneto-Caloric Regenerators, Ibai Mugica, Sebastien Poncet, Jonathan Bouchard

International Refrigeration and Air Conditioning Conference

Magnetic refrigeration uses magnetic field changes to provoke a phase transition in solid Magneto-Caloric Materials (MCM). Then, using a Heat Transfer Fluid, a Brayton-like refrigeration cycle can be produced. Developing these kind of refrigerators is usually costly, due to the amount of rare earth materials needed for the permanent magnet and the MCM. In order to aid in better designing such machines, a 3D DNS solver was developed. The solver includes the simulation of four different physical phenomena: the magnetic field, fluid velocity field, temperature field, and the Magneto-Caloric Effect. To produce an efficient solver, collateral coupling mechanisms were studied …

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Visualization Of R410a Flow Boiling In Diabatic Conditions Inside Horizontal Round Tubes, Cheng-Min Yang, Predrag S. Hrnjak Jan 2018

Visualization Of R410a Flow Boiling In Diabatic Conditions Inside Horizontal Round Tubes, Cheng-Min Yang, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

The objective of this paper is to present the mechanism of flow boiling in horizontal smooth and micro-finned tubes through visualization in diabatic conditions. In most of the literature, the flow regime of flow boiling in the micro-finned evaporator tube is visualized by the sight glass at the exit of the test section under adiabatic condition. In order to better understand effect of micro-fins in flow boiling in the visualization test section, a novel technique to visualize flow of evaporation under diabatic condition has been developed and presented. R410A flow boiling experiments are conducted at 10 °C saturation temperature in …

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Using A Cubic Equation Of State To Identify Optimal Working Fluids For An Orc Operating With Two-Phase Expansion Using A Twin-Screw Expander, Martin T. White, Matthew Read, Abdulnaser I. Sayma Jan 2018

Using A Cubic Equation Of State To Identify Optimal Working Fluids For An Orc Operating With Two-Phase Expansion Using A Twin-Screw Expander, Martin T. White, Matthew Read, Abdulnaser I. Sayma

International Refrigeration and Air Conditioning Conference

For waste-heat recovery applications, operating an organic Rankine cycle (ORC) with two-phase expansion has been shown to increase the utilisation of the waste-heat stream, leading to a higher power output compared to a conventional ORC with single-phase expansion. However, unlike the conventional ORC, working-fluid selection for an ORC operating with two-phase expansion has not been explored in detail within the literature. Therefore, the aim of this paper is to explore which working-fluid parameters make a particular working fluid suitable for this type of cycle. This is conducted by coupling a thermodynamic model of the cycle with the Peng-Robinson cubic equation …

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Void Fraction And Flow Regimes Of R134a In Horizontal And Vertical Round Tubes In Developed Adiabatic Conditions, Hongliang Qian, Predrag S. Hrnjak Jan 2018

Void Fraction And Flow Regimes Of R134a In Horizontal And Vertical Round Tubes In Developed Adiabatic Conditions, Hongliang Qian, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

This paper presents flow regimes and void fraction in horizontal and vertical round tubes ID 7 mm with R134a in the adiabatic conditions and low mass flux (40-150 kg/m2s for horizontal tubes and 65-115 kg/m2s for vertical tubes) captured by a high-speed camera. Horizontal flow patterns are compared to Wojtan-Ursenbacher-Thome flow regime map and some modifications are proposed. Void fraction results for both horizontal and vertical tubes are compared to some widely used correlations. Influences of tube orientation and mass flux on void fraction are discussed. At the same vapor quality condition, void fraction of horizontal tubes is larger than …

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Pressure Drop Model For Condensation From Superheated Vapor, Jiange Xiao, Predrag S. Hrnjak Jan 2018

Pressure Drop Model For Condensation From Superheated Vapor, Jiange Xiao, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

