IBPSA1999

There  are  two  kind  of  supply  fan  rotation  speed control methods, one is the static pressure control method, the other is the float pressure control method. Simulation shows that they have different working point along the whole year. The supply air fan controlled with float pressure control  method need low rotation speed and works on high efficiency, so the float pressure control method need only 30% fan operation energy of the static pressure control  method.  The  layout  of  the  air  duct  may influence the fan control method.

This  paper  referrer  to  the  existence  of  the variety modes and the 'chaos' in building ventilation system, and provides some instances of such varieties and the chaos in forced ceiling chamber smoke exhaust system in building fire. The numerical  calculations are executed by the Newton-Raphson method for the ventilation network models. The ventilation variety up to five modes and the chaos characteristics are obtained  as  the natural result of the non-linear system and illustrated in figures and maps.

Up to now, within the framework of validation of the global building energy simulation software programme CLIM2000, we have not focused on analytical verification. Indeed, the scientific literature is not verbose on this subject due to the fact that only few thermal problems have analytical solutions. In the framework of International Energy Agency (IEA) Solar Heating And Cooling (SHAC) Task 22 (Building Energy Analysis Tools), a working document was established identifying and summarising analytical tests as verification and debugging tests for building energy analysis simulations.

This paper presents the Umidus program which has been developed to model coupled heat and moisture transfer within porous media, in order to analyze higrothemal performance of building  elements when subjected to any kind of climate conditions. Both diffusion and capillary regimes are taken into account, that is the transfer of water in the vapor and liquid phases through the material can be analyzed. The model predicts moisture and temperature profiles within multi-layer walls and low-slope roofs for any time step and calculates heat and mass transfer.

In recent years there have been a number of research and development initiatives directed at integrated energy generation systems which can meet the energy requirements of a building substantially or even completely on-site. With the appropriate integration of passive and active technologies,  it may even be possible for buildings to be net exporters of energy - the "Building as Power Plant". This paper focuses on the computational modeling of such systems. We begin with an overview of the concept, motivation and objectives of the Building as Power Plant.

In calculating the heat flows around the floor plenum of underfloor air distribution system, the convective heat transfer coefficient is an influential factor, but it is not clearly known which value should be taken. The convective heat transfer coefficient was measured with the airflow velocity, and the relationship between them was clarified, involving the airflow and surface temperatures.

Located in an extreme arid natural environment, the city of Mexicali has confronted maximum temperatures of 54C during summertime. The high dependency of electromechanical systems use, in order to achieve interior spaces comfort is predominant, even when this represents a negative impact on economy given for the highest cost of its energy consumption requirements. This work presents the results of a representative housing simulation with the application of two environmental adequation strategies: roof insulation and walls material construction change.

If an insulated and airtight house is cooled by passive ventilation using buoyant convection, the indoor air temperature can be kept lower than the outdoor air temperature, but there is a tendency for the indoor humidity to remain at a high level. In this study, the thermal environment in a house in which a dehumidifier is used in summer is numerically calculated, and the performances of various dehumidifiers are examined. The results shows that a moisture-absorbent type dehumidifier, which has a low cooling load, can create a comfortable indoor thermal environment in summer.

A coarse-grid zonal model of room air convection is formulated and written with the SPARK object- oriented simulation environment. The model consists of a set of coupled equations determined by heat and mass balance on each of the cells into which the room is divided, convection from the room surfaces and radiant exchange among the room surfaces. The equations are first written in MAPLE, from where they are automatically translated into SPARK objects. The objects are connected to build the simulation.