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Development Of 3-Cylinder Rotary Compressor For Large Capacity, Tomohide Shishimoto, Toshimasa Aoki, Koji Hirano, Shogo Shida, Takuya Hirayama May 2021

Development Of 3-Cylinder Rotary Compressor For Large Capacity, Tomohide Shishimoto, Toshimasa Aoki, Koji Hirano, Shogo Shida, Takuya Hirayama

International Compressor Engineering Conference

The authors have developed a large capacity rotary compressor with compact size and low vibration. Recently, we have strong requirements for larger capacity without changing the compressor shell diameter. Considering for larger capacity in conventional 2-cylinder rotary compressor inverter type, there are issues such as high vibration, big sound. As the solution for these problems, we have developed 3-cylinder rotary compressor inverter type which have different compression process of 120 ° phase per revolution for each cylinder. The developed compressor achieves a capacity target, proves one-quarter vibration level comparing with 2-cylinder rotary compressor and ensure the improvement of reliability result. …

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Flow Boiling Heat Transfer And Pressure Drop Characteristics Of R1234yf In A Dimpled Flat Duct, Yuping Gao, Ye Feng, Ke Tang, Pega Hrnjak May 2021

Flow Boiling Heat Transfer And Pressure Drop Characteristics Of R1234yf In A Dimpled Flat Duct, Yuping Gao, Ye Feng, Ke Tang, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

Among various heat transfer enhancement technologies, the dimpled surface, which is inspired by the resistance reduction characteristics of the specific concaves on golf balls, has the potential to improve heat transfer with a relatively low pressure-drop penalty. More and more applications of dimpled surfaces in heat exchangers have shown up in industries. However, the lack of experimental data, especially the heat transfer and pressure drop data for liquidand-vapor two-phase flow, inside the dimpled flow channels prevents the good design of the dimpled heat exchangers. In this study, a facility has been designed and built to investigate the heat transfer and …

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Thermodynamic Comparison Of Magnetocaloric And Vapor Compression Domestic Wine Coolers, Natália Maleski De Sá, Alan Tihiro Nakashima, Jaime Andrés Lozano, Jader Riso Barbosa Jr. May 2021

Thermodynamic Comparison Of Magnetocaloric And Vapor Compression Domestic Wine Coolers, Natália Maleski De Sá, Alan Tihiro Nakashima, Jaime Andrés Lozano, Jader Riso Barbosa Jr.

International Refrigeration and Air Conditioning Conference

This paper presents a comparative study of magnetocaloric and vapor compression wine coolers. The vapor compression system is a commercially available 31bottle climate class N appliance, whereas the magnetic cooling device is a TRL5 prototype connected to the retrofitted insulated cabinet of the same VC cooler. Test procedures included temperature pulldown and standardized steadystate energy consumption tests. Detailed instrumentation of both systems allowed a lowlevel comparison in terms of firstand secondlaw based parameters that is unique in the literature. Although the vapor compression system is more efficient than the present magnetic cooling prototype, the behavior of its internally ideal COP …

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Combination Of Local Heat Transfer And Flow Visualization Of R245fa Flow Boiling In Plate Heat Exchanger, Abdel-Rahman Farraj, Pega Hrnjak May 2021

Combination Of Local Heat Transfer And Flow Visualization Of R245fa Flow Boiling In Plate Heat Exchanger, Abdel-Rahman Farraj, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

This paper presents an experimental study of the local heat transfer coefficient in evaporation and simultaneous flow visualization in plate heat exchangers. The fluid used is R245fa. The temperature profile, local heat flux, and heat transfer coefficient are measured and calculated along the plate using an internally developed heat flux meter. The flux meter is built from two original plates with thermocouples soldered to their surface and sandwiched with a thermal infill material in between. After calibrating the flux meter to determine its local thermal resistance, the flux meter is assembled in a three-channel setup to measure the heat transfer …

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Evaluation Of Heat Pumping And Waste Heat Recovery For Battery Electric Vehicle Thermal Management, Tyler Shelly, Justin Weibel, Davide Ziviani, Eckhard Groll May 2021

