79 research outputs found
A Model for Evaluation of Life-Cycle Energy Savings of Occupancy Sensors for Control of Lighting and Ventilation in Office Buildings
Lighting and ventilation represent the majority of the air conditioning loads in office buildings in hot humid climates. Use of motion sensors is one way to minimize the energy used for these loads. This paper describes the methods used for simulation a case study building with motion sensors installed and the monitoring of system on-off statistics related to occupant patterns. It also
describes the development of the Monte Carlo model
used to predict the on-off status of sensors. The
building using the motion sensors is compared to a
building that controls the lights and ventilators by a
conventional pre-programmed schedule. The
conventional methods of simulation were shown to
generate misleading information regarding electric
demand charges and life-cycle costs of the building.
When comparing to actual use patterns, the Monte
Carlo process was shown to represent an adequate
way to represent the on-off patterns. Computer
simulations further demonstrate the potential life
cycle cost savings from the use of the motion
sensors
Estimated Savings from Turning Off Unnecessary Lights at the Langford Architecture Center During the 1996 Christmas Holidays
During the 1996 Christmas holidays the College of Architecture initiated a trial program to turn off unnecessary lights during unoccupied periods. This effort targeted the unnecessary lights in all studios, classrooms, labs and offices. Had those lights been left on, the building would have consumed 100 kW more electricity every hour. The total electricity savings was about 31,200 kWh over 13 days, which is equivalent to a total cost saving of 13,711, which is 40% of the target savings estimated in the test we performed earlier in 1996. Labor costs to accomplish a manual shutdown are approximately 8,632 per year
The Framework of an Optimization Model for the Thermal Design of Building Envelopes
Careful long term decisions in the design and
operation of buildings can significantly improve the
thermal performance and thus reduce the
consumption of energy. The availability and ease of
use of today's computers can be a sigruficant benefit
to the decision making process of building design.
In dealing with the building as a thermal
system, the proper selection of its components and
their relationships can be organized using a systems
approach. This can be achieved by coupling an
optimization technique into the thermal performance
of buildings early in the design process. This
requires formulating the building as a well-defined
thermal system in a framework suitable for the
application of systematic approaches. The aim of this
paper is to describe the basic framework of a
building thermal design optimization model by
defining building design variables, a criterion of
optimality, constraints, and a suitable thermal
simulation model that can be integrated into the
proper optimization technique
Evaluation of Lightshelf Daylighting Systems for Office Buildings in Hot Climates
This paper presents part of an on-going research
project in the College of Architecture at Texas A&M
University. This research investigates how lightshelf
daylighting delivery systems can manipulate sunlight
and daylight both in terms of their light and heat by
shading view apertures below the shelf to reduce solar
heat gain and glare and by reflecting light deep into the
space through the daylight aperture above the shelf. It
also investigates how to provide view with good
interior lighting in terms of light levels, distribution,
and glare.
Evaluation of these systems are based on two
different experiments. The first uses scale-models for
daylighting evaluation. Methodology of the research is
presented as well as results and evaluation for part of the
first experiment. The second experiment will use
computer program simulations for energy evaluation
that include reducing lighting and cooling loads and
shaving peak loads, especially, when used with selective
low-e glazing for office buildings in hot climates
Effectiveness of External Window Attachments Based on Daylight Utilization and Cooling Load Reduction for Small Office Buildings in Hot Humid Climates
This study explored the effectiveness of
selected external shading devices and glazing
treatments used to minimize the total annual energy
consumption in small office buildings in hot humid
climates. The external shading devices included a
permanent horizontal overhang and a light shelf.
The selected types of glazing included clear,
reflective, tinted, low-emissivity coating, and
heat-mirror glass.
One concern about using external window
attachments is that while reducing the solar heat
gains, they also reduce the amount of the daylight
needed to supplement interior lighting. Therefore the
objective of this study was to explore which strategy
would give a balance between solar heat gain
reduction and daylight utilization and result in the
most energy savings in the building.
Computer simulations using an hourly energy
calculation model were conducted to predict the
building's total energy consumption using each
strategy. The economics of each strategy were
analyzed with lifecycle costing techniques using the
present value technique. Results show that properly
designed overhangs that shade clear glazing are
slightly more cost-effective than specialized low-e
glazing systems. These results are unique for hot
humid climates where winter heating is not an issue.
On the contrary, when used in cold climates,
external shading devices tend to increase the building's energy consumption
A Calibration Methodology for Retrofit Projects Using Short-Term Monitoring and Disaggregated Energy Use Data
This paper presents an improved methodology to
calibrate energy simulation models to better represent
the actual energy use breakdowns in existing buildings.
The goal of this methodology is to help architects
and engineers accurately determine the current
energy use and identify any energy-related problems
in the building before proposing the retrofit design
solutions, without conducting long-term monitoring.
The methodology includes procedures to conduct
systematic data collection, "on-off' tests to determine
the power densities of the electrical loads, up
to four weeks of building energy monitoring to derive
the energy use profiles and temperature settings,
and disaggregation of the measured energy use data.
The procedures also utilize the monthly utility billing
records and site weather data. The calibration to the
measured data is done on both hourly and monthly
basis.
The procedures are built into a computer program
and integrated with previously developed
simulation software. The user interface of the program
includes guidelines to help the user decide
which simulation input variable has to be altered in
order to match the measured data. It also produces
graphical outputs to help in visualizing the results,
and several guidelines to help study different retrofit
strategies after the model has been calibrated
Daylighting Analysis through Scale Model, Full Scale Measurements and Computer Analysis for a Texas A&M University Campus Building
In the first part of this study, daylighting levles in an actualy classroom are compared to scale model measurements and to computer program predictions.
Secondly, the daylighting effects in the building atrium are examined through the studies of an actual building and of a scale model. Results are reported about how these data compare to each other
Estimated Savings from Turning Off Unnecessary Lights at the Langford Architecture Center During the 1996 Christmas Holidays
During the 1996 Christmas holidays the College of Architecture initiated a trial program to turn off unnecessary lights during unoccupied periods. This effort targeted the unnecessary lights in all studios, classrooms, labs and offices. Had those lights been left on, the building would have consumed 100 kW more electricity every hour. The total electricity savings was about 31,200 kWh over 13 days, which is equivalent to a total cost saving of 13,711, which is 40% of the target savings estimated in the test we performed earlier in 1996. Labor costs to accomplish a manual shutdown are approximately 8,632 per year
Enhanced Software for Displaying Orthographic, Stereographic, Gnomic and Cylindrical Projections of the Sunpath Diagram and Shading Mask Protractor
The well-known versions of the sun-path diagrams
and shading mask protractors that appear in the AIA's
Architectural Graphics Standards (Ramsey and Sleeper
1994) are based on the equidistant projections and use a
shading mask protractor developed by Olgyay and Olgyay
at Princeton University in the 1950s. In the previous
papers by McWatters and Haberl(1994a; 1994b;1995) and
Oh and Haberl(1996;1997) the development of a
computerized display of the equidistant projection of the
sunpath diagram and shading mask protractor was
presented. This paper describes enhancements to the
display of the sunpath diagram and shading mask
protractor that include orthographic, stereographic, gnomic
and cylindrical projections. Descriptions of the new
algorithms and examples of the different displays are also
provided
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