Browsing by Subject "Energy Efficiency"
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Item An Analysis of Energy Consumption in Grocery Stores in a Hot and Humid Climate(2013-04-09) Mukhopadhyay, JayaThe intent of this study was to investigate the efficient use of energy by developing an energy efficient grocery store combined with cogeneration. This study demonstrated the potential to reduce the energy use in buildings, by implementing a decentralized source of energy generation that allowed for the use of a portion of the energy generated to be shared across building boundaries. This study considered a high energy use building such as a grocery store to be a part of a residential community, which could potentially participate in the sharing of energy across building boundaries. To better utilize energy resources the study proposed the implementation of a cogeneration facility to supply energy primarily to the store. Surplus energy generated by this cogeneration system was then shared with the requirements of the surrounding residential community. Finally, in order to better account for energy consumption of these buildings both site and source energy was considered. The study focused on hot and humid climates. This study was presented in two parts: Analyzing conventional grocery store systems to determine the maximum savings possible; and examining the option of co-generation systems to provide power to grocery stores and a portion of the community in order to reduce source energy use for the grocery store and a portion of the surrounding community. Source energy savings were in the range of 47% to 54% depending on the energy efficiency measures selected and the cogeneration configuration determined in the grocery store. Economic payback periods in the range of 4 to 7 years (time until zero net present value) were observed. The selection of appropriate options was narrowed down to two options that utilized more thermal energy within the boundaries of the store and generated more amount of surplus energy to be absorbed by the neighboring residential buildings.Item Building Retrofits: Energy Conservation and Employee Retention Considerations in Medium-Size Commercial Buildings(2013-04-29) Freeman, JaniceCommercial buildings are among the largest consumers of energy. In an attempt to control and reduce operating expenses, building owners and organizations leasing commercial space are pursuing energy efficiency measures to generate a higher return on investment. In this study, an extensive literature review is used to identify and discuss energy efficiency considerations for medium-size building owners and how savings from these measures may benefit organizations through employee satisfaction and retention. For the purpose of this study, the specific topics related to commercial building energy efficiency that were investigated include (1) outcomes of building retrofits (2) corporate social responsibility and performance; (3) performance of energy efficient buildings; (4) employee commitment, satisfaction productivity and organizational profitability; (5) green companies and employee attraction; (6) the cost of turnover. There is little literature specifically focused on the impact that energy efficient buildings have on medium-sized building owners and no literature that quantifies the financial benefits through a reduction in employee turnover or attrition. Facility managers of all building sizes will benefit from gaining (1) a broad understanding of the impact of energy efficiency measures on employees (2) the ability to articulate the impact of the building?s role on employee productivity, turnover and other HR related issues (3) the insight needed to contribute to strategic discussions within their organization about how facilities can benefit organizational profitability. This research does not attempt to claim or determine a causal relationship between energy efficiency and employee turnover however it does discuss issues that that could affect employee attrition.. Further research to determine this causality would benefit the study of energy efficiency and its total impact on organizations.Item Cogeneration and community design: performance based model for optimization of the design of U.S. residential communities utilizing cogeneration systems in cold climates(2009-06-02) Rashed Ali Atta, Hazem MohamedThe integration of cogeneration technologies in residential communities has the potential of reducing energy demand and harmful emissions. This study investigated the impact of selected design parameters on the environmental and economic performances of cogeneration systems integrated into residential communities in cold U.S. climates following a centralized or a decentralized integration approach. Parameters investigated include: 1) density, 2) use mix, 3) street configuration, 4) housing typology, 5) envelope and building systems' efficiencies, 6) renewable energy utilization, 7) cogeneration system type, 8) size, and 9) operation strategy. Based on this, combinations of design characteristics achieving an optimum system performance were identified. The study followed a two-phased mixed research model: first, studies of residential community design and three case studies of sustainable residential communities were analyzed to identify key design parameters; subsequently, simulation tools were utilized to assess the impact of each parameter on cogeneration system performance and to optimize the community design to improve that performance. Assessment procedures included: developing a base-line model representing typical design characteristics of U.S. residential communities; assessing the system performance within this model, for each integration approach, using three performance indicators: reduction in primary energy use, reduction in CO2 emissions; and internal rate of return; assessing the impact of each parameter on the system performance through developing 46 design variations of the base-line model representing changes in these parameters and calculating the three indicators for each variation; using a multi-attribute decision analysis methodology to evaluate the relative impact of each parameter on the system performance; and finally, developing two design optimization scenarios for each integration approach. Results show that, through design optimization, existing cogeneration technologies can be economically feasible and cause reductions of up to 18% in primary energy use and up to 42% in CO2 emissions, with the centralized approach offering a higher potential for performance improvements. A significant correlation also existed between design characteristics identified as favorable for cogeneration system performance and those of sustainable residential communities. These include high densities, high mix of uses, interconnected street networks, and mixing of housing typologies. This indicates the higher potential for integrating cogeneration systems in sustainable residential communities.Item Development and Application of a Ground-Coupled Heat Pump Simulation Model for Residential Code-Compliance