English

This paper reports the effect of adsorptive building materials in reducing formaldehyde inindoor air. Although some studies have reported that adsorptive building materials are effective inreducing concentrations in chamber experiments, there are few studies which are carried out in actual room. In this paper we examine the reduction effect of changing the surface area of the adsorptive material in a room and the most effective arrangement of the material. We confirmed that the reduction effect is not always proportional to the adsorption surface area.

For underfloor air distribution (UFAD) systems, more rapid mixing of the supply air with ambient airis desirable for better thermal comfort, and swirling air diffusers are usually used. In order to rigorously simulate the flow characteristics of such diffusers, we used the multi-grid technique and validated it with experimental results. In this paper, the technique is used to compare the square diffuser and the swirling diffuser.

An experiment was carried out to determine the effect of photocatalytic air cleaning on perceivedair quality. Thirty-eight subjects assessed the air quality in a low-polluting, 108 m3 office, with pollution sources either present or absent behind a partition. The pollution sources were carpet, linoleum and chipboard. The office was ventilated with outdoor air at 0.6, 2.5, and 6 h-1. The air temperature was 22C and the relative humidity 40%.

The paper reports on findings from a series of experiments where the supply flow rate wasvaried periodically in time. All experiments were conducted in a small scale model with water as operating fluid. The flow was visualised by adding particles to the water and the streaks were recorded with a digital camera. The main result is that there exist variations that generate a role up of the base flow by generation of vortices that are shed into the stagnant region.

The perceived intensity is investigated by a trained group of 10 to 15 persons. Until now fieldstudies have to be made at the location of interest. All members of a trained group have to visit e.g. a building in order to estimate the perceived intensity of the indoor air. The trained group is influenced by the local environment. This paper presents a new method to sample and to store air probes at arbitrary locations. The air probes can then be transported to the laboratory where a standard group test can be made in the neutral and clean environment of an air quality lab.

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.

This paper introduces a simple method for a natural ventilation strategic design and the evaluation of ventilation effectiveness. A simplified integrated dynamic thermal and air flow model has been developed for natural ventilation building design at the early stage. This analytic method can perform parametric studies and an optimum opening design. The indices of overheating day and ventilation sufficiency have been proposed to evaluate the ventilation effectiveness. Computer program can perform dynamic simulation for the proposed design.

The accumulation of heat, contaminant and water vapour into the upper part of rooms is utilized in stratification and zoning room air conditioning strategies. For the zoning strategy the plume penetration through the supply air jet is an essential parameter in modelling the temperature, concentration and humidity in the lower and upper zones of the room. This paper presents an analytical method for modelling the plume penetration for an air distribution method based on horizontal inclined jets of industrial grilles.

The mean velocity in rooms predicted by CFD simulations based on RANS equations differs from the mean (in time) magnitude of the velocity, i.e. the mean speed, in rooms measured by low velocity thermal anemometers with omnidirectional sensor. This discrepancy results in incorrect thermal comfort assessment by the CFD predictions as well as incorrect validation of the predicted velocity field. In this paper the discrepancies are discussed and identified, and a method for estimating the mean speed based on the CFD predictions of mean velocity and kinetic turbulence energy is suggested.

A Lagrangian-Eulerian model for the dispersion of solid particles in a three-dimensional, incompressible, laminar or turbulent flow is reported, tested and partly validated. Prediction of the continuous phase is done by solving an Eulerian model using a Control-Volume Finite Element Method (CVFEM). A Lagrangian model is also applied, using alternatively an analytical and a Runge-Kutta 4th order method to obtain the particle trajectories. The effect of fluid turbulence upon particle dispersion is taken into consideration through a simple stochastic approach.