Split-system air conditioning is increasingly usedapplications, owing to its low cost and installationboth for residential and commercialease. The indoor split-system unit iscommonly of the wall-mounted type and, due to its dimensions and position, very often itgives rise to appreciable air velocities and temperature gradients in the occupied zone of theroom. This work reports and discusses some experimental data collected in a test room withwall-mounted indoor unit, under different operating conditions.

The purpose of this paper is to evaluate the performance of four kinds of ventilation systems from the point of view of air exchange, indoor air pollution, and space heating load under Japanese conditions by numerical simulation. TVOC and CO2 are selected to characterise the indoor air quality impact to residents. The results show that the equivalent leakage area has great influence on air movement.

Recently well-insulated and well-airtightened houses are increasing in Japan. Those houses havesome problems of air quality because of formaldehyde from construction materials. Ventilationsystems have possibility to solve these problems. The authors have developed a simulation programfor designing building elements, equipment elements to keep balance among comfortabletemperature and humidity, good air quality and energy conservation. The effects of some ventilationsystems in multiple dwellings are revealed by the developed simdation program.

Particle deposition from turbulent duct flow is modelled and related to particle penetration of a ventilation system for a commercial office building. Three published turbulent deposition models capable of accommodating surface roughness are compared to experimental data and used to determine the penetration of 0.1 - 10 (m spherical particles through a sample duct run. Depending on the model employed, penetration fractions varied from 0.40-0.94 for 0.1 (m particles and 0.28-0.73 for 10 (m particles.

An efficient ventilation system is characterised by a well-organised and turbulence-controlled airstream that rapidly corrects disturbances in air quality and thermal comfort in the ventilated space.Air supply and exhaust conditions are investigated here in order to find stable flow conditions andan efficient elimination of both gas and solid phase contaminants. Heat and thermal comfortrequirements are also included.

The influence of natural convection on the thermal properties of insulating porous medium with air cavity is studied. Here, the combined effect of air movement in the air cavity and the air movement inside the insulation is evaluated with the help of numerical analysis. The influence of total natural convection on the thermal properties of mineral wool, loose-fill insulation, insulation made of small and large polystyrene ball with air cavity are studied. The results are presented in terms of dimensionless numbers and the temperature distribution across the insulation.

There is a growing demand for buildings to have a high indoor air quality environment. Twoof the main elements that contribute to this quality are temperature and air distribution withinthe occupied space. In modern office buildings particularly in hot climates, care must be takento design the most economical air distribution system that provides comfort for the occupants.There are many techniques available to predict the air distribution patterns in the space atdesign stage, but these are often not very accurate.

The Paper deals with numerical computations, carried out, in order to predict the effects of natural convection on the thermal performance of porous material. In this paper the effect of natural convection in a horizontal porous layer will be discussed. The study of the above configuration is essential to understand the functioning of insulation of the type used in attics. The influence of natural convection on the thermal properties of mineral wool, loose-fill insulation, insulation made of small and large polystyrene balls are studied.

House-dust mite antigens are a major contributor to allergic sensitisation. Since temperatureand humidity are crucial to house-dust mite physiology, there is considerable interest inreducing mite populations by controlling the indoor environment.

This study is to investigate the characteristics of indoor air temperature distributions and airflow patterns with three air diffusing systems in heating period and to find the methods which can predict those indoor environmental conditions effectively. A series of measurements and corresponding numerical analysis were done. Selected three air diffusing systems for this study are as follows; 1) ceiling supply-ceiling exhaust, 2) ceiling supply-floor exhaust, 3) floor supply-ceiling exhaust.