Evaluation Of Heat Pumping And Waste Heat Recovery For Battery Electric Vehicle Thermal Management, Tyler Shelly, Justin Weibel, Davide Ziviani, Eckhard Groll

International Refrigeration and Air Conditioning Conference

Due to increasing regulation on emissions and shifting consumer preferences, the wide adoption of battery electric vehicles (BEV) hinges on research and development of technologies that can extend system range. This can be accomplished either by increasing the battery size or via more efficient operation of the electrical and thermal systems. This study evaluates the range performance of a BEV integrated thermal management system (ITMS) with heat pumping and waste heat recovery across a range of ambient conditions (-20 °C to 40 °C) and cabin setpoints (18 °C to 24 °C). A dynamic ITMS modelling framework for a long-range electric …

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Mathematical Model Of Ice Slurry Flow To Predict Agglomerations And Phase Interaction Effects, Shaimaa Hefny Badawi, Christiane Thomas, Ullrich Hesse May 2021

Mathematical Model Of Ice Slurry Flow To Predict Agglomerations And Phase Interaction Effects, Shaimaa Hefny Badawi, Christiane Thomas, Ullrich Hesse

International Refrigeration and Air Conditioning Conference

Ice slurry is an energy-intensive secondary fluid, which may play an important role in various cooling purposes. From the system design perspective, it is of great importance to obtain detailed information of the ice slurry flow. A quantification of the complex two-phase flow characteristic is difficult due to the heterogeneous ice slurry flow. The paper includes the theoretical analysis of the ice slurry behaviour with different ice particle conditions (concentration, size) considering pressure drop and agglomeration. In addition to the mathematical model analyses of all important balance equations and other sub-equations (granular properties, phase interactions), various parameters influencing the behaviour …

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Experimental And Numerical Study On The Electrical And Thermal Characteristics Of High Energy Density Lithium-Ion Battery Cell For Application Of Battery Electric Vehicle, Ukmin Han, Hoseong Lee May 2021

Experimental And Numerical Study On The Electrical And Thermal Characteristics Of High Energy Density Lithium-Ion Battery Cell For Application Of Battery Electric Vehicle, Ukmin Han, Hoseong Lee

International Refrigeration and Air Conditioning Conference

In this paper, the electrical and thermal characteristics of the high-energy density of 100 Ah (over 350 Wh/L) pouch-type lithium-ion battery (LIB) cell are analyzed experimentally. To determine the effects of applying current-rate (crate) on its behavior, the battery is charged and discharged in different c-rate ranging from 0.5C to 1.2C. The changes in discharged capacity and heat generation rates of battery cells are examined and its mechanism is analyzed deeply in the view of variations on internal resistance. The battery heat generation is considered with two heat sources, joule and entropic heat. A newly developed inverse calculation method is …

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Air Dehumidification Using Ionic Liquid-Based Fiber Bundle Membrane Contactor, Tugba Turnaoglu, Navin Kumar, Viral Patel, Kyle Gluesenkamp May 2021

Air Dehumidification Using Ionic Liquid-Based Fiber Bundle Membrane Contactor, Tugba Turnaoglu, Navin Kumar, Viral Patel, Kyle Gluesenkamp

International Refrigeration and Air Conditioning Conference

Air dehumidification is essential since excess moisture in the buildings causes discomfort to the occupants, encourages the production of air pathogens such as mold or mildew, and causes corrosion and rotting that degrade building materials. Existing moisture removal processes are mainly focused on condensation and desiccant (liquid or solid) techniques with direct contact between air and desiccant. However, these methods are energy-intensive, or desiccant might be lost or cause corrosion in the process. The main objective of this study is to investigate an ionic liquid-based liquid desiccant absorber based on a membrane fiber bundle. A novel membrane contactor system was …

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A Prediction Method For Slug Limit Of Scroll Compressor Using Cfd Two-Phases Flow Simulation, Kang Zheng, Jiangbo Lin, Liu Wang May 2021

