Engineering Commons^™

Measured Impacts Of Air Conditioner Condenser Shading, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A study has been conducted by the Florida Solar Energy Center (FSEC) to examine if space cooling energy savings can be achieved from shading of residential air conditioning (AC) condenser units. The investigation consisted of before-and-after experiments conducted on three homes over a two year period. A recent EPA study recommends shading of exterior AC condensers, using landscaping or other means, as a method to reduce space cooling energy use (Akbari et al., 1992).

Monitored Energy Use Patterns In Low-Income Housing In A Hot And Humid Climate, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The Florida Solar Energy Center (FSEC) is metering energy use in two Habitat for Humanity developments. The objective is to understand how energy is used in low income housing and how it can be effectively reduced. The ten "control homes" come from a conventional housing project built by in 1993 Habitat for Humanity in Homestead, Florida. Another ten "experimental homes" have been recruited from the 190 home Jordan Commons development in the same vicinity. These houses, which are soon to be metered, are designed to be energy efficient with high SEER air conditioners, reflective roofing, solar water heaters and energy …

Side-By-Side Testing Of Commercial Office Lighting Systems: Two-Lamp Fluorescent Fixtures, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

Lighting systems in commercial office buildings are primary determinants of building energy use. In warmer climates, lighting energy use has important implications for building cooling loads as well as those directly associated with illumination tasks. To research the comparative performance of conventional and advanced office lighting systems, Florida Solar Energy Center (FSEC) set up the Lighting Flexible Test Facility (LFTF) which allows side-by-side comparison of lighting options in two otherwise identical 2.7 m x 3.7 m (9' x 12') south facing offices.

The ceiling of the LFTF contains 0.61 m x 1.2 m (2' x 4') recessed fluorescent fixtures designed …

Measured Performance Of Energy-Efficient Computer Systems, Florida Solar Energy Center, David Floyd

FSEC Energy Research Center®

The intent of this study is to explore the potential performance of both Energy Star computers/printers and add-on control devices individually, and their expected savings if collectively applied in a typical office building in a hot and humid climate. Recent surveys have shown that the use of personal computer systems in commercial office buildings is expanding rapidly. The energy consumption of such a growing end-use also has a significant impact on the total building power demand. In warmer climates, office equipment energy use has important implications for building cooling loads as well as those directly associated with computing tasks. Recently, …

Daylighting Dimming And Energy Savings: The Effects Of Window Orientation And Blinds, Florida Solar Energy Center, Lynn Schrum

FSEC Energy Research Center®

The Daylighting Test Facility (DTF) located at Florida Solar Energy Center, was used to study daylight dimming systems and how orientation and blinds effect energy savings. To evaluate the impact of blinds on dimming savings, the energy consumption was compared in two pairs of offices for all four window orientations: north, south, east and west. One office in each pair had blinds in a fixed position (down and open) and the other office had no blinds. From September through December of 1994, data were collected on the north- and south-facing offices. The DTF was rotated 90 degrees and data were …

Applying Photovoltaics To Disaster Relief, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Hurricanes, floods, tornadoes, earthquakes, and other disasters can happen at any time, often with little or no advance warning. They can be as destructive as Hurricane Andrew leaving several hundred-thousand people homeless or as minor as an afternoon thunderstorm knocking down local power lines to your home. Major disasters leave many people without adequate medical services, portable water, electrical service and communications. In response to a natural disaster, photovoltaic (solar electric) modules offer a source of quite, safe, pollution-free electrical power. Photovoltaic (PV) power systems are capable of providing the electrical needs for vaccine refrigerators, microscopes, medical equipment, lighting, radios, …

Uncontrolled Air Flow In Non-Residential Buildings, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

The objective of this study was to develop the capability to substantially reduce energy use, building degradation and indoor air pollution caused by uncontrolled air flow in nonresidential buildings. For purposes of the study, 'uncontrolled air flow' was defined as air moving across the building envelope or between zones or components of a building, where the pathways of flow, the direction of flow, and the origin of the air are unknown, unspecified, or unintended. The study comes to three major conclusions as follows: 1. Uncontrolled air flow is pervasive in buildings, often resulting in severe -- and sometimes even catastrophic …

Energy Savings From Repair Of Uncontrolled Airflow In Eighteen Small Commercial Buildings, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Uncontrolled airflow, including duct leakage, pressure imbalances caused by closed interior doors, and exhaust/intake airflow imbalance, was characterized in 70 commercial buildings. In 18 of these buildings, uncontrolled airflows were repaired and energy savings from these repairs were monitored. In most buildings the retrofit was duct repair. In other cases, outdoor airflow was reduced and return air transfers were provided. Cooling energy use was reduced by an average 15.1% in these 18 buildings. With an average repair cost of $455 and average cooling energy savings of $195 per year, uncontrolled airflow retrofits proved to be very cost-effective. Various factors indicate …

