Browsing ESL Theses and Dissertations by Title
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Analysis of improved fenestration for code-compliant residential buildings in hot and humid climatesMukhopadhyay, Jaya, 1974- (Texas A&M University, August 2005)[more][less]
Abstract: This thesis presents an analysis of energy efficient residential windows in hot and humid climates. To accomplish this analysis, the use of accurate simulation tools such as DOE-2.1e is required, which incorporates the results from the WINDOW-5.2 simulation program to assess accurate fenestration performance. The thesis also investigates the use of optimal glazing types, which, for future applications, could be specified in the code to reduce annual net energy consumption to zero. Results show that combinations of low-E and double pane, clear-glazed windows, which are optimally shaded according to orientation are the best solution for lowering both annual energy consumption and peak electricity loads. The study also concludes that the method used to model fenestration in the simulation program plays an important role in accurately determining the effectiveness of the glazing option used. In this particular study, the use of the WINDOW-5.2 program is highly recommended especially for high performance windows (i.e., low-E glazing). Finally, a discussion on the incorporation of super high performance windows (i.e., super low-E, ultra low-E and dynamic / switchable glazing) into the IECC code concludes that these types of glazing strategies can reduce annual net energy use of the window to zero. Future work identified by this thesis includes a more extensive examination of the passive solar potential of high performance fenestration, and an examination of the appropriate methods for specifying these properties in future versions of the IECC code. This implies that future specifications for fenestration in the IECC code could aim for zero net annual energy consumption levels from residential fenestration. URI: http://handle.tamu.edu/1969.1/4162 Files in this item: 1
etd-tamu-2005B-ARCH-Mukhopa.pdf (5.655Mb) -
Kootin-Sanwu, Victor (Energy Systems Laboratory, May 2004)[more][less]
Abstract: The purpose of this research is to develop methods that will enable the reduction of owning and operating costs of low-income housing in the hot-humid climates of the U. S. The objectives include investigating various scenarios that will enable the implementation of cost-effective construction of low-income housing using volunteer labor. The research uses a case study approach where a base-line energy use is established using a comparative Princeton Score Keeping Method (PRISM) analysis and measurements from a case study house. A prototype house is then simulated with the DOE-2 building simulation program, and the energy savings calculated by comparing simulated energy and water conservation design measures (E&WCDMs) with the calibrated baseline energy simulation. The cost and maintenance of the house are analyzed with the real cost of construction of a case study house in Bryan/College Station, Texas. URI: http://handle.tamu.edu/1969.1/85753 Files in this item: 1
ESL-TH-04-05-01.pdf (24.12Mb) -
Nutter, Darin Wayne (December 1994)[more][less]
Abstract: The mass flow characteristics of flashing Refrigerant-22 from a small vessel were investigated. A flash boiling apparatus was designed and built. It was modeled after the flashing process encountered by the accumulator of air-source heat pump systems. Three small pyrex glass vessels were used to hold the refrigerant and allow for visualization studies of the flashing process. Baseline experiments were run varying initial pressure, initial refrigerant amount, orifice diameter, and vessel geometry. Three sets of experiments were run using two passive enhancement methods (the addition of steel balls and the addition of small amounts of oil) and one active enhancement method (the addition of an immersion heater). Furthermore, a lumped-parameter analytical model was developed from basic thermodynamic principles that predicted the rate of depressurization for the flashing refrigerant. The study showed that the initial refrigerant amount and the orifice size had the greatest influence on the mass flow and pressure characteristics during each sixty second test. The initial pressure and vessel volume had less of an impact under the conditions tested. Two of the enhancement methods consistently increased the amount of refrigerant flashed during the tests as compared to the baseline data for the same initial conditions. The addition a 1 cm layer of 3.6 mm steel balls to the base of the vessel increased the amount flashed from 21% to 81% and the addition of the 215-watt flat-spiral immersion heater the increased the amount flashed from 47% to 111 %. Foaming at the vapor-liquid interface was observed with the refrigerant-oil mixture experiments as two of the eight test conditions averaged an increase while six averaged a decrease, ranging from a 21% increase to a 27% decrease. The analytical depressurization model predicted general pressure and mass flux trends, and revisions to the model improved pressure predictions to within ±11%. URI: http://hdl.handle.net/1969.1/6426 Files in this item: 1
ESL-TH-94-12-05.pdf (4.956Mb) -
Malhotra, Mini, 1975- (Texas A&M University, December 2005)[more][less]
