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2014

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Disciplinary Discourse In Design Reviews: Industrial Design And Mechanical Engineering Courses, Micah Lande, James Oplinger Jan 2014

Disciplinary Discourse In Design Reviews: Industrial Design And Mechanical Engineering Courses, Micah Lande, James Oplinger

Design Thinking Research Symposium

An increase in focus on design thinking in the engineering community and design education has led to innovative outcomes. A part of the design thinking education comes from the goals and teaching methods of instructors. From a given dataset of design reviews two different courses were evaluated: industrial design and mechanical engineering. This work analyzes how instructor interactions with individuals or teams fulfill course outcomes. From a discussion of the data analysis it is suggested that industrial designers focus on the passion of the product design while mechanical engineers focus on the functionality and completeness of the design. The ideological …

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Making Design Pedagogical Content Knowledge Visible Within Design Reviews, Robin Adams, David Radcliffe, Tiago Forin, Mel Chua Jan 2014

Making Design Pedagogical Content Knowledge Visible Within Design Reviews, Robin Adams, David Radcliffe, Tiago Forin, Mel Chua

Design Thinking Research Symposium

Design pedagogical content knowledge (PCK) is the content-specific specialized teacher knowledge that connects the how (pedagogical knowledge) and what (content knowledge) of teaching design. In this study, we make visible the design PCK in three student design reviews: choreography, undergraduate industrial design, and mechanical engineering. We use cognitive apprenticeship and teaching-as-improvisation frameworks to characterize PK, and design judgment, design task strategies, and process management strategies to characterize CK. We identify and describe four patterns of design PCK: scaffolded articulation, driving for meaning and guidance, breaking the 4th wall to create a teaching moment, and “suggest don’t tell”. Theoretical implications …

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Peering Into The Discourse Of Industrial Design Training Through A Sustainability Lens, Norman M. Su, Haodan Tan, Eli Blevis Jan 2014

Peering Into The Discourse Of Industrial Design Training Through A Sustainability Lens, Norman M. Su, Haodan Tan, Eli Blevis

Design Thinking Research Symposium

Now well established in HCI, the lens of sustainability may be applied to educational practices in industrial design and interaction design. By sustainability, we mean to include notions of mitigation of the environmental effects of climate change. In this paper, we present an analysis of student projects in a junior and senior industrial design class dataset. Drawing from discourse analysis, we examine how the industrial design classroom serves as a space to socially construct the philosophies and goals inherent in “good” design. We then examine how the lens of sustainability is implicated into the industrial design “way” as espoused by …

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Experiences Of Informed Learning In The Undergraduate Classroom, Clarence Maybee Jan 2014

Experiences Of Informed Learning In The Undergraduate Classroom, Clarence Maybee

Libraries Faculty and Staff Scholarship and Research

The same thing can be experienced in a variety of ways. For example, think of a time that you and a friend read the same book, but each got something quite different out of it. Essentially you experienced different aspects of the book. Applying this to higher education, we cannot assume that all students are experiencing their coursework in the same way. In fact, a number of studies reveal that this is not the case. Learning occurs when students begin to experience the thing being learned about in a new way. Learning designs that teach undergraduates to use information require …

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Study Of User Search Activities With Two Discovery Tools At An Academic Library, Xi Niu, Tao Zhang, Hsin-Liang Chen Jan 2014

Study Of User Search Activities With Two Discovery Tools At An Academic Library, Xi Niu, Tao Zhang, Hsin-Liang Chen

Libraries Faculty and Staff Scholarship and Research

The goal of this study was to investigate and compare user search activities of two discovery tools at an academic library. The implementation of a new discovery tool (Primo by Ex Libris) to replace an existing system (VuFind) provided a unique opportunity to collect transaction logs of both systems and examine user search behavior in an empirical test. Results from a transaction log analysis and a user study of this study have contributed to the understanding of users’ search behavior and their preferences and perceptions of the two systems. We find both commonalities and differences between VuFind and Primo for …

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Data Driven Collection Development At Mathematical Sciences Library Of Purdue University, Nastasha E. Johnson Jan 2014

Data Driven Collection Development At Mathematical Sciences Library Of Purdue University, Nastasha E. Johnson

Libraries Faculty and Staff Presentations

No abstract provided.