Cavity Model Analysis Of Microstrip Ring Antennas Using Green's Functions, Javier Gomez Tagle Rangel

Retrospective Theses and Dissertations

Microstrip ring antennas have been experimentally tested by several researchers due to their specific radiation characteristics that make them very suitable for many applications, from medical uses to mobile communications. Ring antennas have been found to have a larger bandwidth compared to other conventional types of microstrip patch antennas. Further more, their size is smaller when compared to circular and rectangular resonant structures. The TM1m modes (m = 2,4,6 .. , where m represents radial variations) radiate conical beams in the broadside direction, while TM nl modes (n = 2,4,6 .. , where n represents azimuthal variations) have a radiation …

Computing Optimal Cocomo Effort Multiplier Values And Optimal Casebase Subsets Using Monte Carlo Methods, Robert Joseph Maidhof

Retrospective Theses and Dissertations

There have been many studies performed and techniques applied to solve the problem of estimating man-month effort for software projects. Despite all the effort expended to solving this problem the results achieved from the various techniques have not been embraced by the software community as very reliable or accurate. This thesis uses Monte Carlo methods to obtain optimal values for COCOMO effort multipliers which minimize the average of the absolute values of the relative errors (AARE) of man-month estimate for two industry supplied casebases. For example, when using three COCOMO cost drivers (complexity, language experience, application experience) and the COCOMO …

Semantic Correlation Of Behavior For The Interoperability Of Heterogeneous Simulations, Christopher James Dean

Retrospective Theses and Dissertations

A desirable goal of military simulation training is to provide large scale or joint exercises to train personnel at higher echelons. To help meet this goal, many of the lower echelon combatants must consist of computer generated forces with some of these echelons composed of units from different simulations. The object of the research described is to correlate the behaviors of entities in different simulations so that they can interoperate with one another to support simulation training. Specific source behaviors can be translated to a form in terms of general behaviors which can then be correlated to any desired specific …

The Effects Of Glucose And Fatty Acids On Enhanced Biological Phosphorus Removal Using A Sequencing Batch Reactor, Tarek Zaki Khouri

Retrospective Theses and Dissertations

Two anaerobic/aerobic sequencing batch reactors (SBRs) were used to evaluate enhanced biological phosphorus removal (EBPR). The first SBR, designated the Glucose SBR, was run for a period of four months. It received a synthetic wastewater plus glucose as a supplemental carbon source. The second SBR, the Isovaleric SBR, was run for three months. During the first month, isovaleric acid was its supplemental carbon source while for the remaining time period, no supplemental carbon source was added to the feed. Steady-state data from the SBR receiving isovalerate yielded the highest phosphorus (P) removals observed during the study, with a mixed liquor …

Analysis Of Threaded Joint Behavior In An Airbag Module Assembly, Rustam Chemat

Retrospective Theses and Dissertations

While some of think of our cars as simply "buckets of bolts", the proper design choices, applications, and assemblies of threaded fasteners/bolted joints play critical roles in automobile safety.

Supplemental Restraint Systems (SRS), more commonly known as airbags, help prevent vehicle occupants from being thrown forward into the dashboard or windshield in the event of a collision. The components comprising the airbag, the inflator, the backing plate, and the cover are connected to each other, and to the vehicle, through a series of threaded fasteners. Proper and timely deployment of the airbag depends largely on the selection of suitable threaded …

Analysis Of Frequency Selective Surfaces With Ferrite Substrates, Youcheng Liu

Retrospective Theses and Dissertations

Frequency selective surfaces (FSS) have numerous applications in several microwave and optical systems. Most frequency selective surface structures have one or more dielectric substrates. In this work, instead of traditional dielectric substrates, ferrite substrates are used under different dc bias conditions. By using ferrite materials, one can change the spectral properties of these structures without physically altering them. An applied magnetic field (dc bias) on the ferrite substrate changes its properties and hence the electrical dimensions of the elements comprising the periodic structure. Thus by simply applying a dc bias, the transmission and reflection properties of the periodic structure can …

Approximate Trigonometric Expansions With Applications To Signal Decomposition And Coding, Qurban A. Memon

Retrospective Theses and Dissertations

Signal representation and data coding for multi-dimensional signals have recently received considerable attention due to their importance to several modern technologies. Many useful contributions have been reported that employ wavelets and transform methods. For signal representation, it is always desired that a signal be represented using minimum number of parameters. The transform efficiency and ease of its implementation are to a large extent mutually incompatible. If a stationary process is not periodic, then the coefficients of its Fourier expansion are not uncorrelated. With the exception of periodic signals the expansion of such a process as a superposition of exponentials, particularly …

Energy Efficient Office Building Design For A Hot And Humid Climate: Florida's New Energy Center, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

Hot and humid climates, such as those in Florida, pose unique challenges to architects and engineers seeking energy efficient office building designs. The severe impact of internal loads on cooling, the intense solar conditions and the need for increased ventilation set against high relative humidities, all serve to limit the success of many conventional methods of reducing building energy use. To provide a high-visibility demonstration of potential energy design solutions, the Florida Solar Energy Center (FSEC) is building a state-of-the-art office complex for its new facility in Cocoa, Florida.