Abstract: Energy-efficient building design involves minimizing the energy use and optimizing the performance of individual systems and components of the building. The benefits of energyefficient design, in the residential sector, are direct and tangible, provided that design strategies with a substantial combined energy and cost-saving potential are adopted. Many studies have been performed to evaluate the energy-saving potential and the costeffectiveness of various design options, and to identify conditions for optimizing the performance of building systems and components. The results of these studies, published in various resources, were analyzed discretely using different techniques, and were reported using different bases for comparison. Considering the complex interaction of, and energy flows through various building components, it is difficult to directly compare/combine the results from various studies to determine the energy-saving potential of combination of strategies, and to select an appropriate set of strategies for making design decisions. Therefore, this thesis develops a comprehensive survey and analysis of energy-efficient design strategies and their energy-saving potential, in isolation as well as in combination, using a DOE-2 simulation model of a prototype house in the hot and humid climate of Houston, Texas. Optimized strategies that included building configuration, materials/ assembly for building envelop components, and efficient mechanical and electrical systems, equipment and appliances, were applied in combination that could minimize the annual energy use. Application of these strategies is expected to allow downsizing systems and equipment and to confirm their operation at their rated performance, resulting in additional installation and operation cost savings. The study is concluded by outlining the procedures for selecting optimized set of strategies, and by developing guidelines for achieving maximum energy-efficiency in singlefamily detached houses in hot and humid climates. Thus, this study will facilitate the selection of energy-saving measures for their individual or combined application for developing energyefficient residences in hot and humid climates. URI: http://handle.tamu.edu/1969.1/3097 Files in this item: 1
etd-tamu-2005C-ARCH-Malhotra.pdf (1.937Mb) -
Sreshthaputra, Atch (November 29, 2007)[more][less]
Abstract: The goal of this research was to develop new techniques for designing and operating unconditioned buildings in a hot-humid climate that could contribute to an improvement of thermal performance and comfort condition. The recommendations proposed in this research will also be useful for facility managers on how to maintain unconditioned buildings in this climate. This study investigated two unconditioned Thai Buddhist temples located in the urban area of Bangkok, Thailand. One is a 100-year-old, high-mass temple. The other is a 5-year-old, lower-mass temple. The indoor measurements revealed that the thermal condition inside both temples exceed the ASHRAE-recommended comfort zone. Surprisingly, the older temple maintained a more comfortable indoor condition due to its thermal inertia, shading, and earth contacts. A baseline thermal and airflow model of the old temple was established using a calibrated computer simulation method. To accomplish this, HEATX, a 3-D Computational Fluid Dynamics (CFD) code, was coupled with the DOE-2 thermal simulation program. HEATX was used to calculate the airflow rate and the surface convection coefficients for DOE-2, and DOE-2 was used to provide physical input variables to form the boundary conditions for HEATX. In this way calibrated DOE-2/CFD simulation model was accomplished, and the baseline model was obtained. To investigate an improved design, four design options were studied: 1) a reflective or low-solar absorption roof, 2) R-30 ceiling insulation, 3) shading devices, and 4) attic ventilation. Each was operated using three modes of ventilation. The low-absorption roof and the R-30 ceiling insulation options were found to be the most effective options, whereas the shading devices and attic ventilation were less effective options, regardless of which ventilation mode was applied. All design options performed much better when nighttime-only ventilation was used. Based on this analysis, two prototype temples was proposed (i.e., low-mass and high-mass temples). From the simulation results of the two prototypes, design and operation guidelines are proposed, which consist of: 1) increased wall and ceiling insulation, 2) white-colored, low-absorption roof, 3) slab-on-ground floor, 4) shading devices, 5) nighttime-only ventilation, 6) attic ventilation, and 7) wider openings to increase the natural ventilation air flow windows, wing walls, and vertical fins. URI: http://hdl.handle.net/1969.1/6164 Files in this item: 1
ESL-TH-03-05-01.pdf (18.16Mb) -
Deng, Song (May 1997)[more][less]
Abstract: This thesis proposes and validates a simplified model appropriate for parameter identification and evaluates several different inverse parameter identification schemes suitable for use when heating and cooling data from a commercial building are available. The validation has been performed using such data generated from a detailed building simulation program for different building geometries and building mass levels in two different climatic locations. Such a synthetic evaluation will validate the model used as well as determine the best parameter identification scheme, i.e., one likely to yield the most accurate set of parameter estimates. A multistep identification scheme has been found to yield very accurate results, and a more careful evaluation has been performed in order to evaluate its accuracy and stability with synthetic data against the effects of solar energy, HVAC system