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Experimental And Numerical Analysis Of Reed Valve Movement In An Impact Fatigue Test System And Reciprocating Compressors, Muhammad Waqas Tofique, Alexander Löf, Eugenio Schillaci, Pablo Castrillo, Joaquim Rigola May 2021

Experimental And Numerical Analysis Of Reed Valve Movement In An Impact Fatigue Test System And Reciprocating Compressors, Muhammad Waqas Tofique, Alexander Löf, Eugenio Schillaci, Pablo Castrillo, Joaquim Rigola

International Compressor Engineering Conference

During operation of a reciprocating compressor, its flapper valve opens to allow the passage of gases and closes by striking against the valve impact plate. This reed valve movement and impact is repeated billions of times. This cyclic movement has a significant influence on the impact fatigue life of the reed valve and, hence, the lifetime of a compressor. Inside a reciprocating compressor, a number of parameters including: the valve design, valve material, compressor operating frequency and suction/exhaust pressure, influence the reed valve movement. The valve movement can be defined in terms of valve frequency, valve lift, valve velocity and …

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Environmental Index For Real Time Feedback On Biowall Indoor Air Quality, William Hutzel, Hengyu Liu, Jun Ho Kim May 2021

Environmental Index For Real Time Feedback On Biowall Indoor Air Quality, William Hutzel, Hengyu Liu, Jun Ho Kim

International High Performance Buildings Conference

This paper describes an ongoing field evaluation of a simplified Environmental Index (EI) that provides a homeowner with an intuitive metric for assessing indoor air quality based on regular measurements of temperature, humidity, and Volatile Organic Compounds (VOC’s). These discrete measurements are used to compute an overall weighted score that correlates with the comfort and health of the living space. Although this environmental index is not a rigorous scientific computation, it is an initial point to improve residents’ understanding of Indoor Air Quality (IAQ) by providing active feedback. The context of this environmental index work is the Biowall, a living …

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Enhanced Integer Permutation Based Genetic Algorithm For Optimization Of Tube-Fin Heat Exchanger Circuitry With Splits And Merges, Zhenning Li, Vikrant Aute May 2021

Enhanced Integer Permutation Based Genetic Algorithm For Optimization Of Tube-Fin Heat Exchanger Circuitry With Splits And Merges, Zhenning Li, Vikrant Aute

International Refrigeration and Air Conditioning Conference

Tube-fin heat exchangers (HXs) are widely used in air-conditioning and heat pump applications. The performance of these heat exchangers is strongly influenced by the refrigerant circuitry. Studies have proved that by optimizing the refrigerant circuitry, the performance of HXs can be significantly improved. In our previous research, an Integer Permutation based Genetic Algorithm (IPGA) was developed to obtain the optimal circuitry designs. Our previous research showed that IPGA demonstrates superior capability to obtain better refrigerant circuitries with lower computational cost than the other methods in literature. And the optimal circuitry designs obtained from IPGA are manufacturable with the available tooling. …

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Promoting Equity By Scaling Up Summer Engineering Experiences: A Retrospective Reflection On Tensions And Tradeoffs, Walter C. Lee, David B. Knight, Monica E. Cardella May 2021

Promoting Equity By Scaling Up Summer Engineering Experiences: A Retrospective Reflection On Tensions And Tradeoffs, Walter C. Lee, David B. Knight, Monica E. Cardella

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

A central challenge in engineering education is providing experiences that are appropriate for and accessible to underserved communities. However, to provide such experiences, we must better understand the process of offering a geographically distributed asset-based out-of-school program. This paper focuses on a collaborative research project that examined the broad implementation of the Summer Engineering Experiences for Kids (SEEK) program organized by the National Society of Black Engineers (NSBE). SEEK is a three-week summer program that engages participants in hands-on, team-based engineering design projects. NSBE’s goal is to make SEEK culturally sustaining, community-connected, and scalable. The purpose of this paper is …

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Transnational Latinx Youths’ Workplace Funds Of Knowledge And Implications For Assets-Based, Equity-Oriented Engineering Education, Amy Wilson-Lopez, Jorge Acosta-Feliz May 2021

Transnational Latinx Youths’ Workplace Funds Of Knowledge And Implications For Assets-Based, Equity-Oriented Engineering Education, Amy Wilson-Lopez, Jorge Acosta-Feliz