The Measured Summer Performance Of Tile Roof Systems And Attic Ventilation Strategies In Hot, Humid Climates, Florida Solar Energy Center, David Beal

FSEC Energy Research Center®

During 1994, simultaneous full-scale testing of residential plywood-decked roofing system was conducted using a flexible roof facility (FRF). The facility consists of a 24-ft by 48ft rectangular building with one large conditioned space under an attic that is partitioned into six separate test cells. Throughout the test protocol one cell was configured as a residential black-shingle roof system, employed as the baseline for comparison of the alternative roofing systems.

Two identical cells were employed during the summer of 1994 to investigate soffit and ridge venting. Tests of two different configurations best illustrate the results. A comparison of a sealed attic …

Measured Cooling Energy Savings From Reflective Roofing Systems In Florida: Field And Laboratory Research Results, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A series of field experiments in Florida have examined the impact of reflective roof coatings on air conditioning energy use in occupied homes. The tests were conducted on nine residential buildings from 1991 to 1994 using a before and after protocol where the roofs were whitened at mid-summer. Measured AC electrical savings in the buildings during similar pre- and post-retrofit periods averaged 19%, ranging from a low of 2% to a high of 43%. Utility peak coincident peak savings averaged 22%. Cooling energy reductions appear to depend on ceiling insulation level and roof solar reflectance, air duct system location and …

Florida Exterior Wall Insulation Field Test: Final Report, Florida Solar Energy Center, Stephen Barkaszi

FSEC Energy Research Center®

The Florida Solar Energy Center (FSEC) and Oak Ridge National Laboratory (ORNL) have conducted a field test of exterior insulation applied to Florida masonry residences. Approximately 50% of Florida's six million existing residences are of concrete block construction. Many of these homes, particularly those 15 years or older, have uninsulated walls.

Within the project, two single-family homes in Central Florida were extensively monitored to measure the energy savings of the technology. The primary objective was to examine the effect exterior insulation has on air conditioning (AC) energy use and peak electrical demand for two typical residences. A secondary objective was …

Smarts2, A Simple Model Of The Atmospheric Radiative Transfer Of Sunshine, Florida Solar Energy Center, Christian Gueymard

FSEC Energy Research Center®

An upgraded spectral radiation model called SMARTS2 is introduced. The solar shortwave direct beam irradiance is calculated from spectral transmittance functions for the main extinction processes in the cloudless atmosphere: Rayleigh scattering, aerosol extinction, and absorption by ozone, uniformly mixed gases, water vapor, and nitrogen dioxide. Temperature-dependent or pressure-dependent extinction coefficients have been developed for all these absorbing gases, based on recent spectroscopic data obtained either directly from the experimental literature or, in a preprocessed form, from MODTRAN2, a state-of-the-art rigorous code. The NO2 extinction effect, in both the UV and visible, is introduced for the first time in a …

Energy Efficiency Technology Demonstration Project For Florida Educational Facilities: Occupancy Sensors, Florida Solar Energy Center, David Floyd

FSEC Energy Research Center®

In 1995 the Florida Department of Education and the Florida Solar Energy Center jointly sponsored a test of occupancy sensors used to control lighting in a Florida school. Occupancy sensors replace conventional light switches and use passive infrared or ultrasonic sensing to control lighting in classroom and other spaces. The test was intended to demonstrate the performance of such controls in saving energy in Florida educational facilities.

The evaluation was performed at Northwest Elementary School in Pasco County on Florida's west central coast. A before and after monitoring protocol was utilized for the study which saw lighting circuits for 33 …

Photovoltaic Applications For Disaster Relief, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Hurricanes, floods, tornadoes, and earthquakes are natural disasters that can happen at any time destroying homes, businesses, and natural surroundings. One such disaster, Hurricane Andrew, devastated South Florida leaving several hundred-thousand people homeless. Many people were without electrical service, functioning water and sewage systems, communications, and medical services for days, even weeks in the aftermath of the storm. Emergency management teams, the military and countless public and private organizations staged a massive relief effort. Dependency on electrical utility power became a pronounced problem as emergency services were rendered to survivors and the rebuilding process started.

