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2016

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Structural Analysis Of Reciprocating Compressor Manifold, Marcos Giovani Dropa Bortoli Jan 2016

Structural Analysis Of Reciprocating Compressor Manifold, Marcos Giovani Dropa Bortoli

International Compressor Engineering Conference

The reciprocating compressor manifold design is very important for the compressor to achieve the goals of energy efficiency, acoustic and reliability. In the same level of importance, the design must take in count the cost related with manufacturing process and raw material. The main components involved in the manifold design are the cylinder, piston, valve plate, valves, cylinder head, bolts and gaskets. The design of a reciprocating compressor manifold is a multifunctional activity, which involves knowledge from thermal, acoustic, structural and tribology areas. The objective of this paper is to present the main aspects related with the structural analysis of …

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A Novel Vapor Injection Structure On The Blade For Rotary Compressor, Baolong Wang, Xingru Liu, Wenxing Shi Jan 2016

A Novel Vapor Injection Structure On The Blade For Rotary Compressor, Baolong Wang, Xingru Liu, Wenxing Shi

International Compressor Engineering Conference

Rotary compressors have been extensively used in room air conditioners and household refrigerators for their advantages, including high efficiency, strong adaptability, and low cost. However, when air source heat pumps with rotary compressors are applied in cold regions, a series of problems appear. The gas injection has been proved an effective technology to enhance both the heating capacity and COP of scroll, screw, and rotary compressors. In the one-cylinder rotary compressor with gas injection, the compressor injection port is often opened on the cylinder wall. In order to extend the injection time for injecting more refrigerant, the injection port is …

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Experimental Investigation Of Damping Coefficient For Compressor Reed Valves, Sergio Koerich Lohn, Evandro Luiz Lange Pereira, Humberto Ferreira Camara, Cesar Jose Deschamps Jan 2016

Experimental Investigation Of Damping Coefficient For Compressor Reed Valves, Sergio Koerich Lohn, Evandro Luiz Lange Pereira, Humberto Ferreira Camara, Cesar Jose Deschamps

International Compressor Engineering Conference

Reed valve dynamics has a major role on the performance and reliability of compressors and has been the subject of many studies over the years. In terms of mathematical modeling, most of these studies describe valve dynamics through a mass-spring-damper system, in which a damping coefficient has to be empirically adjusted. This is a consequence of little knowledge about the effect of different parameters on valve damping. For instance, in spite of great effort to understand viscous effects on the pressure distribution acting on the valve surface, very few works have addressed such effects on valve damping, especially for valve …

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Performance Analysis Of A Reciprocating Compressor Under Typical Transients Of Refrigeration Systems, Marco Carrilho Diniz, Cesar Jose Deschamps Jan 2016

Performance Analysis Of A Reciprocating Compressor Under Typical Transients Of Refrigeration Systems, Marco Carrilho Diniz, Cesar Jose Deschamps

International Compressor Engineering Conference

The performance of reciprocating compressors is usually evaluated under steady-state operating conditions defined in standards. However, the compressor is submitted to quite different conditions in actual refrigeration systems, such as transients associated with the on/off cycling operation. This paper presents a simulation model developed to evaluate the performance of reciprocating compressors during typical transients of refrigeration systems. The model is formed by the coupling of two sub models, one for the compression chamber and the other to calculate the temperatures and mass flow rates in components other than the compression chamber. As the model only simulates the compressor, experimental data …

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Integrating Numerical Models For Efficient Simulation Of Compressor Valves, Ajay Parihar, David Myszka, Benjamin Robinet, Thomas Hodapp Jan 2016

Integrating Numerical Models For Efficient Simulation Of Compressor Valves, Ajay Parihar, David Myszka, Benjamin Robinet, Thomas Hodapp

