simulation

At present, numerical simulation of room airflows is mainly conducted by either the Computational-Fluid-Dynamics (CFD) method or various zonal/network models. The CFD approach needs a large capacity of computer and a skillful expert. The results obtained with zonal/network models have great uncertainties. This paper proposes a new simplified method to simulate three-dimensional distributions of air velocity, temperature, and contan-finant concentrations in rooms. The method assumes turbulent viscosity to be a function of length-scale and local mean velocity.

The detailed dynamic simulation of coupled units in HVAC-systems and buildings is gaining increasing importance as strong tool in HVAC-engiiieering and operation. This investigation deals with the basics in the development of an universally applicable dynamic simulator. General fundamentals are formulated some moduls are outlined. Shnulation of a heated 4-room-residence, a solar system. and a storage tank as applications demonstrate the mode of functioning and the potential of the simulator.

The LCA methodology [SETAC] is applied to buildings. The system limits, functional units and allocation principles are explained. Inventories have been established for 150 buildings materials and linked to the ECOINVENT database. Buildings are described on the basis of specifications which are aggregated to (cost planning)-elements. There is a catalogue of several hundred elements. Energy needs, costs and environmental impact are calculated simultaneously. Different views are possible (type of Impact. life time phase, element).

The purpose of this research is to give an overall prospect of the performance of 4 kinds of ventilation systems for dwellings using numerical simulation under various conditions. The total number of combinations of various parameters for the calculation is 174. Calculations for pollutant concentration, humidity and condensation, interior pressure and airflow rate, heat energy by ventilation, etc. are performed hourly through the heating season.

Concentrations of indoor air contaminants are normally calculated by assuming that they fullyfollow airflow paths in a room. This assumption is also used to predict the local residence timeof contaminants in a room, which may further be used to characterise the ventilation effectiveness.In this paper, a different methodology has been adopted, in which indoor airborne particles do notalways follow the main airstream induced by the ventilation system. Dispersion of particles ispredicted by a drift-flux model.

The OM solar system is one of various passive systems. As is in the general passive system, the technique in the OM solar system works with the designing and architectural space as a unity. In other words, the technique is a part of the designing. Nowadays a lot of new technique have been developed and all kinds of related technology are born. During the past nine years, the system has been already employed in about eight thousand homes and sixty public buildings all over Japan.