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Influences Of Feedback Interventions On Student Concept Generation And Development Practices, Seda Yilmaz, Shanna Daly Jan 2014

Influences Of Feedback Interventions On Student Concept Generation And Development Practices, Seda Yilmaz, Shanna Daly

Design Thinking Research Symposium

Design teaching in many disciplines relies on feedback as a primary way for students and instructors to communicate. Our work focused on identifying feedback types in three different design disciplines (dance choreography, industrial design, and mechanical engineering) and analyzing how those feedback types encouraged students to take convergent or divergent paths with their design ideas. We then compared feedback types and encouragement of convergence or divergence across the three disciplines. Our findings showed many common types of feedback used across the three disciplines, regardless of variance in context and expectations. However, the findings also revealed a high frequency of feedback …

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Three Studio Critiquing Cultures: Fun Follows Function Or Function Follows Fun?, Gabriela Goldschmidt, Hernan Casakin, Yonni Avidan, Ori Ronen Jan 2014

Three Studio Critiquing Cultures: Fun Follows Function Or Function Follows Fun?, Gabriela Goldschmidt, Hernan Casakin, Yonni Avidan, Ori Ronen

Design Thinking Research Symposium

For the longest time, design was an activity with no distinction among disciplines. Over time, separate design disciplines had formed their own cultures and their own educational practices. In this paper, we use data from a limited set of design reviews along with a literature survey to conduct a comparative analysis of contemporary reviewing and critiquing cultures in architecture, industrial design and mechanical engineering. We point out differences and communalities, and conclude with a list of the lessons the three disciplines can learn from one another regarding reviewing in the classroom. We dwell especially on one issue that currently differentiates …

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Strain Modulations As A Mechanism To Reduce Stress Relaxation In Laryngeal Tissues, Eric J. Hunter, Thomas Siegmund, Roger W. Chan Jan 2014

Strain Modulations As A Mechanism To Reduce Stress Relaxation In Laryngeal Tissues, Eric J. Hunter, Thomas Siegmund, Roger W. Chan

School of Mechanical Engineering Faculty Publications

Vocal fold tissues in animal and human species undergo deformation processes at several types of loading rates: a slow strain involved in vocal fold posturing (on the order of 1 Hz or so), cyclic and faster posturing often found in speech tasks or vocal embellishment (1–10 Hz), and shear strain associated with vocal fold vibration during phonation (100 Hz and higher). Relevant to these deformation patterns are the viscous properties of laryngeal tissues, which exhibit non-linear stress relaxation and recovery. In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects …

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A New Dynamic Heat Exchanger Model With Frosting And Defrosting, Hongtao Qiao, Vikrant Aute, Reinhard Radermacher Jan 2014

A New Dynamic Heat Exchanger Model With Frosting And Defrosting, Hongtao Qiao, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

In this paper, a dynamic heat exchanger model that unifies the frosting and defrosting analyses is presented. A novel scheme is proposed to solve the air flow redistribution due to non-uniform frost blockage. Unlike the existing defrost models which separate analysis for tubes and fins, the proposed defrost model unifies the analysis to maintain model consistency. The first-principles based frost and defrost models developed in this research allow for a more realistic assessment of the heat pump systems and greatly facilitate the design of controls. Utilizing the developed models, the transient behavior of a flash tank vapor injection heat pump …

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Comparing Cop Optimization With Maximizing The Coefficient Of System Performance For Refrigeration Systems In Supermarkets, Martin R. Braun, Stephen B. M. Beck, Ha?Im Altan Jan 2014

Comparing Cop Optimization With Maximizing The Coefficient Of System Performance For Refrigeration Systems In Supermarkets, Martin R. Braun, Stephen B. M. Beck, Ha?Im Altan

International Refrigeration and Air Conditioning Conference

In recent years the energy usage of supermarkets, in particular that of their refrigeration systems, has been investigated using a variety of approaches, such as floating pressure set points and integrating the heating and refrigeration systems. Something which has not yet attracted much attention is the energy consumption of the dry condenser fans in refrigeration systems. This is surprising as it has been shown for comparable installations that including the energy consumption of these fans when optimizing the system efficiency was beneficial. To address this deficit, _COP_ maximization has been compared to optimizing the Coefficient of System Performance (_COSP_). The …

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Uncertainty Analysis On Prediction Of Heat Transfer Coefficient And Pressure Drop In Heat Exchangers Due To Refrigerant Property Prediction Error, Long Huang, Vikrant Aute, Reinhard Radermacher Jan 2014