A new pressure drop model based on flow regime map is proposed for condensation inside horizontal smooth round tubes accounting for the non-equilibrium in a vapor compression system. Conventionally, a pressure drop model for two-phase flow only accounts for the prediction between bulk quality 1 and 0. The temperature gradient during condensation, however, creates the non-equilibrium that guarantees two-phase flow beyond bulk quality 1 and 0. The new model determines the onset and end of condensation by tracing the development of the liquid film when the superheated vapor is condensed on the tube wall. The flow regime map designed specifically …

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Advanced Air-Side Heat Transfer Surface Geometries Enabled By Additive Manufacturing, Courtney Leeds, Cassandra Wright, Gregory F. Nellis Jan 2018

Advanced Air-Side Heat Transfer Surface Geometries Enabled By Additive Manufacturing, Courtney Leeds, Cassandra Wright, Gregory F. Nellis

International Refrigeration and Air Conditioning Conference

In a world with a decreasing supply of fresh water, industry is looking for design solutions that depend less on the availability of water. Dry-cooled condensers are one possibility, but they must compete with traditional water-cooled condensers in terms of cost, performance, and fan power. To improve performance, air-side heat transfer designs must be improved. Additive manufacturing offers the freedom to create designs that are difficult to manufacture with traditional methods. While the materials for additive manufacturing are not as conductive as the metals used in conventional heat exchangers, highly filled polymers do allow an improvement in conductivity and strength …

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Refrigerants With Low Environmental Impact For Commercial Refrigeration Systems, Michael Petersen, Gustavo Pottker, Ankit Sethi, Samuel F. Yana Motta Jan 2018

Refrigerants With Low Environmental Impact For Commercial Refrigeration Systems, Michael Petersen, Gustavo Pottker, Ankit Sethi, Samuel F. Yana Motta

International Refrigeration and Air Conditioning Conference

New refrigerants with the positive attributes of both high thermal performance and low environmental impact are currently in development. These refrigerants provide high energy efficiency, which coupled with low GWP significantly reduce the total environmental impact compared with current fluids (R404A, R507, R22 and R134a). Properties, and experimental results are compared and discussed for refrigeration applications. Alternative system architectures for refrigeration applications utilizing the beneficial characteristics of these new fluids are also discussed. A holistic analysis approach is used to evaluate the lifetime environmental and operational impact for the refrigerants and systems presented in this study.

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Experimental Study Of Condensation Heat Transfer Of R134a On Oil-Infusion Surfaces, Hongqing Jin, Yuchen Shen, Wentao Ni, Xiaofei Wang Jan 2018

Experimental Study Of Condensation Heat Transfer Of R134a On Oil-Infusion Surfaces, Hongqing Jin, Yuchen Shen, Wentao Ni, Xiaofei Wang

International Refrigeration and Air Conditioning Conference

Dropwise condensation, since first recognized in 1930, has stimulated interest because its heat transfer coefficient (HTC) is much higher than film condensation. For some applications, not only a higher heat transfer performance is desired, but also the retention of the fluids on the surface can be a big issue. For example, the refrigerant retention in some enhanced tube can block the contact of the vapor-solid interface and increase the thermal resistance; it also can increase the charge of refrigerant because certain amount of refrigerant could not go through the system cycle. Many efforts were dedicated to modifying the surface and …

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Heat Transfer Coefficient, Pressure Drop, And Flow Visualization Of R1234ze(E), And R1234yf In Microchannel Tube, Houpei Li, Predrag S. Hrnjak Jan 2018

Heat Transfer Coefficient, Pressure Drop, And Flow Visualization Of R1234ze(E), And R1234yf In Microchannel Tube, Houpei Li, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

This paper presents heat transfer coefficient, pressure drop, and flow visualization of R1234ze(E) and R1234yf measured in the same facility as introduced in Li and Hrnjak (2016). Experiments are conducted on a 24-port microchannel tube with a hydraulic diameter of 0.643 mm. Mass flux varies from 100 to 200 kg m-2s-1. Heat flux varies from 0 to 6 kW m-2. A comprehensive presentation of measurement will be made in this paper. HTC, PD, and flow pattern will be reported in the same figure. The flow pattern results of R1234yf and R1234ze(E) are shown in the previous paper (Li and Hrnjak, …