International Compressor Engineering Conference

The motion of automatic, self-acting valves is a primary aspect in achieving superior compressor reliability and performance. Simulation of compressor valve mechanics involves a complex set of interactions that include characteristics of the compression chamber, thermodynamics, gas flow, valve motion, and pressure pulsations through the valve passages. One-dimensional (1D) lumped simulation models that encompass these interactions have been formulated and refined over the past several decades. During that same time period, finite element theory for fluid-structural-interaction (FSI) has been developed. Â FSI provides three-dimensional (3D) results across the entire fluid and solid domain and is well-suited for compressor simulation. However, …

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Flap-X: Development Of A New Compressor Reed Material, Alexander Lof, Chris Millward, Azhar Nawaz Jan 2016

Flap-X: Development Of A New Compressor Reed Material, Alexander Lof, Chris Millward, Azhar Nawaz

International Compressor Engineering Conference

Flap-X is a new reed valve steel developed for compressor applications. The development work was undertaken after consistent feedback from customers requiring higher fatigue strength and improved damping properties. The renewed interest in improved valve strip is a direct result of the industry’s latest trends towards energy efficient compressors. Different steel grades were investigated during process development and Flap-X material, which is an optimized version of the well-known compressor steel UHB SS716, showed the most promising results in terms of production feasibility and desired enhancements in alloy design, metallurgy and mechanical properties. Finished valve strip of each candidate material was …

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A Heat Transfer Correlation For The Suction And Compression Chambers Of Scroll Compressors, Evandro L.L. Pereira, Cesar J. Deschamps Jan 2016

A Heat Transfer Correlation For The Suction And Compression Chambers Of Scroll Compressors, Evandro L.L. Pereira, Cesar J. Deschamps

International Compressor Engineering Conference

Heat transfer in the suction and compression chambers of scroll compressors has not been sufficiently studied and typical correlations available in the literature are based on simplified flow conditions. This paper presents the results of a model developed to predict fluid flow and heat transfer inside the suction and compression chambers of scroll compressors. Due to the particular geometry of scroll compressors, an algorithm was developed to automatically adapt the computational mesh for each orbiting angle. Convective heat transfer is strongly affected by the flow in the near- wall region and for this reason a low Reynolds number turbulence model …

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Updated Performance And Operating Characteristics Of A Novel Rotating Spool Compressor, Joe Orosz, Craig R Bradshaw, Greg Kemp, Eckhard A Groll Jan 2016

Updated Performance And Operating Characteristics Of A Novel Rotating Spool Compressor, Joe Orosz, Craig R Bradshaw, Greg Kemp, Eckhard A Groll

International Compressor Engineering Conference

The basic mechanism of the novel rotary spool compressor has been described previously by Kemp et al. (2008, 2010). The device combines various aspects of rotary and reciprocating devices that are currently well understood. Â Due to increasing pressure in the global market for refrigerants with very low GWP levels extensive modeling was conducted to explore a spool compressor design for operation on medium pressure low GWP refrigerants in sizes applicable to the commercial air conditioning marker, specifically for application on air and water cooled chillers. The basis for a compressor design in this space is operation on R134a realizing …

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Comparative Analysis Of Two Types Of Positive Displacement Compressors For Air Conditioning Applications, Marco Carrilho Diniz, Cesar Jose Deschamps Jan 2016

Comparative Analysis Of Two Types Of Positive Displacement Compressors For Air Conditioning Applications, Marco Carrilho Diniz, Cesar Jose Deschamps

International Compressor Engineering Conference

Different types of positive displacement compressors are employed in low-capacity air conditioning applications. Understanding the advantages and drawbacks of each of these technologies is important in order to identify the ranges of cooling capacities at which a specific compression technology is more efficient. This paper presents a comparative analysis between two positive displacement compressors (rolling piston and scroll) designed for air conditioning applications. The compressors operate with R-22 and present a nominal cooling capacity of 18000 BTU/h at the AHRI-A checkpoint condition. First, the compressors were tested in a hot-cycle test bench to measure the mass flow rate and power …

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Refrigeration Cycle And Compressor Performance For Various Low Gwp Refrigerants, Jit Guan Edwin Ong, Kim Tiow Ooi Jan 2016

