258 research outputs found
Inelastic chaotic scattering on a Bose-Einstein condensate
We devise a microscopic scattering approach to probe the excitation spectrum
of a Bose-Einstein condensate. We show that the experimentally accessible
scattering cross section exhibits universal Ericson fluctuations, with
characteristic properties rooted in the underlying classical field equations.Comment: 11 pages, 5 figure
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Evaporative-cooling potential for office buildings
This paper presents the results of both a performance and an economic assessment of the evaporative-cooling potential for office buildings in 11 US climate zones. Evaporative-cooling systems of the direct and combined direct/indirect type that are part of the heating, ventilating and air-conditioning (HVAC) system were evaluated. Thermal-storage strategies were not considered in this study. The DOE-2 building-energy-analysis computer program was used to simulate the evaporative-cooling performance of typical single-story and multistory office buildings. Performance results are presented as energy and peak demand reductions for each type of office building in each climate zone. Economic results are summarized as investment targets and aggregate/energy cost savings
ASHRAE's New Performance Measurement Protocols for Commercial Buildings
ASHRAE, CIBSE and USGBC are developing a standardized, consistent set of protocols to facilitate the comparison of the measured performance of buildings, especially those claimed to be green, sustainable, and/or high performance. Such protocols are needed because claims of high performance cannot be credible without such standardized protocols being applied consistently in the U.S. as well as internationally. The protocols will identify what is to be measured, how it is to be measured (instrumentation and spatial resolution), and how often it is to be measured. They will address both the use and reporting of the measured data, as well as appropriate benchmarks for each of the following characteristics: Energy Use (site, and source), Indoor Environmental Quality (IEQ)-Thermal Comfort, IEQ-Indoor Air Quality, IEQ-Lighting/ Daylighting Quality, IEQ-Acoustics and Water Use.
The primary users of the protocols document will be building owners and facility managers, rating and labeling system developers, government officials, as well as architects and design engineers. To date, a scoping document has been developed, an extensive literature review has been performed (available on ASHRAE’s web site), and a committee formed to write the protocols, which are intended for publication in January 2009
Evaluating Texas State University Energy Consumption According to Productivity
The Energy Utilization Index, energy
consumption per square foot of floor area, is the
most commonly used index of building energy
consumption. However, a building or facility exists
solely to support the activities of its occupants. Floor
area alone is not a complete measure of the amount
of service a facility provides. The energy
consumption of a service institution, such as a
university, could be evaluated according to its annual
level of service. However, the variety of services
delivered by an institution of higher education
cannot be measured by a single, readily available
number. Data Envelopment Analysis, a tool used
primarily in management science, can find
"benchmark" input consumption levels for
productive entities with multiple inputs and outputs.
It finds a consumption target for each form of energy
consumed by an institution, based on the actual
performance of comparable institutions. This
method is applicable to the energy consumption of
Texas state institutions of higher education
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Solar Energy Research Institute Validation Test House Site Handbook
The Validation Test House at the Solar Energy Research Institute in Golden, Colorado, is being used to collect performance data for analysis/design tool validation as part of the DOE Passive Solar Class A Performance Evaluation Program
Development of Revised Energy Standards for Texas Buildings: Preliminary Results
In 1977, the State of Texas published a two-part
Energy Conservation Manual to aid designers,
builders, and contractors in the design of energy-efficient
state buildings. Under the sponsorship
of the Governor's Energy Management Center, the
Center for Energy Studies (CES) at The University
of Texas at Austin is revising and updating the
nonresidential building portion of the Energy
Conservation Manual.
The proposed revision is a Texas-specific
adaptation of ASHRAE Standard 90.1P ("Energy
Efficient Design of New Buildings Except Low-Rise
Residential Buildings"). These modifications
include editorial changes, such as deletion of
criteria that do not apply to Texas climates, as
well as improved envelope criteria and the
addition of HVAC system performance criteria.
This paper documents the approach taken in
the development of the revised Texas standards.