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

Due to economic inequality in society, millions of Latinx high school youth work after-school jobs and summer jobs in order to provide additional income for their families. The purpose of this qualitative study, conducted with transnational Latinx youth, was to identify the engineering-related skills and bodies of knowledge they developed and applied while in different workplaces. This study is framed in complementary theories of funds of knowledge, Vygotskian theories of mediated action, and theories of resistant capital. Specifically, this study is based in the premise that youth can develop engineering-related funds of knowledge through tool-mediated, goal-directed activities jointly conducted with …

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The Ingenuity Of Everyday Practice: A Framework For Justice-Centered Identity Work In Engineering In The Middle Grades, Angela M. Calabrese Barton, Kathleen Schenkel, Edna Tan May 2021

The Ingenuity Of Everyday Practice: A Framework For Justice-Centered Identity Work In Engineering In The Middle Grades, Angela M. Calabrese Barton, Kathleen Schenkel, Edna Tan

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

Inequities in opportunities to learn and become in engineering, especially for minoritized youth, are enduring and systemic. How students experience engineering education, through curriculum, pedagogy, and teacher/student interactions, all shape opportunities for identity development. In this paper we draw upon cultural studies and critical ethnography to explore how and why students engage in engineering for sustainable communities and its relationship to their identity work. We ground our work in a justice-centered asset-based stance that centers how people’s lived lives and community wisdom yield powerful forms of cultural knowledge/practice relevant to learning and engaging in science, technology, engineering, and mathematics. We …

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Elementary Teacher Adaptations To Engineering Curricula To Leverage Student And Community Resources, Jennifer L. Chiu, Sarah J. Fick, Kevin W. Mcelhaney, Nonye Alozie, Reina Fujii May 2021

Elementary Teacher Adaptations To Engineering Curricula To Leverage Student And Community Resources, Jennifer L. Chiu, Sarah J. Fick, Kevin W. Mcelhaney, Nonye Alozie, Reina Fujii

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

This paper addresses an important consideration for promoting equitable engineering instruction: understanding how teachers contextualize curricular materials to draw upon student and community resources. We present a descriptive case study of two 5th grade teachers who co-designed a Next Generation Science Standards (NGSS)-aligned curricular unit that integrated science, engineering, and computational modeling. The five-week project challenged students to redesign their school grounds to reduce water runoff and increase accessibility for students with disabilities. The teachers implemented the project with one Grade 5 class with a large proportion of students having individualized learning plans and cultural backgrounds minoritized in science, technology, …

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Heating And Air-Conditioning Technology For Radiant Heat Recovery In Kiln Wall Of Cement Plant, Zhongbao Liu, Banghua Zhao, Xin Qi May 2021

Heating And Air-Conditioning Technology For Radiant Heat Recovery In Kiln Wall Of Cement Plant, Zhongbao Liu, Banghua Zhao, Xin Qi

International Refrigeration and Air Conditioning Conference

There is a large amount of energy waste in the cement production process, in which the waste of rotary kiln heat and the waste of high temperature exhaust gas at the kiln tail are the most serious. Therefore, the full and reasonable utilization of this waste heat resource is an important measure to improve the utilization degree and energy efficiency of waste heat, effectively reduce the heat pollution caused by waste heat emission to the environment, and protect the ecological environment. It is of great significance to realize energy conservation and emission reduction and regional sustainable development. The strategic goals …

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The Life And Legacy Of William Rankine, Andy Pearson May 2021

The Life And Legacy Of William Rankine, Andy Pearson

International Refrigeration and Air Conditioning Conference

Professor William Rankine, who was born on July 5 1820, made a substantial contribution to the science of heat and power and his influence in refrigeration and air-conditioning is still apparent today. This paper gives a short overview of Rankine’s life and work and then considers how his legacy is relevant to the challenges facing refrigeration, air conditioning and heat pump engineers in the 21st century. These include system efficiency, expansion methods, alternative cycles and novel working fluids.