Refrigeration Cycle And Compressor Performance For Various Low Gwp Refrigerants, Jit Guan Edwin Ong, Kim Tiow Ooi

International Compressor Engineering Conference

The problem of global warming is crucial, with temperature rise estimated to about 0.4 and 0.8 °C over the past 100 years, and is predicted to rise between 1.4 and 5.8 °C by the year 2100. The meetings of the global leaders in the recent COP21 have gathered global consensus to fight the global warming. One of the important approach in aiding toward fighting global warming is to use environmental friendly refrigerants. Recently a few new low GWP refrigerants have been introduced. In this paper, we will first discuss the refrigeration cycle efficiencies of these new low GWP refrigerants as …

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Development Of A New Dual-Cylinder Rotary Compressor For Vi System, Guoyong Yang, Cheng Zhang, Yanping Wu, Siqing Liao Jan 2016

Development Of A New Dual-Cylinder Rotary Compressor For Vi System, Guoyong Yang, Cheng Zhang, Yanping Wu, Siqing Liao

International Compressor Engineering Conference

On the vapor compression refrigeration system, Vapor injection (VI, the phase separator type injection or the internal heat exchanger type injection) compression cycle’s superiority over non-injection cycle has been well known. VI system produces the high heating/cooling capacity, and its power consumption is less than the non-injection system. But if a VI compression cycle uses a single rotary compressor, there is the problem that refrigerant injection increases the indicated power by mixture loss. If we use a two-stage rotary compressor, indicated power also increases because of its two times exhaust process. To solve these problems, we developed a new dual-cylinder …

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A Comprehensive Evaluation Of Regression Uncertainty And The Effect Of Sample Size On The Ahri-540 Method Of Compressor Performance Representation, Vikrant Aute, Cara Martin Jan 2016

A Comprehensive Evaluation Of Regression Uncertainty And The Effect Of Sample Size On The Ahri-540 Method Of Compressor Performance Representation, Vikrant Aute, Cara Martin

International Compressor Engineering Conference

AHRI-540 is the current standard defining the methods for representing compressor performance data. While this standard is widely used across the industry, multiple factors contribute to inaccuracies in data representation including measurement uncertainty, regression uncertainty, compressor to compressor variation, and operation outside of the normal operating envelope (extrapolation). In addition, the number and location of points in the operating envelop also affects the accuracy of the resulting 10-coefficient polynomial. The measurement uncertainty is well known and can be factored into the data reduction. However, the measurement uncertainty is generally not propagated into the regression uncertainty and hence the overall uncertainty …

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Design Methodology Improvements Of A Rotating Spool Compressor Using A Comprehensive Model, Craig R Bradshaw, Greg Kemp, Joe Orosz, Eckhard A Groll Jan 2016

Design Methodology Improvements Of A Rotating Spool Compressor Using A Comprehensive Model, Craig R Bradshaw, Greg Kemp, Joe Orosz, Eckhard A Groll

International Compressor Engineering Conference

An improvement to the design process of the rotating spool compressor is presented. This improvement utilizes a comprehensive model to explore two working fluids (R410A and R134a), various displaced volumes, at a variety of geometric parameters. The geometric parameters explored consists of eccentricity ratio and length-to-diameter ratio. The eccentricity ratio is varied between 0.81 and 0.92 and the length-to-diameter ratio is varied between 0.4 and 3. The key tradeoffs are evaluated and the results show that there is an optimum eccentricity and length-to-diameter ratio, which will maximize the model predicted performance, that is unique to a particular fluid and displaced …

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Optimal Structural Design Of Swing Double-Vane Compressor, Junjie Ma, Xiang Chen, Xu Yang, Zongchang Qu Jan 2016

Optimal Structural Design Of Swing Double-Vane Compressor, Junjie Ma, Xiang Chen, Xu Yang, Zongchang Qu

