Terrorist attack in buildings by chemical and biological agents (CBAs) is a reality in our lives. This study applies computational fluid dynamics (CFD) to predict CBA dispersion in an office building in order to find the best locations for CBA sensors and to develop effective ventilation systems to protect building occupants in case of indoor CBA releases. It is found that the CFD is a useful tool for such an application, while some challenges remain.
Together with the definition of innovative plant and envelope technological solutions for buildings, many simulation tools (models) have been developed to make the design choices easier. However the definition of analytical structures able to describe the characteristics of building components installed under real conditions is still difficult. The paper presents some experiences made by ITC. They have been carried out by using System Identification techniques to simulate and predict the performances of various components analysed also through experimental campaigns under real conditions.
This paper outlines the extension of a CFD model using DBM modelling approach. Primarily adynamic CFD model is proposed for adiabatic ventilation system. At the inlet a step rise in temperature of the incoming air with steady flow rate is used for the CFD simulation and temperature responses at 36 monitoring locations were extracted. In the second stage, the inlet and the extracted temperature profiles were used to develop DBM models at individual locations. Finally the developed compact DBM model was used to construct model based predictive control algorithm.
As particles in room air can cause lung diseases, it is important to study how they are transported and dispersed in buildings. This investigation numerically studied particle dispersion by using the Lagrangian approach. The turbulent airflow is solved by the RNG k-e model; and a discontinuous random walk (DRW) model is applied to account for the stochastic effect of particle movement in turbulent flow. The computed results agree reasonably well with the experimental data for particle dispersion in a wind tunnel.
Zoning room air conditioning strategy is based on the idea of controlling the conditions of one zone by supply air and, at the same time, utilizing the stratification of temperature and contaminants in another zone. The aim of this study was to assess the ability of CFD-simulation to predict the supply air flow pattern and the overall performance of the system. The study was based on a series of laboratory experiments and corresponding CFD-simulations.
An energy simulation program, ESP-r, was used for simulation of the energy requirements and indoor climate in a well-insulated terraced house in Sweden. A parameter study was performed to investigate the influence of different control schemes on energy requirement. The influence on both energy requirement and indoor climate were analysed for two different measures. Changed placement of the air temperature sensor in the heating system decreases the energy demand without deteriorating of the indoor climate.
New equations derived from the recent ASHRAE-sponsored research project RP-1026 will enable HVAC system designers to better predict aero-acoustic performance of sheet metal plenums. This paper deals primarily with the aerodynamic performance of flow-through plenums and presents new
total pressure drop equations for some of the most common plenum configurations. Comparisons are made between these equations, computational fluid dynamics (CFD) analyses, and hand-calculation methods. The practical uses of plenums are discussed along with prescriptive rules of thumb to help
Currently, a design of the maximum velocity stress in the occupied zone is based on applicationof the jet theory equations or on the data from the manufacturers catalogue. However, thesemethods are based on the idealized test conditions in empty rooms and do not necessarily predictthe conditions existing in realistic rooms with heat sources and sinks. Furthermore, little data isavailable of the distributions inside the occupied zone. A new statistical method for occupiedzone maximum velocity prediction is introduced and verified using experimental data.
This paper considers the predictions obtained using a recently developed ventilation parameter (VP) for evaluating the ventilation performance which combines the indices for indoor air quality and thermal comfort. This ventilation parameter is used to analyse the changes in ventilation performance with changes in the position of workstation in a room ventilated using mixing ventilation.
This study suggests a computer model capable of predicting thermal environment of an atriumand calculating indoor sol-air temperature, which can evaluate the influence of heat loads thatthe atrium space puts on the adjoining rooms. The computer model is based on zonal modelcombined with the solar radiation model using the Monte Carlo method and ray-tracingtechnique. The accuracy of computer model was validated through scale model test and fieldmeasurement. The average relative error of solar radiation model for predicting solar radiationintensity in atrium space was 11.8%.