A Prediction Method For Slug Limit Of Scroll Compressor Using Cfd Two-Phases Flow Simulation, Kang Zheng, Jiangbo Lin, Liu Wang

International Compressor Engineering Conference

Slug test is used to simulate a real application work condition in lab. During operation, a compressor eventually gets to endure dynamic slugging which is characterized by the arrival of a liquid refrigerant at the suction side when the compressor is already running. Because of this dynamic, the liquid is able to reach the compression side. The presence of incompressible liquid in the scrolls (volumetric compression) involves mechanical strength quickly becoming unbearable for the compressor involute breakage or Oldham coupling breakage are the consequences suffered by the compressor following a severe slugging. In this paper, a prediction method of slug …

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Adaptive Grey-Box Models For Model Predictive Building Control Using The Unscented Kalman Filter, Svenne Freund, Gerhard Schmitz May 2021

Adaptive Grey-Box Models For Model Predictive Building Control Using The Unscented Kalman Filter, Svenne Freund, Gerhard Schmitz

International High Performance Buildings Conference

Model predictive control (MPC) for buildings is a promising approach to reduce the energy consumption of buildings while at the same time the thermal user comfort can be improved. The core of this control strategy consists of building models that can describe the thermal behavior of particular zones accurately. Grey-box models are frequently used modeling approaches for control-oriented models, however, these models often have limitations regarding their general applicability. Furthermore, the modeling and identification of models used in MPC still require significant effort and is one of the main obstacles for the actual practical implementation of building predictive control. This …

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Model Based Co-Simulation Platform For Integrated Building System Control And Design Optimization, Jian Sun, Bo Shen May 2021

Model Based Co-Simulation Platform For Integrated Building System Control And Design Optimization, Jian Sun, Bo Shen

International High Performance Buildings Conference

Both steady-state and dynamic simulations have been widely used by HVAC&R industry to support product/equipment development for decades. Steady-state simulation focuses on the system mass, energy and momentum balance of an equilibrium state. It is based on high-fidelity components models, and thus is suitable for system and component design optimization. Dynamic simulation studies the system transient response and is generally used for controls development and verification. It usually does not require rigorous component models of high accuracy because 1) the commonly used PID control is feedback control whose control performance evaluation doesn’t require high fidelity system/plant model; 2) high-fidelity dynamic …

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Optimization Of Multi-Zone Building Hvac Energy Consumption By Utilizing Fuzzy Model Based Predictive Controller, Ahmad Esmaeilzadeh, Brian Deal, Aghil Yousefi-Koma, Mohammad Reza Zakerzadeh May 2021

Optimization Of Multi-Zone Building Hvac Energy Consumption By Utilizing Fuzzy Model Based Predictive Controller, Ahmad Esmaeilzadeh, Brian Deal, Aghil Yousefi-Koma, Mohammad Reza Zakerzadeh

International High Performance Buildings Conference

The rapid improvement of living standards has led to increased energy consumption in buildings worldwide. Globally, the energy consumed in buildings accounts for 20.1% of total delivered energy (EIA 2016). Improving energy efficiency in buildings therefore is an important component for combating climate change. This paper aims to improve end use energy efficiency in multi-zoned residential buildings through the application of thermal comfort based, energy optimization algorithms. We use a case study approach with a detailed analysis of a 4-story residential apartment building in central Illinois. The study building constitutes 21 thermal zones modeled in EnergyPlus. The model is validated …

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Reinforcement Learning For Building Management Systems, Parastoo Delgoshaei, Amanda Pertzborn, Mohammad Heidarinejad May 2021

Reinforcement Learning For Building Management Systems, Parastoo Delgoshaei, Amanda Pertzborn, Mohammad Heidarinejad

International High Performance Buildings Conference

It is increasingly common to design buildings with advanced sensing and control systems to improve energy efficiency, indoor air quality which impacts health and productivity. However, there has been limited progress in making building automation systems “intelligent,” as the performance of such buildings is often limited by reactive control systems, primarily using setpoint limits and fixed operation schedules. The complex nature of building control problems motivates the application of state-of-the-art software engineering methods and techniques. Agent-based models (ABM) are well-suited for controlling complex engineering systems such as those employed in building heating, ventilation, and air-conditioning (HVAC) systems. In this paradigm, …