International Compressor Engineering Conference

In this paper, a novel rotary compressor, namely Swing Double-vane Compressor, was introduced. Based on the working principle of the compressor, thermodynamic model and kinetic model of upper and down vanes, rotor and eccentric shaft were established. Combined with each model, with the working efficiency as the objective function, the main structural sizes were optimally designed for the compressor by optimization algorithm, after which the working efficiency can be to 0.8757 and its theoretical displacement has improved by 66.94% compared with the single-vane compressor. According to this optimal design, it will provide theoretical foundation to improve the performance of the …

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Theoretical Study Of Seal Spring In A Wankel Compressor, De-Lou Zhang, Yu-Ting Wu, Jing-Fu Wang, Chun-Xu Du, Xia Chen, Rui Ma, Chong-Fang Ma Jan 2016

Theoretical Study Of Seal Spring In A Wankel Compressor, De-Lou Zhang, Yu-Ting Wu, Jing-Fu Wang, Chun-Xu Du, Xia Chen, Rui Ma, Chong-Fang Ma

International Compressor Engineering Conference

The successful fabrication of a miniature Wankel compressor relies on its seal performance.The factors that influence the seal of a miniature Wankel compressor mainly include axial double mechanical seal and apex seals.Axial mechanical seal depends on machining precision on the end face.In the compression cavity, the springs for seal flake on the Wankel rotor put pressure on cylinder ,which generates the desired amount of pressing force.When springs fails,high-pressure cavity and low-pressure cavity will be connected.Spring performance will directly affect the efficiency of a Wankel compressor.In this paper,we aim to introduce kinematic analysis of apex seals and force analysis of springs …

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Analysis On Lubricant Film Force For Two Types Of Meshing Pair Profile In Single Screw Compressor, Feilong Liu, Jia Xie, Davide Ziviani, Quanke Feng, Martijn Van Den Broek, Michel De Paepe Jan 2016

Analysis On Lubricant Film Force For Two Types Of Meshing Pair Profile In Single Screw Compressor, Feilong Liu, Jia Xie, Davide Ziviani, Quanke Feng, Martijn Van Den Broek, Michel De Paepe

International Compressor Engineering Conference

Single screw compressors are widely used in various industrial fields, however the performance usually drops obviously after thousands of hours of operation due to the wear between the star-wheel and the gate rotor. A lot of meshing pair profiles and manufacturing methods are proposed to solve this problem. Thus, good oil lubrication conditions are conducive to improve the wear resistance of the meshing pair so as to increase the compressor‘s operation life. In this paper, the geometric models of the clearances for both profiles, a kind of multi-column profile and single-column profile for oil flooded compressors are carried out, and …

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Fluid-Structure Interaction Of A Reed Type Valve, Ignacio Gonzalez, Oriol Lehmkuhl, Alireza Naseri, Joaquim Rigola, Assensi Oliva Jan 2016

Fluid-Structure Interaction Of A Reed Type Valve, Ignacio Gonzalez, Oriol Lehmkuhl, Alireza Naseri, Joaquim Rigola, Assensi Oliva

International Compressor Engineering Conference

This paper aims at studying numerically the flow of a fluid through reed type valves, which are generally used in some reciprocating compressors and engines. The analysis and design of these valves serve not only to improve the performance of filling or discharging, but also to ensure system reliability. The valve opening-closing process involves fluid dynamics and deformation of a flat plate structure, both physics being completely coupled. To overcome this and other kind of fluid-structure interaction (FSI) problems, an in-house CFD-CSD (Computational Fluid Dynamics-Computational Structural Dynamics) coupled solver has been implemented within TermoFluids code. The CFD solver consists of …

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On The Use Of A Parallel Object-Oriented Code For Solving The Heat Transfer In Hermetic Reciprocating Compressors, Lopez Mas, Rigola Joaquim, Lehmkuhl Oriol, Oliva Assensi Jan 2016

On The Use Of A Parallel Object-Oriented Code For Solving The Heat Transfer In Hermetic Reciprocating Compressors, Lopez Mas, Rigola Joaquim, Lehmkuhl Oriol, Oliva Assensi

