In Hong Kong, design and construction of new operating rooms and upgrading of older ones have been based on the UK Health Building Notes. In a case study, field measurements showed that the airflow and some design features did not tally with the specifed requirements.
As the risk of contamination in an operating room can be minimized through appropriate filtration and air distribution scheme, a CFD analysis was carried out with the simulation of the temperature distribution, airflow pattern and the contaminant dispersion.
For that study , three german buildings with double facades have been monitored for at least one year in order to evaluate their energetic performance. The first building had no air conditioning facilities, the second one had cooling equipment without mechanical ventilation, and the third one had cooling equipment combined with mechanical ventilation.
Designing an HVAC system has different aims, the first one is to satisfy the user with a long-term functioning system in the most energy efficient way and the second is to increase the supply air flow. So the main objective of this paper is to give the fundamentals for a system design that takes into account the 3 factors. The benefit of a pressure controlled variable air volume (VAV) system is presented .
The values of the normalized concentration in the occupied zone (Cn) in an office space arecalculated by CFD for five different ventilation systems and the minimum ventilation rate which maintains the average concentration in the occupied zone under the regulated value is analyzed. Energy consumptions associated with the change in ventilation rate are analyzed. In this analysis, for most ventilation systems, the value of Cn is around 1.0, but for large circulation flow ventilation systems it changes greatly depending on the supply inlet velocity and temperature.
Integration of building components and ventilation systems is an effective way to control thermal loads, especially cooling loads. The key point of the system which has been studied in this paper is a special hollow building slab which allows the penetration of variable ventilation air flows. The ventilation rate may be adjusted following a specific control strategy, in order to activate the thermal mass of the slab, and enhance the free cooling effect in the night time.
Arthur Rosenfeld cited a study showing that the huge link between IAQ and productivity in anoffice building and the serious initiative to improve indoor air quality will have a tremendous return. This study attempts to analyze the working spaces with different variances. The chamber measurements in the laboratory constructed in Shu-Te University will be taken, and the numerical simulation using CFD techniques will also be applied. The results from both should be compared. The different inlet layout of HVAC system, especially the UFAD system, and the boundary conditions will be discussed.
The fluctuating characteristics of airflow have impacts on the thermal comfort of people. Two kinds of mechanical airflows in indoor environment were tested and analyzed in the paper. Spectrum analysis, chaos analysis were used to study the rule of the fluctuating characteristics shifting of the mechanical airflows. The results show that the fluctuating characteristics of different kinds of mechanical winds are different. It is also found that the characteristic parameters of the mechanical airflow, such as power spectrum etc.
We describe the flow in an underfloor plenum. We show that the geometry of the plenum causes the flow to exhibit two-dimensional dynamics and to develop flow patterns that are determined by the inlets of the underfloor into the plenum void. We describe laboratory experiments that simulate these flows and also show that the location and number of diffusers in the plenum has little effect on the underfloor flow. Depending on the location of the inlets to the plenum, the flow can exhibit complex vortex patterns and may be time dependent.
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.
An experimental study was conducted in a field environmental chamber with the aim of comparingceiling-based mixing ventilation (MV) system and under-floor supply system (UF) from the perspectives of indoor air quality and thermal comfort. Six tropically acclimatized female subjects participated in the experiments and they were required to complete a set of questionnaire pertaining to IAQ and thermal sensation every 20 minutes during each exposure of 2 hours.
Login