E.W., *et al.*, *Simulations of IAQ and comfort in multizone buildings.*
Indoor Air 93, 1993: pp 533-538.Strategies for IAQ improvement often
impact building energy use. The optimum strategy for IAQ requires a
trade-off between improving IAQ and increasing energy use to attain it.
Modeling can be particularly effective in defining the optimal strategy
for a particular site. Modeling IAQ for building applications requires
at least 4 different modeling efforts: (1) human dose-response
relationship, (2) building pollutant load analysis, (3) operating cost
and (4) dynamic IAQ prediction. Effective design of control systems and
operating strategies in IAQ mitigation equipment requires dynamic
simulation of typical applications, including adsorption/desorption
effects for pollutant species. The coupling of energy analysis to IAQ
analysis shows the energy savings available from using heat recovery
combined with increased ventilation for the solution to IAQ problems.
Sample calculations show that ventilation rates must be high to limit
pollutant transport between zones. Ventilation must continue long after
an event to limit discomfort.

F., P. Depecker, and F. Allard, *Optibat: A real scale cell in simulated
climatic environment for multizone air flow pattern in building.* 13th
AIVC Conf., 1992: pp 519-527.One of the main problems about air flows
pattern studies remains the experimental validation of numerical codes
developed for interzone air flow and pollutant diffusion prediction. A
few years ago, CETHIL developed a real scale experiment made of a 88 m2
dwelling built in our laboratory hall in a controlled climatic
environment. This experimental tool allows a full control of outdoor
climatic conditions: air temperature, relative humidity, pressure drop
can be controlled on the six faces of the cell: OPTIBAT is thus a
reference tool for multizone air flow measurement techniques, and
experimental data sets available for validation of numerical models. The
first phase of this experimental project allowed us to determine air
leakage characteristics of indoor and outdoor walls of the cell. The
second element required for the validation of multizone air flow codes
is the knowledge of all the interzone air flows. The vast majority of
the air flow measurements made to date have involved multiple tracer gas
techniques. Using the OPTIBAT facility, we have first used only one
tracer gas to determine all the air flows. The present paper describes
the experimental cell and gives the first results about air flows
measurements using tracer gas technique. The interzone air flows are
computed using 2 methods. Each method is completed by an error analysis
which defines the uncertainty of each result. Both methods give the same
results.

*An Evaluation of the Effect of CO2-Based Demand-Controlled Ventilation
Strategies on Energy Use and Occupant-Source Contaminant
Concentrations*, . 1995, Enermodal Engineering Limited.This study
examines the effectiveness of using CO2-based DCV to provide adequate
IAQ with minimum energy use. A detailed building energy analysis program
ENERPASS was combined with CONTAM to perform the analysis. The combined
program was used to evaluate the annual heating and cooling energy
consumption and CO2 and formaldehyde concentrations. The assessment was
made on a mid-sized commercial building designed to comply with ASHRAE
90.1 for 4 climate zones (Chicago, Nashville, Phoenix, and Miami). 3
separate hvac systems were studied: single zone, multizone and VAV. The
simulations wer made for 5 ventilation control strategies: fixed
ventilation, building return air controlled to 1000 ppm and 800 ppm,
floor return air controlled to 1000 ppm and each zone controlled to 1000
ppm. For single zone systems, DCV offers superior performance to fixed
ventilation. At a CO2 setpoint of 1000 ppm, heating energy use is
reduced by approximately 30% and average office CO2 concentrations is
similar to a fixed ventilation system. At a setpoint of 800 ppm, heating
energy use is reduced by 20%, and average office CO2 levels are 50 to 90
ppm lower than with the fixed ventilation case. There is little impact
on cooling energy use with the addition of CO2 controlled ventilation.
CO2 control of ventilation air is recommended for single zone HVAC
systems especially for zones with variable occupance (e.g. meeting
rooms) in order to ensure better IAQ. Using CO2-based DCV with VAV
systems offers energy savings similar to those of the single zone
system. For multizone systems. the reduction in heating is similar in
absolute terms but, because of the larger heating load, is smaller in
percentage terms (5 to 12%). For both systems, the average CO2
concentraiton with a control setting of 1000 ppm is 70 to 150 ppm higher
than with the fixed ventilation case. Lowering the setting to 800 ppm
results in lower CO2 levels than the fixed ventilation case and keeps
the maximum concentrations below 1000 ppm for all zones. CO2 controlled
ventilation is recommended in multizone and VAV systems for most
climates to save heating energy. In warm climates, however, the heating
savings are small and probably do not justify a CO2 based system.
Providing additional sensors in the return duct of each floor had little
impact on energy use and IAQ. Installing sensors in each zone increases
energy use slightly and ensures that the concentration in each zone
stays below 1000 ppm. This would, of course, be a more expensive control
option. Central control set to 800 ppm offers similar performance to
sensors in each zone, but at a much lower installed cost. Demand
controlled ventilation did not control the concentration of formaldehyde
as well as the fixed ventilation case for any of the control strategies
studied. CO2 control of ventilation should include a morning purge cycle
where non-occupant generation of pollutants is of concern.ASHRAE paper
by Stephen Carpenter.

J.W., *Indoor Air Quality Modeling Phase II Report*, . 1987, National
Institute of Standards and Technology: Gaithersburg.This interim report
presents the results of Phase II of the NBS General Indoor Air Pollution
Concentration Model Project. It describes the theoretical basis of a
general-purpose nonreactive contaminant dispersal analysis model for
buildings, the computational implementation of a portion of this model
in the program CONTAM86, and examples of the application of this model
to practical problems of contaminant dispersal analysis. Presently the
model is being extended to handle problems of reactive contaminant
dispersal analysis and full computational implementation of all portions
of the model is being completed.

contaminant dispersal analysis model is based upon the idealization of
building airflow systems as an assemblage of flow elements connected to
discrete system nodes corresponding to well-mixed air zones within the
building and its HVAC system. Equations governing the airflow processes
in the building (e.g., infiltrations, exfiltration, HVAC system flow,
and zone-to-zone flow) and equations governing the contaminant dispersal
due to this flow, accounting for contaminant generation or removal, are
formulated by assembling element equations so that the fundamental
requirement of conservation of mass is satisfied in each zone. The
character and solution of the resulting equations is discussed and
steady and dynamic solution methods outlined.

J.W., *Progress Toward A General Analytical Method for Predicting Indoor
Air Pollution in Buildings - Indoor Air Quality Modeling Phase III
Report*, . 1988, National Institute of Standards and Technology:
Gaithersburg.

J.W. and R. Grot, *The Coupled Airflow and Thermal Analysis Problem in
Building Airflow System Simulation.* ASHRAE Transactions, 1989. Vol.
95.2: pp 621-628.The IAQ and V group at NIST has developed a method of
building airflow analysis, based upon element assembly techniques, that
has been successfully applied to the determination of the macroscopic
characteristics of infiltration, exfiltration, and interzonal airflows
in complex building airflow systems driven by wind pressures, buoyant
forces, and the building HVAC system. This analytical method was
formulated to be compatible with a discrete thermal analysis method,
also based on element assemblyn techniques and developed earlier, which
may be applied to problems of building thermal analysis. This paper will
review the theoretical bases of these two related methods and present a
theoretical framework to solve the coupled airflow and thermal analysis
problem in building airfl,ow system simulation. Formulation of the
coupled airflow-thermal analysis problem will be presented and numerical
methods for the solution of this problem will be outlined.

J.W., *Multi-zone dispersal analysis by element assembly.* Building and
Environment, 1989. Vol. 24(2): pp 113-130.general theoretical discussion
of multizone modeling which includes consideration of non well-mixed
zones (2 node convection diffusion element to model duct flow)

J.W., *Element Assembly Techniques and Indoor Air Quality Analysis.*
1990: pp 115-120.Element assembly techniques have been applied to
develop methods to model a) airborne contaminant dispersal, b) airflow,
and c) heaat transfer in complex multi-zone building systems.
Individually, these methods allow an integrated consideration of the
building envelope, construction, and mechanical system interaction, are
computationally non-demanding, and can be employed to model whole
building systems of arbitrary complexity. As a group, these methods are,
in principle, computationally compatible and are presently being
integrated to provide comprehensive IAQ analysis capabilities. This
paper will present an outline of the theory underlying these methods and
describe the US NIST families of programs that implement them.

J.W., *Adsorption Modeling for Macroscopic Contaminant Disperal
Analysis.* 1990.Two families of macroscopic adsorption models are
formulated, based on fundamental principles of adsorption sciene and
technology, that may be used for macroscopic contaminant dispersal
analysis. The first family of adsorption models - the Equilibrium
Adsorption Models - are based upon the simple requirement of equilibrium
between adsorbent and room air. The second family - the Boundary Layer
Diffusion Controlled Adsorption Models - add to the equilibrium
requirement a boundary layer for diffusion of the adsorbate from the
room air to the adsorbent surface. Two members of each of these families
are explicityly discussed, one based on the linear adsorption isotherm
model and the other on the Langmuir model. The linear variants of each
family are applied to model the adsorption dynamics of formaldehyde in
gypsum wallboard and compared to measured data.; N;

J.W. and D. Lorenzetti, *Sorption Transport Models for Indoor Air
Quality Analysis.* ASTM STP 1205, 1992.Sorption filtration is presently
being investigated as one means to control the quality of air in
buildings, yet methods to integrate models of sorption filtration
devices with multizone indoor air quality procedures - to enable
rational design of these devices - have not appeared. This paper reviews
the theoretical bases of sorption models recently developed for
multizone contaminant dispersal analysis and presents new work to extend
these models to the problem of sorption filtration modeling. Four
generic families of models are presented that account for (a) the
equilibrium limits of reversible sorption processes with or without (b)
boundary layer diffusion transport at the adsorbent surface and (c)
diffusion transport within the adsorbent proper, and, for filtration
devices, (d) convection-diffusion transport within the filtration
medium. All models are formulated as mass transport elements that may be
directly assembled with existing elements to model contaminant dispersal
in multizone building/HVAC systems of arbitrary complexity. A comparison
of the model families is made, criteria are presented to aide in the
selection of the model family to use, and results of first applications
of these models are presented that provide some validation of the
theory.

J.W. *Macroscopic formulation and solution of ventilation design
problems*. in *18th AIVC Conference*. 1997.

J.W., *Passive Ventilation for Residential Air Quality Control.* ASHRAE
Transactions, 1999. Vol. 105(2).Discussion of passive ventilation
systems, components, operation, and design. Presentation of design
methodology utilizing loop equations. Theoretical background is provided
along with simple example of design method.

J.W. *Design and Simulation of Natural Ventilation Systems Using Loop
Equations*. in *Healthy Buildings 2000*. 2000. Espoo, Findland.

M.R. *Passive Ventilators in New Zealand Homes: Part 1 Numerical Studies
and Part 2 Experimental Trials*. in *15th AIVC Conference - The Role of
Ventilation*. 1994. Buxton, Great Britain: AIVC.This paper is part one
of a study of passive ventilation options for NZ homes. It explores
numerically a range of ventilator sizes and locations in typocal homes
modelled in the climate of major New Zealand cities. Part two offers
experimental verification of the ventilator performance data calculated
here. A numerical multizone airflow model was used to calculate the
effect of adding stack and window type passive vents to huses of a range
of airtightness levels. Wind pressure was found to be the dominant
driving force of airflows delivered by window-mounted passive
ventilators. Stack ventilators reduced the strong dependence of window
ventilator airflows on wind speed when both types were preesent in a
building, but when the ventilation system made small changes to the
overall airtightness of the house, the role of the stack ventilator was
less obvious. A simple linear function linking ventilator opening area
with average added ventilation rates is presented for wall-mounted
passive ventilator systems in NZ buildings.