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The Efficient Computational Tools For The Design Process Of The Transcritical Two-Phase Ejectors For Natural-Based Working Fluids, Jakub Bodys, Michal Palacz, Michal Haida, Jacek Smolka, Andrzej J. Nowak May 2021

The Efficient Computational Tools For The Design Process Of The Transcritical Two-Phase Ejectors For Natural-Based Working Fluids, Jakub Bodys, Michal Palacz, Michal Haida, Jacek Smolka, Andrzej J. Nowak

International Refrigeration and Air Conditioning Conference

Naturalbased working fluids for refrigeration are becoming a standard commercial solution due to the dynamic research and development in this area as well as law regulations. The stateoftheart ejector technology for R744 systems reached current status due to a significant interest on modelling approaches and effective regulation concepts. The development path of the fast and efficient design tools based on the numerical simulations could be described as a key feature for the R744 commercial technology. In this study, one of the most effective numerical approaches dedicated for the twophase CO2 ejector design and analysis is discussed. Namely, homogeneous equilibrium and …

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Study On Optimal Middle Temperature Of Cascade-Condenser In Co2/Nh3 Cascade Refrigeration Systems With Two Temperature Ranges, Xi Pan, Shizhong Sun, Haojie Wang, Huagen Wu, Ziwen Xing May 2021

Study On Optimal Middle Temperature Of Cascade-Condenser In Co2/Nh3 Cascade Refrigeration Systems With Two Temperature Ranges, Xi Pan, Shizhong Sun, Haojie Wang, Huagen Wu, Ziwen Xing

International Refrigeration and Air Conditioning Conference

This paper analyzes a CO2/NH3 cascade refrigeration system of two temperature range applied in the cold storage. A mathematical model is presented to determine the optimal middle temperatures of the cascade-condenser for obtaining the maximum coefficient of performance (COP) under different operation conditions. Three main parameters including the evaporation temperature in the cold storage, the evaporation temperature in the refrigerated storage and the condensation temperature in the high temperature stage are used to study the optimal middle temperature of CO2 in the cascade-condenser. The results show that the optimal middle temperature increases with the increment of three main parameters. Moreover, …

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External Water Subcooling To Improve The Performance Of A Co2 Heat Pump For Water Heating That Uses Greywater As Heat Source, Ramón A. Otón-Martínez, Fernando Illán-Gómez, José Ramón García-Cascales, F. Javier Sánchez-Velasco, Víctor Sena-Cuevas May 2021

External Water Subcooling To Improve The Performance Of A Co2 Heat Pump For Water Heating That Uses Greywater As Heat Source, Ramón A. Otón-Martínez, Fernando Illán-Gómez, José Ramón García-Cascales, F. Javier Sánchez-Velasco, Víctor Sena-Cuevas

International Refrigeration and Air Conditioning Conference

The use of CO2 heat pumps for water heating combined with energy recovery from greywater is a promising technology that can help to improve the efficiency of both domestic hot water (DHW) generation and space heating. A key aspect to keep in mind during the design of any CO2 refrigeration or heat pump system is the fact that the optimal gas cooler pressure in a transcritical CO2 cycle is mainly dependent on the refrigerant temperature at the gas cooler outlet. In space heating applications as well as DHW generation, operating conditions require high temperatures of refrigerant at the gas cooler …

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Quantitative And Qualitative Evaluation Of Various Positive-Displacement Compressor Modeling Platforms, Mohsin Mohsin Tanveer, Craig R. Bradshaw May 2021

Quantitative And Qualitative Evaluation Of Various Positive-Displacement Compressor Modeling Platforms, Mohsin Mohsin Tanveer, Craig R. Bradshaw

International Compressor Engineering Conference

Several regulatory measures aimed to mitigate climate change are forcing compressor manufacturers to replace current refrigerants to those with low Global Warming Potential (GWP). New refrigerants need to be evaluated to ensure adequate efficiency for use in modern products. Evaluation can be done heuristically, which is expensive and timeconsuming, while a carefully designed simulation model can provide similar outcomes for a significantly reduced cost. This paper presents a comparison between various userdeveloped and existing reciprocating compressor models to assist in the selection of a suitable modeling platform for a wideranging study. The reciprocating compressor is selected because of the simplicity …

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A Generalized Approach For Automated Compressor Performance Mapping Using Artificial Neural Network, Jie Ma, Xin Ding, W. Travis Horton, Davide Ziviani May 2021

A Generalized Approach For Automated Compressor Performance Mapping Using Artificial Neural Network, Jie Ma, Xin Ding, W. Travis Horton, Davide Ziviani

International Compressor Engineering Conference

In the last decades, several research and development efforts led to new compressor technologies that have been successfully introduced into market such as hermetic compressors with variable-speed motors, compressors with economization lines (both vapor and liquid injection lines), hermetic linear compressors, novel capacity modulations, and oil-flooding among others. During the process of implementing new compressor technologies, performance mapping is essential to predict the system behavior across different operating conditions. However, current standard AHRI-540 for compressor performance rating utilizes a 10-coefficient polynomial model that has severe limitations to include compressor enhancement technologies and variable operating range. In addition, it is common …

