Bibliographies J-R

Bibliography J-R

Jones, 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.
Kafetzopoulos, 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.
Kerestecioglu, 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.
Klobut, 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.; ;
Klobut, 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.
Klobut, 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.
Klote, 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.
Klote, John H., D.Sc., P.E. Smoke Management Applications of CONTAM. 2002, ASHRAE Annual Meeting: While CONTAM was developed for indoor air quality purposes, it is probably the most extensively used computer program for analysis of smoke control systems in the world. CONTAM can analyze conventional pressurization systems that use pressure differences at barriers to restrict smoke movement. These systems include pressurized stairwells, pressurized elevators, and zoned smoke control. CONTAM can also be used to design systems intended to maintain tenability. Analysis of tenability systems includes people movement calculations, tenability calculations, and smoke transport calculations. For a specific fire with generation of soot and toxic gases, CONTAM can calculate smoke transport throughout a complex building. An example analysis is discussed. Attention needs to be paid to the details of the simulation to ensure that the CONTAM model is appropriate for the specific application.
Kronvall, J. and A. Blomsterberg. Performance of passive stack ventilation in a single-family house: a computational simulation study. in 16th AIVC Conference. 1995: AIVC.
Lansari, A., et al., Dispersion of automotive alternative fuel vapors within a residence and its attached garage. Indoor Air, 1996. Vol. 6: pp 118- 126.
Li, 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.
Li, 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.
Liddament, M., Annex 23 Multizone Air Flow Modelling - A New IEA Annex. Air Inf. Rev., 1990. Vol. 12: pp 6-7.
Mansson, L.-G., Evaluation and demonstration of domestic ventilation systems - State of the Art, . 1995, Swedish Council for Building Research.
McDowell, Timothy P.; Thornton, Jeff W.; Emmerich, Steven J.; Walton, George; Integration of Airflow and Energy Simulation Using CONTAM and TRNSYS National Institute of Standards and Technology, Gaithersburg, MD. Thermal Energy System Specialists, Madison, Wisc. ASHRAE Transactions, Volume 109, Part 2. KC-03-10-2; 2003: The impact of infiltration and ventilation flows on energy use in commercial buildings has received limited attention. One of the reasons for this lack of study is that the commonly used programs for estimating the energy use of buildings do not incorporate the interzonal airflow modeling techniques required to adequately account for the effect of these factors on energy usage. To address this issue and provide insight into the impact of these flows, the CONTAM airflow modeling tool was incorporated into the TRNSYS energy analysis program. This integrated approach was then used to estimate the energy usage of 25 buildings representing the U.S. core office building stock over a range of infiltration and ventilation conditions. This paper will discuss the process of modeling the buildings in both programs, the integration of the two programs into a cohesive simulation, and some initial results of the study.
Milke, 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).
Modera, 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.
Molhave, 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.
Moser, 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.
Musser, Amy; Persily, A. K., Multizone Modeling Approaches to Contaminant-Based Design. ASHRAE Transactions, 2002. V. 108, Pt. 2. HI-02-9-1.: Indoor air quality is currently addressed in the design process primarily through prescriptive building codes based on specified flow rates. However, a contaminant-based design approach opens the door to design innovation, offering opportunities for improved indoor air quality, energy conservation, and reduced environmental impact. This paper discusses current design approaches and some possibilities for the future of contaminant-based design. Techniques and modeling approaches that could be used today are demonstrated using examples from a case study building. A multizone network airflow model is used to simulate airflow rates, pressure relationships, and contaminant transport to support the design. These simulations are utilized to specify minimum ventilation rates to control non-occupant-related contaminants for a system with carbon dioxide demand control. Contaminant buildup during an overnight shutdown is also studied, and strategies for a pre-occupancy purge are developed. The model is also used to size an exhaust fan to negatively pressurize an enclosure housing a biological process. The design is then reevaluated based on experimental measurements of envelope airtightness and contaminant emissions that were conducted in the building. The case study identifies the critical, or “design,” conditions that must be addressed, discusses strategies that could be used to meet them with contaminant-based design, and considers the role that available measurements can take.
Musser, 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.
Musser, 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.
Musser, Amy, Ph.D., P.E.; Andrew K. Persily, Ph.D., Multizone Modeling Approaches to Contaminant-Based Design 2002, ASHRAE Annual Meeting: Indoor air quality is currently addressed in the design process primarily through prescriptive building codes based on specified flow rates. However, a contaminant-based design approach opens the door to design innovation, offering opportunities for improved indoor air quality, energy conservation, and reduced environmental impact. This paper discusses current design approaches and some possibilities for the future of contaminant-based design. Techniques and modeling approaches that could be used today are demonstrated using examples from a case study building. A multizone network airflow model is used to simulate airflow rates, pressure relationships, and contaminant transport. These simulations are utilized to specify minimum ventilation rates to control non- occupant-related contaminants for a system with carbon dioxide demand control. Contaminant buildup during an overnight shutdown is also studied,and strategies for a pre-occupancy purge are developed. The model is also used to size an exhaust fan to negatively pressurize an enclosure housing a biological process. The design is then re-evaluated based on experimental measurements of envelope airtightness and contaminant emissions that were conducted in the building. The case study identifies the critical, or "design," conditions that must be addressed, discusses strategies that could be used to meet them with contaminant-based design, and considers the role that available measurements can take.
