These reports may be ordered, free of charge, from the Simulation Research Group at Lawrence Berkeley National Laboratory.
LBNL-44636 RESIDENTIAL
HEATING AND COOLING LOADS COMPONENT ANALYSIS: FINAL REPORT
Abstract:
This study uses parametric computer simulations of 112
single-family and 63 multi-family residential building prototypes to
quantify the contributions of building components such as roofs, walls,
windows, infiltration, outside air, lighting, equipment and people to
the aggregate heating and cooling loads in U.S. residential buildings,
and the overall efficiencies of typical residential heating and cooling
systems in meeting these loads. The prototypical buildings are based on
previous LBNL work that defined prototypical buildings by vintage and
location to represent existing and new U.S. residential buildings.
Parametric simulations were done using the DOE-2.1E program to
determine the contribution of the following building components --
roof, wall, foundation, window solar gain, window conduction,
infiltration, people, lighting and appliances -- to the total heating
and cooling loads of these buildings.
LBNL-44306
FEASIBILITY STUDY OF A US-CHINA DEMONSTRATION ENERGY-EFFICIENT
COMMERCIAL BUILDING
In July 1998, the U.S. Department of
Energy and China's Ministry of Science and Technology signed an
historic statement of work to determine the feasibility of a joint
energy-efficient demonstration building and design center. The proposed
11,000m2 to 13,000m2 9-story office building would use U.S.
energy-efficient materials, space-conditioning systems, controls and
design principles that could be widely replicable throughout China. The
building's energy performance and associated greenhouse gas emissions
reductions would be measured consistent with Decision 5/CP.1 of the
Conference of the Parties of the United Nations Framework Convention on
Climate Change. The Sino-U.S. statement provides that China would
contribute the land and base building features, while the United States
would be responsible for the additional (or marginal) costs associated
with the package of energy efficiency and renewable energy improvements
to the building.
LBNL-44097 NUMERICAL
PERFORMANCE OF THE SPARK GRAPH-THEORETIC SIMULATION PROGRAM
Abstract:
The Simulation Problem Analysis and Research Kernel
(SPARK) uses graph-theoretic techniques to match equations to variables
and build computational graphs, yielding solution sequences indicated
by needed data flow. Additionally, the problem graph is decomposed into
strongly connected components, thus reducing the size of simultaneous
equation sets, and small cut sets are determined, thereby reducing the
number of iteration variables needed to solve each equation set. The
improvement in computational nature of the problem. The paper explores
the improvement one might expect in practice in three ways. First, two
problems chosen to span the range of performance are studied and some
of the factors determining the performance are identified and
discussed. The problem selected to exhibit a large improvement
consists of a set of sparsely coupled non-linear equations. The
problem selected to represent the other end of the performance spectrum
is a set of equations obtained by discretizing Laplace's equation in
EnergyPlus
ENERGYPLUS: A NEW-GENERATION BUILDING ENERGY
SIMULATION PROGRAM (rev)
Abstract:
Many of the popular building energy simulation programs around
the world are reaching maturity some
use simulation methods (and even code) that originated in the
1960s. For more than two decades, the U.S.
government supported development of two hourly building energy
simulation programs, BLAST and
DOE2. Designed in the days of mainframe computers, expanding
their capabilities further has become
difficult, time-consuming, and expensive. At the same time, the
30 years have seen significant advances
in analysis and computational methods and providing an
opportunity for significant improvement
in these tools.
In early 1996, a Federal agency began developing a new building
energy simulation tool, EnergyPlus,
building on development experience with DOE2 and BLAST.
EnergyPlus includes a number of
innovative simulation such as variable time steps, built-in
template and external modular
systems that are integrated with a heat balance-based zone
and input and output data
structures tailored to facilitate third party module and
interface development. Other planned simulation
capabilities include multi-zone airflow, and electric power and
solar thermal and photovoltaic simulation.
Beta testing of EnergyPlus begins in early 1999.
LBL-37208
COMMERCIAL HEATING AND COOLING LOADS COMPONENT ANALYSIS:
FINAL REPORT
Abstract:
This study uses computer simulations of 120 commercial
building prototypes to quantify the contributions of building
components such as roofs, walls, windows, infiltration, outside air,
lighting, equipment and people to the aggregate heating and cooling
loads in U.S. commercial buildings, and the efficiencies of typical
commercial heating and cooling systems in meeting these loads.