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An Overset Mesh Methodology For Cfd Modelling Of Rotary Compressors, Wai Chang Poh, Kim Tiow Ooi, Basman Elhadidi May 2021

An Overset Mesh Methodology For Cfd Modelling Of Rotary Compressors, Wai Chang Poh, Kim Tiow Ooi, Basman Elhadidi

International Compressor Engineering Conference

Full 2D and 3D unsteady CFD simulations are gradually replacing the widely used lumped parameters simulations for rotary compressors. Lumped parameter models predict the overall thermodynamic processes; however, they cannot reveal the spatial and temporal variations in the working chamber and account for complex fluid interactions and losses. The complex and continuously deforming working chamber geometry is challenging for CFD. The overset method has been implemented here for the simulation of a 2D Coupled Vane Compressor (CVC). The method was compared to a dynamic mesh formulation using a remeshing technique and has shown; (1) it is 3-4 times faster computationally …

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A Non Symmetric Interfacial Area Density Formulation For Transcritical Co2 Ejectors, Egoi Ortego May 2021

A Non Symmetric Interfacial Area Density Formulation For Transcritical Co2 Ejectors, Egoi Ortego

International Refrigeration and Air Conditioning Conference

The reduction of global warming potential gases emissions in industrial refrigeration devices requires the development of efficient cycles using low GWP gases. The supercritical C02 cycle assisted by a transcritical two phase ejector is a nice example of such cycles. The design of such ejectors is not obvious and an intense development of performance prediction tools is observed in literature especially regarding two-phase CFD modeling. The two phase flow CFD models are limited today by their lack of flexibility and difficulties to empirically calibrate them. The main drawback of classical Hertz-Knudsen or HRM phase change models is their difficulty to …

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Compressor Performance Comparison Of R454a And R454c For Refrigeration, Lars Sjoholm, Youngchan Ma, Gurudath Nayak, Matt Stinson May 2021

Compressor Performance Comparison Of R454a And R454c For Refrigeration, Lars Sjoholm, Youngchan Ma, Gurudath Nayak, Matt Stinson

International Compressor Engineering Conference

The intent of this paper is to compare compressor performance of two low GWP refrigerants that are mildly flammable. Since there are limited test capabilities for compressors with flammable refrigerants, the compressor tests in this paper are based on a non-flammable refrigerant, in this case R513A. The tested compressor is an open type screw compressor that is driven by an external motor and is vapor injected. A physical compressor model is created from test data. This compressor model is not based on maps for efficiencies, capacity, or power consumption, but rather a basis of physical bulk elements, such as pressure …

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Absorption Cooling For Data Centers Powered By Solid Oxide Fuel Cell Waste Heat, Alejandro Lavernia, Maryam Asghari, Mastropasqua Luca, Jacob Brower May 2021

Absorption Cooling For Data Centers Powered By Solid Oxide Fuel Cell Waste Heat, Alejandro Lavernia, Maryam Asghari, Mastropasqua Luca, Jacob Brower

International Refrigeration and Air Conditioning Conference

Thermal integration of a solid oxide fuel cell and a lithium bromide absorption chiller is proposed for air conditioning at data centers. Solid oxide fuel cells (SOFC) can be effectively implemented as primary energy producers at data centers due to their efficiency, environmental friendliness, and fuel flexibility. This study focuses on row-level SOFC power in the range of 150 – 200 kW. Operating at temperatures greater than 700°C, SOFC systems can produce high quality heat that can be utilized by absorption technology to provide supplemental cooling for the servers. This study investigates the operation of a triple-effect absorption chiller (AC) …

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Comprehensive Modeling Of A Chemical Looping Heat Pump With A Reverse Fuel Cell, Junyoung Kim, Nelson A. James, James E. Braun, Eckhard A. Groll, Davide Ziviani May 2021

Comprehensive Modeling Of A Chemical Looping Heat Pump With A Reverse Fuel Cell, Junyoung Kim, Nelson A. James, James E. Braun, Eckhard A. Groll, Davide Ziviani

International Refrigeration and Air Conditioning Conference

HVAC, refrigeration, and water heating accounted for approximately 22 quads of primary energy consumed in the United States in 2018, according to US EIA. Most of HVAC&R industry still relies on vapor compression and heat-driven technologies. The development of highly efficient technologies that would significantly improve both COP and annual energy savings is an open challenge for the new decade. Among the novel technologies, the Chemical Looping Heat Pump (CLHP) combined with a reverse fuel cell has been modeled with estimates of a COP increase of over 20% relative to a conventional vapor compression (VC) cycle. However, limitations of simplified …