Uncertainty Analysis On Prediction Of Heat Transfer Coefficient And Pressure Drop In Heat Exchangers Due To Refrigerant Property Prediction Error, Long Huang, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Numerical simulation is extensively used in heat exchanger design and performance evaluation. While evaluating potential working fluids, pure fluids and fluid mixtures with different component combinations and fractions are compared based on simulation results. Two of the challenges while conducting such studies are the uncertainties of refrigerant properties and the applicability of empirical heat transfer and pressure drop correlations. Pure refrigerant property uncertainties are associated with experimental testing technique. The uncertainties of refrigerant mixtures are significantly higher when mixing rules are applied due the lack of measured data. Most of the empirical correlations are developed for certain refrigerants with a …

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Realtime Optimization Of Mpc Setpoints Using Time-Varying Extremum Seeking Control For Vapor Compression Machines, Walter K. Weiss, Daniel J. Burns, Martin Guay Jan 2014

Realtime Optimization Of Mpc Setpoints Using Time-Varying Extremum Seeking Control For Vapor Compression Machines, Walter K. Weiss, Daniel J. Burns, Martin Guay

International Refrigeration and Air Conditioning Conference

Recently, model predictive control (MPC) has received increased attention in the HVAC community, largely due to its ability to systematically manage constraints while optimally regulating signals of interest to setpoints. For example, in a common formulation of an MPC control problem for variable compressor speed vapor compression machines, the setpoints often include the zone temperature and the evaporator superheat temperature. However, the energy consumption of vapor compression systems has been shown to be sensitive to these setpoints. Further, while superheat temperature is often preferred because it can be easily correlated to heat exchanger efficiency (and therefore cycle efficiency), direct measurement …

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The Effects Of Gas Cooler Inlet Pressure On System Performance In Heat Pump Tumble Dryers, Serkan Erdem, Cenk Onan, Hasan Alpay Heperkan, Derya Burcu Özkan Jan 2014

The Effects Of Gas Cooler Inlet Pressure On System Performance In Heat Pump Tumble Dryers, Serkan Erdem, Cenk Onan, Hasan Alpay Heperkan, Derya Burcu Özkan

International Refrigeration and Air Conditioning Conference

Heat pumps working with CO2 as a refrigerant have low energy consumptions if right application areas and operating conditions are selected. The use of CO2 in heat pump dryers is feasible if operating temperatures are appropriate. In heat pump dryers working with CO2 according to the transcritical cycle, one of the most important operating conditions is optimum gas cooler inlet pressure, which gives the maximum coefficient of performance (COP). In this study, a model was developed by using MATLAB software for heat pump tumble dryer working with CO2. The model was validated by experimental data taken from existing literature. Then, …

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Thermal Comfort Evaluation Of A Heat Pump System Using Induced-Air Supply Unit, Jiazhen Ling, Jian Xu, Vikrant Aute, Reinhard Radermacher Jan 2014

Thermal Comfort Evaluation Of A Heat Pump System Using Induced-Air Supply Unit, Jiazhen Ling, Jian Xu, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Traditional heat pump systems supply conditioned air to space at certain temperatures such as, in summer, about 16°C. When the supply-air temperature drops too low, most occupants tend to feel uncomfortable. On the other hand, a certain amount of dehumidification has to be carried out and sometimes, the velocity of supply-air has to be high which in turn creates a draught. This paper introduces a new air supply method to reduce fan power consumption as well as to improve thermal comfort of occupants. Using this method, colder fresh air at 13°C is generated by air handling units and pumped to …

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Analysis Of A Data Center Using Liquid-Liquid Co2 Heat Pump For Simultaneous Cooling And Heating, Supriya Dharkar, Orkan Kurtulus, Eckhard A. Groll, Kazuaki Yazawa Jan 2014

Analysis Of A Data Center Using Liquid-Liquid Co2 Heat Pump For Simultaneous Cooling And Heating, Supriya Dharkar, Orkan Kurtulus, Eckhard A. Groll, Kazuaki Yazawa

International Refrigeration and Air Conditioning Conference

Liquid–liquid CO2 heat pump systems are a promising technology for commercial building applications, which require simultaneous heating and cooling. This paper presents the investigation of a data center on the Purdue University, West Lafayette campus. The data center located in the Department of Mathematics is the most energy intensive data center on campus. The cooling load of the data center is approximately 750 kW/hour. The heating season in West Lafayette is 7 to 8 months and the heating load of the buildings is very high during the coldest months. The heating load of the Mathematics building can go to as …