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Local Sensing And Personalized Thermal Comfort: Model-Predictive Vs Conventional Control Approaches, Hejia Zhang, Xiaoqi Liu, Seungjae Lee, Athanasios Tzempelikos May 2021

Local Sensing And Personalized Thermal Comfort: Model-Predictive Vs Conventional Control Approaches, Hejia Zhang, Xiaoqi Liu, Seungjae Lee, Athanasios Tzempelikos

International High Performance Buildings Conference

Model-based and model predictive control (MPC) based on personalized thermal preferences has the potential to minimize energy consumption and guarantee occupant thermal comfort. This paper presents the implementation of personalized controls that satisfy personalized thermal preferences in private offices. Two control strategies, a simple PID control and a real-time model predictive control, were implemented through the Building Management System in two adjacent identical office spaces. In each office, monitoring and control of indoor thermal conditions was achieved either by using a conventional wall thermostat or by using a low-cost wireless local sensing network -both integrated with the building management system. …

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Pattern Analysis Of Dynamic Grid Incentives And The Implications On Optimal Control Of Building Thermal Energy Storage, Lily X. Li, Gregory S. Pavlak May 2021

Pattern Analysis Of Dynamic Grid Incentives And The Implications On Optimal Control Of Building Thermal Energy Storage, Lily X. Li, Gregory S. Pavlak

International High Performance Buildings Conference

Building thermal energy storage has been utilized for decades for various objectives, such as reducing peak electrical demand, reducing building operating expenses, and increasing the efficiency of systems when charged from waste heat or free cooling. As building thermal storage control strategies become more dynamic, optimization of building performance often considers multiple objectives that aim to improve building performance in energy, economic, environmental, and grid support categories. The dynamics of the incentive signal used for one objective, as well as its relation to signals from other objectives—for instance, whether the signals are “in sync” or are “conflicting”—heavily influence the tradeoffs …

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A Practical Data-Driven Multi-Model Approach To Model Predictive Control: Results From Implementation In An Institutional Building, Etienne Saloux, Nunzio Cotrufo, José Candanedo May 2021

A Practical Data-Driven Multi-Model Approach To Model Predictive Control: Results From Implementation In An Institutional Building, Etienne Saloux, Nunzio Cotrufo, José Candanedo

International High Performance Buildings Conference

Model-based Predictive Control (MPC) is an effective solution to improve building controls. It consists of the use of weather and occupancy forecasts along with a control-oriented model to predict the behaviour of the building a few hours or days ahead, and thus optimize the operation of its systems. Although the potential of MPC is widely recognized, and plentiful operational data is often available, the development of a model requires a great deal of effort, significant technical expertise and knowledge of building systems. The challenge of creating a model is a hurdle that makes the on-site implementation of MPC in buildings …

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Recurrent Neural Network-Based Economic Mpc Applied To Building Hvac Systems, Matthew Ellis, Venkatesh Chinde May 2021

Recurrent Neural Network-Based Economic Mpc Applied To Building Hvac Systems, Matthew Ellis, Venkatesh Chinde

International High Performance Buildings Conference

No abstract provided.

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Two-Stage Compression With Vapor Injection: A Study On A Disregarded Solution In Co2 Booster Applications For Supermarket Refrigeration, Javier Ignacio Vega, Camila Dávila, Vincent Lemort May 2021

Two-Stage Compression With Vapor Injection: A Study On A Disregarded Solution In Co2 Booster Applications For Supermarket Refrigeration, Javier Ignacio Vega, Camila Dávila, Vincent Lemort

