These reports may be ordered, free of charge, from the Simulation Research Group at
Lawrence Berkeley National Laboratory.
Kathy Ellington
MS: 90-3147
Lawrence Berkeley National Laboratory
Berkeley, CA 94720
USA
Fax: 510-486-4089
Email:
info@gundog.lbl.gov
EnergyPlus ENERGYPLUS: THE MERGER OF BLAST AND DOE-2
Abstract:
The Federal Government, as the largest owner and operator of buildings
in the United States, has long been aware of the importance of energy
conscious building design and operation. Energy conscious engineering
has the potential to save building owners and tenants millions of
dollars and contribute to the conservation of vital natural resources.
In an effort to promote energy efficiency, both DOD and DOE have
separately funded the development of building energy analysis tools
since the 1970s.
At the outset, both research efforts charted separate courses toward the same goal: a robust and comprehensive building energy analysis program. There was no way of knowing a priori which path would achieve the goal; therefore, it was prudent to fund multiple development efforts toward the same end. As it turned out, both research projects succeeded in producing useful energy analysis tools. The DOD effort produced the Building Loads Analysis and System Thermodynamics (BLAST) program that has its origins in the NBSLD program developed at the US National Bureau of Standards (now NIST). The DOE effort produced the DOE-2 program that has its origins in the Post Office program written for the US Post Office. The two programs are comprised of hundreds of subroutines each designed to solve a specific problem in achieving the overall goal. In some cases, the subroutines developed by the DOE-2 team were more accurate. In other cases, the subroutines developed by the BLAST team were more accurate.
The research initiative outlined in this paper describes the current efforts to consolidate the research and development gains of the last two decades. The name chosen for the new program is EnergyPlus. The goal is to take the best features and capabilities of BLAST and DOE-2 and combine them in a new program. Many new building technologies that cannot be evaluated by either BLAST or DOE-2 will be accessible with the new tool. In addition, a number of building simulation models that today can only be used by researchers will be included in the new program.
LBL-39098
-- TWO- AND THREE-DIMENSIONAL NATURAL AND MIXED CONVECTION SIMULATION
USING MODULAR ZONAL MODELS
Abstract:
We demonstrate the use of the zonal model approach, which is a
simplified method for
calculating natural and mixed convection in rooms. Zonal models use a
coarse grid and use balance equations, state equations, hydrostatic
pressure drop equations, and power law equations of the form m = C?n.
The advantages of the zonal approach and its modular implementation are
discussed. The zonal model resolution of nonlinear equation systems is
demonstrated for three cases: a 2-D room, a 3-D room, and a pair of 3-D
rooms separated by a partition with an opening. A sensitivity analysis
with respect to physical parameters and grid coarseness is presented.
Results are compared to computational fluid dynamics (CFD) calculations
and experimental data.
LBL-38505 --
DYNAMIC ANALYSIS OF MOISTURE AND COOLING LOADS IN WALLS IN THE HOT/HUMID
CLIMATE OF FLORIANOPOLIS, BRAZIL
Abstract:
We describe the use of a dynamic model of combined heat and mass
transfer to analyze the effects on cooling loads of transient moisture
storage and transport through walls with porous building materials,
under varying boundary conditions. The materials studied were brick,
lime mortar, and autoclaved cellular concrete. The physical properties
of these materials, such as mass transport coefficients, thermal
conductivity, and specific heat, were taken to be functions of moisture
content. The simulation results were compared to those obtained by pure
conduction heat transfer without moisture effects. Also analyzed were
the influence on cooling loads of high moisture content due to rain
soaking of materials and the influence of solar radiation on sunny and
cloudy days. The weather used was a hot/humid period in Florianopolis
(southern Brazil). It is shown that neglecting moisture migration, or
assuming that the physical properties of wall materials does not depend
on moisture content, can result in large errors in sensible and latent
heat transfer.
LBL-36281 --
NEW TOOLS FOR THE ANALYSIS AND DESIGN OF BUILDING ENVELOPES
Abstract:
We describe the integrated development of PowerDOE, a new version of
the DOE-2 building energy analysis program, and the Building Design
Advisor (BDA), a multimedia-based design tool that assists building
designers with the concurrent consideration of multiple design
solutions with respect to multiple design criteria.