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Pneumatically Driven Environmental Control System In Aircrafts Based On A Vapor-Compression Cycle, Steffen Golle, Ullrich Hesse, Frank Klimpel Jan 2014

Pneumatically Driven Environmental Control System In Aircrafts Based On A Vapor-Compression Cycle, Steffen Golle, Ullrich Hesse, Frank Klimpel

International Refrigeration and Air Conditioning Conference

The environmental control system is an essential subsystem of an aircraft, which has to comply some vital tasks. These include the setting of the desired temperature, humidity and cabin pressure, as well as ensuring the fresh air or oxygen supply and air quality. The requirements must be achieved in very different ambient conditions. This refers to the environmental conditions in the flight and ground cases, and also to the different climate zones. In addition, the existing interfaces to the aircraft must be taken into account. State of the art in currently used commercial aircrafts is an environmental control system, which …

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Prediction Of Evaporator Frosting In Household Refrigerators Subjected To Periodic Door Opening, Bruno N. Borges, Cláudio Melo, Christian J. L. Hermes Jan 2014

Prediction Of Evaporator Frosting In Household Refrigerators Subjected To Periodic Door Opening, Bruno N. Borges, Cláudio Melo, Christian J. L. Hermes

International Refrigeration and Air Conditioning Conference

This paper describes a quasi-steady-state simulation model for predicting the transient behavior of a household refrigerator subjected to periodic door opening. A semi-empirical steady-state sub-model was developed for the refrigeration loop, and a transient sub-model was devised to predict the energy and mass transfer into and within the refrigerated compartments as well as the evaporator frosting. The key empirical heat and mass transfer parameters required by the model were derived from a set of experiments carried out in a climate-controlled chamber. In general, it was found that the model predictions followed closely the experimental trends for the power consumption (deviations …

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Analysis On Parameters Of Regeneration Subsystem In Liquid Desiccant Dehumidification Systems, Min Tu, Chengqin Ren, Huanxin Cheng, Haijia Lin Jan 2014

Analysis On Parameters Of Regeneration Subsystem In Liquid Desiccant Dehumidification Systems, Min Tu, Chengqin Ren, Huanxin Cheng, Haijia Lin

International Refrigeration and Air Conditioning Conference

Along with the widely use in industries and lives, the dehumidification systems have consumed a large amount of energy. Fortunately, the application of liquid desiccant dehumidification system can greatly reduce the consumption of high-grade energies. To improve the advantages of liquid desiccant system compared with the conventional dehumidification system, one of the key measures is to increase the efficiency of the regeneration sub-system. In this study, models for the regeneration tower and counter-current heat exchanger, which are recognized by previous experiments, are employed and the corresponding VC++ computer program modules are used to describe the heat and mass transfer processes …

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Exergy Based Methodology For Optimized Integration Of Heat Pumps In Industrial Processes, Karim Besbes, Assaad Zoughaib, Florence De Carlan, Jean-Louis Peureux Jan 2014

Exergy Based Methodology For Optimized Integration Of Heat Pumps In Industrial Processes, Karim Besbes, Assaad Zoughaib, Florence De Carlan, Jean-Louis Peureux

International Refrigeration and Air Conditioning Conference

Industrial processes may use heat pumps to recover low grade heat or to combine heating and cooling needs. In many cases, this technology leads to reduced energy consumption and greenhouse gases emissions. In this paper, a methodology, based on exergy analysis of heat sources and heat sinks, helping in optimizing industrial heat pumps design is presented. The optimization variables are: the refrigerant choice (pure fluid, azeotropic mixture, non azeotropic mixture), the thermodynamic state of the refrigerant (subcritical, supercritical) and the architecture of the heat pump (heat pump in reverse series). The heat pump is modelled in Modelica language: "pinch" method …

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A New Method For Calculating Viscosity And Solubility Of Lubricant- Refrigerant Mixtures, Jung-Tsung Hung, Jeng-Shiang Tsaih, Hsu-Hua Tang Jan 2014

A New Method For Calculating Viscosity And Solubility Of Lubricant- Refrigerant Mixtures, Jung-Tsung Hung, Jeng-Shiang Tsaih, Hsu-Hua Tang