International Compressor Engineering Conference

The heat transport phenomenon in a hermetic reciprocating compressor is addressed in this work. This is far from straightforward. It involves several transient physical phenomena interacting to each other. The heat is exchanged between the refrigerant fluid and the solid parts of the compressor (suction muffler, cylinder head, crankcase, etc.). At the same time, the solid parts exchange heat to each other by means of conduction and radiation. Moreover, the phenomenon happens in non-symmetrical complex geometries and the solid parts are made of different materials. This is interesting from both the software engineering and the compressor design viewpoint. A parallel …

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Lubrication Tests To Support Optimal Performance Design Guidelines For Thrust Slide-Bearings In Scroll Compressors, Noriaki Ishii, Eiji Nonoguchi, Keiko Anami, Atsushi Sakuda, Yuya Terada, Yusuke Imai, Kiyoshi Sawai, Charles William Knisely Jan 2016

Lubrication Tests To Support Optimal Performance Design Guidelines For Thrust Slide-Bearings In Scroll Compressors, Noriaki Ishii, Eiji Nonoguchi, Keiko Anami, Atsushi Sakuda, Yuya Terada, Yusuke Imai, Kiyoshi Sawai, Charles William Knisely

International Compressor Engineering Conference

This study focuses on the role of lubrication in the optimal performance design guidelines for the thrust slide-bearings in scroll compressors. The theoretical analysis of Ishii et al. showed that the minimum friction power loss in the thrust slide-bearing occurs at a certain outer radius of the friction surface. In the theoretical development, the physical thrust slide-bearing was modeled as a cylindrical thrust plate, representing the orbiting scroll, and the flat plate, representing the fixed scroll, with the same friction area as the physical bearing. The outer radius of the friction surface was varied for a fixed inner radius, where …

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Modeling And Testing The Thermal Effect Of Lubricating Oil Sprayed In Sliding-Vane Air Compressors Using Pressure-Swirl Nozzles, Gianluca Valenti, Stefano Murgia, Ida Costanzo, Giulio Contaldi, Alessandro Valenti Jan 2016

Modeling And Testing The Thermal Effect Of Lubricating Oil Sprayed In Sliding-Vane Air Compressors Using Pressure-Swirl Nozzles, Gianluca Valenti, Stefano Murgia, Ida Costanzo, Giulio Contaldi, Alessandro Valenti

International Compressor Engineering Conference

Positive-displacement compressors and, among them, sliding-vane machines are widely used in the compressed air sector. As in many other industrial fields, the efficient utilization of energy has become a major goal also in this sector. The aim of the present activity is the numerical modeling and the experimental testing of the positive thermal effect due to spraying the lubricating oil inside sliding-vane air compressors using pressure-swirl nozzles. The benefits of proper oil atomization in positive-displacement compressors have been documented already by a number of investigations (Singh and Bowman, 1986; Stosic et al., 1988; Fujiwara and Osada, 1995; Valenti et al., …

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Gradient-Based Estimation Of Air Flow And Geometry Configurations In A Building Using Fluid Dynamic Adjoint Equations, Runxin He, Humberto Gonzalez Jan 2016

Gradient-Based Estimation Of Air Flow And Geometry Configurations In A Building Using Fluid Dynamic Adjoint Equations, Runxin He, Humberto Gonzalez

International High Performance Buildings Conference

Real-time estimations of temperature distributions and geometric configurations are important to energy efficient buildings and the development of smarter cities. In this paper we formulate a gradient-based estimation algorithm capable of reconstructing the states of doors in a building, as well as its temperature distribution, based on a floor plan and a set of thermostats. Our algorithm solves in real time a convection-diffusion Computer Fluid Dynamics (CFD) model for the air flow in the building as a function of its geometric configuration. We formulate the estimation algorithm as an optimization problem, and we solve it by computing the adjoint equations …

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Sensitivity Analysis For The Pmv Thermal Comfort Model And The Use Of Wearable Devices To Enhance Its Accuracy, Mohammad H. Hasan, Fadi M. Alsaleem, Mostafa Rafaie Jan 2016