P. *Prediction of the concentration decay in a ventilated enclosure by
the multizone model*. in *Roomvent 94*. 1994.

A., *Ventilation and Airtightness in Energy Balance.* 10th AIVC Conf.,
1989: pp 305-324.The air exfiltration part of ventilation is often
difficult to determine and its part of the energy balance is therefore
usually determined as a remainder or given a constant value. This paper
examines ventilation systems in six different modern houses. The
constant concentration tracer gas technique tended to underestimate the
total ventilation. A simplified theoretical one-zone model made accurate
estimations of the air exfiltration. For detailed information on air
flows a multi-zone network model was useful. Different levels of
airtightness should be required depending upon the ventilation system.
It is recommended to couple predictions with tracer gas measurements.
Determining the energy balance, eg, using a constant air change rate for
the mechanical and/or natural ventilation is in most cases inaccurate,
unless the house is very tight.

A., *Ventilation Control within Exhaust Fan Ventilated Houses.* 12th
AIVC Conf., 1991: pp 285-305.Modern one-family houses in Scandinavia are
often ventilated by an exhaust fan. Most of the outdoor air probably
enters through whatever cracks and openings there are and only a small
part enters through the supply vents in many of these houses. The
overall supply of outdoor air might be adequate, but some rooms often do
not get enough of outdoor air. The constant concentration tracer gas
technique was used to examine the supply of outdoor air. Fan
pressurization combined with infrared photography were employed to
characterize the air leakage of the building. A multizone network model
was used to further e aluate the measurements. A reasonable level of
outdoor air, upstairs in an airtight two-storey house, can be ensured by
locating the supply venta upstairs close to the floor. If that is not
possible additional exhaust vents can be installed. If more that 3/4 of
the outdoor air is to enter throught the supply vents, then the
airtightness should be better than 1.0 ach at 50 Pa. The performance of
an exhaust fan system is very much dependent upon the overall
airtightness (including open supply vents) and the distribution of the
airtightness of the building.

A. and M. Wall, *The energy impact of ventilation and air infiltration
in an atrium.* 14th AIVC Conf., 1993. Vol. 1.Many modern office and
residential buildings in Sweden include an atrium. The atria are often
mechanically ventilated and sometimes they are heated. Very little is
known about the ventilation and air infiltration in built atria. These
issues were examined in an apartment building with a nonheated and
mechanically ventilated atrium, built in 1986 in Sweden. The ventilation
of the atrium is coupled to the apartments. The pper examines the
ventilation, air infiltration, airtightness and the energy impact of an
atrium. Fan pressurization was employed to characterize the air leakage
of the atrium and the apartments. The energy use and temperatures in the
atrium and in the apartments were monitored continuously for a year. A
multizone network model was used to further evaluate the ventilation and
the air infiltration. The energy balance was estimated using a dynamic
simulation model. The roof of the tested atrium is very leaky and
therefore the exfiltration is large. The energy use for space heating of
the tested apartments can be reduced if the atrium and the apartments
are made tighter. The knowledge concerning the real airtightness and
ventilation of atria and surrounding buidings is insufficient. There are
also many ideas as to how to ventilate an atrium.

R., M. Cali, and M. Torchio, *Experimental Evaluation of COMIS Results
for Ventilation of a Detached House.* 1995.The comparation of the
measured air flow in a detached house built by ITALGAS with the results
of a simulation model are given in this paper. The detached house has
been built mainly for experimental purposes and therefore allows very
detailed measurements of the internal and outside microclimate (e.g.
wind velocity, air temperature, humidity, etc.). Furthermore, the air
permeability of the house has been characterised by means of the
pressurisation technique. The ventilation measurements have been carried
out using the tracer gas technique (decay method with 2 gases: SF6 and
N2O). A mobile, multizone, multitracer apparatus designed and built at
the Dipartimento di Energetica of the Politecnico di Torino has been
used. The measured data has been analysed using an inverse problem
technique in order to calculate the time histories of the air flow rates
during the measurement period and their uncertainties. The building
envelope air leakage coefficients and the meteorological data has been
used in COMIS to obtain the simulated air flow rates. The comparison
with the measured airflow allows one to define the application limits of
the here studied model.; ;

K.-C., *The evaluation of total IAQ in a multizone model of a building.*
Indoor Built Environment, 1996. Vol. 5: pp 291-302.

J.A. and J. Hensen, *An Approach to the Simulation of Coupled Heat and
Mass Flows in Buildings.* Proceedings of the 11th AIVC Conference, 1990.
Vol. 1.This paper describes the techniques used within the ESP system to
represent and solve the heat and mass conservation equations relating to
combined building and plant systems. In particular, it describes the
equation-sets used to represent inter-zonal (building) and
inter-component(plant) fluid flow and the method used for the
integration of the nonlinear heat and mass flow equations. By means of a
case study, the application in a real design context is demonstrated.

J.A., W.M. Dempster, and C. Negrao, *The implementation of a CFD
algorithm within the ESP-r system.* Building Simulation 95, 1995. Vol.
x: pp 166-175.This paper describes the implementation of a cfd algorithm
within the ESP-r building energy modeling system. While the
implementation is specific to ESP-r, the conflation approach is general
anc could be applied to other building performance appraisal programs.
The paper also presents an example application to indicate the potential
effects of the enhanced modelling resolution and some of the new issues
to emerge.

J.A., J.L.M. Hensen, and C.O.R. Negrao, *Predicting indoor air flow by
combining network approach, CFD and thermal simulation.* 16th AIVC
Conf., 1995. Vol. x: pp 145-174.This paper describes a method which aims
to generatean overall view of multizone building air flow by integrating
methods for bulk air flow analysis, air flow field analysis, and thermal
analysis. This has been achieved by implementing a CFD approach within
the ESP-r buiding energy simulation environment which already
incorporated a nodal air flow network approach. The current state of the
method is demonstrated by a case study. The main conclusion form this is
that the integrated method is very promising . Other preliminary
conclusions concern the difficulty of finding suitable boundary
conditions and numerical values for input parameters.

D., *et al.*, *An Indoor Air Quality Prediction Model.* Indoor Air 90,
1990. Vol. 4: pp 165-170.The analysis, use and validation of a model has
been briefly presented here, it has a broad scope since it covers
different professions (engineers, doctors) and skills. Modelling should
afford a better analysis and understanding of the findings of the
socio-cultural analysis (simulation using representative cases).
Parametrical simulation studies will allow cost specifications to be
proposed with respect to services and equipment meeting the desired
health an safety criteria.

Gids, W.F. and J.C. Phaff, *Recirculation of Air in Dwellings.* 9th AIVC
Conf., 1988: pp 301-310.The Dutch Std NEN 1087 \"Ventilation of
dwellings\". Requirements, is at this moment under review. A statement
is made that outside air is required as fresh air for bedrooms.
Bathroom, kitchen, W.C. and living room are allowed to be ventilated
with air from other rooms. During the last years air heating systems
became more popular. These systems have n its most simple form
recirculation of air from the LR the the bedrooms. The requirement of
frest outside air for bedrooms can only be reached with these systems
when selective recirculation takes place. During the reviewing process
of the std, TNO has carried out some studies to investigate the
differences in concentrations of contaminants in dwellings due to
different ventialtion and heating systems. Measurements and calculations
have been made in a lot of conditions to reconsider the requirement of
pure outside air for bedrooms. In this investigation the following
aspects were studied;,

W.S., G.N. Walton, and K. Denton, *CONTAMW 1.0 User Manual*, . 2000,
National Institute of Standards and Technology: Gaithersburg.This manual
describes the computer program CONTAMW developed by NIST. CONTAMW is a
multizone indoor air quality and ventilation analysis program designed
to help you determine: *airflows *- infiltration, exfiltration, and
room-to-room airflows in building systems driven by mechanical means,
wind pressures acting on the exterior of the building, and buoyancy
effects induced by temperature differences between the building and the
outside; *contaminant concentrations *- the dispersal of airborne
contaminants transported by these airflows and transformed by a variety
of processes including chemical and radio-chemical transformation,
adsorption and desorption to building materials, filtration, and
deposition to building surfaces; and/or *personal exposure *- the
prediction of exposure of building occupants to airborne contaminants
for eventual risk assessment.can be useful in a variety of applications.
Its ability to calculate building airflows is useful for assessing the
adequacy of ventilation rates in a building, to determine the variation
in ventilation rates over time, to determine the distribution of
ventilation air within a building, and to estimate the impact of
envelope air-tightening efforts on infiltration rates. The prediction of
contaminant concentrations can be used to determine the indoor air
quality performance of buildings before they are constructed and
occupied, to investigate the impacts of various design decisions related
to ventilation system design and building material selection, to
evaluate indoor air quality control technologies, and to assess the
indoor air quality performance of existing buildings. Predicted
contaminant concentrations can also be used to estimate personal
exposure based on occupancy patterns.

V., *et al.*, *Evaluation of COMERL with the LESO Dataset*, . 1992,
EMPA.

V. and J.-M. Furbringer. *Comparison of multizone air flow measurements
and simulations of the LESO building including sensitivity analysis*. in
*14th AIVC Conference*. 1993.

V. and A. Weber, *Simulation of Passive Cooling and Natural Facade
Driven Ventilation.* 15th AIVC Conf., 1994.IN many design cases, energy
as well as ocupant comfort are the relevant ccriteria which are studied
using computer simulation programs. Comfort evaluations cover air
quality, thermal, visual and acoustical domfort. For all these
individual aspects, specific simulation programs are available today,
but very few programs allow for the integrated evaluation of several or
all relevant parameters. The more, heat transport, ventilation as well
as lighting are physically coupled and therefore must be integrally
modelled in the simulation process. This paper gives a short description
of the concept used for the coupling of the air flow simulation code
COMVEN with the building and systems simulation code TRNSYS. Then, 2
application examples typical for a building design study situation are
presented. The first example shows a multi-story biulding which is
passively cooled at night-time due to natural stack airflow. The
influence of the operation of the openings on the maximum room
temperatures is discussed for a hot summer period case. The facade of
the ubilding of example 1 shall be retrofitted with a glazed outer
facade. In example 2, the natural ventilation of this building is
studied. Ventilation is provided by naturally driven shaft ventilatoin
through the facade spaces. Control strategies for the openings and the
blinds are discussed in respect to overheating risk and minimum air flow
rates.

R. and C. Irwin, *An overview of methodologies for the assessment of the
performance of domestic ventilaton systems.* 15th AIVC Conf., 1994. Vol.
1.As levels of thermal insulation used in dwellings increase, so the
significance of the choice of ventilation strategy increases, in terms
of range of factors such as energy consumption, pollutant control, and
running and maintenance costs. It is generally desirable to be able to
make use of computer based performance assessment tools. This paper
briefly discusses the key dwelling performance factors which are
influenced by choice of ventilaton strategy, and compares a cross
section of assessment tools with differing capabilities. It is found
that the degree of integration of performance factor assessment is poor,
particularly with regard to financial implications.

S.J., A.K. Persily, and D.A. VanBronkhorst, *A Workplan to Analyze the
Energy Impacts of Envelope Airtightness in Office Buildings*, . 1995,
National Institute of Standards and Technology.The purpose of this study
was to estimate the energy use in commercial buildings due to
infiltration and ventilation airflows and to investigate the potential
for energy savings that could be realized by envelope tightening
efforts. A set of 25 buildings was used as a representative sample of
the U.S. commercial building stock as of 1995. Buildings were located in
cities throughout the U.S. so that a representative sample of climates
was also taken into account. Leakage characteristics were assigned to
each building based on limited envelope leakage data that exist for U.S.
office buildings.