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Efficient Simulation Method For Parallel Tube Evaporators For Vehicle Battery Cooling, Bernhard Einberger, Christoph Zainer, Andreas Ennemoser, Sebastian Möller, Andreas Egger, Michael Lang May 2021

Efficient Simulation Method For Parallel Tube Evaporators For Vehicle Battery Cooling, Bernhard Einberger, Christoph Zainer, Andreas Ennemoser, Sebastian Möller, Andreas Egger, Michael Lang

International Refrigeration and Air Conditioning Conference

Due to its size, the cooling of a vehicle battery by means of a refrigeration system has to be implemented e.g. via parallel evaporator tubes. After the throttle, the two-phase refrigerant flow must be uniformly distributed into several cooling channels so that uniform cooling can be achieved throughout the entire volume. The simulation of the three-dimensional effects in the distributor and also in the collector of an evaporator with several parallel evaporator tubes can only be done by computational fluid dynamics (3D CFD). However, the 3D CFD simulation of the evaporator is time consuming and can be replaced by a …

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Numerical Analysis For Heat Driven Ejector Refrigeration Systems For Various Refrigerants, Tokitaka Yoshida, Takeshi Matsubara, Masaaki Ajima, Masamichi Iwasaki, Stefan Elbel May 2021

Numerical Analysis For Heat Driven Ejector Refrigeration Systems For Various Refrigerants, Tokitaka Yoshida, Takeshi Matsubara, Masaaki Ajima, Masamichi Iwasaki, Stefan Elbel

International Refrigeration and Air Conditioning Conference

In this study, a numerical efficiency analysis for ejector refrigeration systems driven by low grade waste heat (65-85 °C) is performed. A 1-D numerical ejector model which was validated is applied to estimate the characteristics of the ejector. Investigation is focused on various refrigerants such as HFC (R134a, R245fa, R365mfc), HFO (R1234yf, R1234ze(E), R1233zd(E), R1336mzz(Z)), and natural refrigerants (NH3, R600, R600a), and their COPs (Coefficient of Performance) are compared. Main operating conditions (e.g. generation temperature, evaporation temperature, condensation temperature) are also considered to compare the system characteristics for each refrigerant. Simulations are performed for different operating conditions and their effects …

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Applying Two-Phase Zeotropic Heat Transfer Fluids To Solid-State Cooling Cycle And Comparison With Baseline Using Single Phase Water, Minwoong Kang, Stefan Elbel May 2021

Applying Two-Phase Zeotropic Heat Transfer Fluids To Solid-State Cooling Cycle And Comparison With Baseline Using Single Phase Water, Minwoong Kang, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Solid-state caloric cooling cycles are considered to be a promising alternative to conventional cooling technology. Theoretically, they can compete with the conventional vapor compression cycle and are much more efficient. However, this technology does have one problem: its performance decreases rapidly if the temperature difference between the condenser and evaporator gets larger. The environment where cooling technology is used often has large temperature differences between condenser and evaporator. For instance, in a typical automotive system, the condenser operates at 45°C and the evaporator at 5°C. Thus, the temperature difference between the condenser and evaporator reaches 40°C. The cooling load of …

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Numerical Simulation Of Ice Slurry Flow In Improved Plate Heat Exchanger Geometries With Consideration Of Different Phase Interaction Parameters, Shaimaa Hefny Badawi, Christiane Thomas, Ullrich Hesse May 2021

Numerical Simulation Of Ice Slurry Flow In Improved Plate Heat Exchanger Geometries With Consideration Of Different Phase Interaction Parameters, Shaimaa Hefny Badawi, Christiane Thomas, Ullrich Hesse

International Refrigeration and Air Conditioning Conference

Concerning the cold supply, ice slurry technology is a safe, environmentally friendly and efficient solution for energy storage. Previous studies have shown that ice slurry is potentially one of the most important phase change material (PCM) slurries used as a secondary refrigerant due to its high cooling capacity and flexibility in application. However, agglomeration phenomena are observed with ice particle slurry flows, which can lead to blocking of e.g. heat exchangers and pipes. The study applies an Euler-Euler approach based on the kinetic theory of granular flow to describe the melting of an ice slurry flow. The Eulerian model was …

