Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Purdue University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1711 - 1740 of 8612

Full-Text Articles in Entire DC Network

Pros & Cons Of Using Hot-Wall Condensers In Household Refrigerators, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Claudio Melo Jan 2018

Pros & Cons Of Using Hot-Wall Condensers In Household Refrigerators, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Claudio Melo

International Refrigeration and Air Conditioning Conference

This work focuses on the pros and cons of using hot-wall condensers in household refrigerators, based both in numerical and experimental approaches. To this end, eight different refrigerator samples of the same model were manufactured with distinct designs of hot-wall condensers. The design parameters were the following: (i) adhesive tape (aluminum or polyethylene), (ii) tube outer diameter (4 or 4.76 m), (iii) total length (10 or 11.5 m) and (iv) lay-out. An in-house mathematical model for hot-wall condensers was added to an in-house system simulation tool to predict the samples performance. Experiments were also conducted in a climate-controlled test chamber …

Go to article

Numerical Simulation Of Fault Impacts For Commercial Walk-In Freezers, Alireza Behfar, David P. Yuill Jan 2018

Numerical Simulation Of Fault Impacts For Commercial Walk-In Freezers, Alireza Behfar, David P. Yuill

International Refrigeration and Air Conditioning Conference

Refrigeration systems can undergo many faults that could negatively affect their operation and performance. This paper describes a modeling process to simulate the fault impacts on the operation of a commercial walk-in freezer using semi-empirical models. These models often require less modeling effort than full forward models and could be used in scenarios where detailed information is missing, such as in field-measured systems. An important characteristic of a typical walk-in refrigeration system is the existence of a liquid-line receiver after the condenser, which significantly changes the behavior of the cycle, in comparison to a receiver-less system. Component models described in …

Go to article

Novel Visualization Method To Quantify Local Air-Side Heat Transfer Coefficient, Min Che, Stefan Elbel Jan 2018

Novel Visualization Method To Quantify Local Air-Side Heat Transfer Coefficient, Min Che, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Low air-side heat transfer coefficients (HTC) are often the bottleneck of heat exchanger performance. However, the measurement of local air-side heat transfer coefficients for the entire heat transfer surface is not a trivial task. Current experimental methods often only work on scaled-up samples which typically cannot deliver continuous HTC distributions across the surface of interest. Moreover, some methods require very precise and costly equipment such as lasers. Therefore, a novel visualization method is designed to obtain local air-side HTC distributions of an entire heat exchanger with a relatively simple experimental facility. The method relies on measuring mass transfer and applying …

Go to article

Surface Tension Measurement Of Low Gwp Refrigerant Mixture Hfo-1123/Hfc-32 And Hfo-1234ze(E)/Hfc-32, Chieko Kondou, Taisuke Matsuzono, Yukihiro Higashi Jan 2018

Surface Tension Measurement Of Low Gwp Refrigerant Mixture Hfo-1123/Hfc-32 And Hfo-1234ze(E)/Hfc-32, Chieko Kondou, Taisuke Matsuzono, Yukihiro Higashi

International Refrigeration and Air Conditioning Conference

HFOs (hydro-fluoro-olefins), HFO-1123 and HFO-1234ze(E) with GWP (global warming potential) of less than 1 attracted attention in a field of air conditioning and refrigeration engineering. However, the use of those HFO alone in such heat pump systems lucks adequate capacity or chemical stability. To compensate the shortcomings, mixtures coupled with R32 is considered to be one solution. This paper presents the surface tension measurement data of HFC-32, HFO-1123, and HFO-1234ze(E), and also their binary mixtures HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32 at various mass fractions. The capillary constant and surface tension of those are measured across temperature range from 267 K to 307 …

Go to article

Evaluation Of Binary And Ternary Refrigerant Blends As Replacements For R134a In An Air-Conditioning System, Ian Bell, Piotr Domanski, Greg Linteris, M. O. Mclinden Jan 2018

Evaluation Of Binary And Ternary Refrigerant Blends As Replacements For R134a In An Air-Conditioning System, Ian Bell, Piotr Domanski, Greg Linteris, M. O. Mclinden

International Refrigeration and Air Conditioning Conference

We investigated refrigerant blends as possible low-GWP (global warming potential) alternatives for R134a in an air-conditioning application. We carried out an extensive screening of the binary and ternary blends possible among a list of 10 pure refrigerants comprising three hydrofluoroolefins (HFOs), six hydrofluorocarbons (HFCs), and carbon dioxide. The screening was based on a simplified cycle model, but with the inclusion of pressure drops in the evaporator and condenser. The metrics for the evaluation were nonflammability, low-GWP, high COP (coefficient of performance), and a volumetric capacity similar to the R134a baseline system. While no mixture was ideal in all regards, we …