S.J. and A.K. Persily, *Multizone Modeling of Three Residential Indoor
Air Quality Control Options*, . 1996, National Institute of Standards
and Technology.The National Institute of Standards and Technology (NIST)
performed a preliminary study of the use of central forced-air heating
and cooling system modifications to control indoor air quality (IAQ) in
residential buildings. The objective of this effort was to provide
insight into the use of state-of-the-art multizone airflow and IAQ
models to evaluate such modifications, the potential of these
modifications to mitigate residential IAQ problems, the pollutant
sources they are most likely to impact, and their potential limitations.
This study was not intended to determine definitively whether the IAQ
control options studied are reliable and cost-effective. Another
important objective of the project was to identify issues related to the
use of multizone IAQ models and to identify areas for follow-up work.

report summarizes the three phases of this effort, each of which
consisted of three main tasks. The Phase I tasks included conducting a
literature review, developing a plan for computer analysis, and holding
a workshop to discuss the plan. The Phase II.A tasks included baseline
simulations of contaminant levels without indoor air quality (IAQ)
controls, design of the IAQ control retrofits, and preliminary
simulations of contaminant levels with the IAQ control retrofits. The
Phase II.B tasks included computer simulations of contaminant levels
with IAQ control retrofits, evaluation of the effectiveness of the IAQ
control retrofits, and development of recommendations for future
research. This report is a consolidation of the three previous reports
on the project: Emmerich and Persily 1994 on Phase I, Emmerich and
Persily 1995a on Phase II.A, and Emmerich and Persily 1995b on Phase
II.B.

multizone airflow and pollutant transport program CONTAM93 was used to
simulate the pollutant concentrations due to a variety of sources in
eight buildings with typical HVAC systems under different weather
conditions. Three indoor air quality control technologies were into the
house models to determine their effectiveness in controlling the modeled
pollutant sources. The technologies include the following: electrostatic
particulate filtration, heat recovery ventilation, and an outdoor air
intake damper on the forced-air system return.

results indicate that the system modifications reduced pollutant
concentrations in the houses for some cases. However, the heat recovery
ventilator and outdoor air intake damper increased pollutant
concentrations in certain situations involving a combination of weak
indoor sources, high outdoor concentrations, and indoor pollutant
removal mechanisms. In cases where the IAQ controls reduced pollutant
concentrations, they led to larger relative reductions in the tight
houses than in the houses with typical levels of airtightness, though
the typical houses still had lower post-control concentrations. The
controls had the largest impact on concentrations of a non-decaying
pollutant from a constant source. Limited system run-time under mild
weather was identified as a limitation of IAQ controls that operate in
conjunction with forced-air systems.

S.J. and A.K. Persily. *Energy Impacts of Infiltration and Ventilation
in U.S. Office Buildings Using Multizone Airflow Simulation*. in *IAQ
and Energy 98*. 1998. New Orleans, Louisiana: ASHRAE.

S.J. and S.J. Nabinger, *Measurement and Simulation of the IAQ Impact of
Particle Air Cleaners in a Single-Zone Building*, . 2000, National
Institute of Standards and Technology.This report describes the initial
phase of an effort to evaluate the ability of multizone airflow and
pollutant transport models to predict the impact of residential IAQ
control technologies. Measurements of the performance of several
particulate air cleaning devices and related particle transport
parameters were performed in a one-room test house. These measurements
were used to calculate building air change rates, particle deposition
rates and penetration factors, and air cleaner removal efficiencies. Two
separate 24 h tests were performed with two of the tested air cleaners,
and the measured air change rates and particle concentrations were
compared to predicted values obtained with the CONTAM model. For both
tests, simulated 24 h average air change rates were within 5 % of
measured air change rates and simulated 24 h average particle
concentrations were within 30 % of measurements for all particle sizes.
Simulations were also performed to predict the impact of the air
cleaners compared to a typical furnace filter.

J.B. and A.K. Persily, *Airflow and Radon Transport Modeling in Four
Large Buildings.* ASHRAE Transactions, 1995. Vol. 101(1).Computer
simulations of multizone airflow and contaminant transport were
performed in four large buildings using the program CONTAM88. This paper
describes the physical characteristics of the buildings and their
idealizations as multizone building airflow systems. These buildings
include a 12-story multifamily residential building, a 5-story
mechanically ventilated office building with an atrium, a 7-story
mechanically ventilated office building with an underground parking
garage, and a one-story school building. The air change rates and
interzonal airflows of these buildings are predicted for a range of wind
speeds, indoor-outdoor temperature differences, and percentages of
outdoor air intake in the supply air. Simulations of radon transport
were also performed in the buildings to investigate the effects of
indoor-outdoor temperature difference and wind speed on indoor radon
concentrations.

J.B. and A.K. Persily, *Computer Simulations of Airflow and Radon
Transport in Four Large Buildings*, . 1995, National Institute of
Standards and Technology.Computer simulations of airflow and radon
transport in four large buildings were performed using CONTAM. The
buildings modeled included a twelve-story multi-family residential
building, a five-story mechanically-ventilated office building with an
atrium, a seven-story mechanically-ventilated office building with an
underground parking garage, and a one-story mechanically-ventilated
school building. Interzone airflow rates and radon concentrations were
predicted in these buildings as a function of wind speed and direction,
indoor-outdoor temperature difference, and ventilation system operation.
Ventilation system factors that were studied included the operation of
exhaust fans in the apartment building and variations in the percent
outdoor air intake in the office buildings. Simulations in the office
buildings were also made with the ventilation systems off and with
variations in the balance of the supply and return airflow rates.

F., *Air distribution and contaminant mobility modeling throughout
commercial passenger aircraft.* 1996.

M.J. *Analysis of Smoke Control System Design Using a Computer-based
Airflow Analysis*. in *Pacific Rim Conference and Second International
Conference on Performance-Based Codes and Fire Safety Design Methods*.
1998. Maui, Hawaii.

H.E., *Mathematical Modelling of Infiltration and Ventilation.* 10th
AIVC Conf., 1989: pp 157-179.It is particularly important to be aware of
the ir flow pattern in a building when determining indoor air quality
problems or calculating space conditioning loads for energy consumption.
Correct sizing of space conditioning equipment is also dependent upon
accurate air flow information. A number of infiltration models have been
developed to calculate infiltration-related energy losses and the
resulting air flow distribution in both, single-zone and multi-zone
buildings. International infiltration research has been conducted since
the early twenties - infiltration modeling, however, is a relatively new
task. Most of the modeling effort has taken place during the last 15
years. This paper gives an overview of the development of infiltration
models.

H.E., *et al.*, *The COMIS Infiltration Model.* 10th AIVC Conf., 1989:
pp 233-251.The COMIS workshop, using a multi-national, is planning to
develop a reliable, smooth running multizone infiltration model on a
modular base. This model not only takes crack flow into account but also
covers flow through large openings, single-sided ventilation, cross
ventilation and HVAC systems. The model contains a large number of
modules which are peripheral to a steering program. COMIS can also be
used as a basis for future expansion in order to increase the ability to
simulate buildings. Small task groups were formed to work on particular
problems in developing the modules. Each COMIS team member works on
several task groups.

H.E., *The COMIS Air Flow Model a Tool for Multizone Applications.*
Indoor Air 90, 1990. Vol. 4.It is particularly important to be aware of
the air flow pattern in a building when determining IAQ problems or
calculating space conditioning loads for energy consumption. A number of
infiltratin models have been developed to calculate infiltration-related
energy losses and the resulting air flow distribution in both,
single-zone and multizone buildings. The COMIS workshop, using a
multi-national team, developed a multizone infiltration model on a
modular basis. This model not only takes crack flow into account but
also covers flow through large openings, single-sided ventilation, cross
ventilation and HVAC systems. COMIS can also be used as a basis for
future expansion in order to increase the ability to simulate buildings.
This paper gives an overview of the workshop and the developed model.

H.E. and J. Dieris, *A Survey of Air Flow Models for Multizone
Structures.* 1991.Air flow models are used to simulate the rates of inc
oming and outgoing air flows for a building with known leakage under
given weather and shielding conditions. Additional information about the
flow paths and air-mass flows inside the building can only be made by
using multizone air flow models, a literature review was performed in
1984. A second literature review and a questionnaire survey performed in
1989, revealed the existence of 50 multizone air flow models, all
developed since 1966, two of which are still under development. All
these programs use similar flow equations for crack flow, but differ in
the versatility to describ4e the full range of flow phenomena and the
algorithm provided for solving the set of nonlinear equations. This
literature review has found that newer models are able to describe and
simulate the ventilation systems and interrelation of mechanical and
natural ventilation.; ;

A.J., W.J. Batty, and S.D. Probert, *A Multizone model to facilitate
predicting natural ventilation through buildings.* 12th AIVC Conf.,
1991. Vol. 1: pp 139-159.A mathematical model ahs been developed which
will facilitate the prediction of infiltration rates withing multizone
buildings. The aim was to cater for: (i) significantly different
temperatures in different parts of the building; (ii) flow paths at any
height, including vertical connections between zones; and (iii) flow
paths extending over large vertical distances. These aims led to the
requirement in the associated computer program that the variation of
pressure with height be accounted for independently within each zone of
the building. In order to achieve these aims, the flows between zones
were modelled by considering pressure differences and flow resistances.
The neutral pressure level approach was found to introduce unnecessary
complications. If the pressure in each zone varies with height, and at a
rate which depends ohn the zone temperature, it is necessary to
determine the pressure in each zone at a reference height. The floor
level of each zone was chosen as the reference height. The total
building pressures are solved simultaneously to give these reference
pressures. Predictions obtained from the developed computer program have
been compared with analytical solutions for simple systems as well as
experimental data.

R.D. and R.A. Cudnik, *The House-II Computer Model for Dynamic and
Seasonal Performance Simulation of Central Forced-air Systems in
Multi-zone Residences.* ASHRAE Transactions, 1993. Vol. 99, Pt 1.This is
the first of a series of papers on the HOUSE-II computer model developed
in Phase IV of ASHRAE SP 43 for dynamic and seasonal performance
simulation of a central forced-air space conditioning system in a
multizone residence. This paper reviews our prior work with the
single-zone model, discusses the need for a multi-zone version of the
model, describes the conversion to multi-zone capability, and describes
modeling capability and the present status of the HOUSE-II multi-zone
model.

J.M. and R. Borchiellini, *Technique of Sensitivity Analysis Applied to
an air Infiltration Multizone Model.* ASHRAE Transactions, 1993. Vol. 99
Pt 2.This paper presents the results of simulations of test houses using
a nodal simulation infiltration code. The two detached houses are 3
level family houses consisting of a basement where technical rooms and
instruments are placed; the first floor, which is the test level; and a
loft. The paper also presents the fractional factorial experimental
design used to estimate parameter and interactive effect coefficients;
by varying input parameters, such as airtightness and wind speed, for
example, it is possible to make obvious which are the critical
parameters and what level of confidence is required for input parameters
to guarantee a given confidence in the output. The capability of the
sensitivity analysis and the mean age-of-air to serve as tools for air
quality evaluation is discussed. Comments on parameter interaction, as
well as recommendations for a more general sensitivity study including
several types of buildings, are also provided.

J.-M., *et al.* *Air flow simulation of the LESO building including a
comparison with measurements and a sensitivity analysis*. in *Indoor Air
93*. 1993.