International Refrigeration and Air Conditioning Conference

CO2 refrigeration has been largely implemented, especially in supermarket applications. Nonetheless, one solution that has been often disregarded in these applications has been the inclusion of TwoStage compression cycles including vapour injection. Available literature has not yet compared these solutions with Booster applications. Thus, this paper presents the modelling of two solutions of TwoStage vapour injection cycles in a Booster configuration application: Flash Tank vapour injection (FTVI) and Subcooled Vapour injection (SCVI). The adopted methodology is more focused on the thermodynamic cycle rather than detailed components modelling. An analysis of the optimal displacement ratio between compression stages has been conducted, …

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Cfd Simulation Of Laminar Film Condensation On A Vertical Surface, David Vilar, Elena Martín, Jaime Sieres May 2021

Cfd Simulation Of Laminar Film Condensation On A Vertical Surface, David Vilar, Elena Martín, Jaime Sieres

International Refrigeration and Air Conditioning Conference

Two-dimensional simulations of laminar film condensation on a vertical surface are presented. A modified version of the interFoam solver present in OpenFOAM was developed, in order to take into account for energy and mass transfer. The Volume of Fluid (VOF) method is used to track the vapor-liquid interface, with the effects of interfacial stress, gravity and surface tension being considered. Concerning the mass transfer model between phases, several models are used in the literature. Some authors have chosen empiric models, which incorporate some parameters that must be tuned by trial and error. The right estimate of those parameters is essential, …

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A Numerical Study On The Pool Boiling With Foam Surface Enhancement Using Different Refrigerants, Mingkan Zhang, Kashif Nawaz, Cheng-Min Yang, Matthew Sandlin, William Asher, Brian Fricke, Anthony Gehl May 2021

A Numerical Study On The Pool Boiling With Foam Surface Enhancement Using Different Refrigerants, Mingkan Zhang, Kashif Nawaz, Cheng-Min Yang, Matthew Sandlin, William Asher, Brian Fricke, Anthony Gehl

International Refrigeration and Air Conditioning Conference

The pool boiling process can be observed in several energy conversion processes including commercial and industrial refrigeration, industrial air-cooling operations, and power generation. The process becomes more involved when pool boiling in a tube bundle is considered. In the current study, a numerical model is developed to predict the key performance parameters of a flooded evaporator while considering a range of working fluids. A kettle reboiler configuration was considered, and a performance model was developed to account for boiling on individual tubes, merging of vapor bubbles, and movement under gravity. A volume of fluid (VOF) model was used to deal …

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Modeling And Analysis Of Pressure Drop Oscillations In Horizontal Boiling Flow, Hongtao Qiao, Christopher Laughman May 2021

Modeling And Analysis Of Pressure Drop Oscillations In Horizontal Boiling Flow, Hongtao Qiao, Christopher Laughman

International Refrigeration and Air Conditioning Conference

In general, two-phase flow phenomena can be described based on the one-dimensional conservation laws. Models with different formulations can be obtained with different assumptions. This paper presents three models with different complexity to simulate pressure drop oscillations. The direct comparison indicates that there are substantial differences between these models. The mechanism of pressure drop oscillations is discussed and the effect of operating parameters on system instability is explored. It is shown that two bifurcation points can exist when varying heat input and inlet subcooling. Root locus analysis corroborates the simulation results.

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Heat Transfer And Pressure Drop Characteristics Of Water Flow Boiling In Internally Enhanced Tubes, Cheng-Min Yang, Kashif Nawaz, Anthony Gehl, Jorge Alvarado, Hitomi Yamaguchi, Fang Xu May 2021

Heat Transfer And Pressure Drop Characteristics Of Water Flow Boiling In Internally Enhanced Tubes, Cheng-Min Yang, Kashif Nawaz, Anthony Gehl, Jorge Alvarado, Hitomi Yamaguchi, Fang Xu

International Refrigeration and Air Conditioning Conference

Flow boiling is a critical process for many thermal conversion processes such as HVAC&R, water heating, power generation, and desalination applications. The goal of this paper is to enhance the in-tube heat transfer for flow boiling of water and thus improve the efficiency of the boiler. This paper presents an experimental investigation of the heat transfer and pressure drop characteristics for water under forced convection and boiling conditions inside both smooth and enhanced tubes. The results in the smooth copper tube are compared with several relevant correlations and the findings have been used as a baseline. The two-phase heat transfer …