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A Novel Solar-Assisted Membrane-Based Liquid Desiccant Air Conditioning System For Hot And Humid Climatic Conditions, Gurubalan A, Maiya M P, Shaligram Tiwari Jan 2018

A Novel Solar-Assisted Membrane-Based Liquid Desiccant Air Conditioning System For Hot And Humid Climatic Conditions, Gurubalan A, Maiya M P, Shaligram Tiwari

International Refrigeration and Air Conditioning Conference

1. Introduction According to the energy statistics of India, building sector consumes 40% of electricity out of which nearly one third is consumed by heating, ventilation and air conditioning (HVAC) systems [1]. Currently, more than 90% of the HVAC systems are of vapor compression refrigeration type which are energy inefficient for humidity control [2]. Therefore, it is desirable to meet such HVAC demands using an alternative system which is not only energy efficient, but can also utilize the low grade energy sources such as solar or waste heat. The liquid desiccant system is one such prospective alternative which can utilize …

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Investigation Of The Pressure Drop In Refrigerant Pipes Of An R744 Automotive Air Conditioning System, Christoph Subei, Gerhard Schmitz Jan 2018

Investigation Of The Pressure Drop In Refrigerant Pipes Of An R744 Automotive Air Conditioning System, Christoph Subei, Gerhard Schmitz

International Refrigeration and Air Conditioning Conference

For the design of air conditioning systems the automotive industry often uses the AirConditioning Library written in the modeling language Modelica. In this one-dimensional modeling approach system components are discretized only in flow direction. The refrigerant pipes connecting components like compressor, evaporator and condenser are usually modeled as straight pipes with equivalent length or they are neglected. Due to the arrangement of components in the engine compartment refrigerant pipes contain a large number of bends, contractions and expansions as well as corrugated tubes. This leads to a considerably higher pressure drop of these pipes compared to straight pipes. On the …

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Investigation On Start-Up And Reliability During Unsteady Process Of Low Temperature Air Source Heat Pump, Youxuan Liang, Jun Shen, Huan Zhao, Feng Tan, Peiyu Lei Jan 2018

Investigation On Start-Up And Reliability During Unsteady Process Of Low Temperature Air Source Heat Pump, Youxuan Liang, Jun Shen, Huan Zhao, Feng Tan, Peiyu Lei

International Refrigeration and Air Conditioning Conference

In this paper the air source heat pump variable refrigerant flow (VRF) of two-stage vapor injection system were analyzed, to investigate the compressor start-up performance at low ambient temperature and the system reliability during unsteady operating process. The start-up control logic of VRF were designed, which combined the control of the electronic expansion valves (EEV), the oil switch valve (SV) and the elevator rate of compressor frequency, to achieve the unit steadily started up at -35℃. In the study on the reliability during unsteady process of the system, the phenomena of the refluence vapor and the enthalpy increasing by vapor …

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Transient Simulation Of Small-Capacity Reciprocating Compressors For On-Off Controlled Refrigerators, Marco C. Diniz, Christian Hermes, Marco C. Diniz Jan 2018

Transient Simulation Of Small-Capacity Reciprocating Compressors For On-Off Controlled Refrigerators, Marco C. Diniz, Christian Hermes, Marco C. Diniz

International Refrigeration and Air Conditioning Conference

This paper presents a simulation model for the transient behavior of vapor compression refrigerating appliances subjected to on-off control patterns focusing on the reciprocating compressor. A detailed compressor model is put forward based on two sub-models: one for the compression cycle, which can predict the valve dynamics, heat transfer in the compression chamber and the pressure pulsations in mufflers, and the other for the compressor shell, which calculates the temperature and mass flow rate in components other than the compression chamber. The remaining components of the single-door frost-free refrigerator considered in this work (i.e. condenser, evaporator, refrigerated compartment) are modeled …

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Exergy Analysis Of A Vapor Absorption Refrigeration System Using Carbon Dioxide As Refrigerant, Samsher Gautam, Apoorva Roy, Bhuvan Aggarwal Jan 2018