J.-M. *Comaprison of the accuracy of detailed and simple model of air
infiltration*. in *15th AIVC Conference*. 1994.

E.J., *et al.*, *Modeling Indoor Air Concentrations Near Emission
Sources in Imperfectly Mixed Rooms.* Eng. Sol. to IAQ Prob.,
1995.Assessments of exposure to indoor air pollutants usually employ
well-mixed models which assume homogeneous concentrations throughout a
building or room. However, practical experience and experimental data
indicate that concentrations are not uniform in rooms containing point
sources of emissions; concentrations tend to be greater inclose
proximity to the source than they are further from it. This phenomenon
could account for the observation that personal air monitors frequently
yield higher concentrations than nearby microenvironmental monitors. In
this project, we systematically studied the concentraitons of a tracer
gas at various distances from its emission source in a
controlled-environment room-size chamber, under a variety of ventilation
conditions. Measured concentrations in the proximity of the source
deviated significantly above the predictions of a conventional
well-mixed single-compartment mass balance model. The deviation was
found to be a function of distance from the source and ventilation rate.
At typical room ventilation rates, the average concentraiton at arm\'s
length (\~0.4m) from the source exceeds theoretical by a ratio of about
2:1. However, this ratio is not constant; the monitored concentraiton
appears to randomly vary from near the theoretical value to several
times above it. Concentration data were fitted to a two-compartment
model with the source located in a small virtual compartment within the
room compartment. These two compartments are linked with a stochastic
air transfer rate parameter. The resulting model provides a more
realistic simulation of exposure concentrations than does the well-mixed
model for assessment of exposure to emissions from active sources.
Parameter values are presented for using the enhanced model in a variety
of typical situations.

T. and J. Spengler, *Relationship between ventilation and indoor air
quality: a review.* indoor air, 1996. Vol. 6: pp 135-145.

D.T., *et al.* *Radon entry into large buildings and energy
conservation*. in *Indoor Air 96*. 1996.

M., D. Marino, and E. Parisi. *A wind pressure distribution calculation
program for multizone airflow models*. in *Building Simulation \'95*.
1995. Madison, WI: International Building Performance Simulation
Association\...order to obtain a more detailed evaluation, taking the Cp
distribution on the envelope of buildings into account, a numerical
model (CPCALC+) based on a parametrical analysis of wind tunnel test
results was developed at LBL for the COMIS multizone airflow calculation
program and upgraded with the CEC-DGXII PASCOOL program. CPCALC+
calculates Cp values at any position of a surface element on the
envelope of a rectangular shaped building with flat or tilted roof for
given conditions of terrain roughness, density of surrounding buildings,
shape ratios,m and wind direction. This paper describe3s the
parametrical approach used to analyse the reference Cp data as well as
the algorithms included in the calculation model. The variation of Cp
with respect to reference boundary condition was analysed in relation to
several parameters: wind velocity profile exponent, plan area aspect
ratios, wind incidence angle, roof tilt angle, facade element
positioning co-=ordinates. Some of the relevant cuve-fitting function
are shown. A flowchart of the program is also presented.

R.A. and J.A. Axley, *Structure of Models for the prediction of air flow
and contaminant dispersal in buildings.* Proceedings of the 11th AIVC
Conference, 1990: pp 223-266.This paper treats the structure of models
for predicting interzonal airflow and contaminant dispersal in
buildings. It will discuss the mathematical structure of such models,
the use of modern data structures, the application of structured program
techniques and the use of object-oriented structures for the development
of user interfaces and building description processes. Two computer
models developed at NIST will be used as examples of how these
techniques can be applied to air flow analysis and contaminant
dispersal: NBSAVIS - a building description processor for multizone
buildings, and CONTAM88 - an interzonal airflow and contaminant disperal
analysis program. NBSAVIS treats the building as a collection of
physical objects which have flow and leakage characteristics and creates
a building idealization (flow paths, zones and contaminant source data)
from the physical description building. It will be demonstrated that
with the proper data structure, general interfaces which are both
user-friendly and physically correct can be developed. CONTAM88 combines
previously developed interzonal airflow and contaminant dispersal
analysis programs AIRMOV, CONTAM86, AND CONTAM87 into one model which
includes such features as contaminant reactions, pressure induced
contaminant sources for modeling radon entry and plateout and
disposition of contaminants onto surfaces. An example is presented on
the use of these programs for airflow and contaminant dispersal analysis
in a large apartment building.

F. and J. Rao, *Computer-aided building ventilation system design - a
system-theoretic approach.* Energy and Buildings, 1991. Vol. 17: pp
147-155.An understanding of the pattern of airflow is an important
element in the design of ventilation systems. The airflows are caused by
wind effect, stack effect and mechanical ventilation systems. Several
models have been developed to analyse the airflow in buildings. So far,
the focus has been on the modelling process. In this paper, the
modelling and analysis of building ventilation sytems using a
system-theoretic procedure are presented. The emphasis is on presenting
a theoretic derivation of nodal-governing equations for building airflow
systems and obtaining efficient procedures for automatic formulation of
the system equations. This approach is based on matrix algebra,
therefore is easy to implement on a computer.

F. and A. Megri, *A comprehensive validation of two airflow models -
COMIS and CONTAM.* Indoor Air, 1996. Vol. 6: pp 278-288.

T. and K. Cooper, *The potential for residential demand controlled
ventilation.* 12th AIVC Conf., 1991: pp 235-243.

J. and M.-L. Pallari. *Improvement of Domestic Ventilation Systems*. in
*15th AIVC Conference - The Role of Ventilation*. 1994. Buxton, Great
Britain: AIVC.The aim of the study was to identify methods for the
renovation of ventilation systems in domestic buildings which are 3 - 8
eight storeys high. Three typical buildings were selected and the
problems in ventilation were examined. The designers made their
proposals for repairs and the research team analyzed the solutions and
made improvements. The special problems compared with new buildings
included less aritight building envelopes and leakages in existing
ventilation ducts.analysis was performed, using a multi-zone airflow
model, for the whole year and therefore the ventilation heat loss could
be found in each case. As anticipated, the airflow rate of passive stack
ventilation was too high in winter an too low in summer, bu the system
can be improved with demand-controlled ventilation instead of time
control. The installation of heat recovery sytem requires improved
sealing of the building envelope to minimuze cross ventilation. The
proposed systems will be tested and followed up later in experimental
buildings.

P., *Concentration distribution in the centre plane of a ventilated room
under isothermal conditions.* Indoor Air, 1993. Vol. 3: pp 34-40.This
paper presents a series of full-scale measurements of the concentration
distribution in the centre plane of a room with isothermal mixing
ventilation.profiles of the concentration in the middle of the room have
been measured under different conditions. With the contamination source
in the middle of the room the vertical profiles were changed radically
with an increase of the air change rate from n=1.5h-1 to n=6h-1 due to a
change in the flow structure in the room. With a constant air change
rate, the location of the contamination source in the room showed a
great influence on the vertical profile. A high velocity around the
contamination source resulted in a uniform contaninant distribution in
the room, while a low velocity resulted in considerable differences.of
concentraiton in the centre plane of the room have been measured using
different contaminant densities. The densities were low, neutral and
high in relation to the density of air. The results showed that the
contaminant distribution in the room with the chosen flow conditions
depended strongly on the contaminant desntiy, and that the high density
case gave the highest concentraitons in the occupied zone.has journal.

J.L.M., *On the thermal interaction of building structure and heating
and ventilating system.* 1991.In this dissertation, developments in the
field of building performance evaluation tools are described. The
subject of these tools is the thermal interaction of building structure
and heating and ventilating system. The employed technique is computer
simulation of the integrated, dynamic system comprising the occupants,
the building and its heating and ventilating system. With respect to
buildings and the HVAC systems which service them, the practical
objective is ensuring thermal comfort while using an optimum amount of
fuel. While defining the optimum had to be left for other workers, the
issue of thermal comfort is addressed here. The conventional theory of
thermal comfort in conditions characteristic for dwellings and offices
assumes steady-state conditions. Yet thermal conditions in buildings are
seldom steady, due to the thermal interaction between building
structure, climate, occupancy, and auxilliary systems. A literature
review is presented regarding work on thermal comfort, specifically
undertaken to examine what fluctuations in indoor climate may be
acceptable. Form the results, assessment criteria are defined. Although
its potentials reach beyond the area of Computer Aided Building Design,
a description is given of biulding and plant energy simulation within
the context of the CABD field of technology. Following an account of the
present state-of-the-art, the choice for starting from an existing
energy simulation environment (ESPr) is justified. The main development
areas of this software platform - within the present context - are
identified as: fluid flow simulation, plant simulation, and their
integration with the building side of the overall problem domain. In the
field of fluid flow simulation, a fluid flow network simulation module
is described. The module is based on the mass balance approach, and may
be operated either in stand-alone mode of from within the integrated
buiding and plant energy simulation system. The program is capable of
predicting pressures and mass flows in a user-defined building / plant
network comprising nodes (i.e. buiding zones, plant components, etc.)
and connections (i.e. air leakages, fans, pipes, ducts) when subjected
to lfow control (eg thermostatic valves) and/or to transient boundary
conditions (eg due to wind). The modelling and simulation techniques
employed to predict the dynamic behaviour of the HVAC system, are
elaborated. The simultaneous approach of the plant and its associated
control is described. The present work involved extensions to the ESPr
energy simulation environment with respect to robustness of the program,
and with respect to additional plant simulation features, supported
plant component models and control features. The coupling of fluid flow,
plant side energy and mass, and buiding side energy simulation into one
integrated program is described. It is this \"modular-simulatneous\"
technique for the simulation of combined heat and fluid flow in a
building/plant context, which enables an integral approach of the
thermal interaction of building structure and hvac system. A multistage
verification and validation methodology is described, and its
applicability to the present work is demonstrated by a number of
examples addressing each successive step of the methodology. A number of
imaginary and real world case studies are described to demonstrate
application of the present work both in a modelling orientated context
and in a building engineering context.; ;

J. *Modelling coupled heat and air flow: ping-pong vs onions*. in *16th
AIVC Conference*. 1995: AIVC.

M.K. and F. Allard, *Solution Methods for the air balance in multizone
buildings.* Energy and Buildings, 1992. Vol. 18: pp 159-170.Air
infiltration programs establish infiltration and ventilation rates in a
building by the solution of a nonlinear system of equations. This paper
discusses various modifications of the Newton-Raphson method and the
special characteristics of the resulting linear system of equations. The
air of the paper is selecting efficient and robust methods to solve the
system of equations representing the airflow distribution in multizone
buildings. Taking into account the special characteristics of the system
of equations, we recommend a skyline-Cholesky\'s method for the linear
solver. This method can be used in a general way for these problems and
it appears to be very efficient in avoiding unnecessary operations on
zero elements. The choice of an under-relaxation process to ensure the
convergence and efficiency is not obvious. Two different methods are
used to find the under-relaxation coefficients. The extrapolated method
uses two steps of fixed-point iteration to calculate the starting value
for the next step of the process. The optimized method uses a search
routine where the direction of search is determined by Newton-Raphson
and the distance of movement is determined by minimization of a related
one-dimentional function. In studying the methods on the same sample of
test cases, we found that they azRE very similar regarding CPU time.
However, the optimized method appears to be safer and more efficient in
the resolution of the nonlinear system. We, therefore, recommend using
the optimized method for the nonlinear solver.

M.K., *Air-Flow Studies in Multizone Buildings - Models and
Applications*, . 1993, Royal Institute of Technology.