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Comprehensive Study Of Heat Transfer And Pressure Drop In Regenerator And Optimization Of Solid-State Caloric Cooling Cycles Using Realistic Hydraulic Diameter Of Regenerator, Minwoong Kang, Stefan Elbel May 2021

Comprehensive Study Of Heat Transfer And Pressure Drop In Regenerator And Optimization Of Solid-State Caloric Cooling Cycles Using Realistic Hydraulic Diameter Of Regenerator, Minwoong Kang, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Many researchers have used very small hydraulic diameters in regenerators of solid-state caloric cooling cycles, because smaller diameters can generate higher cooling capacity and system COP. However, using very small diameters hardly represent the real performance of the caloric cooling cycle, because they cannot be manufactured for a real system. Therefore, this paper has used more realistic hydraulic diameter which is used in commercial heat exchangers. To get the more accurate heat transfer coefficient and friction factor, the model used in this paper incorporates hydrodynamic and thermal developing regions which are usually neglected in other papers. This paper shows that …

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Numerical Simulation Of The Heat Transfer In A Refrigerated Trailer Equipped With Eutectic Plates For Frozen Food Delivery, Jihyuk Jeong, Alla Eddine Benchikh Le Hocine, Sergio Croquer, Sébastien Poncet, Jocelyn Bonjour, Benoit Michel May 2021

Numerical Simulation Of The Heat Transfer In A Refrigerated Trailer Equipped With Eutectic Plates For Frozen Food Delivery, Jihyuk Jeong, Alla Eddine Benchikh Le Hocine, Sergio Croquer, Sébastien Poncet, Jocelyn Bonjour, Benoit Michel

International Refrigeration and Air Conditioning Conference

The present work reports the Computational Fluid Dynamics simulation and analysis of the heat transfer inside a refrigerated truck trailer equipped with three eutectic plates and fans. The numerical model solves the conjugated heat transfer inside the trailer in 2D using the �� −�� Shear Stress Transport (SST) turbulence model. It has been already favorably validated against the numerical and experimental data of Lafaye de Micheaux el al. (2015) by Croquer et al. (2019). These simulations are used to improve the configuration of the refrigeration system with the eutectic plates as well as to investigate the feasibility of the eutectic …

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A Numerical Analysis Of Latent Thermal Energy Storage For Refrigerated Trucks, Michele Calati, Claudio Zilio, Giulia Righetti, Giovanni Antonio Longo, Kamel Hooman, Simone Mancin May 2021

A Numerical Analysis Of Latent Thermal Energy Storage For Refrigerated Trucks, Michele Calati, Claudio Zilio, Giulia Righetti, Giovanni Antonio Longo, Kamel Hooman, Simone Mancin

International Refrigeration and Air Conditioning Conference

In this work, an innovative insulated wall concept for refrigerated truck is proposed. A 2D transient numerical model of the truck cell is developed and simulated considering the solar radiation from 6 AM to 4 PM of a typical summer day in Vicenza (Italy). The innovative composite wall consists of a traditional polyurethane (PU) insulation layer wrapping a layer of PCM (reference melting temperature of 2 °C) with different thickness from 0.5 cm to 2 cm. The results confirm that the proposed solution is very promising because even the smallest thickness can assure an adequate temperature inside the cell for …

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Solar-Powered Mechanical Subcooling Refrigeration System For Hot Climates, Sara Barghash, Ammar Bahman, Osama Ibrahim May 2021

Solar-Powered Mechanical Subcooling Refrigeration System For Hot Climates, Sara Barghash, Ammar Bahman, Osama Ibrahim

