Bibliographies S-Z

Publications

Bibliography S-Z

Said, 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.
Said, 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.
Sandberg, 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.
Sauer, 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,
Schaelin, 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.
Schaelin, 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.
Schaelin, 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.
Schaelin, 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.
Schalin, 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.
Schneider, 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.
Sibbitt, 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.
Sparks, 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.
Sparks, 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.
Sparks, 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.
Tichenor, B. and L. Sparks, Managing exposure to indoor air pollutants in residential and office environments. Indoor Air, 1996. Vol. 6: pp 259-270.
van 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.
Walker, 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.
Wallace, Lance A.; Emmerich, Steven J. ; Howard-Reed, Cynthia, Effect of central fans and in-duct fiﬁlters on deposition rates of ultrafiﬁne and ﬁfine particles in an occupied townhouse, National Institute of Standards and Technology, Gaithersburg, MD. US Environmental Protection Agency, Reston VA; 3 October 2003: Airborne particles are implicated in morbidity and mortality of certain high-risk subpopulations. Exposure to particles occurs mostly indoors, where a main removal mechanism is deposition to surfaces. Deposition can be affected by the use of forced-air circulation through ducts or by air fiﬁlters. In this study, we calculate the deposition rates of particles in an occupied house due to forced-air circulation and the use of in-duct fiﬁlters such as electrostatic precipitators (ESP) and ﬁbrous mechanical fiﬁlters (MECH). Deposition rates are calculated for 128 size categories ranging from 0.01 to 2.5 mm. More than 110 separate ‘‘events’’ (mostly cooking, candle burning, and pouring kitty litter) were used to calculate deposition rates for four conditions: fan off, fan on, MECH installed, ESP installed. For all cases, deposition rates varied in a ‘‘U’’-shaped distribution with the minimum occurring near 0.1 mm, as predicted by theory. The use of the central fan with no fiﬁlter or with a standard furnace fiﬁlter increased deposition rates by amounts on the order of 0.1–0.5 h^-1. The MECH increased deposition rates by up to 2 h^-1 for ultraﬁne and fiﬁne particles but was ineffective for particles in the 0.1–0.5 µm range. The ESP increased deposition rates by 2–3 h^-1 and was effective for all sizes. However, the ESP lost efﬁficiency after several weeks and needed regular cleaning to maintain its effectiveness. A reduction of particle levels by 50% or more could be achieved by use of the ESP when operating properly. Since the use of fans and fiﬁlters reduces particle concentrations from both indoor and outdoor sources, it is more effective than the alternative approach of reducing ventilation by closing windows or insulating homes more tightly. For persons at risk, use of an air ﬁfilter may be an effective method of reducing exposure to particles.
Walton, G.N., AIRNET - A Computer Program for Building Airflow Network Modeling, . 1989, National Institute of Standards and Technology: Gaithersburg.
Walton, 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.
Walton, 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.
Weir, 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.
Yoshino, 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.
Yoshino, 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. Calculations 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. A 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.
Yuill, 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.
Yuill, 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.

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