Nantka, 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.
Nantka, M.B. Evaluation of wind pressure effects on ventilation rates in multizone dwelling houses. in Roomvent 94. 1994.
Okuyama, 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.
Orme, 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.
Orme, Malcolm and Nurul Leksmono, AIVC Guide 5 - Ventilation Modeling Data Guide. 2002: Numerical ventilation and air infiltration models are used to calculate air flow rates into and out of buildings and between individual rooms or zones within a building. This report discusses the input data that must be provided in order to use them and highlights areas of application. It is intended to give an introduction to these models for building services practitioners and designers and assumes a basic knowledge of ventilation-related building physics.
Owen, 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.
Passard, 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.
Pelletret, R.Y., Internal Heat Transfers and Heating Needs of Buildings. ICBEM'87, 1987. Vol. 2: pp 121-128.
Pelletret, 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.
Pelletret, 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.
Perera, 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.
Persily, A.; Crum, J.; Nabinger, S.; Lubliner, M.; Ventilation Characterization Of A New Manufactured House. National Institute of Standards and Technology, Gaithersburg, MD. 2003;: A manufactured home has been installed on the NIST campus for ventilation, energy and indoor air quality studies. The primary purposes of the facility are to study mechanical ventilation requirements for U.S. manufactured homes and to investigate the systems used to meet these requirements. In addition, the building will be used to investigate moisture issues, indoor air quality impacts of combustion appliances, and VOC emissions from building materials and furnishings. The first phase of this multiyear effort has focused on airtightness, system airflows and air change rates. This paper describes the measurement results including envelope and duct airtightness, ventilation system airflow rates, and whole house air change rates under different ventilation configurations and weather conditions. In addition, a model of the building in the multizone airflow program CONTAMW is presented along with comparisons between model predictions and measurements of air change rates. The results indicate that the envelope and air distribution ductwork are fairly leaky, but not unusually high for U.S. manufactured homes, and that the predicted air change rates are in good agreement with the measured values.
Persily, A.; Leber, D.; A Suite Of Homes Representing The U.S. Housing Stock. National Institute of Standards and Technology, Gaithersburg, MD. 2003;: In order to facilitate nationwide analysis of ventilation and indoor air quality issues in residential buildings, a set of homes has been defined to represent the housing stock of the United States. This so-called “suite of homes” is based on two residential housing surveys, the U.S. Department of Energy Residential Energy Consumptions Survey (RECS) and the U.S. Census Bureau American Housing Survey (AHS). The RECS dataset includes about 6000 U.S. residences and the AHS covers about 60!000, and are both intended to periodically characterize the U.S. housing stock. Based on these datasets, about 175 buildings were defined that represent approximately 75 % of the U.S. housing stock, and just over 200 to represent 80 %. These buildings are grouped into four categories: detached, attached, manufactured homes and apartment buildings. This paper describes the RECS and AHS datasets and how they were used to define this suite of homes. Among the key characteristics addressed in defining these homes are age, floor area, number of floors, foundation type and presence of a garage. As an extension of this effort, these homes will be set up in the multizone airflow model CONTAMW and made available for analyzes of residential ventilation, energy and indoor air quality issues.
A. Persily, A. Musser, S. Emmerich, M. Taylor; Simulations of Indoor Air Quality and Ventilation Impacts of Demand Controlled Ventilation in Commercial and Institutional Buildings; National Institute of Standards and Technology, Gaithersburg, MD. / Department of Architectural Engineering, University of Nebraska. The 24th AIVC and BETEC Conference, 2003.: Carbon-dioxide (CO2) based demand controlled ventilation (DCV) offers the potential for more energy efficient building ventilation compared with constant ventilation rates based on design occupancy. A number of questions related to CO2 DCV exist regarding energy benefits, optimal control strategies, and indoor air quality impacts for contaminants with source strengths that are independent of the number of occupants. In order to obtain insight into these issues, a simulation study was performed in six commercial and institutional building spaces. This paper reports on one of the spaces, a lecture hall, in which six different ventilation strategies were compared, three of them using CO2 DCV. The results depend on occupancy patterns, design ventilation rate and ventilation system operating schedule as well as assumed contaminant source strengths and system-off infiltration rates. In these simulations, CO2 DCV resulted in significant decreases in ventilation rates and energy loads accompanied by increased indoor CO2 and volatile organic compound (VOC) concentrations. The increases in CO2 were generally in the range of 300 mg/m3. The VOC levels increased by a factor of two or three, but the absolute concentrations were still low. The annual energy load reductions with CO2 control ranged from about 50 % to 75 % depending on the space type, climate and ventilation strategy.
Persily, 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.
Persily, 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.
Persily, 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.
Persily, A.K. and E.M. Ivy, Input Data for Multizone Airflow and IAQ Analysis, .2001, National Institute of Standards and Technology: Gaithersburg.: 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.
Persily, 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.
Phaff, 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.
Rao, 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.
Reusing, 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.
Rodriguez, 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.

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