operation, internal load schedule, building thermal mass and geometry, and climatic location. This method is also evaluated using data from different time periods and when utility bill data (i.e. monthly data) only is available. The model is then applied to energy use data from two buildings being monitored under the Texas LoanSTAR Program, which are in different locations and have different HVAC systems. With parameters thus determined, two energy use indices, Energy Delivery Efficiency (EDE) and Multizone Efficiency Index (MEI), are calculated to present some insights into the benefits of retrofit from a constant volume (CV) to a variable air volume (VAV) system and of continuous commissioning (CC) work done to these two buildings, respectively. Uses and limitations of EDE and MEI are also discussed. Based on these findings, it is suggested that the multistep regression approach is an accurate and practical building physical parameter determination method, and the combined use of the EDE and MEI indices calculated from these parameters can provide insights into the HVAC system, and the potential for optimizing its operation. URI: http://hdl.handle.net/1969.1/6428 Files in this item: 1
ESL-TH-97-05-02.pdf (23.32Mb) -
Baltazar-Cervantes, Juan-Carlos (December 2006)[more][less]
Abstract: This dissertation provides one methodology to determine potential energy savings of buildings with limited information. This methodology is based upon the simplified energy analysis procedure of HVAC systems and the control of the comfort conditions. Numerically, the algorithm is a tailored exhaustive search over all the independent variables that are commonly controlled for a specific type of HVAC system. The potential energy savings methodology has been applied in several buildings that have been retrofitted and/or commissioned previously. Results from the determined savings for the Zachry building at Texas A&M after being commissioned show a close agreement to the calculated potential energy savings (about 85%). Differences are mainly attributed to the use of simplified models. Due to the restriction of limited information about the building characteristics and operational control, the potential energy savings method requires the determination of parameters that characterize its thermal performance. Thus, a calibrated building is needed. A general procedure has been developed to carry out automated calibration of building energy use simulations. The methodology has been tested successfully on building simulations based on the simplified energy analysis procedure. The automated calibration is the minimization of the RMSE of the energy use over daily conditions. The minimization procedure is fulfilled with a non-canonical optimization algorithm, the Simulated Annealing, which mimics the Statistical Thermodynamic performance of the annealing process. That is to say, starting at a specified temperature the algorithm searches variable-space states that are steadier, while heuristically, by the Boltzmann distribution, the local minima is avoided. The process is repeated at a new lower temperature that is determined by a specific schedule until the global minimum is found. This methodology was applied to the most common air-handler units producing excellent results for ideal cases or for samples modified with a 1% white noise. URI: http://hdl.handle.net/1969.1/6456 Files in this item: 1
ESL-TH-06-12-01.pdf (3.649Mb) -
Sung, Yong Hoon (Texas A&M University, August 2004)[more][less]
Abstract: In this dissertation I will present and test a model linking actual applicant-interviewer demographic, human capital, and cultural capital similarity to an interviewer's recommendation to hire. Actual similarity is proposed to influence an interviewer's perceptions of similarity with an applicant. These perceptions, in turn, lead to the interviewer's perceptions of the applicant's Person-Organization (PO) fit and the applicant's Person-Job (PJ) fit. Two main mechanisms are proposed to mediate the relationship between an interviewer's perceptions of similarity and an interviewer's perceptions of an applicant's fit: liking and negative behavioral expectations. Lastly, both an interviewer's PO and PJ fit perceptions of an applicant are posited to influence the interviewer's recommendation to hire. A total of 118 interviewer-applicant dyads contacted through the Career Center Office at a University located in the southwestern United States participated in the study. Results partially support the model. An interviewer's perceptions of similarity with an applicant are positively related to an interviewer's fit evaluations. An interviewer's negative behavioral expectations of an applicant mediate this relationship. Furthermore, perceived similarity is positively related to an interviewer's liking of an applicant. In turn, liking is positively related to an interviewer's PO fit perceptions. However, liking does not function as a mediator between perceived similarity and fit evaluations. Finally, fit evaluations are positively related to hiring recommendations. I discuss the main implications of the study as well as strengths, limitations, and future research. URI: http://handle.tamu.edu/1969.1/1263 Files in this item: 1
etd-tamu-2004B-ARCH-Sung-2.pdf (8.657Mb) -
Song, Suwon (September 25, 2007)[more][less]
