Browsing by Author "Clark, Jordan Douglas"
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Item Modeling of transport processes for the reduction of energy use in commercial buildings(2013-12) Clark, Jordan Douglas; Novoselac, AtilaBuildings are responsible for over a third of the energy consumption in the United States annually. This energy consumption contributes to some of the most pressing problems facing our society. Modeling of buildings and their systems is an integral part of most strategies for reduction of energy use in buildings. Modeling allows for informed building designs, optimization of systems, and greater market acceptance of new energy-saving technologies. This work addresses two particular modeling applications concerned with reduction of energy usage in buildings: convective heat transfer modeling in perimeter zones, and liquid desiccant dehumidification modeling. The first objective of this work is concerned with modeling convective transport in buildings and creation of inputs for energy modeling programs and passive pollutant removal calculations. This is accomplished through four investigations. In the first investigation, the influence of floor diffusers on convection heat transfer at perimeter zone windows in commercial buildings is measured. In the second, the impact of blinds on convection under a variety of circumstances is quantified. In the third, movement of air jets issuing from floor diffusers is predicted, and the effect of buoyancy on convective heat transfer at perimeter zone surfaces is analyzed. In the fourth investigation, convective mass transfer at indoor surfaces is investigated. Full scale experiments were conducted in support of these four investigations and semi-empirical correlations vii consistent with theory are given to predict jet movement and convective transport under a variety of circumstances. The second objective of this dissertation is concerned with modeling and analysis of liquid desiccant dehumidification systems and is pursued through three additional investigations. The first is concerned with modeling small-scale transport within the channels of a liquid desiccant absorber and regenerator. Physical and empirical models are developed which agree well with laboratory data. During the second investigation, a dynamic model of a liquid desiccant dehumidification system is developed and integrated into a full-building energy simulation. This is used to assess the potential applicability of the system in supermarkets in various climates. The models developed are used to optimize the system and develop a procedure to size components in the final investigation.Item Semi-empirical model of convection heat transfer at windows and blinds near floor diffusers for use in building energy modeling(2010-08) Clark, Jordan Douglas; Novoselac, Atila; Siegel, JeffreyAccurate modeling of energy flows in buildings is necessary for optimization of mechanical systems, and architectural designs and components. One specific process which has been studied little is that of forced convection on the interior surfaces of window assemblies, which is present in the majority of newly constructed commercial buildings. To this end, energy flows associated with a specific Heating Ventilation and Air-Conditioning (HVAC) configuration- a floor register near a glass curtain wall with or without Venetian blinds- are analyzed experimentally and partially described with accepted theory. Natural convection at the same surface is analyzed as well, both to establish a baseline and to experimentally validate the experimental setup. A 60 cubic meter environmental chamber with precisely controlled interior conditions and electrical resistance heating panels is employed to study heat transfer at the interior surfaces of a building’s envelope. Convection heat transfer processes for various blind angles, HVAC regimes, surface temperatures, and window sizes are examined. Results show that convection at window and blind surfaces is highly dependent on blind angle, supply temperature and flow rate, moderately dependent on room-supply air temperature difference and HVAC regime, and weakly dependent on surface-supply air temperature difference. A simplified model of convection heat transfer in this particular situation is proposed for easy implementation in energy modeling software.