International Refrigeration and Air Conditioning Conference

This study investigates the performance of a solar-powered mechanical subcooling cycle to improve the performance of a refrigeration system in hot climates. The mechanical subcooling cycle helped the main refrigeration cycle by further subcool the refrigerant and improve the cooling capacity. The mechanical subcooling cycle used the energy generated by the solar photovoltaics to run its own compressor. The system was evaluated under Kuwait’s weather condition for a typical residential air conditioning (AC) unit of 5 tons of refrigeration (17.6 kW), where different refrigerants were examined in the mechanical subcooling cycle. The refrigerants considered in this study were R-410A, R-32, …

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Simulation-Based Study On Predicting The Flow-Induced Noise Near The Expansion Device, Yingyue Zhang, Stefan Elbel May 2021

Simulation-Based Study On Predicting The Flow-Induced Noise Near The Expansion Device, Yingyue Zhang, Stefan Elbel

International Refrigeration and Air Conditioning Conference

The flow-induced noise near the expansion device can be very disturbing to users. Studies related to the relationship between the flow-induced noise and flow regimes are calling more and more attention in recent decades. However, current studies lack a quantitative relationship between flow characteristics and the flow-induced noise. Therefore, in this paper, a noise-prediction model is proposed to predict the sound pressure level of flow-induced noise. The paper utilizes a pumped R134a loop with a needle valve for synchronized measurements between flow-induced noise and flow regimes. Synchronized high-speed measurements obtained from a microphone and a high-speed camera enable simultaneous investigation …

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A Novel Distributed Scroll Booster Architecture For Supermarket Refrigeration, Mike Saunders, Jason Born, Andre Patenaude, Rajan Rajendran May 2021

A Novel Distributed Scroll Booster Architecture For Supermarket Refrigeration, Mike Saunders, Jason Born, Andre Patenaude, Rajan Rajendran

International Refrigeration and Air Conditioning Conference

Today’s supermarket system architectures are being designed to minimize global warming potential (GWP) from both direct and indirect carbon emissions. To achieve this, many supermarkets are primarily employing one of two leading strategies: (1) designing and using systems that require smaller refrigerant charges, such as self-contained, secondary, or distributed systems; and (2) using lower-GWP refrigerants such as CO2 in a transcritical system. While both strategies have proved effective, each approach leaves room for improvement. The purpose of this paper is to introduce a third strategy: utilizing a distributed scroll booster system as an emerging alternative for distributed systems. The distributed …

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Equitizing Engineering Education By Valuing Children’S Assets: Including Empathy And An Ethic Of Care When Considering Trade-Offs After Design Failures, Pamela S. Lottero-Perdue, John Settlage May 2021

Equitizing Engineering Education By Valuing Children’S Assets: Including Empathy And An Ethic Of Care When Considering Trade-Offs After Design Failures, Pamela S. Lottero-Perdue, John Settlage

Journal of Pre-College Engineering Education Research (J-PEER)

The broad case being made in this paper is that recognizing student assets—rather than focusing on deficits—is essential for making engineering education more equitable. The paper begins with our exploration of an epistemic practice of engineering, ‘‘making trade-offs,’’ as enacted by kindergartners after experiencing design failure and during redesign. We then acknowledge through a reexamination of data that our understanding of children’s grappling about a trade-off was incomplete without considering another asset that children brought to the design experience: ‘‘enacting empathy and an ethic of care.’’ We argue for the inclusion of this asset as an epistemic practice of engineering. …

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Reflections On Asset-Based Pre-College Engineering Education To Promote Equity: An Introduction To The Special Issue, Lee Martin, Kristen B. Wendell May 2021

Reflections On Asset-Based Pre-College Engineering Education To Promote Equity: An Introduction To The Special Issue, Lee Martin, Kristen B. Wendell

Journal of Pre-College Engineering Education Research (J-PEER)

In our call for proposals, we argued that engineering education is in need of a paradigm shift that takes students’ assets as epistemologically primary to our conception of what engineering, and engineering education, can and should be. The 12 papers collected in this special issue show how a focus on youth assets can realign engineering education to be more humane, more inclusive, and just as meaningful as that of a traditional model. The papers offer both theoretical argumentation and empirical evidence to support their answers to the question of how asset-based approaches can improve engineering education. An emergent theme in …

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