International Refrigeration and Air Conditioning Conference

A new model was developed to determine viscosity and solubility of lubricant-refrigerant mixture, using concepts from lattice model in liquid state, reaction rate theory for viscosity, and local composition theory. The computing results from our new model showed high degree of accuracy, and are comparable to the results from NRTL model and Flory-Huggins model. Various type of POE lubricants (viscosity ranges from 68~220cst) in R134a refrigerant have been fitted for the new model to describe the viscosity and pressure of binary systems. The tests were conducted in temperature ranging from 0? to 100?. Typical average absolute deviation (AAD%) of these …

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Theoretical And Experimental Analysis Of Supercritical Carbon Dioxide Cooling, Martin Van Eldik, Paul Marius Harris, Werner Heinrich Kaiser, Pieter Gerhardus Rousseau Jan 2014

Theoretical And Experimental Analysis Of Supercritical Carbon Dioxide Cooling, Martin Van Eldik, Paul Marius Harris, Werner Heinrich Kaiser, Pieter Gerhardus Rousseau

International Refrigeration and Air Conditioning Conference

With on-going developments in the field of trans-critical carbon dioxide (R-744) vapour compression cycles, a need to effectively describe the heat transfer of supercritical carbon dioxide for application in larger diameter tube-in-tube heat exchangers was identified. This study focuses on the in-tube cooling of supercritical carbon dioxide for application in the gas cooler of a trans-critical heat pump. A literature study has revealed Nusselt number correlations specifically developed for the cooling of supercritical carbon dioxide. These correlations were proven to be accurate only for certain operating conditions and tube geometries. A shortcoming identified in the literature reviewed was a generic …

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Optimized Performance Of One-Bed Adsorption Cooling System, Takahiko Miyazaki, Ibrahim I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama Jan 2014

Optimized Performance Of One-Bed Adsorption Cooling System, Takahiko Miyazaki, Ibrahim I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama

International Refrigeration and Air Conditioning Conference

Adsorption cooling system can be driven by solar energy or waste heat, so it will effectively reduce fossil fuel consumptions when total system is well-designed. On the other hand, the system tends to have a large size, which will be an obstacle to install adsorption cooling systems to small to medium scale cooling demands, such as automobiles, houses, or shops. The study was aiming at the reduction of system size of adsorption cooling systems for refrigeration and air-conditioning applications. To simplify the system, we investigated one-bed configuration of adsorption cooling system. In general, one-bed adsorption cooling system would result in …

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The Performance Matching Of Inverter Room Air Conditioner, Bo Huang, Xiyuan Zhu, Hong Tao, Da Shi Jan 2014

The Performance Matching Of Inverter Room Air Conditioner, Bo Huang, Xiyuan Zhu, Hong Tao, Da Shi

International Refrigeration and Air Conditioning Conference

Some key parameter like suction superheat, compressor frequency, indoor and outdoor air volume, have been explored using simulation tools for the performance matching of the inverter room air conditioner. It was found that the all above parameters can be further optimized in every matching condition (including intermediate cooling, rated cooling, maximum cooling, middle heating and rated heating, etc.). The optimum range for all above parameter has been found and can be used in the variable frequency control module to ensure optimal overall performance of the system.

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An Improved Moving Boundary Heat Exchanger Model With Pressure Drop, Hongtao Qiao, Vikrant Aute, Reinhard Radermacher Jan 2014

An Improved Moving Boundary Heat Exchanger Model With Pressure Drop, Hongtao Qiao, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

A literature review indicates that almost all moving boundary heat exchanger models used in dynamic simulations of heat pumps rely on the common hypothesis that the refrigerant pressure drop is negligible. In fact, it is important to include the momentum balance in some applications, such as electronics cooling where microchannels are commonly used and significant pressure drop is observed and large-scale heat exchangers in solar thermal plants where tube length can be longer than several hundred meters. In addition, a comprehensive and robust switching approach is needed to handle transitions between different model states due to phase change. It is …

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The Effects Of Fin Spacing And Tube Outer Diameter Of Evaporator On System Performance In Heat Pump Tumble Dryers, Cenk Onan, Serkan Erdem, Derya Burcu Özkan, Hasan Alpay Heperkan Jan 2014

The Effects Of Fin Spacing And Tube Outer Diameter Of Evaporator On System Performance In Heat Pump Tumble Dryers, Cenk Onan, Serkan Erdem, Derya Burcu Özkan, Hasan Alpay Heperkan