Exergy Analysis Of A Vapor Absorption Refrigeration System Using Carbon Dioxide As Refrigerant, Samsher Gautam, Apoorva Roy, Bhuvan Aggarwal

International Refrigeration and Air Conditioning Conference

Vapor absorption refrigeration systems can be an alternative to vapor compression systems in many applications as they can operate on a low-grade heat source and are environment friendly. Widely used refrigerants such as CFCs and HFCs cause significant global warming. Natural refrigerants can be used instead of them, among which carbon dioxide is promising. Its inherent safety, ability to withstand high pressure and high heat transfer coefficient coupled with easy availability make it a likely choice for refrigerant. [Bmim][PF6] is a room temperature ionic liquid (RTIL) composed of a large organic cation and an inorganic anion. Its properties such as …

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Detailed Thermal Model Of An Open-Drive Single-Screw Expander For Orc Applications, Davide Ziviani, Michel De Paepe, James E. Braun, Eckhard A. Groll Jan 2018

Detailed Thermal Model Of An Open-Drive Single-Screw Expander For Orc Applications, Davide Ziviani, Michel De Paepe, James E. Braun, Eckhard A. Groll

International Compressor Engineering Conference

A comprehensive mechanistic model of an open-drive single-screw expander for waste heat recovery applications by means of an Organic Rankine Cycle (ORC) has been previously developed and validated by the authors. The model included sub-models of geometry, leakage flows, in-chamber heat transfer, simplified friction losses and a single-lumped temperature overall energy balance. Furthermore, a non-symmetric approach was also implemented to simulate the simultaneous expansion process occurring on both side of the central rotor. In this work, the mechanistic model has been extended to compute the loads on the starwheels bearings as well as the main rotor. Forces and moments analyses …

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A Point Sink Superposition Method For Predicting Droplet Interaction Effects During Vapor-Diffusion-Driven Dropwise Condensation In Humid Air, J. E. Castillo, J. A. Weibel Jan 2018

A Point Sink Superposition Method For Predicting Droplet Interaction Effects During Vapor-Diffusion-Driven Dropwise Condensation In Humid Air, J. E. Castillo, J. A. Weibel

CTRC Research Publications

During dropwise condensation from the ambient environment, water vapor present in air must diffuse to the surface of each droplet. The spatial distribution of water vapor in the local surroundings of each individual droplet determines the total condensation rate. However, available models for dropwise condensation in humid air assume that such systems of droplets grow either as an equivalent film or that the growth of each droplet is completely isolated; the interactions between droplets are poorly described and, consequently, predictions of total condensation rates may mismatch experimental observations. This paper presents a reduced-order analytical method to calculate the condensation rate …

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Development And Validation Of A Semi-Empirical Model For Two-Phase Heat Transfer From Arrays Of Impinging Jets, C. Mira-Hernández, M. D. Clark, J. A. Weibel, S V. Garimella Jan 2018

Development And Validation Of A Semi-Empirical Model For Two-Phase Heat Transfer From Arrays Of Impinging Jets, C. Mira-Hernández, M. D. Clark, J. A. Weibel, S V. Garimella

CTRC Research Publications

Two-phase jet impingement is a compact cooling technology that provides high-heat-flux dissipation at manageable pressure drop, with applications in cooling power electronics and server modules. The extensive set of geometrical parameters and operating conditions that determine the heat transfer behavior of jet impingement systems provide an attractive level of design flexibility. In the present study, a semiempirical approach is developed to predict heat transfer from arrays of jets of liquid that undergoes phase change upon impingement. In the modeling approach developed, the jet array is divided into unit cells centered on each orifice that are assumed to behave identically. Based …

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A Hierarchical Manifold Microchannel Heat Sink Array For High-Heat-Flux Two-Phase Cooling Of Electronics, K. P. Drummond, D. Back, M. D. Sinanis, D. B. Janes, D. Peroulis, J. A. Weibel, S V. Garimella Jan 2018

A Hierarchical Manifold Microchannel Heat Sink Array For High-Heat-Flux Two-Phase Cooling Of Electronics, K. P. Drummond, D. Back, M. D. Sinanis, D. B. Janes, D. Peroulis, J. A. Weibel, S V. Garimella