Sensitivity Analysis For The Pmv Thermal Comfort Model And The Use Of Wearable Devices To Enhance Its Accuracy, Mohammad H. Hasan, Fadi M. Alsaleem, Mostafa Rafaie

International High Performance Buildings Conference

This paper studies the sensitivity of the Predicted Mean Vote (PMV) thermal comfort model relative to its environmental and personal parameters. PMV model equations, adapted in the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 55–Thermal Environmental Conditions for Human Occupancy, are used in this investigation to generate two-dimensional (2D) and three-dimensional (3D) comfort zone plots for different combinations of parameters. It is found that personal parameters such as clothing and metabolic rate, which are usually ignored or simply assumed to be constant values, have the highest impact. In this work, we demonstrate the use of smart wearable …

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Parallel Object-Oriented Algorithms For Building Performance Simulation. Application To An Existing Dwelling., Lopez Joan, Capdevila Roser, Souaihi Oussama, Rigola Joaquim, Oliva Assensi Jan 2016

Parallel Object-Oriented Algorithms For Building Performance Simulation. Application To An Existing Dwelling., Lopez Joan, Capdevila Roser, Souaihi Oussama, Rigola Joaquim, Oliva Assensi

International High Performance Buildings Conference

In the present work an existing dwelling, situated in the Netherlands, has been modeled by means of a parallel object-oriented simulation tool, called NEST-Buildings. The model is based on a pre-defined collection of elements (e.g., walls, rooms, openings, outdoors, occupants, ventilation tubes and boxes, solar radiation distributors, HVAC equipment, etc.) that are connected to each other conforming a dynamic thermal system. New configurations can be easily handled by adding or removing elements. Moreover, the building elements can be modeled at distinct levels of accuracy ranging from lumped volumes mixed with one-dimensional to detailed CFD&HT models. This approach makes possible the …

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Stochastic Modeling Of Short-Term Occupancy For Energy Efficient Buildings, Jin Dong, Chris Winstead, Seddik M. Djouadi, James J. Nutaro, Teja Kuruganti Jan 2016

Stochastic Modeling Of Short-Term Occupancy For Energy Efficient Buildings, Jin Dong, Chris Winstead, Seddik M. Djouadi, James J. Nutaro, Teja Kuruganti

International High Performance Buildings Conference

The primary energy consumer of smart buildings are Heating, Ventilation, and Air-Conditioning (HVAC) systems, approximately 30% of the building energy use, which usually operate on a fixed schedule. Currently, most modern buildings still condition rooms with a set-point assuming maximum occupancy rather than actual usage. As a result, rooms are often over-conditioned needlessly. Occupancy-based controls can achieve significant energy savings by temporally matching the building energy consumption and building usage, conservative user behavior can save a third of expended energy. Â In this paper, we present a simple yet effective algorithm to automatically assign reference temperature set-points based on the …

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System Identification For Model Predictive Control Of Building Region Temperature, Matthew J Ellis, Michael J Wenzel, Robert D Turney Jan 2016

System Identification For Model Predictive Control Of Building Region Temperature, Matthew J Ellis, Michael J Wenzel, Robert D Turney

International High Performance Buildings Conference

Model predictive control (MPC) is a promising technology for energy cost optimization of buildings because it provides a natural framework for optimally controlling such systems by computing control actions that minimize the energy cost while meeting constraints. In our previous work, we developed a cascaded MPC framework capable of minimizing the energy cost of building zone temperature control applications. The outer loop MPC computes power set-points to minimize the energy cost while ensuring that the zone temperature is maintained within its comfort constraints. The inner loop MPC receives the power set-points from the outer loop MPC and manipulates the zone …

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A Multi-Objective Approach To Optimal Battery Storage In The Presence Of Demand Charges, Reza Kamyar, Matthew Monnig Peet Jan 2016