Preliminary results are presented for the new
envelope calculation procedures that will be
included in the compliance software. This
software will parallel that provided for the
envelope and lighting sections in the ASHRAE
Standard and will ultimately extend the standard
to include a performance-based approach for HVAC
systems and whole-building Energy Targets
Energy Analysis of the Texas Capitol Restoration
This paper presents the methodology and results of a detailed energy analysis of the Texas Capitol Restoration. The purpose of this analysis was two-fold: 1) to determine the projected energy cost savings of a series of design alternatives for the Capitol Restoration, and 2) to calibrate the simulation model of the Capitol in its prerestored condition (in September 1991) using monitored energy use data from the Texas LoanSTAR program.
The Capitol in its proposed restored condition was simulated using the DOE-2 building energy analysis computer program with long-term Austin weather data to project the annual energy use, peak electric demand, and annual energy cost. Then a series of 13 energy efficient design altematives was simulated. The results were compared to those of the base case to determine the projected annual energy and energy cost savings for each measure, and for combinations of several of the measures.
Finally, the paper documents the calibration of the DOE-2 model for the Capitol in its prerestored condition, using monitored hourly whole-building electric data (excluding heating and cooling energy)
Energy Savings Resulting from Shading Devices on Single-Family Residences in Austin, Texas
Potential annual energy savings resulting from
window shading devices on three prototypical
Austin, Texas, single-family residences were
computed in this study. Savings were calculated
for interior (shades, blinds, draperies, window
film, and tinted windows) and exterior (solar
screens, awnings, overhangs, and the effects of
recessed windows and vegetation) shading devices.
The analysis was conducted with the DOE-2
building energy analysis computer program. Nominal
baseline cases (single glazing, gas heating, and
nominal shading from eaves and neighboring
buildings) were run for each prototype. Selected
baseline variants (double glazing, all electric,
and no eaves or neighbor shading) were run to test
parameter sensitivity.
Results are reported in terms of the annual
heating and cooling energy use and energy cost,
with each device in place, as compared to the
baseline cases. The devices are ranked in term of
energy savings and energy coat savings. Another
significant result is the multiple-regression
correlation of annual heating and cooling energy
savings with Shading Coefficient and U-value that
generalizes the performance of the shading devices
Development of HVAC System Performance Criteria Using Factorial Design and DOE-2 Simulation
A new approach is described for the development
of Heating, Ventilating, and Air-conditioning
(HVAC) System Performance Criteria for the Texas
Building Energy Design Standard. This approach
integrates a design of experimental methodology and
DOE-2 simulation to identify the effects of control
parameters on HVAC system energy performance.
Three new criteria - transport, plant, and system
performance factors-are used as measures of system
performance. The procedure has been applied to the
development of criteria for a variable-air-volume
(VAV) and a constant-air-volume (CAV) system in
three Texas climates. The results show that the air
distribution system pressure loss, cooling coil exit
temperature set-pint, operation of an economizer,
and use of dead band controls have significant effects
on air transport energy use and total system
performance. The selection of control strategies and
set-points have a clear impact on energy use. There is
also a great energy-saving potential of converting
from a CAV to a VAV system
An Expert System for Determining Compliance with the Texas Building Energy Design Standard
Demonstration of compliance with the Texas
Building Energy Conservation Design Standard
involves completion of a summary checklist for each
of its sections. This manual checking is tedious.
Furthermore, no comprehensive documentation of the
user's compliance is provided and the compliance
checker must manage the data collected. To assist
designers in complying with the Standard and to
reduce the time required, the Center for Energy
Studies (CES) at the University of Texas at Austin
has developed an expert system to serve as both the
compliance procedure and its documentation. This
expert system directs the user with queries (screen
menus), prompting the user for all relevant
information. A graphical user interface has been
developed to facilitate quick navigation through the
Standard, easy data entry, and identification of
compliance failures. This paper describes the research
approach to the expert system, the system features,
current status of project, and the benefits to be derived
from this innovative compliance tool
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