ASHRAE (presented at the 1998 Winter meeting)
MEASURED AND SIMULATED PERFORMANCE OF REFLECTIVE
ROOFING SYSTEMS IN RESIDENTIAL BUILDINGS
Abstract:
A series of experiments in Florida residences have measured the impact of
increasing roof solar reflectance on space cooling. In tests on eleven
homes with the roof color changed in mid-summer, the average cooling
energy use was reduced by 19%. Measurements and infrared thermography
show that a significant part of the savings is due to interactions when
the duct system is located in the attic space. An improved residential
attic and duct simulation model, taking these experimental results into
account, has been implemented in the DOE-2.1E building energy
simulation program. The model was then used to estimate the impact of
reflective roofing in fourteen different climatic locations around the
United States.
LBL-42734
ENERGYPLUS: A NEW-GENERATION BUILDING ENERGY SIMULATION PROGRAM
Abstract:
Many of the popular building energy simulation programs around the
world are reaching maturity -- some use simulation methods (and even
code) that originated in the 1960s. For more than two decades, the U.S.
government supported development of two hourly building energy
simulation programs, BLAST and DOE-2. Designed in the days of
mainframe computers, expanding their capabilities further has become
difficult, time-consuming, and expensive. At the same time, the 30
years have seen significant advances in analysis and computational
methods and power -- providing an opportunity for significant
improvement in these tools.
In early 1996, a Federal agency began developing a new building energy simulation tool, EnergyPlus, building on development experience with DOE-2 and BLAST. EnergyPlus includes a number of innovative simulation features -- such as variable time steps, built-in template and external modular systems that are integrated with a heat balance-based zone simulation -- and input and output data structures tailored to facilitate third party module and interface development. Other planned simulation capabilities include multi-zone airflow, and electric power and solar thermal and photovoltaic simulation. Beta testing of EnergyPlus begins in early 1999.
LBL-42963
SIMULATED PERFORMANCE OF CIEE'S "ALTERNATIVES TO COMPRESSOR
COOLING" PROTOTYPE HOUSE UNDER DESIGN CONDITIONS IN VARIOUS CALIFORNIA
CLIMATES
Abstract:
Since 1993, the author has been involved with a team of researchers,
engineers and architects in the "Alternatives to Compressor Cooling"
project sponsored by the California Institute for Energy Efficiency
(CIEE) with the goal to design and construct a house for California
Transition Climates that would not require mechanical air-conditioning.
There is no rigorous definition of the Transition Climates, but they
can be roughly delineated as the area between the Pacific Coast and the
Central Valley or Southern desert where the climates are alternately
affected by marine or inland influences. The rationale for the project
is that as urbanization expands into the transition climates, new
housing is being constructed with central air-conditioning systems that
operate for a limited number of days and add an extremely
disadvantageous electricity
load to the utility district on hot
summer afternoons.
LBL-42871
RESIDENTIAL FENESTRATION PERFORMANCE ANALYSIS USING RESFEN 3.1
Abstract:
This paper describes the development efforts of
RESFEN 3.1, a PC-based computer program for calculating the heating and
cooling energy performance and cost of residential fenestration
systems. The development of RESFEN has been coordinated with ongoing
efforts by the National Fenestration Rating Council (NFRC) to develop
an energy rating system for windows and skylights to maintain maximum
consistency between RESFEN and NFRC's planned energy rating system.
Unlike previous versions of RESFEN, that used regression equations to
replicate a large data base of computer simulations, Version 3.1
produces results based on actual hour-by-hour simulations. This
approach has been facilitated by the exponential increase in the speed
of personal computers in recent years. RESFEN 3.1 has the capability of
analyzing the energy performance of windows in new residential
buildings in 52 North American locations.
LBL-42355
SIMULATION MODEL: FINNED WATER-TO-AIR COIL WITHOUT
CONDENSATION
Abstract:
A simple simulation model of a
finned water-to-air coil without condensation is presented. The model
belongs to a collection of simulation models that allows efficient
computer simulation of heating, ventilation, and air-conditioning
(HVAC) systems. The main emphasis of the models is short computation
time and use of input data that are known in the design process of an
HVAC system. The target of the models is to describe the behavior of
HVAC components in the part load operation mode, which is becoming
increasingly important for energy efficient HVAC systems. The models
are intended to be used for yearly energy calculation or load
calculation with time steps of about 10 minutes or larger. Short-time
dynamic effects, which are of interest for different aspects of control
performance, are neglected. The part load behavior of the coil is
expressed in terms of the nominal condition and the dimensionless
variation of the heat transfer with change of mass flow and temperature
on the water side and the air side.
