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.

Investigation the modelling of the mathematical model of expediency of project decisions of building materials including the human safety the asbestos. The asbestos is most widely used in the production of roof cover-slate. At this moment the building materials in which composition the asbestos is used, become the actual ecological and economical problem of the country.

Parametric studies have often been used for sensitivity analyses in the field of the pharmaceuticaland agricultural sector. All such studies aims at bringing some kind of order out of complicatedrelationships between influencing factors and some response parameter(s). With experimentaldesigns and statistical analysis methods, it is possible to trace and quantify influencesof individual as well as combinations of input factors on the response parameter. Thisprocedure has so far very seldom been used within the building sector.

The necessity to provide and maintain high cleanness of air in the rooms of the highestcleanliness classes requires a proper adaptation of selection and designing methods for airfilters. The level of air cleanliness for such rooms is defined numerically by the determinationof the permissible number of dust particles whose diameters are equal or higher than the givenlimit values.

New thermodynamic energy "water potential" based on the chemical potential of a component of mixture gases is defined as the driving force of gaseous phase water flux. Adhesive power, which is a kind of stress call "capillary attraction" and a part of the water potential, is proved as the driving force of liquid phase water flux. Then numerical model of coupled heat and water transfer using the water potential is introduced and influences of stress such as gravity and stationary pressure on water flux are clarified from the viewpoint of thermodynamics.

Air flow patterns in rooms can roughly be classified as one of three types: Displacement flow, source flow and mixed flow. Displacement flow in its original meaning is only used in special applications like clean rooms. Mixed flow is generally found in air-conditioned spaces, source flow which is frequently also called "displacement flow" is the usual type of flow in naturally ventilated spaces. This type had become more and more common in air-conditioned spaces in recent years.

Temperature and relative humidity have been measured in a BRE test house to investigate the vapour content in the void beneath the timber floor. The void can be ventilated naturally or by means of a fan supplying or extracting air. The results show that air flow into and out of the void is stack dominated. The fan needs to supply or extract large volumes of air in order to disrupt this. Measurements and modelling have shown that the vapour content in the void is generally dependent on the level in external air, and that the contribution from the ground is usually small by comparison.

The objectives of thisinvestigation were to examine the dynamic water vapour sorption offurnishing materials and to compare the experimental results withpredictions obtained from the Moisture Admittance Model. Dynamic sorption measurementswere carried out for common building materials. The measurements were made by placingspecimens of the materials in a humidity chamber and varying the ambient humidity between46% and 90% RH at constant 22C. The weight of the specimens was monitored in situduring this procedure.