M.K., *Multizone Airflow and Contaminant Modelin: Performance of Two
Common Ventilation Systems in Swedish Apartment Buildings.* ASHRAE
Transactions, 1999. Vol. 105(1).The goal of this work was to assess the
performance of two common ventilation systems, an exhaust and an
exhaust-supply system, in Swedish apartent building. Since correct
air-exchange ain interzonal airflows are important for removing
contaminants and improving indoor air quality, these airflows were
analyzed by systematic computer calculations when selected input
parameters were varied around their default values. The research
specifically involved establishing characteristics of a prototypical
building, determining appropriate boundary conditions (climate and
operation), developing necessary physical/mathematical models, and
establishing a protocol for carrying out the parametric studies required
to assess airflow in buildings of this type.

P.J., G. Powell, and D.K. Alexander, *The energy impact of ventilation
on industrial buildings.* 14th AIVC Conf., 1993. Vol. 1.A combined
thermal and ventilation model has been used to investigate the seasonal
variation of air infiltration rates and ventilation heat losses inmodern
industrial buildings. The model was initially compared to measurements
of ventilation rates, temperatures and heating loads in such a buildng,
and was found to agree well. The model was then used to predict
infiltration rates, temperatures, ventilation heat losses and space
heating loads for a standard heating season for that building. The
effects of variation in the building airtightness, and of the
intermittent use of the loading door were also investigated. The results
indicated that modern design and construction practices could
significantly reduce infiltration and so reduce energy use.

M.G. and K.O. Suen, *Coupling of thermal and airflow calculation
programs offering simultaneous thermal and airflow analysis.* Building
Serv. Eng. Res. Technol., 1995. Vol. 16: pp 33-36.This paper assesses
the feasibility of coupling a thermal simulation software (Apache) with
a multi-zone airflow software (Swifib). The simultaneous multi-zone
airflow and thermal analysis is particularly important in large
enclosure buildings, such as atria. The study highlights the need for
such analysis and shows that a new generation of combined thermal and
airflow software can be produced by coupling the currently available
thermal and airflow simulation software together. The combined software
provides the design engineers with a fast, effective and computationally
less demanding tool for analysing the performance of the built
environment.

A., *et al.*, *Modeling Heat, Moisture and Contaminant Transport in
Buildings: Toward a New Generation Software.* 1989.This paper describes
a general purpose software, FSEC 1.1, that is capable of solving various
transport equations used in building science( eg, combined heat and
moisture transfer, fluid flow, contaminant dispersion). The governing
equations are solved by finite element methods. General capabiolities
and an overview of the software structure are given. Results are
presented for several types of combined heat and moisture transfer
simulations: 1) in buldings; 2) in the presence of natural convection;
3) in a typical wall.; ; Software developed by modifying TARP.

K., *Distribution of Contaminants in Buildings by Air Recirculation and
Other Airflows*. 1991, Helsinki: Helsinki University of Technology.
107.The computer program was developed for simultaneous dynamic
simulation of contaminant concentrations, pressure distribution,
airflows and temperatures in multizone buildings. Physical coupling
existing between thermal behaviour of building structure and interzonal
air movements has an impact on the distribution of contaminants in
building. Consideration of this coupling in the calculation method used
in the program is a considerable improvement when compared to other
hitherto published programs of the same field. Network model was used
for simulation of a building. Using extracts from the program SMOV the
procedure was developed for calculating the pressure distribution in the
network and resulting one-way airflows. Two-way airflows through large
openings were calculated according to the method used earlier in the
program MULTIC. The procedure for calculating the temperatures was
developed using the thermal model of a room presented earlier in
literature. An estimation of the temperature gradient in the room was
enabled by permitting the room air to the theoretically divided into
vertically stacked zones. The program is able to handle three
source-strength / contaminant-concentraiton units. Air quality is
evaluated if concentraitons are calculated using pol units. The
reliability of the program was tested in a number of validation cases
and very good agreement was obtained between the simulation results and
comparison data. An example building was used in simulations. The
dynamic distributions of contaminant concentrations in the building were
determined in several setups of positions of doors, with and without the
return air and with different thermal loads. The simulation results
emphasized the importance of simultaneous calculation of temperatures
and airflows. The present version of the program works well and may
readily be used for research purposes. An extensive validation by means
of measurements should be performed before it could be applied for
design purposes.; ;

K., *et al.*, *Simultaneous Calculation of Airflows, Temperatures and
Contaminant Concentrations in Multi-zone Buildings.* 12th AIVC Conf.,
1991: pp 103-122.The computer programs published so far have enabled the
calculation of airflows at constant temperatures or of air temperatures
at constant airflows. The first version of a new microcomputer program
has now been developed in which the airflows and temperatures are
calculated simulttaneously. The time-dependency of temperatures,
airflows and contaminant concentrations is considered in the calculation
method. The source strength of contaminants, outdoor air temperature,
wind velocity and direction, convection and radiation loads can all be
freely scheduled. The supply air temperature in mechanical ventilation
can be selected as: (1) constant (and scheduled), (2) equal to that of
the outdoor air, (3) calculated as the temperature of the mixture of
outdoor air and return air. Constant temperature cases were simulated
with the program and the results compared with those obtained from more
sophisticated programs. Other cases, with variable temperatures, were
compared with the measurements. Good agreement of the results was
obtained in all cases. the paper describes the main features of the new
program and gives some simulation results.

K., *Theoretical Evaluation of Impact of Return Air and Thermal Load on
Air Quality in a Multizone Building.* ASTM STP 1205, 1993: pp
158-172.The computer programs published so far enabled the computation
of airflows assuming constant temperatures or the calculation of air
temperatures assuming constant airflows. Recently, a new microcomputer
program was developed in which thermal conditions were considered when
predicting the spread of contaminants in buildings. The program enabled
simultaneous dynamic simulations of contaminant distribution, airflows,
and temperatures in a multizone building. Using the new program, the
dynamic distributions of contaminant concentrations oand air quality in
an example building were determined with and without the recirculation
of ventilation air, with different thermal loads and with several door
positions. for comparison, some simulations were repeated in isothermal
conditions. The results showed that a high thermal load increased the
spread of contaminant. Recirculation of the ventilatoin air had a
deteriorative impact on the air quality in the simulated building. There
was a clear difference in the air qualities predicted by the respective
simulations carried out with and without thermal analysis. It is
believed that the inclusion of thermal analysis considereably improved
the calculation method for the evaluation of contaminant distribution in
a building.

J.H. and J.A. Milke, *Design of Smoke Management Systems*. 1992:
ASHRAE.ASHRAE Special Publication that presents an excelent overview of
\"state-of-the-art\" in design of smoke management systems. John Klote
is the author of ASCOS which is a multizone modeling tool created for
analyzing smoke management systems.

J. and A. Blomsterberg. *Performance of passive stack ventilation in a
single-family house: a computational simulation study*. in *16th AIVC
Conference*. 1995: AIVC.

A., *et al.*, *Dispersion of automotive alternative fuel vapors within a
residence and its attached garage.* Indoor Air, 1996. Vol. 6: pp
118-126.

Y., *Predictions of IAQ in multi-room buildings.* Indoor Air 93, 1993.
Vol. 5: pp 557-562.3 indoor air problems in multiroom buildings are
simulated by a multizone air flow model and an air quality model. They
are: odor complaints by the occupants in a Swedish single family house;
moisture content vs time relationships for kitchen air; and radon
concentrations in a residence with an oil-burning heating system.
Suggestions have been made to improve IAQ in these buildings. Both the
air change rates and air flow direction have considerable influence on
the concentratin of pollutants produced in buildings and could be used
effectively to control the accumulation of such pollutants. The level of
air in the distribution of leakage or an opening can result in a
different air flow rate and direction; and thus a different level of
iaq.

Y. and S. Holmberg, *General flow- and thermal-boundary conditions in
indoor air flow simulation.* Indoor Air 93, 1993. Vol. 5: pp 551-556.The
concepts of general flow and thermal boundary conditions are introduced
to treat interaction between indoor and outdoor thermal environments in
CFD simulations. The results from a multizone model are used to supply
the general flow boundary conditions. The energy balance equation at
wall-air interface is used to supply the general thermal boundary
conditions. An example calculation in a 13 room building shows that
infiltration influences indoor air flow patterns considerably. The air
flow in a room with 2 surface coatings ventilated by displacement is
measured and simulated. Implementation of these 2 boundary conditions is
essential in predicting air flow pattern, air quality, and thermal
comfort in a real building.

M., *Annex 23 Multizone Air Flow Modelling - A New IEA Annex.* Air Inf.
Rev., 1990. Vol. 12: pp 6-7.

L.-G., *Evaluation and demonstration of domestic ventilation systems -
State of the Art*, . 1995, Swedish Council for Building Research.

J.A., *Using Models to Support Smoke Management System Design.* Fire
Protection Engineering, 2000(Summer 2000 Number 7): pp 17-22.A review of
the types of modeling/simulation tools available to the designers of
smoke management systems. Includes the use of small scale models,
computer-based zone models, CFD models and network airflow models (e.g.
CONTAM).

M.P. and R. Jansky, *Residential Air-Distribution Systems: Interactions
with the Building Envelope.* TPoEEB, 1992. Vol. V: pp
623-631.Residential ADS, used both for heating and cooling and less
commonly for ventilation, have important interactions with the building
envelope. These systems can either be enclosed withing the envelope or
pass outside the envelope (in which case they represent an extension of
the envelope). This paper addresses the three major types of interaction
between ADS that pass outside the envelope and sigle-family
buildings: 1) duct leakage and duct conduction when the distribution fan
is off, which act like a thermal bridge in the envelope; 2) duct leakage
during system operation, which creates large changes in the quantity and
location of air infiltration and exfiltration through the envelope; and
3) supply/return flow imbalances within individual zones during fan
operation, which create elevated envelope pressure differentials,
infiltration rates, and exfiltration rates. A simulation tool that was
developed to take into account all of these interactions is presented
and applied. The simulation tool - which is based upon the DOE-2 thermal
simulation model, a multizone airflow network model (COMIS), and an
equipment model for the ducts - is used to examine the magnitude of all
3 interactions. The interaction issues examined include air
infiltration/exfiltration magnitude and location, overall thermal
exchange when the system is off, and air exchange when the system is
operating, with and without internal doors closed. The most surprising
result of the analyses presented was that the thermal siphon effect for
perfectly sealed ducts was shown to have an impact on heat exchange
between the house and unconditioned spaces that can be more thatn 4x
larger than that due to typical duct leakage when the fan is not in
operation. This result suggests that this issue merits more careful
examination than it has received in the past.

L., *et al.*, *The Danish twin apartment study - part II: Mathematical
modeling of the relative strength of sources of indoor air pollution.*
Indoor Air, 1996. Vol. 6: pp 18-30.

A., *The Message of Annex 20: Air Flow Patterns Within Buildings.* 12th
AIVC Conf., 1991. Vol. 1: pp 1-26.The IEA task-sharing project \"Air
flow within buildings: was initiated in May 1988 for a duration of 3 1/2
years. 12 nations contribute work and expertise and \"share the task\"
specified in the project\'s objectives. This project and the AIVC belong
to the same Implementing Agreement. As \"Attachments to the Implementing
Agreement, they are called Annexes. The general objective of the Annex
is to evaluate the performance of single- and multi-zone air and
contaminant flow simulation techniques and to establish their viability
as design tools. To reach this goal, the work was divided into two
parallel subtasks: one on single-room air and contaminant flow and the
other on multi-zone air and contaminant flow and measurement techniques.
This survey paper reviews project objectives and approach, both
technically and from the point of view of project management. It offers
an overview of the work performed and solutions contributed by the
participating countries, it discusses problems encountered during the
project and how these were solved, and summarizes final results. It
shows how the various technical Annex 20 contributions to this
conference are related to the overall Annex effort. General conclusions
are drawn, consequences for future international projects are examined,
and the main message of the multi-national program is formulated.