Abstract: During the past decade, utility companies and others have offered new construction programs to promote energy savings based on energy-efficient design, which maximize design flexibility as well as energy savings. For such programs, the concept of Measurement and Verification (M&V) of a new building continues to become more important because efficient design alone is often not sufficient to deliver an efficient building. Simulation models that are calibrated to measured data can be used to evaluate the energy performance of new buildings if it is compared to energy baselines such as similar buildings, energy codes, and design standards (IPMVP 2003; Torcellini et. 2004). Unfortunately, there is a lack of detailed M&V methods and analysis methods to measure energy savings from new buildings that would have hypothetical energy baselines. In addition, many important questions remain, for example: how to simulate and calibrate a simulation with measured data, how to develop energy baselines for comparison to the new building, and how to calculate energy savings compared to energy baselines. Therefore, this study developed and demonstrated several methodologies for evaluating the energy performance of new commercial buildings using a case-study building in Austin, Texas, in terms of: 1) Whole-building energy metering with in-situ measurements, 2) Simulation and calibration methods applicable to new buildings, and 3) Building energy baselines and savings assessments. Consequently, three new M&V methods were developed in this study to enhance the generic M&V framework (IPMVP 2003) for new buildings, including: 1) The development of a procedure to synthesize weather-normalized cooling energy use (i.e., Btu cooling production) from a correlation of MCC electricity use when chilled water use is unavailable, 2) The development of an improved method to analyze measured solar transmittance against incidence angle for sample glazing using different solar sensor types, including an Eppley PSP and Li-Cor sensor, and 3) The development of an improved method to analyze chiller efficiency and operation at part-load conditions. Second, three new methods were also developed and analyzed in the process of the as-built model simulation and calibration, including: 1) A new percentile analysis to the previous signature method (Wei et al. 1998) for use with a DOE-2 calibration, 2) A new analysis to account for undocumented exhaust air in DOE-2 calibration, and 3) An analysis of the impact of synthesized direct normal solar radiation using the Erbs correlation (Duffie and Beckman 1991) on DOE-2 simulation. Third, an analysis of the actual energy savings compared to three different energy baselines was performed, including: 1) Energy Use Index (EUI) comparisons with sub-metered data, 2) New comparisons against Standards 90.1-1989 and 90.1-2001, and 3) A new evaluation of the performance of selected ECDMs. Finally, potential energy savings were also simulated from selected improvements, including minimum supply air flow, undocumented exhaust air, and daylighting. As a result, the calibrated models were determined to have an overall 20.38% CV(RMSE) and a 0.63% MBE for the 2001 model and an overall 23.82% CV(RMSE) and a 0.61% MBE for the 2004 model, which compares well with the previous research (Kreider and Haberl 1994; Bou-Saada 1994; ASHRAE 2002). It was found that the end-use EUIs, such as cooling, heating, and Motor Control Center (MCC) electricity use can begin to provide information about the building’s heating and cooling efficiencies compared to similar buildings in a control groups. It was also determined that the REJ building is 20.79% more efficient than the Standard 90.1-1989 and approximately equal to the Standard 90.1-2001. Using an ECDM-subtraction method, the REJ building was shown to use approximately 67% less energy than the base-case building without the ECDMs. Potential savings were simulated to be 7,053.3 MMBtu (19.26%) from the combined improvements when compared to the 2004 as-built simulation. URI: http://handle.tamu.edu/1969.1/6056 Files in this item: 1
ESL-TH-06-08-01.pdf (15.67Mb) -
Landman, David Shea (October 23, 2007)[more][less]
Abstract: Indices are an important tool used to increase the accuracy and efficiency of the energy audit process. This thesis describes methods for using annual, monthly, daily, and hourly indices to improve current energy auditing processes. Eleven schools in different regions in Texas were identified for the case studies. The results show that certain indices match what is recommended by on-site visits and actually provide additional information that is sometimes not identified by a site visit. The indices developed provide a useful means by which energy audit firms and building owners/administrators can identify those areas of a building that have the most potential for energy cost reduction measures and operation and maintenance measures prior to a site visit. These indices assist the energy auditor in performing more efficient energy analyses on buildings. Each school in this thesis was audited prior to this study as part of the Texas LoanSTAR program. The indices were then developed using data from the period between September 1991 and December 1993. Retrofits to the case study buildings were completed during this period also. The sites were then reaudited to confirm the results from the previous audits, the usefulness of the indices, and/or discover new areas for energy savings. Two important new findings from this thesis are: 1) that schools are better modeled by grouping data into separate occupancy profiles consisting of school year months and summer months; and 2) the school year base-level electricity consumption can be calculated by taking the 25th percentiles of all twelve months of data reported. This approximately matches the base-level determined when running a 3-parameter cooling models on monthly energy consumption data and has the advantage that it does not require coincident weather data. URI: http://handle.tamu.edu/1969.1/6058 Files in this item: 1