Many of the energy needs …

Indoor Air Quality Impacts Of Uncontrolled Air Flow And Depressurization In Eight Commercial Buildings In Central Florida, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Field investigations were done in 68 commercial buildings to identify uncontrolled air flows and pressure imbalances. Results from eight buildings (six restaurants and two sports facilities) are reported in this paper. Testing included building airtightness tests, identification of building air barrier location, duct system airtightness, characterization of pressure differentials, building air flow balance, and infiltration/ventilation rates. Six restaurants and one sports facility were found to operate at negative pressures which ranged from -0.003 inWC (-0.8 Pa) to -0.173 inWC (-43 Pa) and averaged -0.051 inWC (-12.7 Pa) under normal operation. A second sports facility operates partially at positive pressure and …

Field Commissioning Of A Daylight-Dimming Lighting System, Florida Solar Energy Center, David Floyd

FSEC Energy Research Center®

An Elementary School cafeteria in Florida was commissioned with a fluorescent lighting system that dims in response to available daylight. The lighting system's performance and commissioning aspects were evaluated through real time measurement of lighting and air conditioning power, work plane illumination, and interior/exterior site conditions. The new system produced a 27% reduction in lighting power due to dimming. Lower than expected dimming system performance was observed prior to effective commissioning. Difficulties encountered are discussed as well as recommendations for performance improvements.

Photovoltaic Applications For Disaster Relief. 11-95. Copies 1, 2&3., Florida Solar Energy Center, William Young

FSEC Energy Research Center®

No abstract provided.

Assessment Of Infiltration Practices In The Florida Energy Code, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

The Florida Department of Community Affairs has contracted with the Florida Solar Energy Center (FSEC) to review the current infiltration practices of the Florida Energy Code to determine, based on analysis of the best currently available infiltration data, whether there is need for three infiltration practices, and to make recommendations of what "point multipliers" should be applied to the infiltration practice(s). An advisory committee of industry, utility, and research representatives was formed to review the findings of the project and express opinions about the form the infiltration practices should take. This committee met twice, reviewed each of the reports produced …

Nonlinear Robust Control Of A Series Dc Motor Utilizing The Recursive Design Approach, Michael J. Burridge

Retrospective Theses and Dissertations

In this thesis, the investigation of asymptotic stability of the series DC motor with unknown load-torque and unknown armature inductance is considered. The control technique of recursive, or backstepping, design is employed. Three cases are considered. In the first case, the system is assumed to be perfectly known. In the second case, the load torque is assumed to be unknown and a proportional-integral controller is developed to compensate for this unknown quantity. In the final case, it is assumed that two system parameters, load torque and armature inductance, are not known exactly, but vary from expected nominal values within a …

The Design Of Fir Filters With Linear Or Non-Linear Phase Using The Kaiser Window Function And A Novel Superposition Method, Cai Zurong

Retrospective Theses and Dissertations

A new design method for FIR filters using the Kaiser window is presented in this paper. Near optimal frequency response and impulse response can be obtained for a given • set of specifications. The synthesis procedure uses the summation of frequency translated and scaled Kaiser functions. The method can be used to design linear phase or non-linear phase filters, and symmetric or non-symmetric arbitrary magnitude response filters. This design method is based on the frequency domain using the approximate Fourier transform of the Kaiser window function. The design procedures and examples for linear and arbitrary phase filters are discussed in …

Calculating Cross Slot Flux Losses In High Voltage Stator Coils, John D. Amos

Retrospective Theses and Dissertations

At present there are several methods for calculating temperature for inner-cooled stator coils for large electric generators. Determining the highest temperature in a stator coil is very important and is a major limiting factor for the maximum capability of steam turbine synchronous generators.

The load current in the stator winding causes losses in the conductor resistance. That same current excites leakage fluxes that link contours inside the conductors causing non-uniform current distribution and additional losses. these additional losses are caused by eddy currents induced inside the stator coils. These eddy losses are grouped as radial flux losses, cross slot flux …

Gaussian Beam Resonator Formalism Using The Yy Method, Kenneth A. Menard

Retrospective Theses and Dissertations

A simple and powerful new paraxial ray formalism is shown to provide an alternate method for designing Gaussian Beam Resonators. The theory utilizes the Delano yybar diagram approach and is an extension of the recent work by Shack and Kessler for laser systems. The method is shown to be complementary to the conventional ABCD method and is founded upon J.A. Arnaud's pioneering ideas for complex rays. The thesis develops an analytic formulation of a ray based complex wavefront curvature and yields a clearly generalized description of spherical wave propagation, for which Gaussian beams are considered a special case. The resultant …