A. and G. Yuill, *Comparison of Residential Air Infiltration Rates
Predicted by Single-Zone and Multizone Models.* ASHRAE Transactions,
1999. Vol. 105(Part 1).Compares use of multizone model (CONTAM) and
single-zone model (LBL model) in predicting infiltration rates of a
single-family residential building. Fan pressurization measurements were
made. Multizone model of the house consisted of over 2,000 zones and
7,000 leakage paths. Four different ventilation configurations were
simulated including no mechanical ventilation or exhaust, supply fan
only, exhaust fan only, and balanced supply and exhaust fans.
Observations were made with respect to wind-related input parameters,
envelope leakage distribution and utilizing both single-zone and
multizone models to achieve simulation results faster than using only
the multizone model.

A. *Multizone Modeling as an Indoor Air Quality Design Tool*. in
*Proceedings of Healty Buildings 2000*. 2000. Espoo, Finland.Increased
public awareness and changing industry standards have highlighted the
importance of indoor air quality in the building design process. At the
same time, many owners would like to construct buildings that conserve
energy and minimize environmental impact. To accomplish both of these
goals, the designer must be able to understand airflow rates, pressure
relationships, and contaminant transport in buildings. This paper
describes the use of a multizone model to perform design calculations
for a new building on a college campus in the United States. The
building incorporates a number of environmentally \"progressive\"
features, such as natural ventilation, energy recovery, a biological
wastewater treatment process, and CO2 demand controlled ventilation. The
multizone modeling tool CONTAM is used to size an exhaust fan for source
isolation, select minimum ventilation quantities to control building
related contaminants, and specify procedures for flushing out
contaminants prior to occupancy. The multizone model is also used to
predict transient contaminant levels, taking into account weather and
associated infiltration. The generalization of these design and analysis
techniques to a wider range of indoor air quality design applications is
also discussed.

M.B., *New concepts aimed to improve the multizone model for predicting
the air flows in the buildings.* Indoor Air 93, 1993: pp
563-568.Computer simulation is one of the basic means to obtain complex
information concerning the air flows in a multizone building structure.
Presented briefly in this paper are the fundamentals of the newly
developed simulation method. The major departures are addressed which
distinguish this new method from the other multizone models. These
include the principles of dividing a building into zones and the
accomplishment of the simulation of the system. Attention is paid to the
universality of the new method, the flexibility in regard to
modifications and the usefulness in mathematical verification of other
simulation results.

M.B. *Evaluation of wind pressure effects on ventilation rates in
multizone dwelling houses*. in *Roomvent 94*. 1994.

H. *New Progress on the Multi-chamber Airflow Measurement System*. in
*International Symposium on Room Air Convection and Ventilation
Effectiveness*. 1992. Tokyo, Japan: Society of Heating, Air Conditioning
and Sanitary Engineers of Japan.The measurement method for multi-chamber
airflow is an important research theme because of the limitations and
errors inherent in conventional single chamber method. The fundamental
theory for this measurement and several application examples by the have
been published. The theory is based on the tracer gas dispersion general
model in multi-chamber system called Thermal Network state equation
which is also applicable to heat transfer system. To estimate the
airflows in multi-chamber system is considered as a type of system
identification of the state equation model and two calculation
procedures have been deduced from the least squares method. Several
field measurements and verificational test have shown the practicality,
accuracy and also defects of the measurement system. In the present
paper some improvements on these defects and the verification in the
field measurement are described.

M., *A Comparison of Multi-zone Air Flow Models - Annex 23 Report.*
1994.The purpose of this section is to report on a comparison of the
results of several multizone air flow models which have been configured
using the same sets of input data. The results are presented below in
Section V, in the form of mass flow rates through every leakage path,
for each of the models. It was not intended to test the full
capabilities of each model, and therefore only a straightforward
configuration was devised for the test. It was found that when identical
data are applied to each model, the variations between the total
outgoing air flow rates predicted by the models were low, shoen in Table
2, as were the variatins for the individual zones. In absolute terms,
the standard deviation of the results for each opening was low in
magnitude and reasonably constant. On the other hand, the relative
spread of the values around the mean value was significantly higher for
some openings, in particular for path 9.; ;

M.K., *et al.*, *Predicting indoor air quality with IAQPC.* Proceedings
of the Jacques Cartier Conference, 1992: pp 101-108.The ability to
predict the level of air contamination for any building for known
sources and air cleaners has long been desired. IAQ consultants,
building occupants, and especially, building designers and builders must
be able to predict what type of indoor environment will result from
their decisions. This paper presents the results of a model study using
the IAQPC. The building modeled is a test house characterized in several
studies. Experimental values for air cleaners efficiencies, source
strengths, and ventilation rates have been combined to predict the
contamination level in the house. In particular this paper addresses the
effect of vacuum cleaning and cigarette smoking on a home\'s air supply
and investigates the results of employing furnace filters relative to an
ASHRAE rated filter and an electronic air cleaner.

J., *Analysis of air circulation through a building.* Bldg Res & Pract,
1990.This paper provides a detailed acount of the development of a
numerical model for estimating the airflow rates through openings and
cracks in the building envelope.

R.Y., *Internal Heat Transfers and Heating Needs of Buildings.*
ICBEM\'87, 1987. Vol. 2: pp 121-128.

R. and H. Khodr, *Development and Validation of New Aeraulic Model
Designed for Thermal Computation with Particular Attention to the
Problems of Air Quality.* Bldg Res & Pract, 1990.The air flows in large
openings, due to the buoyancy effect, can reach high values in
comparison iwth the values of the air flows due to air leakage and
ventilation. For example, through a standard opening, a difference of
temperature 0.1 creates a circulation of air of about 120 m3/h. A
difference of 1 in temperature creates an air circulation of about 390
m3/h. The buoyancy effect plays a major role in the diffusion of
pollutants. To model the influence of the buoyancy effect, simplified
models can sometimes be used. Such a model has been designed and
partially validated. Its application field for the computation of air
flows is limited to the case when the temperature profiles in the rooms
are almost linear, and there is no multiple neutral plane. If there is a
multiple neutral plane, the air flow rates can be very important
although the average temperature of the rooms are equal. If a C2 class
model is inapplicable, a C3 model must be used. But, to be very
accurate, the c3 model has to take into account the vertical temperature
gradients in the rooms. This kind of computation is not very complicated
if the temperatuire profiles are known but it becomes complicated if
temperature profiles are variables. In addition, the on-going
experimental study would provide some data to velidate a model to
compute the discharge coefficient of the large openings. Some elements
of reflection could be provided about the physical mean of the discharge
coefficient and its relevant use.

R., *et al.*, *The concept of Intelligent Simulation Environment.*
1992.The demand for powerful and easy-to-use simulation tools is growing
both in the research community and also among the professionals. Some
powerful simulation codes already exist or are under development but
their use is restricted to inititated researchers circles. Today,
concepts an dtools have been developed in order to facilitate the use of
these simulation codes; one of the goals of Annex 23 is to apply these
new concepts ot a Multizone Air Flow an dPollutant Transport simulation
code: COMIS. The goal is to develop a socalled Intelligent Simulation
Environment (ISE). After a brief description of the existing COMIS
model, the papaer focuses on the concept of ISE developed by CSTB. The
three main ideas on which this concept is built are: the sharing of data
through an Integrated Data Model, the coupling of various simulation
tolls via the ISE, the automatization of modelling and simulating tasks
with the use of expert sytems. Briefly discusses coupling COMIS with
TRNSYS.

M.D.A.E.S. and P.R. Warren, *Influence of Open Windows on the Interzone
Air Movement within a Semi-detached Dwelling.* 6th AIC Conf., 1985: pp
9-28.In this paper, a multicell airflow computer program called BREEZE
is used to determine the influence of open windows on the ventilation
rates of a semidetached house for a variety of weather conditions. For a
limited number of cases, the predicted values are compared with field
measurements to indicate the degree of confidence which can be placed in
the computer simulation. The effect of closing internal doors on
ventilation rates and interzonal airflows is also considered.

A.K. and R.A. Grot, *The Airtightness of Office-building Envelopes.*
TPoEEB, 1985. Vol. III: pp 125-143.Although airtightness, infiltration,
and ventilation are important considerations in large office buildings,
these issues have been studied less in office buildings than in
residential buildings. Several features of office buildings make their
air exchange characteristics different from homes. These features
include curtain wall de4sign and construction, mechanical ventilation
systems, specific occupancy patterns, large volumes and building
heights, and low surface to volume ratios. The recent development of
measuring procedures and computer simulation programs for large
buildings has enabled the study of air leakage in large buildings and
the effects of air exchange on energy use and IAQ. This paper discusses
the airtightness of building envelopes in modern office buildings and
the relationship between envelope airtightness and air exchange rates.
Results of whole building pressurization measurements and tracer gas
measurements of air exchange rates in several office buildings are
discussed, along with the relationship between these measurement
results. A multizone computer simulation program developed at the NBS is
applied to two office buildings to examine this relationship further.
The results of the simulations reveal the importance of envelope
airtightness, floor-to-floor coupling, and mechanical ventilation to the
air change rates in these two buildings.

A.K., *Modeling Radon Transport in Multistory Residential Buildings.*
ASTM STP 1205, 1993: pp 226-242.Radon concentrations have been studied
extensively in single-family resdiential buildings, but relatively
little work has been done in large buildings, including multistory
residential buildings. The phenomena of radon transport in multistory
residential buildings is made more complicated by the multizone nature
of the airflow system and the numerous interzone airflow paths that must
be characterized in such a system. This paper presents the results of a
computer simulation of airflow and radon transtport in a 12 story
residential building. Interzone airflow rates and radon concentrations
were predicted using the multizone airflow and contaminant dispersal
program CONTAM88. Limited simulations were conducted to study the
influence of two different radon source terms, indoor-outdoor
temperature difference and exterior wall leakage values on radon
transport and radon concentration distributions.

A.K., *A Modeling Study of Ventilation, IAQ and Energy Impacts of
Residential Mechanical Ventilation*, . 1998, National Institute of
Standards and Technology.Based on concerns about indoor air quality and
trends towards tighter envelope construction, there has been increasing
interest in mechanical ventilation in residential buildings. A variety
of ventilation approaches have been examined through both field
measurements and computer simulation studies. This paper reports on a
simulation study of indoor air quality, ventilation and energy impacts
of several mechanical ventilation approaches in a single-family
residential building. The study focused on a fictitious two-story house
in Spokane, Washington and employed the multizone airflow and
contaminant dispersal model CONTAM. The model of the house included a
number of factors related to airflow including exhaust fan and
forced-air system operation, duct leakage and weather effects, as well
as factors related to contaminant dispersal including
adsorption/desorption of water vapor and volatile organic compounds,
surface losses of particles and nitrogen dioxide, outdoor contaminant
concentrations, and occupant activities. The contaminants studied
include carbon monoxide, carbon dioxide, nitrogen dioxide, water vapor,
fine and coarse particles, and volatile organic compounds. One-year
simulations were performed for four different ventilation approaches: a
base case of envelope infiltration only, passive inlet vents in
combination with exhaust fan operation, an outdoor intake duct connected
to the forced-air system return balanced by exhaust fan operation, and a
continuously-operated exhaust fan. Results discussed include whole
building air change rates, air distribution within the house, heating
and cooling loads, contaminants concentrations, and occupant exposure to
contaminants.