International Refrigeration and Air Conditioning Conference

In heat pump tumble dryers, moisture separates from the laundry and leaves the dryer system at the evaporator. Moist air goes out the drum and enters the evaporator whose outer surface is below the dew point temperature. Air cools and then leaves its moisture. At the airside of the evaporator the wet surface develops and simultaneous heat-mass transfer occurs. Fin-and-tube heat exchangers are used as evaporators in household heat pump tumble dryers. In addition to optimum operating conditions, optimum evaporator geometry can significantly affect system performance. In this study, a model was developed for household heat pump tumble dryer. The …

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Transient 1d Heat Exchanger Model For The Simulation Of Domestic Cooling Cycles Working With R600a, Erwin Berger, Martin Heimel, Stefan Posch, Raimund Almbauer, Martin Eichinger Jan 2014

Transient 1d Heat Exchanger Model For The Simulation Of Domestic Cooling Cycles Working With R600a, Erwin Berger, Martin Heimel, Stefan Posch, Raimund Almbauer, Martin Eichinger

International Refrigeration and Air Conditioning Conference

Generally, domestic refrigerators and freezers are running in non-continuous operation mode most of the time, which is a necessity to match cooling capacity to thermal loads. In currently available domestic appliances this matching is realized either by on/off or variable frequency control of the hermetic compressor, leading to a repetitive and transient change of the system state. On the other hand, if the runtimes of the compressor are longer because cooling capacity demand is high (e.g. pull down cycles, initial operation), steady state operating conditions might be reached. The cycling transients cause losses in system efficiency thus they should be …

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Exergy And Energy Analysis Of Waste Heat Recovery Options For Cooling Capacity Production, Chantal Maatouk, Rayan Slim Jan 2014

Exergy And Energy Analysis Of Waste Heat Recovery Options For Cooling Capacity Production, Chantal Maatouk, Rayan Slim

International Refrigeration and Air Conditioning Conference

Electricity production in Lebanon stands at around 1.5 GW while the demand exceeds 2.5 GW at peak times and peak cooling demands, resulting in rationing cuts from between 3 to 20 hours a day which is the worst performance in the Middle East. Due to the country energy shortfall, a large number of small-scale backup generators is installed to address the electric and cooling needs. The proliferation of use of these backup generators presents an interesting potential for waste heat recovery in order to achieve additional power generation and cooling capacity production. This paper investigates two possible configurations for waste …

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Theoretical And Experimental Research On Co2 Electrical Heating Pool Boiling Heat Transfer Outside A Horizontal Tube, Lan Li, Shengchun Liu, Jinghong Ning Jan 2014

Theoretical And Experimental Research On Co2 Electrical Heating Pool Boiling Heat Transfer Outside A Horizontal Tube, Lan Li, Shengchun Liu, Jinghong Ning

International Refrigeration and Air Conditioning Conference

Numerical simulation on electrical heating pool boiling heat transfer with CO2 as refrigerant outside a horizontal tube is carried. A voltage-controlled heating method has been used in the experiment, with the advantages of good stability and adjustability of the experimental heat flux density. After a series of preliminary calculation and pre-work, numerical simulation is carried based on a software FLUENT. Bubble behaviors are observed, the distribution regularity of volume fraction of vapor is obtained and compared with the experimental results. The results show that numerical simulation and experimental results are in good agreement. Furthermore, by changing the heat flux density, …

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Thermodynamic Analysis And Optimization Of Cascade Condensing Temperature Of A Co2(R744)/R404a Cascade Refrigeration System, Baris Yilmaz, Nasuh Erdonmez, Mustafa Kemal Sevindir, Ebru Mancuhan Jan 2014

Thermodynamic Analysis And Optimization Of Cascade Condensing Temperature Of A Co2(R744)/R404a Cascade Refrigeration System, Baris Yilmaz, Nasuh Erdonmez, Mustafa Kemal Sevindir, Ebru Mancuhan

International Refrigeration and Air Conditioning Conference

Synthetic refrigerants are widely used in refrigeration applications. However, it is shown that such refrigerants have negative impacts on the ozone layer of atmosphere. Recently, natural refrigerants such as carbon dioxide and various hydrocarbon compounds are proposed to replace synthetic refrigerants in the industrial refrigeration systems. Carbon dioxide is one of the most promising and environment-friendly refrigerant solution due to its thermo-physical properties, low ozone depletion value and low global warming potential. In this study thermodynamic analysis of a two stage sub-critical cascade refrigeration system using CO2 and R404a refrigerants in low temperature and high temperature cycles is presented. The …

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