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Full-Text Articles in Engineering

Analysis Of The System Response Of A Spray Passive Downdraft Evaporative Cooling System, Daeho Kang, Richard K. Strand Jun 2019

Analysis Of The System Response Of A Spray Passive Downdraft Evaporative Cooling System, Daeho Kang, Richard K. Strand

Publications and Research

A spray Passive Downdraft Evaporative Cooling (PDEC) system achieves great savings for space cooling and improves indoor environmental quality by supplying a large amount of fresh outdoor air. As previous studies heavily focused on the energy saving capability of a spray PDEC system due to lack of methods for a detailed analysis, the influence of cool humid supply air from a spray PDEC system in a space in buildings has not been comprehensively studied. This study is intended to evaluate the competence of a spray PDEC system as a primary cooling system in typical spaces in a primary school building …


Performance Control Of A Spray Passive Down-Draft Evaporative Cooling System, Daeho Kang, Richard K. Strand Mar 2018

Performance Control Of A Spray Passive Down-Draft Evaporative Cooling System, Daeho Kang, Richard K. Strand

Publications and Research

A spray passive down-draft evaporative cooling system has been regarded as a low-energy cooling system that leads significant energy savings in the cooling of buildings. While the energy saving capability of the system has been proven, the ability to control a comfortable indoor environment is still inadequate due to strong climatic dependency. This study seeks viable solutions to advance the control competence of the system by mitigating critical problems of the system to be a reliable cooling application in the cooling of buildings. It proposes potential control strategies for the system and alternative operations. It develops a control algorithm for …


Communication Based Control For Dc Microgrids, Mahmoud S. Saleh, Yusef Esa, Ahmed Mohamed Jan 2018

Communication Based Control For Dc Microgrids, Mahmoud S. Saleh, Yusef Esa, Ahmed Mohamed

Publications and Research

Centralized communication-based control is one of the main methods that can be implemented to achieve autonomous advanced energy management capabilities in DC microgrids. However, its major limitation is the fact that communication bandwidth and computation resources are limited in practical applications. This can be often improved by avoiding redundant communications and complex computations. In this paper, an autonomous communication-based hybrid state/event driven control scheme is proposed. This control scheme is hierarchical and heuristic, such that on the primary control level, it encompasses state-driven local controllers, and on the secondary control level, an event-driven MG centralized controller (MGCC) is used. This …


Significance Of Parameters Affecting The Performance Of A Passive Down-Draft Evaporative Cooling (Pdec) Tower With A Spray System, Daeho Kang, Richard K. Strand Jun 2016

Significance Of Parameters Affecting The Performance Of A Passive Down-Draft Evaporative Cooling (Pdec) Tower With A Spray System, Daeho Kang, Richard K. Strand

Publications and Research

PDEC towers with spray systems are known to achieve substantial energy savings. Various parameters such as the wet-bulb depression, the tower height, and the wind speed have been known to be key factors affecting the performance of the system. To date, the significance of these parameters and other important factors have not been adequately treated in the literature. There also has been a lack of models that can successfully investigate potential benefits of the system under various conditions where this particular system could be applicable. To address these critical issues, this study performed a parametric analysis by using a FLUENT …


Coalescence-Induced Jumping Of Droplet: Inertia And Viscosity Effects, Samaneh Farokhirad, Jeffrey F. Morris, Taehun Lee Jan 2015

Coalescence-Induced Jumping Of Droplet: Inertia And Viscosity Effects, Samaneh Farokhirad, Jeffrey F. Morris, Taehun Lee

Publications and Research

The problem of coalescence-induced self-propelled jumping of droplet is studied using three-dimensional numerical simulation. The focus is on the effect of inertia and in particular the effect of air density on the behavior of the merged droplet during jumping. A lattice Boltzmann method is used for two identical, static micro-droplets coalescing on a homogeneous substrate with contact angle ranging from 0◦ to 180◦. The results reveal that the effect of air density is significant on detachment of the merged droplet from the substrate at the later stage of the jumping process; the larger the air density, the larger the jumping …


A Building Energy Efficiency Optimization Method By Evaluating The Effective Thermal Zones Occupancy, Anna Laura Pisello, Michael Bobker, Franco Cotana Dec 2012

A Building Energy Efficiency Optimization Method By Evaluating The Effective Thermal Zones Occupancy, Anna Laura Pisello, Michael Bobker, Franco Cotana

Publications and Research

Building energy efficiency is strongly linked to the operations and control systems, together with the integrated performance of passive and active systems. In new high quality buildings in particular, where these two latter aspects have been already implemented at the design stage, users’ perspective, obtained through post-occupancy assessment, has to be considered to reduce whole energy requirement during service life. This research presents an innovative and low-cost methodology to reduce buildings’ energy requirements through post-occupancy assessment and optimization of energy operations using effective users’ attitudes and requirements as feedback. As a meaningful example, the proposed method is applied to a …