A.K. and S.R. Martin, *A Modeling Study of Ventilation in Manufactured
Houses*, . 2000, National Institute of Standards and Technology:
Gaithersburg.The HUD Manufactured Home Construction and Safety Standards
(Part 3280, 1994) contain requirements intended to provide adequate
levels of outdoor air ventilation in manufactured homes. In the
implementation of these standards, questions have arisen regarding the
impact and significance of some of these requirements. Some of these
questions relate to the actual ventilation rates in homes built to the
standards and the means of providing supplemental mechanical ventilation
to meet the requirements of the standards. Other questions have arisen
as to how specific ventilation system components such as duct leakage,
local exhaust fans and ventilation inlets affect ventilation rates, air
movement patterns, and building pressures. In order to obtain some
insight into these issues, the multizone airflow and indoor air quality
program CONTAM was used to simulate a double-wide unit under several
different ventilation scenarios. These scenarios include envelope
infiltration only, infiltration plus the effects of local exhaust and
forced-fan operation, an outdoor air intake duct installed on the
forced-air return, and whole house exhaust with and without passive
inlet vents. Simulations were performed to predict outdoor air
ventilation rates into the house due to infiltration and mechanical
ventilation, interzone airflow rates between the rooms, building air
pressures, and ventilation air distribution. Annual simulations were
performed in three cities to assess ventilation rates and energy
consumption associated with these scenarios. The results show that
despite the assumption in the HUD standards that infiltration
contributes 0.25 h-1, the predicted infiltration rates are lower than
this value for many hours of the year. The supplemental ventilation
systems investigated in this study provide ventilation rates that meet
or exceed the total ventilation requirement of 0.35 h-1, but the impacts
of such systems are dependent on their operating schedules. In addition,
in these simulations, the impacts of a whole house exhaust fan are
independent of whether this fan is located in the main living area or in
a bathroom off the main living area. Also, for the case of ventilation
with a whole house exhaust fan, the inclusion of passive inlet vents is
not critical given the level of envelope airtightness used in these
simulations. The results of these simulations are presented and
discussed, and recommendations are made for changes to the HUD standards
and for future research.

J.C. and W.F. de Gids, *Airflow Driven Contaminants. Transport through
Buildings. ANNEX 20 Subtask 2.5.* 12th AIVC Conf., 1991: pp 123-140.Air
is the main transport for contaminants in buildings. Minimizing source
strengths has first priority, second is to control air flow rates,
supply and exhaust, and directions between zones in buildings. Computer
simulation models for ventilation and pollutant spread in buildings have
been proven to give useful predictions. Large measurement campaigns for
optimizing ventilaiton and pollutant problems are complex and expensive.
They are often jammed by too many vague parameters influencing the
result. The computer models are an alternative and form a supplement to
measurements. New ventilation systems or control strategies can be
tested to some extent with the models. Measurements for checks and
determination of source and sink coefficients for different materials
are needed to tune the simulation models.

J. and F. Haghighat, *A procedure for sensitivity analysis of airflow in
multi-zone buildings.* Building and Environment, 1993. Vol. 28(1): pp
53-62.

G.L. and G.M. Bragg, *A Multi-Chamber Ventilation Model with Random
Parameters.* Bldg. & Env., 1990. Vol. 25: pp 339-347.A generalized
multi-chamber model is developed for air contaminant prediciton problems
where the parameters of the system, such as airflow rates, are described
by Gaussian probability distributions. A numerical solution, utilizing
stochastic differential equations, is provided to facilitate its
application. The model is used to calculate contaminant concentration
histories described by means and standard deviations. It is also used to
show the sensitivity of concentrations to the variation of such
parameters as infiltration flows and contaminant source rates. Sample
applications of the model are provided.

E.A. and F. Allard, *Coupling COMIS airflow model with other transfer
phenomena.* Energy and Buildings, 1992. Vol. 18: pp 147-157.One of the
main characteristics of thermal and fluid mechanical behaviour of
buildings is that it is dominated by coupled heat and mass transfer
phenomena. In this paper we describe the main phenomena influencing the
behaviour of buildings and propose a general formulation of these
coupled phenomena. We then apply this formalism to two important
problems. The first one deals with the coupling between a multizone
thermal model and a multizone airflow model. The second one presents the
coupling between the transport fo pollutants and airflow calculation in
a multizone building. In order to illustrate our proposition we give
various kinds of examples of coupled configuration.

M.N.A. and R.A. MacDonald, *An evaluation of a network smoke control
model.* ASHRAE Transactions, 1991. Vol. 97: pp 275-282.This paper
describes the evaluation of the air and smoke movement model developed
at a Canadian research institute. To verify the model, predicted data
are compared with data from full-scale fire tests involving a
pressurized stair shaft smoke control system. The tests were conducted
in the 10-story experimental fire tower at the National Fire Laboratory
of the National Research Council of Canada. Predicted data exhibit good
agreement with measured data. The paper also discusses the effects of
large exterior and interior openings and the pressure due to the fire on
the building\'s pressures and on smoke migration.

M.N.A., *et al.*, *Computer simulation of ventilation strategies for
maintaining an acceptable indoor air quality in office buildings.*
ASHRAE Transactions, 1995: pp 1118-1125.

M., *The Multi-chamber Theory Reconsidered from the Viewpoint of Air
Quality Studies.* Bldg. & Env., 1984. Vol. 19: pp 221-233.A general
multi-chamber model is presented and explored form the viewpoint of air
quality studies. The model involves the following key concepts: purging
flow rate and age distribution of both air and contaminants. From the
physical and mathematical properties of the model, are deduced estimates
of the magnitude of, and the relations between, the key concepts. The
practical use of the model is illustrated.

H.J. and R.H. Howell, *Estimating the indoor air quality and energy
performance of VAV systems.* ASHRAE Journal, 1992. Vol. 34:7: pp
43-50.VAV system simulation program based on AIRNET,

A., *et al.* *A new method for linking results of detailed air flow
pattern calculation with multizone models.* in *13th AIVC Conference*.
1992. Nice, France: AIVC.Multi-zone models are a common tool for
calculating air and contaminant exchange within rooms of a building and
between building and outdoors. Usually a whole room is then modelled by
one calculation node with the assumption of homogeneously mixed
conditions within this room whereas in real cases temperature and
contaminant concentrations vary in space. The exchange to the
neighbouring nodes via the flow paths is then a function of the local
values of these variables. Detailed knowledge can be obtained from the
solution of the transport equations for the airflow pattern within the
room at the expense of far higher computation cost. This work shows a
new approach called \"method of detailed node values\" to include
results from detailed calculations in multi-zone models to give a better
description of the real cases. Parameter transfer between a multi-zone
program and a detailed air flow simulation program is discussed for
different flow paths of practical importance. The method is demonstrated
in an example case with air in/exfiltration, ventilation and contaminant
propagation, and discussed in a second example with large openings. This
new method promises to improve the multizone model predictions with few
additional CFD computations.

A., *et al.*, *Application of a new method for improved multizone model
predictions.* 14th AIVC Conf., 1993. Vol. x: pp x.This work shows the
application to several examples of a new method which includes results
from detailed calculations for oe room of importance in a multizone
model of a whole building. The examples with air in/exfiltration,
ventilation and contaminant propagation show the effects on the results
of the predictions of the air flow and the contaminant spread by
relaxing the homogeneity assumptions. The proposed name of the method is
\'detailed flow path value method\' (DFPV) as separate local variable
values are considered for each flow path from the room of importance to
the neighbouring rooms instead of one average value. It is discussed in
which situations the DFPV method can be expected to improve the
multizone model predictions.

A., *et al.*, *Improvement of multizone model predictions by detailed
flow path values from CFD calculations.* ASHRAE Transactions, 1993. Vol.
99-2.Multizone models are a common tool for calculating air and
contaminant exchange within the rooms of a building and between a
building and the outdoors. Usually a whole room is modeled by one
calculation node with the assumption of homogeneously mixed conditions
within this room, but in real cases, temperature and contaminant
concentrations vary in space. The exchange to neighboring nodes via flow
paths is a function of the local values of these variables. Detailed
knowledge can be obtained from the solution of the transport equations
for the airflow pattern (computational fluid dynamics, CFD) within the
room at the expense of far higher computation costs. This work shows how
results from CFD calculations can enhance the accuracy of multizone
model prediction to give a better description of real cases. Para eter
transfer between a multizone program and a detailed airflow simulation
program is discussed. The method is then aplied to example cases with
air in/exfiltration, ventilation, and contaminant propagation and flow
through large openings and shows its ability for a more accurate
prediction of the contaminant spread. In the cases shown, concentration
values differ by up to a factor of 2.5 from the purely multizonal
prediction is 0.12 ppm for the concentrations in a neighboring room,
whereas the corresponding values of the new method vary between 0.05 and
0.23 ppm for different source positions.

A., *et al.*, *Improvement of Multizone Model Predictions by Detailed
Flow Path Values from CFD Calculations.* ASHRAE Transactions, 1994. Vol.
100(2): pp 709-720.Multizone models are a common tool for calculating
air and contaminant exchange within the rooms of a building and between
a building and the outdoors. Usually a whole room is modeled by one
calculation node with the assumption of homogeneously mixed conditions
within this room, but in real cases, temperature and contaminant
concentrations vary in space. The exchange to neighboring nodes via flow
paths is a function of the local values of these variables. Detailed
knowledge can be obtained from the solution of the transport equations
for the airflow pattern (computational fluid dynamics, CFD) within the
room at the expense of far higher computation cost. This work shows how
results from CFD calculations can enhance the accuracy of multizone
model predictions to give a better description of real cases. Parameter
transfer between a multizone program and a detailed airflow simulation
program is discussed. The method is then applied to example cases with
air in/exfiltration, ventilation, and contaminant propagation and flow
through large openings and shows its ability for a more accurate
prediction of the contaminant spread. In the cases shown, concentration
values differ by up to a factor of 2.5 from the purely multizonal
approach. In the case with open windows, the multizonal prediction is
0.12 ppm for the concentrations in a neighboring room, whereas the
corresponding values of the new method vary between 0.05 and 0.23 ppm
for different source positions.

A., *et al.*, *A New Method for Linking Results of Detailed Air Flow
Pattern Calculation with Multizone Models.* 13th AIVC Conf., 1992: pp
63-76.Multizone models are a common tool for calculating air and
contaminant exchange within rooms of a building and between bulding and
outdoors. Usually a whole room is then modelled by one calculation node
with the assumption of homogeneously mixed conditions within this room
whereas in real cases temperature and contaminant concentrations vary in
space. The exchange to the neighbouring nodes via the flow paths is then
a function of the local values of these variables. Detailed knowledge
can be obtained from the solution of the transport equations for the air
flow pattern within the room at the expense of far higher computation
cost. This work shows a new approach called \"method of detailed node
values\" to include results from detailed calculations in multizone
models to give a better description of the real cases. Parameter
transfer between a multizone program and a detailed air flow simulation
program is discussed for different flow paths of practical importance.
The method is demonstrated in an example case with air in/exfiltration,
ventilation and contaminant propagation, and discussed in a second
example with large openings. This new method promises to improve the
multizone model predicitons with few additional CFD computations.