ESL-TH-98-05-01.pdf (51.05Mb) -
Rodriguez, Angel Gerardo (November 29, 2007)[more][less]
Abstract: <p>An experimental study was conducted to quantify the effect of several installation items on the high outdoor ambient temperature performance of air conditioners. These installation items were: improper amount of refrigerant charge, reduced evaporator airflow, and return air leakage from hot attic spaces. There were five sets of tests used for this research: two of them for the charging tests, two for the reduced evaporator airflow, and one for the return air leakage tests. </p> <p> For the charging tests, the indoor room conditions were 80°F (27.8°C) dry-bulb and 50% relative humidity. The outdoor conditions ranged from 95°F (35°C) all the way up to 120°F (48.9°C). Charge levels ranged from 30% undercharged to 40% overcharged for the short-tube orifice unit. For the thermal expansion valve (TXV) unit, charge levels ranged from -36% charging to +27% charging. Performance was quantified with the following variables: total capacity, energy efficiency ratio (EER), and power. The performance of the orifice unit was more sensitive to charge than it was for the TXV unit. For the TXV unit on the -27% to +27% charging range, the capacity and EER changed little with charge. A TXV unit and a short-tube orifice unit were also tested for reduced evaporator airflow. As evaporator airflow decreased, the capacity and EER both decreased as expected. However, the drop was not as significant as with the charging tests. For the extreme case of 50% reduced evaporator airflow, neither unit's capacity or EER dropped more than 25%. </p> <p> Return air leakage from hot attic spaces was simulated by assuming adiabatic mixing of the indoor air at normal conditions with the attic air at high temperatures. Effective capacity and EER both decreased with increased return air leakage. However, power consumption was relatively constant for all variables except outdoor temperature, which meant that for the same power consumption, the unit delivered much lower performance when there was return air leakage. The increase in sensible heat ratio (SHR) with increasing leakage showed perhaps the most detrimental effect of return air leakage on performance, which was the inability of the unit to absorb moisture from the environment. </p> URI: http://hdl.handle.net/1969.1/6163 Files in this item: 1
ESL-TH-95-08-01.pdf (28.21Mb) -
Visitsak, Sopa (Energy Systems Laboratory, December 2007)[more][less]
Abstract: To be successful in sustainable building design, architects must consider energy efficient design strategies in the early design stage. Unfortunately, many architects still rely on simplified analysis, synthesis techniques, and historical examples. Although, building energy simulations are becoming more common in the design of buildings, architects rarely use simulation in the early design stage. The “Bioclimatic” charts have been used in the early design stage to define potential building design strategies to achieve indoor thermal comfort. Currently, many architects use the Givoni-Milne bioclimatic design chart (Milne and Givoni, 1979), which was developed based on principle reasoning and heuristics. There have been many attempts to develop computerized programs to further the bioclimatic analysis; however, there have been very limited efforts to test and evaluate the design strategies of the chart using simulations of a thermostatically-controlled building. Therefore, the purpose of this research is to promote comfortable buildings that reduce energy use through appropriate building design strategies. The objectives of the research are to develop a more accurate bioclimatic chart for a thermostaticallycontrolled residence by testing and evaluating the Givoni-Milne bioclimatic chart. The analysis is performed with DOE-2.1e program (Winkelmann, 1993) and TMY2 weather data (Marion and Urban, 1995) for several climates. To achieve these objectives, four main tasks were accomplished: 1) investigate the Givoni-Milne Bioclimatic Chart using representative weather data from several climates, 2) analyze and modify the design strategy boundaries using DOE-2 program and TMY2 weather data to simulate the effects of varied conditions of a thermostatically-controlled residence in different climates, 3) compare these new design strategy boundaries to the original Givoni-Milne design strategy boundaries, and 4) develop general guidelines for the new bioclimatic chart. In summary, there were some differences in the results from the Givoni-Milne bioclimatic chart and the DOE-2 simulation results. These results imply that without further modification, the G-M Chart may have only a limited use for a thermostaticallycontrolled residence. Therefore, to improve the usefulness of the bioclimatic chart the new bio-climatic chart for choosing design strategies for a thermostatically-controlled residence in the hot-humid climate of Houston, Texas, was developed. This new bioclimatic chart for a thermostatically-controlled residence will be a useful tool for architects and engineers in the early design stage. Similar versions of the new bioclimatic for other climates could then be developed. URI: http://hdl.handle.net/1969.1/6410 Files in this item: 1
ESL-TH-07-08-01.pdf (35.15Mb) -
McJimsey, Bert Ashford (December 1994)[more][less]