Go to article

Dynamics Of Frost Growth On Vertical Superhydrophobic Surfaces, Kalyan Satyadeep Boyina, Kazi Fazle Rabbi, Wei Su, Anand Thamban, Nenad Miljkovic, Xiaofei Wang Jan 2018

Dynamics Of Frost Growth On Vertical Superhydrophobic Surfaces, Kalyan Satyadeep Boyina, Kazi Fazle Rabbi, Wei Su, Anand Thamban, Nenad Miljkovic, Xiaofei Wang

International Refrigeration and Air Conditioning Conference

Superhydrophobic surfaces, which promote the efficient removal of condensing droplets prior to supercooling and freezing through coalescence induced jumping, have been shown to delay frosting significantly. The performance of fin and tube heat exchangers used in refrigeration and heat pump applications has the potential for improvement when coated with suitably designed superhydrophobic coatings. Currently, state-of-the-art (SOA) fins and their spacing are designed carefully to optimize pressure drop and heat transfer. The interaction amongst condensate droplets on adjacent fins can enhance the rate of condensate removal, and contribute to frost formation delay. Therefore, understanding the dynamics of droplet jumping within the …

Go to article

Experimental Analysis Of Natural Refrigerant Blends For Household Application, Ramona Nosbers, Franziska Schmieder, Ullrich Hesse Jan 2018

Experimental Analysis Of Natural Refrigerant Blends For Household Application, Ramona Nosbers, Franziska Schmieder, Ullrich Hesse

International Refrigeration and Air Conditioning Conference

Hydrofluorocarbon (HFCs), due to their high global warming impact, are not considered a desirable solution for future household application. In accordance to the Kigali Amendment to the Montreal Protocol, numerous countries committed the significant face- down of the production and consumption of HFCs over the next two to three decades. Natural refrigerants as well as their blends are considered viable alternatives due to their low global warming potentials. Additionally, the use of non-azeotropic refrigerant blends can positively influence the cycle performance of refrigerators and heat pump tumble dryers. Moreover, the knowledge of the behaviour of the oil-refrigerant-mixture is a necessity …

Go to article

Development And Validation Of A Mechanistic Vapor-Compression Cycle Model, Ammar M. Bahman, Davide Ziviani, Eckhard A. Groll Jan 2018

Development And Validation Of A Mechanistic Vapor-Compression Cycle Model, Ammar M. Bahman, Davide Ziviani, Eckhard A. Groll

International Refrigeration and Air Conditioning Conference

Detailed models are crucial tools for engineers in designing and optimizing systems. In particular, mechanistic modeling of vapor compression systems for accurate performance predictions at both full- and part-load conditions have been improved significantly in the past decades. Yet, fully deterministic models present still challenges in estimating charge inventory in order to optimize the performance. In this work, a generalized framework for simulating vapor compression cycles (VCC) has been develvoped with emphasis on a charge-sensitive model. In order to illustrate the capabilities of the tool, a direct–expansion (DX) cycle has been considered. In the cycle model, the compressor was mapped …

Go to article

A Theoretical And Experimental Analysis Of A Self-Contained R-290 Refrigeration Unit Applied To A Glass Door Reach-In Supermarket Display Case, Adriano Francisco Ronzoni, Gerson Heinzle, André Furlan, Marcelo C. Nazário, Daniel Hense Jan 2018

A Theoretical And Experimental Analysis Of A Self-Contained R-290 Refrigeration Unit Applied To A Glass Door Reach-In Supermarket Display Case, Adriano Francisco Ronzoni, Gerson Heinzle, André Furlan, Marcelo C. Nazário, Daniel Hense

International Refrigeration and Air Conditioning Conference

This paper presents a theoretical and experimental analysis of a self-contained variable speed R290 refrigeration unit applied to a typical 1.25m long two-glass-door reach-in supermarket display case, originally designed to run on an integrated R404a single speed refrigeration unit. A semi-empirical mathematical model was put forward to predict system energy consumption and cabinet psychometrics as a function of environmental conditions (ambient temperature and relative humidity), compressor model (single-speed, variable-speed and compressor displacement), refrigerant fluid (R290 and R404a) and geometry (heat exchangers overall heat transfer coefficient). One energy consumption test was performed at 32°C ambient temperature and used to calibrate components …