Simulation in Texas(2014-04-18) Do, Sung LokThe intent of this study was to improve residential energy efficiency in Texas by developing an improved tool for home builders and code officers to use for evaluating their designs. It was achieved by developing a new ground-coupled heat pump (GCHP) model for residential systems to be used with the DOE-2.1e simulation program. To accomplish this, this study investigated closed-loop ground heat exchanger (GHX) models, including horizontal, surface water, and vertical GHX models. This study selected a case-study house in Texas which has a custom-built GHX using a combination of a horizontal GHX and a surface water GHX. This study developed a custom-built GHX model for the case-study house to calculate the entering water temperatures (EWTs). The custom-built GHX model was then validated using the measured EWT data from the case-study house. The results showed the monthly average EWTs differences between the measured and calculated EWTs were observed to be about 2.2 F during the heating season and about 3.2 F during the cooling season. Therefore, this study concluded the slightly over-estimated EWTs were acceptable considering the other uncertainties of the field conditions. In addition, a vertical GHX DOE-2.1e model was developed by using the DOE-2.1e FUNCTION command. The g-function values approximated in this study was used for the vertical GHX DOE-2.1e model. To develop a new DOE-2.1e GCHP simulation model, this study then incorporated the vertical GHX DOE-2.1e input FUNCTION within an air-source heat pump (ASHP) simulation module by modifying existing DOE-2 calculation algorithms. To evaluate the new DOE-2.1e GCHP model, this study also developed simplified residential ASHP/GCHP base-case models for Houston and Dallas, using DOE-2.1e, eQUEST, IC3, REM/Rate, and EnergyGauge. The DOE-2.1e simulation results were then compared against the other programs to verify the accuracy of the new DOE-2.1e GCHP model. The comparison showed good agreement in the total site energy use within 3.3 MMBtu/yr (5.3%) differences. In addition, the simulation results showed the GCHP system benefits: for the total site energy savings, 9.7% in Houston and 13.1% in Dallas, and for the heating plus cooling energy savings, 27.3% in Houston and 35.3% in Dallas.Item Methodology for the Preliminary Design of High Performance Schools in Hot and Humid Climates(2010-07-14) Im, PiljaeA methodology to develop an easy-to-use toolkit for the preliminary design of high performance schools in hot and humid climates was presented. The toolkit proposed in this research will allow decision makers without simulation knowledge easily to evaluate accurately energy efficient measures for K-5 schools, which would contribute to the accelerated dissemination of energy efficient design. For the development of the toolkit, first, a survey was performed to identify high performance measures available today being implemented in new K-5 school buildings. Then an existing case-study school building in a hot and humid climate was selected and analyzed to understand the energy use pattern in a school building and to be used in developing a calibrated simulation. Based on the information from the previous step, an as-built and calibrated simulation was then developed. To accomplish this, five calibration steps were performed to match the simulation results with the measured energy use. The five steps include: 1) Using an actual 2006 weather file with measured solar radiation, 2) Modifying lighting & equipment schedule using ASHRAE's RP-1093 methods, 3) Using actual equipment performance curves (i.e., scroll chiller), 4) Using the Winkelmann's method for the underground floor heat transfer, and 5) Modifying the HVAC and room setpoint temperature based on the measured field data. Next, the calibrated simulation of the case-study K-5 school was compared to an ASHRAE Standard 90.1-1999 code-compliant school. In the next step, the energy savings potentials from the application of several high performance measures to an equivalent ASHRAE Standard 90.1-1999 codecompliant school. The high performance measures applied included the recommendations from the ASHRAE Advanced Energy Design Guides (AEDG) for K- 12 and other high performance measures from the literature review as well as a daylighting strategy and solar PV and thermal systems. The results show that the net energy consumption of the final high performance school with the solar thermal and a solar PV system would be 1,162.1 MMBtu, which corresponds to the 14.9 kBtu/sqft-yr of EUI. The calculated final energy and cost savings over the code compliant school are 68.2% and 69.9%, respectively. As a final step of the research, specifications for a simplified easy-to-use toolkit were then developed, and a prototype screenshot of the toolkit was developed. The toolkit is expected to be used by non-technical decision-maker to select and evaluate high performance measures for a new school building in terms of energy and cost savings in a quick and easy way.Item Methodology to Develop and Test an Easy-to-use Procedure for the Preliminary Selection of High-performance Systems for Office Buildings in Hot and Humid Climates(2010-10-12) Cho, Sool YeonA procedure has been developed for the preliminary selection of high-performance systems for office buildings in hot and humid climates. High-performance building systems and components were surveyed for buildings in the U.S., which were applicable for office buildings in hot and humid climates. This research developed a calibrated DOE-2.1e simulation model of a prototypical large office building. In addition, a Simplified Geometry DOE-2.1e (SGDOE-2.1e) model, was also developed, which used a simplified geometry to demonstrate the use of a proposed easy-to-use tool. The calibrated DOE-2.1e simulation model and the SGDOE-2.1e were compared and showed a good match with each. The SGDOE-2.1e model was then further modified based on the ASHRAE Standard 90.1-1999 commercial building energy code. A code-compliant (ASHRAE Standard 90.1-1999) SGDOE-2.1e simulation model was then used as a baseline for the evaluation of the high-performance measures. A total of 14 high-performance measures were implemented including the energy savings, while the comfort level was maintained based on the ASHRAE comfort zone. In addition to the 14 high-performance measures, solar thermal and solar PV system analysis were integrated with the SGDOE-2.1e simulation model to further reduce the annual energy use. Finally, specifications of the proposed easy-to-use simulation tool were developed. This tool includes options to choose systems from the 14 high-performance measures and solar systems. The proposed easy-to-use systems selection tool can be used for new building practitioners and existing building owners as well to evaluate the performance of their new buildings compared to the ASHRAE Standard 90.1-1999 code-compliant building, and to assess the feasibility of implementing high-performance measures to their existing buildings in terms of energy and cost savings.