Abstract: The heat transfer coefficients and pressure drops of HCFC-22 and a 50% mass mixture of HFC-32/HFC-125 were experimentally measured under flow boiling conditions in a smooth tube. The refrigerants were flowed through an 8 mm diameter smooth tube at mass fluxes of 277, 434, 520 and 700 kg/sm^2. Heat fluxes were applied at values of 5100, 7100 and 11000 W/m^2. The heat transfer coefficients and pressure drops were measured at refrigerant qualities of 10, 15, 20, 25, 30, 40 and 60 percent. The refrigerants were examined at temperatures near 4°C. Oil was added to the HFC-32/HFC-125 mixture in concentrations of 2.6% and 5.4%. Experiments were repeated with the oil laden refrigerant. The heat transfer coefficients for HCFC-22 increased with quality, mass flux and heat flux. The heat transfer coefficients for HFC-32/HFC-125 often decreased at low qualities and increased with quality at high qualities. The pressure drop increased with quality and mass flux for both refrigerants. The heat transfer had a minimal effect upon pressure drop. HFC-32/HFC-125 had a lower pressure drop than HCFC-22 for all conditions. The addition of oil increased the pressure drop. A pressure drop correlation and heat transfer correlation were developed for HFC-32/HFC-125. URI: http://hdl.handle.net/1969.1/6423 Files in this item: 1
ESL-TH-94-12-12.pdf (4.536Mb) -
Munger, Bryce Kirtley (Energy Systems Laboratory, December 1997)[more][less]
Abstract: This thesis describes the development of an improved multipyranometer array (MPA) for the continuous remote measurement of direct and diffuse solar radiation. The MPA described in this thesis is an improvement over previously published MPA studies due to the incorporation of an artificial horizon that prevents reflected ground radiation from striking the tilted sensors, the development of an improved solution scheme for the calculation of the beam and diffuse solar radiation components, and the development of an empirical spectral correction for the photovoltaic-type sensors used in the MPA. In this thesis a description of the NIST-traceable calibration facility is provided and results are presented that compare the MPA predicted beam to beam measurements from a precision normal incidence pyrheliometer. URI: http://hdl.handle.net/1969.1/6409 Files in this item: 1
ESL-TH-97-12-02.pdf (37.02Mb) -
Bou-Saada, Tarek Edmond (Energy Systems Laboratory, December 1994)[more][less]
Abstract: With the increased use of building energy simulation programs, calibration of simulated data to measured data has been recognized as an important factor in substantiating how well the model fits a real building. Model calibration to measured monthly utility data has been utilized for many years. Recently, efforts have reported calibrated models at the hourly level. Most of the previous methods have relied on very simple comparisons including bar charts, monthly percent difference time-series graphs, and x-y scatter plots. A few advanced methods have been proposed as well which include carpet plots and comparative 3-D time-series plots. Unfortunately, at hourly levels of calibration, many of the traditional graphical calibration techniques become overwhelmed with data and suffer from data overlap. In order to improve upon previously established techniques, this thesis presents new calibration methods including temperature binned box-whisker-mean analysis to improve x-y scatter plots, 24-hour weather-daytype box-whisker-mean graphs to show hourly temperature-dependent energy use profiles, and 52-week box-whisker-mean plots to display long-term trends. In addition to the graphical calibration techniques, other methods are also used including indoor temperature calibration to improve thermostat schedules and architectural rendering as a means of verifying the building envelope dimensions and shading placement. Several statistical methods are also reviewed for their appropriateness including percent difference, mean bias error (MBE), and the coefficient of variation of the root mean squared error. Results are presented using a case study building located in Washington, D.C. In the case study building, nine months of hourly whole-building electricity data and site-specific weather data were measured and used with the D0E-2.1D building simulation program to test the new techniques. Use of the new calibration procedures were able to produce a MBE of -0.7% and a CV(RMSE) of 23.1% which compare favorably with the most accurate hourly neural network models. URI: http://handle.tamu.edu/1969.1/86260 Files in this item: 1
ESL-TH-94-12-01.pdf (63.93Mb) -
Noboa, Homero L. (August 1993)[more][less]
Abstract: The purpose of this project was to model and quantify the increase of the absorptivity of radiant barriers caused by the accumulation of dust on the surface of radiant barriers. This research was the continuation of a previous work by the author at Texas A&M University in which a radiation energy balance inside the attic enclosure was developed. The particles were considered as flat, circular planes, all having the same radii. That early model showed that there was a linear relationship between the fraction of area of the foil covered by dust and the mean absorptivity of the dusty radiant barrier. In the present work, it was found that the assumption of treating the dust particles as plane circles, underestimated the effective area of the particles by about 20%. Experimental measurements indicated that dust particles achieved the same temperature as the radiant barrier. The new model used the linear relationship just described, and simulated the dust