Go to article

Validation Of A Charge-Sensitive Vapor-Injected Compression Cycle Model With Economization, Ammar M. Bahman, Davide Ziviani, Eckhard A. Groll Jan 2018

Validation Of A Charge-Sensitive Vapor-Injected Compression Cycle Model With Economization, Ammar M. Bahman, Davide Ziviani, Eckhard A. Groll

International Refrigeration and Air Conditioning Conference

In recent years, research on economized vapor injected (EVI) compression systems showed potential improvements to both cooling capacity and coefficient of performance (COP). In addition, the operating range of compressors can be extended by reducing the discharge temperature. However, the optimum operation of such systems is directly related to the amount of refrigerant charge, which often is not optimized. Therefore, an accurate charge estimation methodology is required to further improve the operation of EVI compression systems. In this paper, a detailed cycle model has been developed for the economized vapor injected (EVI) compression system. The model aims to predict the …

Go to article

Intersection Of Art And Science Ii, Petronio Bendito, Tim Korb Jan 2018

Intersection Of Art And Science Ii, Petronio Bendito, Tim Korb

Lawson Building Exhibitions on the Intersection of Art and Science

The Intersection of Art and Science exhibition is an interdisciplinary educational project that examines a wide range of expressive approaches explored by international artists working at the intersection of art, mathematics, computer science, and technology. It is a joint collaboration between the Department of Computer Science and the Patti and Rusty Rueff School of Visual and Performing Arts at Purdue University. Featured artists: Manuel Baez, Sarah Berube, Robert Bosch, Sage Jenson, Jean-Marc Castera, Marc Chamberland, Marion Chamberland, Laura De Decker, Bathsheba Grossman, Colin Liotta, Vincent J. Matsko, Kerry Mitchell, Janna Schimka, Rolf Schmuck, and Markus Schwehm. The exhibition was curated …

Go to article

Experimental Research On Indicator Diagrams Of A Water Lubricated Screw Air Compressor, Chuang Wang, Yafen Tian, Wenqing Chen, Ziwen Xing Jan 2018

Experimental Research On Indicator Diagrams Of A Water Lubricated Screw Air Compressor, Chuang Wang, Yafen Tian, Wenqing Chen, Ziwen Xing

International Compressor Engineering Conference

In recent years, water-lubricated screw compressors have attracted more and more attention, because this type of compressors can produce the high quality air completely free of oil and there is no contamination. However, poor sealing and lubricating properties of water might result in different operating characteristics compared with those of oil-injected compressors. A good understanding of the operating mechanisms is essential in any attempt to increase the performance of the compressor, which can be achieved by means of the indicator diagram. In this paper, a prototype of the water-lubricated screw air compressor was developed and a test rig was established. …

Go to article

Investigations Of Automatic Meshing In Modeling A Dry Twin Screw Compressor, David Henry Rowinski, Yanheng Li, Karan Bansal Jan 2018

Investigations Of Automatic Meshing In Modeling A Dry Twin Screw Compressor, David Henry Rowinski, Yanheng Li, Karan Bansal

International Compressor Engineering Conference

In order to design screw compressors for optimal performance, it is crucial to understand the complex fluid flow processes within them. Computational fluid dynamics (CFD) is one approach for doing so. Considerable progress has been made over the last several years in both commercial and academic solution packages for this application; however, due to the complex moving geometries of the screw rotors and the tight clearances between the moving parts, a major challenge that remains is the generation of numerical grids that are increasingly efficient, accurate, robust, and easily created. In this study, an alternate methodology for this problem is …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

Thermodynamic Modelling Of Reciprocating And Wankel Type Compressor For Household Refrigerators, Konrad Klotsche, Thomas W. Moesch, Gotthard Will, Ullrich Hesse Jan 2018

Thermodynamic Modelling Of Reciprocating And Wankel Type Compressor For Household Refrigerators, Konrad Klotsche, Thomas W. Moesch, Gotthard Will, Ullrich Hesse

International Compressor Engineering Conference

Recent studies point out various benefits of trochoid-type compressors in vapor compression heat pump cycles and air compression applications. However, the field of small household refrigeration is still dominated by reciprocating compressors. This study comparatively investigates the thermodynamic behavior of a reciprocating and Wankel-type compressor in household refrigerators using the compressor simulation software KVA, which has been developed at the TU Dresden. The results of the KVA calculations are compared to available experimental data of a typical household refrigeration compressor. The comparative investigation reveals the differences between both compressor types regarding internal losses such as flow losses and internal leakages …