A Multi-Objective Approach To Optimal Battery Storage In The Presence Of Demand Charges, Reza Kamyar, Matthew Monnig Peet

International High Performance Buildings Conference

In this paper, we propose an optimization framework for optimal energy storage, in the form of batteries, by residential customers. Our goal is to determine the value of battery storage to those customers whose electricity bills consist of both Time-of-Use charges ($/kWh, with different rates for on-peak and off-peak hours) and demand charges ($/kW, proportional to the peak rate of consumption in a month). The customers may have access to a local power generating source in the form of solar PhotoVoltaic (PV). In order to quantify the benefits from the battery storage, we pose a battery optimization problem which minimizes …

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Adaptive Personalized Shading Control Strategies To Maximize Occupant Satisfaction While Reducing Lighting Energy Use In Buildings, Jie Xiong, Seungjae Lee, Athanasios Tzempelikos, Panagiota Karava Jan 2016

Adaptive Personalized Shading Control Strategies To Maximize Occupant Satisfaction While Reducing Lighting Energy Use In Buildings, Jie Xiong, Seungjae Lee, Athanasios Tzempelikos, Panagiota Karava

International High Performance Buildings Conference

In this study, a personalized shading control framework is developed to maximize occupant satisfaction while minimizing lighting energy use using a multi-objective optimization scheme. A personalized satisfaction model was developed based on specially-designed experiments in private offices, to quantify the occupant satisfaction level with motorized roller shades by predicting the override probability of occupants considering different variables. Then, a multi-objective optimization algorithm was constructed, considering the shading override probability and predicted lighting energy use as objectives, where the occupants are the decision makers in the final balancing between their personalized comfort limits and energy use considerations. The developed method serves …

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Independent Domination Of Subcubic Graphs, Bruce Allan Priddy Jan 2016

Independent Domination Of Subcubic Graphs, Bruce Allan Priddy

Electronic Theses and Dissertations

Let G be a simple graph. The independent domination number i(G) is the minimum cardinality among all maximal independent sets of G. A graph is subcubic whenever the maximum degree is at most three. In this paper, we will show that the independent domination number of a connected subcubic graph of order n having minimum degree at least two is at most 3(n+1)/7, providing a sharp upper bound for subcubic connected graphs with minimum degree at least two.

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An Adapted Approach To Process Mapping Across Alloy Systems And Additive Manufacturing Processes, Luke Charles Sheridan Jan 2016

An Adapted Approach To Process Mapping Across Alloy Systems And Additive Manufacturing Processes, Luke Charles Sheridan

Browse all Theses and Dissertations

The continually growing market for metal components fabricated using additive manufacturing (AM) processes has called for a greater understanding of the effects of process variables on the melt pool geometry and microstructure in manufactured components for various alloy systems. Process Mapping is a general approach that traces the influence of process parameters to thermal behavior and feature development during AM processing. Previous work has focused mainly on Ti-6Al-4V (Ti64), but this work uses novel mathematical derivations and adapted process mapping methodologies to construct new geometric, thermal, and microstructural process maps for Ti64 and two nickel superalloy material systems. This work …

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Metabolism Of Herpes Simplex Virus 1 Infected Raw 264.7 Macrophages, Mary K. Jenkins Jan 2016

Metabolism Of Herpes Simplex Virus 1 Infected Raw 264.7 Macrophages, Mary K. Jenkins

Browse all Theses and Dissertations

Macrophages are immune cells that phagocytize pathogens and act as antigen presenting cells. Macrophages are critical in regulating the adaptive immune response and play a key role in neutralizing infection. Macrophages exhibit a variety of phenotypes which have different energy requirements. In the case of HSV-1 infection the virus has been shown to alter metabolic processes of its host. Utilizing a XF24 Extracellular Flux Analyzer the metabolic activity of M0, M1, and M2 (IL-4, IL-13, and IL-10) RAW 264.7 macrophages was quantified for both uninfected cells and in response to HSV-1 infection. The analysis showed uninfected M0 and M2 (IL-4, …

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