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An Updated Quantification Method For Liquid Refrigerant Distribution In Microchannel Evaporators Using Infrared Thermography, Yuping Gao, Daniel Silsbee, Ke Tang, Stefan Elbel May 2021

An Updated Quantification Method For Liquid Refrigerant Distribution In Microchannel Evaporators Using Infrared Thermography, Yuping Gao, Daniel Silsbee, Ke Tang, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Refrigerant distribution in the parallel tubes of a microchannel evaporator significantly affects its heat transfer performance, which can further affect the coefficient of performance of the whole air-conditioning or refrigeration system. This paper proposes an easy-to-implement quantification method using infrared thermography for the liquid refrigerant distribution in microchannel evaporators to update the original method developed by Li and Hrnjak (2015). Before the detailed discussion of the new quantification method, the effect of surface emissivity on the infrared thermography is investigated, and the calibration process of the infrared thermography is presented for a microchannel heat exchanger sample. Then, the updated quantification …

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A Critical Analysis Of The Characterization Of Scroll Compressors Energy Consumption, Javier Marchante-Avellaneda, Jose Miguel Corberan, Emilio Navarro-Peris, Som S. Shrestha May 2021

A Critical Analysis Of The Characterization Of Scroll Compressors Energy Consumption, Javier Marchante-Avellaneda, Jose Miguel Corberan, Emilio Navarro-Peris, Som S. Shrestha

International Compressor Engineering Conference

This paper presents the analysis of the energy consumption of scroll type compressors. The study has included the data of several AHRI reports: (especially AHRI-11 and AHRI-21) as well as data from other source. A total of 8 different scroll compressors, of different size, some of them tested with various refrigerants (R134a, R32, R410A, R404A…) have been considered in the study. The values of the compressor consumption, and of the corresponding compressor efficiency, and the shape of the corresponding response surfaces, for all the studied compressors and refrigerants, have been analyzed with the objective of understanding better the dependence of …

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Development Of A New Dual-Cylinder Rolling Piston Compressor, Li Zhang, Chunhui Liu, Ruixiong Wang, Lei Zhang May 2021

Development Of A New Dual-Cylinder Rolling Piston Compressor, Li Zhang, Chunhui Liu, Ruixiong Wang, Lei Zhang

International Compressor Engineering Conference

In recent years, the requirement of energy efficiency for refrigeration and air condition systems becomes more and more higher while the cost needs to be more and more lower, at the same time some new applications of refrigeration and air condition systems are emerging rapidly. All of these demands need a new compressor to meet. In this paper, a new dual-cylinder rolling piston compressor with two independent suction ports and two independent discharge ports was proposed. The structure and working principal of this compressor were described, and the performance was tested. Then simulation model was built to research the performance …

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Performance Comparison Between Rolling Piston And Coupled Vane Compressor, Qi Jing Chen, Kim Tiow Ooi May 2021

Performance Comparison Between Rolling Piston And Coupled Vane Compressor, Qi Jing Chen, Kim Tiow Ooi

International Compressor Engineering Conference

In this paper, the performance of the rolling piston compressor and the coupled vane compressor are compared, and differences or similarities are presented and discussed. The comparison is based on one of the available sizes of the rolling piston compressor as used in a room air-conditioner. The extent of the theoretical comparison includes their respective design features, relative sizes, individual flow and frictional energy losses, details of PV diagrams, valve flow analysis and other performance parameters such as “compressor” COP. The coupled vane compressor is a novel compressor recently design with the objective to save raw materials in the production …

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A Unified Mpc Formulation For Control Of Commercial Hvac Systems In Multiple Climate Zones, Naren Srivaths Raman, Bo Chen, Prabir Barooah May 2021

A Unified Mpc Formulation For Control Of Commercial Hvac Systems In Multiple Climate Zones, Naren Srivaths Raman, Bo Chen, Prabir Barooah

International High Performance Buildings Conference

Model predictive control (MPC) has been widely investigated for climate control of commercial buildings for both energy efficiency and demand flexibility. However, most MPC formulations ignore humidity and latent heat. The inclusion of moisture makes the problem considerably more challenging, primarily since a cooling and dehumidifying coil model which accounts for both sensible and latent heat transfers is needed. In our recent work, we proposed an MPC controller in which humidity and latent heat were incorporated in a principled manner, by using a reduced-order model of the cooling coil. Because of the highly nonlinear nature of the process in a …

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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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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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