LBL-42354
SIMULATION MODEL: AIR-TO-AIR PLATE HEAT EXCHANGER
Abstract:
A simple simulation model of an air-to-air plate heat exchanger
is presented. The model belongs to a collection of simulation models
that allows the efficient computer simulation of heating, ventilation,
and air-conditioning (HVAC) systems. The main emphasis of the models
is to shorten computation time and to use only input data that are
known in the design process of an HVAC system. The target of the
models is to describe the behavior of HVAC components in the part-load
operation mode, which is becoming increasingly important in energy
efficient HVAC systems. The models are intended to be used for yearly
energy calculations or load calculations with time steps of about 10
minutes or larger. Short- time dynamic effects, which are of interest
for different aspects of control theory, are neglected. The part-load
behavior is expressed in terms of the nominal condition and the
dimensionless variation of the heat transfer with change of mass flow
and temperature.
LBL-42734
BEYOND BLAST AND DOE-2: ENERGYPLUS, A
NEW-GENERATION ENERGY SIMULATION PROGRAM
Abstract:
Many of the popular building energy simulation programs around
the world are reaching maturity -some use simulation methods
(and even code) that originated in the 1960s. For more than two
decades, the U.S. government supported development of two hourly
building energy simulation programs, BLAST and DOE-2. Designed
in the days of mainframe computers, expanding their capabilities
further has become difficult, time-consuming, and expensive. At
the same time, the 30 years have seen significant advances in
analysis and computational methods and power-providing an
opportunity for significant improvement in these tools.
In early 1996, a Federal agency began developing a new building
energy simulation tool, EnergyPlus, building on development
experience with DOE-2 and BLAST. EnergyPlus includes a number of
innovative simulation features-such as variable time steps,
built-in template and external modular systems that are
integrated with a heat balance-based zone simulation-and input
and output data structures tailored to facilitate third party
module and interface development. Other planned simulation
capabilities include multi-zone airflow, and electric power and
solar thermal and photovoltaic simulation. Beta testing of
EnergyPlus begins in mid 1999.
LBL-42241
VALIDATION STUDIES OF THE DOE-2 BUILDING ENERGY SIMULATION
PROGRAM -- FINAL REPORT
Abstract:
This report documents many of the validation studies of the
DOE-2 building energy analysis simulation program that have taken place
since 1981. Results for several versions of the program are presented
with the most recent study conducted in 1996 on Version 2.1E and the
most distant study conducted in 1981 on Version DOE-1.3. This work is
part of an effort related to continued development of DOE-2, particularly
its use as a simulation engine for new, specialized versions of the
program such as the recently released RESFEN-3.1.
RESFEN-3.1 is a program that specifically deals with analyzing the
energy performance of windows in residential buildings. The intent in
providing the results of these validation studies is to give potential
users of the program a high degree of confidence in the calculated results.
IMPROVING THE WEATHER INFORMATION AVAILABLE TO SIMULATION PROGRAMS
Abstract:
Developers
of building simulation tools have been continuously improving their
programs and adding new capabilities over the last thirty years. Time
steps of less than an hour are now common and even necessary to
properly simulate the complex interactions of building components and
systems. For example, some control issues, such as daylighting, require
much shorter time steps of minutes-more traditional hourly time steps
have been shown to introduce errors as large as 40% in illumination
calculations. Despite these increased capabilities, many simulation
programs are still using the same limited set of hourly
climatic/weather data they started with- temperature, humidity, wind
speed and cloud cover or solar radiation. This often forces users to
find or calculate missing weather data such as illuminance, solar
radiation, and ground temperature from other sources or developers to
calculate it within their program.
LBL-42175
RESIDENTIAL EQUIPMENT PART-LOAD CURVES FOR USE IN DOE-2
Abstract:
DOE-2 includes several correlation curves that predict the energy use of
systems under part load conditions. DOE-2 simulates systems on an
hour-by-hour basis, so the correlations are intended to predict part
load energy use (and efficiency) as a function of the part load ratio
(PLR) for each hour, where PLR = HourlyLoad/Available Capacity.
Generally residential and small commercial HVAC equipment meets the load
at off-design conditions by cycling on and off. Therefore, the part
load correlations must predict the degradation due to this on and off
operation over an hourly interval.