particles as flat circular planes having random radii and laying in random locations within the radiant barrier surface. The new model calculated the fraction of radiant barrier area covered by particles using a digital array in which the clean barrier was represented as zeroes and the dust particles were represented as a set of ones appropriately dimensioned inside the array. The experimentation used natural dust and Arizona Road Test Dust. Using an infrared emissometer, the emissivities (absorptivities) of the clean and dusty barriers were measured and using an electronic scale, the dust loading was measured. An electron microscope was used to experimentally find the fraction of radiant barrier covered by the dust particles to correlate the experimentally found absorptivity with the experimentally found fraction of dust coverage. The limited experimental data available were also used to correlate the absorptivity of the dusty radiant barrier with the time of dust accumulation and the location of the barrier inside the attic. A linear relationship between the absorptivity and the time of dust accumulation was found that can be applied to predict future barrier effectiveness based upon the rate of dust accumulation for a given location. URI: http://hdl.handle.net/1969.1/6425 Files in this item: 1
ESL-TH-93-08-02.pdf (4.280Mb) -
Noboa, Homero L. (December 1991)[more][less]
Abstract: A model of the radiant heat transfer in attics containing dusty radiant barriers was developed. The geometrical model was a triangular enclosure in which the temperatures of the enclosing surfaces were known. The dust particles were simulated as areas of diameter equal to the mean diameter of the real dust to be analyzed and an emissivity substantially larger than the emissivity of the radiant barrier. Several shape factors were calculated using shape factor algebra, including a procedure to find the shape factor between a small rectangle and a triangular surface perpendicular to the rectangular plane. The thermal model was developed using the "Net Radiation Method" in which the net heat exchange between the surfaces surrounding the enclosure was found by solving a system of equations that has as many equations as the number of surfaces involved in the calculations. This led to the necessity of solving a very large system of equations in order to account for the dust particles in a representative amount. The solution of the system of equations provided the heat flux for each element of the enclosure. Finally, replacing the radiant barrier and the dust particles for an equivalent surface corresponding to the dusty radiant barrier provided the means to calculate the emissivity of this dusty radiant barrier. The theoretical model was tested to assess its validity. The experimentation was carried out using a reflection emissometer to measure the increase of the emissivity of aluminum radiant barrier when known quantities of dust were artificially applied to it. The experimental results showed good agreement with the theoretical model. A linear relationship between the emissivity and the area of dust coverage was found. The simple relation developed can be used in future research which still has to deal with the determination of the area of dust coverage by using the geometrical model of dust superposition or other statistical model to simulate the random location of random size dust particles over the radiant barrier. URI: http://hdl.handle.net/1969.1/6461 Files in this item: 1
ESL-TH-91-12-01.pdf (18.99Mb) -
Rasisuttha, Sakkara, 1971- (Texas A&M University, May 2003)[more][less]
Abstract: The purpose of this research is to develop methods that reduce energy consumption in a residential building in a hot and humid climate region (Thailand) using efficient architectural building components and renewable energy (solar energy) to produce electricity, domestic hot water, and supplemental cooling by night sky radiation. Improving the architectural building components, including building materials, is an option to reduce energy consumption in a building. Using renewable energy sources is another option to reduce the consumption of non-renewable energy. In residential buildings, solar energy has been utilized for space heating and domestic hot water using active solar collector systems and for generating electricity using photovoltaic (PV) systems. One photovoltaic system, the hybrid photovoltaic-thermal (PV-T) collector system, has been developed by several researchers over the last 20 years. The hybrid photovoltaic-thermal (PV-T) collector system is a combination photovoltaic (for producing electricity) and solar thermal collector (for producing hot water). Theoretical and experimental studies of this collector have highlighted the advantages of the hybrid PV-T collector system over separate systems of PV and solar collector in term of system efficiency and economics. Unfortunately, very little experimental data exists that demonstrates the advantages of a combined system. Therefore, one of the objectives of this study conducted was an experimental study of this system as an auxiliary energy source for a residential building. Night sky radiation has also been studied as a cooling strategy. However, no attempt so far could be found to integrate it to a hybrid PV-T collector system. The night sky radiation strategy could be operated with the hybrid PV/T collector system by using existing resources that are already present in the solar system. The integration of the night sky radiation into the hybrid PV-T collector system should yield more productivity of