CTRC Research Publications

High-heat-flux removal is necessary for next-generation microelectronic systems to operate more reliably and efficiently. Extremely high heat removal rates are achieved in this work using a hierarchical manifold microchannel heat sink array. The microchannels are imbedded directly into the heated substrate to reduce the parasitic thermal resistances due to contact and conduction resistances. Discretizing the chip footprint area into multiple smaller heat sink elements with high-aspect-ratio microchannels ensures shortened effective fluid flow lengths. Phase change of high fluid mass fluxes can thus be accommodated in micron-scale channels while keeping pressure drops low compared to traditional, microchannel heat sinks. A thermal …

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Improving The Reliability Of A Domestic Refrigerator Compressor Subjected To Repetitive Loading, Seongwoo Woo, Dennis O'Neal Jan 2018

Improving The Reliability Of A Domestic Refrigerator Compressor Subjected To Repetitive Loading, Seongwoo Woo, Dennis O'Neal

International Compressor Engineering Conference

As a reliability quantitative specification, parametric accelerated life testing was used to assess the reliability of a newly designed compressor of a commercial refrigerator subjected to repetitive stresses. A generalized life-stress failure model and new sample size equation with a new load concept were derived starting with the basic refrigeration cycle. The sample size equation with the acceleration factor also enabled the parametric accelerated life testing to quickly evaluate the expected lifetime. The design of this testing should help an engineer uncover the design parameters affecting reliability during the design process of the compressor system. Consequently, it should help companies …

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Improving The Reliability Of A Domestic Refrigerator Compressor Subjected To Repetitive Loading, Seongwoo Woo, Dennis O'Neal Jan 2018

Improving The Reliability Of A Domestic Refrigerator Compressor Subjected To Repetitive Loading, Seongwoo Woo, Dennis O'Neal

International Compressor Engineering Conference

As a reliability quantitative specification, parametric accelerated life testing was used to assess the reliability of a newly designed compressor of a commercial refrigerator subjected to repetitive stresses. A generalized life-stress failure model and new sample size equation with a new load concept were derived starting with the basic refrigeration cycle. The sample size equation with the acceleration factor also enabled the parametric accelerated life testing to quickly evaluate the expected lifetime. The design of this testing should help an engineer uncover the design parameters affecting reliability during the design process of the compressor system. Consequently, it should help companies …

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High-Performance Rotary Screw Compressor Test Stand, David A. Penz Jan 2018

High-Performance Rotary Screw Compressor Test Stand, David A. Penz

International Compressor Engineering Conference

ABSTRACT A new high-performance test stand tests both constant speed and variable speed semi-hermetic rotary screw R134A water chiller compressors ranging from approximately 250 to 600kW rated refrigeration capacity. The stand produces rapid post-production functional tests with excellent accuracy, higher measurement accuracy laboratory-quality tests, and also manually-directed tests of any duration. All tests include startup, warmup and steady state data recording at three operating conditions (typically full load displacement, intermediate load and unload). Some compressor models additionally perform an oil shuttle control valve test. The test sequence is automatic, requiring operator intervention only to mount and connect the Unit Under …

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Research Of Nopd Technology Applied On Vibration Reduction Of Rotor Compressor, Bo Huang, Yinxiao Lu Jan 2018

Research Of Nopd Technology Applied On Vibration Reduction Of Rotor Compressor, Bo Huang, Yinxiao Lu

International Compressor Engineering Conference

The vibration of compressor shafting cause the uneven air gap between stator and rotor which intensify the Electromagnetic vibration of motor. The traditional damping technique cannot be used under high temperature and high pressure condition inside compressor. In order to make a vibration reduction of compressor shafting, a technique named Non-obstacle Particle Damping was used. Some special NOPD shock absorbers were designed for shafting vibration reduction. According to the structure of one inverter compressor, 4 NOPD shock absorbers with different number of particle filled in and material were made and fixed to the rotor to achieve optimum design parameters. Results …

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