Go to article

Compressor Friction Losses Due To Oil Viscosity And Asperity Contact Surfaces: A Numerical Study On Crankshaft Bearings Lengths, Clearances And Roughness Parameters, Anderson Moises Meier, Mauricio Pereira Tada, Guilherme Espindola Jan 2018

Compressor Friction Losses Due To Oil Viscosity And Asperity Contact Surfaces: A Numerical Study On Crankshaft Bearings Lengths, Clearances And Roughness Parameters, Anderson Moises Meier, Mauricio Pereira Tada, Guilherme Espindola

International Compressor Engineering Conference

High energy efficiency refrigeration compressors have been increasingly demanded. This is achievable not only by the use of an efficient thermodynamic system and an efficient electric motor, but also by the design technologies applied to the compressor mechanism. In this work, a crankshaft bearing power losses optimization is presented regarding journal/shell surfaces run-in. The crankshaft bearings asperity friction power losses, combined with the viscous friction power losses, has been minimized for a reciprocating compressor running at ASHRAE condition. The core of the present approach was exploring a design space – computing asperity friction and viscous friction power losses – regarding …

Go to article

Numerical Modeling Of Fin-And-Tube Condenser With Wet-Wall Desuperheating, Hongtao Qiao, Christopher Laughman Jan 2018

Numerical Modeling Of Fin-And-Tube Condenser With Wet-Wall Desuperheating, Hongtao Qiao, Christopher Laughman

International Refrigeration and Air Conditioning Conference

Current heat exchanger simulation models typically divide the condenser into three regimes (desuperheating, two-phase and subcooled) and assume that condensation does not start until the bulk refrigerant flow reaches a state of saturated vapor. However, plenty of experiments have verified that condensation can occur much earlier than that when the tube wall surface temperature drops below the dew point of refrigerant even though the bulk flow is still superheated. This phenomenon is called wet-wall desuperheating (also referred to as wet-desuperheating, or condensation from desuperheated vapor in some publications). Wet-wall desuperheating is rarely modelled in the extant heat exchanger simulations due …

Go to article

Combined Power, Cooling And Desalination Using Natural Refrigerant Powered By Low-Grade Heat Source, Praveen Kumar Govindasamy, Saravanan R, Alberto Coronas, Patrick E. Phelan Jan 2018

Combined Power, Cooling And Desalination Using Natural Refrigerant Powered By Low-Grade Heat Source, Praveen Kumar Govindasamy, Saravanan R, Alberto Coronas, Patrick E. Phelan

International Refrigeration and Air Conditioning Conference

Contemporary facilities experience growing demand of energy-intensive products like cooling, power and fresh water, which turn in results in energy and environmental concerns. The separate production of these intensive products potentially consumes more primary energy compared with combined production (polygeneration). We therefore seek the most sustainable and suitable polygeneration technology. The driving energy source for the polygeneration system is assumed to be low-grade heat available from solar thermal, geothermal, industrial waste heat, etc. The natural refrigerant based ammonia-water absorption system has the potential for more exploration in the field of polygeneration. In the past decades, ammonia-water based Combined Cooling and …

Go to article

Experimental Study On A Finned-Tube Internally Cooled Contactor For Liquid Desiccant Air Conditioning Systems With Ionic Liquid, Takahiro Sato, Richard Jayson Varela, Seiichi Yamaguchi, Kiyoshi Saito, Hiroshi Nakayama, Xinming Wang Jan 2018

Experimental Study On A Finned-Tube Internally Cooled Contactor For Liquid Desiccant Air Conditioning Systems With Ionic Liquid, Takahiro Sato, Richard Jayson Varela, Seiichi Yamaguchi, Kiyoshi Saito, Hiroshi Nakayama, Xinming Wang

International Refrigeration and Air Conditioning Conference

This paper presents an experimental study on the dehumidification performance of a finned-tube internally cooled contactor as compared to that of an adiabatic contactor in liquid desiccant air conditioning systems with ionic liquid. The contactor is the most significant component in liquid desiccant systems; it is the component responsible for the dehumidification and regeneration processes. When air and absorptive solution are in contact in the contactor, absorption/desorption of the solution occurs due to the difference in vapor pressure. This results to the transfer of heat and mass between the air and solution. Conventionally, adiabatic contactors, which only have air and …

Go to article

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. …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

First Prev Next Last