the system than the operation of the Hybrid PVT system alone. The research methods used in this work included instrumentation of a case-study house in Thailand, an experimental PV-T collector system, and a calibrated building thermal simulation. A typical contemporary Thai residential building was selected as a case-study house. Its energy use and local weather data were measured and analyzed. Published energy use of Thai residential buildings was also analyzed as well to determine average energy consumption. A calibrated computer model of the case-study building was constructed using the DOE-2 program. A field experiment of the thermal PV system was constructed to test its ability to simultaneously produce electricity and hot water in the daytime, and shed heat at night as a cooling strategy (i.e., night sky radiation). The resultant electricity and hot water produced by the hybrid PV-T collector system helped to reduce the use of non-renewable energy. The cooling produced by the night sky radiation also has to potential to reduce the cooling load. The evaluation of the case-study house and results of the field experiment helped to quantify the potential reduction of energy use in Thai residential buildings. This research provided the following benefits: 1) experimental results of a hybrid PV-T solar collector system that demonstrates its performance compared to typical system of separate photovoltaic and solar collector, 2) results of night sky radiation experiments using a photovoltaic panel as a radiator to demonstrate the performance of this new space cooling strategy, and 3) useful data from the case-study house simulation results and guidelines to assist others in transferring the results to other projects. URI: http://handle.tamu.edu/1969.1/2297 Files in this item: 1
etd-tamu-2005A-ARCH-Rasisut.pdf (7.261Mb) -
Wei, Guanghua (August 1997)[more][less]
Abstract: This thesis presents a broadly useful diagnostic methodology to engineers and plant managers for finding the in-situ operating characteristics of power plant boilers when metered data is either missing or obviously erroneous. The methodology is able to analyze conflicting measurements and utilize analytic redundancy (AR) to deduce the measurement or measurements which are substantially in error without shutting down the plant and recalibrating all instrumentation. It is shown, through the case study power plant, that the methodology is quite robust in identifying faulty instruments in plants which possess a low degree of hardware redundancy. Once the malfunctioning meters are identified and the historical data are corrected, boiler characteristic curves can be generated to guide the daily operation and assist future implementation of on-line optimal load allocation. Finally, suggestions are given for the on-line diagnostics of instrument performance, as well as some operational guidelines useful to plant engineers for improved boiler operation. URI: http://hdl.handle.net/1969.1/6427 Files in this item: 1
ESL-TH-97-08-01.pdf (23.72Mb) -
Im, Piljae (Texas A&M University, December 2003)[more][less]
Abstract: Currently, four areas of Texas have been designated by the United States Environmental Protection Agency (EPA) as non-attainment areas because they exceeded the national one-hour ground-level ozone standard of 0.12 parts-per-million (ppm). Ozone is formed in the atmosphere by the reaction of Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx) in the presence of heat and sunlight. In May 2002, The Texas State Legislature passed Senate Bill 5, the Texas Emissions Reduction Plan (TERP), to reduce the emissions of NOx by several sources. As part of the 2001 building energy performance standards program which is one of the programs in the TERP, the Texas Legislature established the 2000 International Energy Conservation Code (IECC) as the state energy code. Since September 1, 2001, the 2000 IECC has been required for newly constructed single and multifamily houses in Texas. Therefore, this study develops and applies portions of a methodology to calculate the energy savings and NOx emissions reductions from the adoption of the 2000 IECC to new single family houses in non-attainment and affected counties in Texas. To accomplish the objectives of the research, six major tasks were developed: 1) baseline data collection, 2) development of the 2000 IECC standard building simulation, 3) projection of the number of building permits in 2002, 4) comparison of energy simulations, 5) validation and, 6) NOx emissions reduction calculations. To begin, the 1999 standard residential building characteristics which are the baseline construction data were collected, and the 2000 IECC standard building characteristics were reviewed. Next, the annual and peak-day energy savings were calculated using the DOE-2 building energy simulation program. The building characteristics and the energy savings were then crosschecked using the data from previous studies, a site visit survey, and utility billing analysis. In this thesis, several case study houses are used to demonstrate the validation procedure. Finally, the calculated electricity savings (MWh/yr) were then converted into the NOx emissions reductions (tons/yr) using the EPA's eGRID database. The results of the peak-day electricity savings and NOx emissions reductions using this procedure are approximately twice the average day electricity savings and NOx emissions reductions. URI: http://handle.tamu.edu/1969.1/309 Files in this item: 1
etd-tamu-2003C-ARCH-Im-1.pdf (11.38Mb)
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