P.S., J.-J. Roux, and J. Brau, *Strategies for Solving the Air
Flow-Thermal Problem in Multiroom Buildings.* Bldg. & Env., 1995. Vol.
30: pp 277-286.Iterative and direct methods for solving the coupled
problem of heat and mass transfers in buildings are presented and
compared. Numerical problems often trouble the resolution of this
problem and a choice between different strategies can be a way to
overcome instabilities of calculus and running-time difficulties. The
state of the zones of air is represented as a function of temperature
and pressure. The iterative method consists of separating the problem
into two subsets, the first being a function of temperature and the
other a function of pressure. The direct method simultaneously carries
out the resolution of the original set. Two simulation codes were
developed based on the \'coupling method\', which is a method of solving
the thermal problem by splitting it into levels of coupleing. The direct
option needs more computational effort, but is easier to run by
non-experts. In contrast, the iterative method is better adopted to the
connection of different programs. Simulation results are presented, and
the performances of the two strategies are compared and discussed.

B.E. and T.L. Hamlin, *Meeting Canadian Residential Ventilation Standard
Requirements with Low-cost Systems.* ASHRAE Transactions, 1991. Vol. 97,
Pt 2.Several low-cost ventilation systems, intended to meet the
continuous-ventilation requirements specified in the Canadian
residential ventilation standard, CSA F326, were investigated. 8
ventilation system configurations were installed, commissioned, and
tested in the field to obtain operating experience withthe syustems and
to establish confidence in the simulation software. CO2 and HCHO levels
were simulated inhouses with several different ventilation system
configurations. The cases modeled included houses with and without
forced-air recirculation systems, average and tight building envelopes,
and average and heavy occupancies. It was determined that several
low-cost techniques, including fan-driven limited-distribution systems
combined with one or more exhaust fans, canbe effective in providing
good indoor air quality control, while some other techniques should not
be relied on. Examination of continuous CO2 measurements in 2
mechanically ventilated houses suggested that the fresh air supply rates
specified by CSA F326 provide good control of this contaminant.

L.E., M.D. Jackson, and B.A. Tichenor, *Comparison of EPA Test House
Data with Predictions of an Indoor Air Quality Model.* IAQ 88, 1988: pp
251-264.An easy-to-use iaq model is described. It is a multi-component
model based on a well-mixed mixing model. Sources and sinks are allowed
in each compartment. A menu-driven fill-in-the form user interface is
used to control program flow and obtain data from the user. On-screen
graphical output is provided. The model estimates the effects of HVAC,
air cleaning, room-to-room air movement, and natural ventilation on
pollutant concentrations. Experiments conductd in the EPA test house
using moth crystal cakes for model verification are described. The
agreement between small chamber emission factors, model predictions, and
test house data is very good. Predicted weight loss of the moth crystal
cakes was within 5 % of the measured weight loss. Predicted room
concentrations of p-dichlorobenzene are within 20 % of the measured
values. Future directions for model development and experimental studies
are discussed.

L.E., *et al.*, *Verification and uses of the environmental protection
agency (EPA) IAQ model.* IAQ 89, 1989: pp 146-150.This paper describes a
set of experiments used to verify an IAQ model for estimating the impact
of various sources on IAQ in a multi-room building. The model treats
each room as a well mixed chamber that contains pollutant sources and
sinks. The model allows analysis of the impact of room-to-room airflows,
HVAC systems, and aircleaners on IAQ. The model is written for personal
computers. The experiments were conducted in a test house. 3 different
pollution sources were used in the experiments - moth crystals, kerosene
heaters, and drycleaned cloths. The model predictions were in good
agreement with the experimental data, especially when a sink term was
included in the model. The paper presents a brief discussion of the
theory on which the model is based. Preliminary data and theory of
sources and sinks are also discussed. Examples demonstrating the use of
the model to analyze IAQ control options and to estimate exposure from a
pollutant are included.

L.E., *et al.*, *An Integrated Approach to Research on the Impact of
Sources on Indoor Air Quality.* Indoor Air 90, 1990.An approach for
analyzing the impact of sources on IAQ based on chamber studies,
modeling, and test house studies is described. Source emission factors
are developed in chamber studies. The emission factors are used in an
IAQ model that incorporates room-to-room air movement, sinks, and air
exchange with the outdoors to predict indoor air pollution
concentrations from the source. Test house experiments are used to
verify the model and identify unmodeled factors. The agreement between
model predictions based on chamber emission factors and test house data
is excellent.

B. and L. Sparks, *Managing exposure to indoor air pollutants in
residential and office environments.* Indoor Air, 1996. Vol. 6: pp
259-270.

der Maas, J. and C.-A. Roulet, *Multizone cooling model for calculating
the potential of night time ventilation.* 14th AIVC Conf., 1993. Vol.
1.One of the options to increase the energy efficiency of buildings in
the cooling season, is to extract heat from the building envelope during
the night by natural or forced ventilation. The exploitation of this
technique by architects and designers requires the development of guide
lines and a predesign tool showing how the potential cooling power
depends on the influence of opening sizes and positions and on the
interaction with the thermal mass. While a single zone model is
sufficient to estimate roughly the heat extracted form the building, a
multizone extension allows one to predict the distribution of air and
wall temperatures and therefore the distribution of cooling power over
the air flow path (when the zones are ventilated in series. A zonal
cooling model based on the principles of mass and energy conservation
and coupling ventilation with both heat transfer and a thermal model for
the walls. The parameters of the ventilation model are the size and
position of the openings, the stack height, and climatic parameters like
temperature swing and wind characteristics. The heat transfer is
parametrized by the exposed surface area of thermal mass, while the heat
storage for heavy weight constructions is only characterized by both
that surface area and the thermal effusivity of the exposed wall
material. The predictions are compared with measurements for a simple
flow path configuration.

L.S., *Distribution System Leakage Impacts on Apartment Building
Ventilation Rates.* ASHRAE Transactions, 1999. Vol. 105(1).Forced air
distribution systems in residential buildings are often located outside
the conditioned space, for example, in attics, crawl spaces, garages,
and basemets. Leaks from the ducts to these unconditioned spaces or
outside can change flows through the registers and change the
ventilation rates of the conditioned spaces. In this study, duct leakage
flows were measured in several low-rise apartment buildings. The leakage
flow measurements and other data about the apartments were used to
develop a prototype apartment building. The multizone arflow model COMIS
was then used on this prototype building to determine internal flows
within the building, airlflows through the building envelope, and the
impacts of the duct leakage on the ventilation rates. The effects of
sealing the duct leaks were also examined in order to determine changes
in infiltration rates resulting from duct retrofits. The simulation
results showed that for the prototype tested here, the excess return
leakage tended to decrease envelope infiltration flows by about 20%, but
the total infiltration load, including return duct leaks, more than
doubled during system operation.

G.N., *AIRNET - A Computer Program for Building Airflow Network
Modeling*, . 1989, National Institute of Standards and Technology:
Gaithersburg.

G.N. *CONTAM94: A Multizone Airflow and Contaminant Dispersal Model with
a Graphic User Interface*. in *Building Simulation \'95 - Proceedings of
4th Conference of International Building and Performance Simulation
Association*. 1995. Madison, WI: IBPSA.CONTAM94 is an easily used,
public domain airflow and contaminant migration analysis proram
combining algorithms for modeling airflow and contaminant dispersal in
multizone buildings. It employs a simplified graphic description of the
building for both data entry and the presentation of simulation results.
It runs on commonly available 486DX calss PC compatible computers with
VGA graphics and MS-DOS. It can handle buildings containing a large
number of zones.

G.N., *CONTAM96 User Manual*, . 1997, National Institute of Standards
and Technology: Gaithersburg.This manual describes the use of a computer
program, CONTAM96, for analyzing the air movement and indoor air quality
in multizone buildings. The program is used to create and edit the
building description including data for all features relating to airflow
or to the generation and removal of contaminants. It uses a graphic
interface to establish the spatial relationship of these features. These
data along with weather data are used to calculate the airflows and
dynamic levels of indoor contaminants. The results of the calculation
may be reviewed graphically and printable files may be generated. This
program is an extension of the earlier CONTAM93 program.

B.R., *et al.*, *Specification of indoor air model characteristics.*
Indoor Air 90, 1990.Indoor air models are reviewed for applicability to
general and specific problems of human exposure and risk. Each model is
evaluated for its suitability for driving exposure and risk analyses and
for its ability to address scientific and policy issues. The models\'
input data requirements are reviewed. Factors limiting the range of
applicability are identified and characterized. Sensitivity of each of
the models to input parameters is discussed.

H., *et al.*, *Analysis on Improvement of Residential Building
Performance by Multizone Thermal and Airflow Model.* ASHRAE
Transactions, 1993. Vol. 99.Many factors affect the indoor environment
of residential buildings. Among those factors are thermal insulation,
airtightness, and the space-heating patterns. The influence of these
factors on indoor thermal environment and space-heating load is
investigated by a multizone thermal and airflow simulation including
mutual radiation. The computer simulation was done on a model of a
detached house with 10 rooms. The results obtained from This study show
the degree of the effect of these factors on thermal environment and
heating load.

H., *et al.*, *Numerical Analysis of Ventilation System Performance by
COMIS Model.* ASHRAE Transactions, 1999. Vol. 105(1).This research
evaluated the performance of four kinds of ventilation systems for
dwellings under various conditions by means of numerical simulation. the
total number of combinations of various parameters for the caculations
was 174. were performed hourly for indoor pollutant concentration,
humidity and condensation, indoor-outdoor pressure difference, airlflow
rate, and heat energy by ventilation, etc., through the heating
season.multizone infiltration and pollutant trasport model (COMIS) was
used to perform the simulation. A new term, \"acceptable ratio,\" is
introduced in this study to evaluat the performance of ventilation
systems from the point of view of CO2 level and energy consumption. In
addition, by means of statistical methods, the effect of various factors
on ventilation system performance is discussed. a set of predictive
equations for ventilation systems are derived in this paper to try to
evaluate ventilation system performance in an easy way under any
conditions.

G.K. and M.R. Jeanson, *An analysis of several ventilation strategies
for four ventilation systems.* Indoor Air 90, 1990. Vol. 4.The relative
performance of 2 ventilation systems in terms of energy consumption and
controlling occupant exposure to indoor air pollutants was determined
using computer simulations. The 2 ventilation systems modelled were; a
heat recovery ventilator with a conventional forced air furnace and a
continuous exhaust ventilator window system with electric baseboard
heating. Each of the ventilation systems was simulated according to 2
different control strategies. One control strategy used constant exhaust
fan flow rates. The other strategy operated by modulating the exhaust
fan flow rates to keep the CO2 concentration in the exhaust stream
constant (demand controlled exhaust). It was found in general that the
continuous exhaust systems performed as well as or better than the
demand controlled exhaust systems at controlling occupant exposure to
the pollutants modelled.

G.K., M.R. Jeanson, and C.P. Wray, *Simulated Performance of Demand
Controlled Ventilation Systems Using Carbon Dioxide as an Occupancy
Indicator.* ASHRAE Transactions, 1991. Vol. 97 Pt 2.A central supply
ventilation system and a distributed supply ventilation system were
simulated to determine their relative performance in controlling
occupant exposure to indoor air pollutants. 2 different control
strategies were used: (1) constant exhaust flow rates (continuous
ventilation) and (2) modulation of the exhaust flow rates to keep the
CO2 concentration in the exhaust airstream constant (DCV). The DCV
systems showed no clear advantage over the continuous ventilation
systems. They reduced the exposures to some pollutants and increased the
exposures to others. In some cases, the relative performance of the DCV
systems depended strongly on whether central supply or distributed
supply ventilation was used.