English

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.

Based  on  the  thermal  and  airflow  network  model with simple but perfect generic formulations and stable solving methods, a computer program NETS for the practical simulation of coupled building heat, gas and air transfer system has been developed. NETS can simulate the feedback or the schedule control on models' structural changes and various driving condition changes. A pre-processing system called NETSGEN and a post-processing system called NETSOUT have been also developed.

In this report, recently developed computer program named TB3D/FDM(Thermal Bridge Computa- tion by 2- or 3-Dimensional Finite Difference Method) is introduced. This program enables steady state heat transfer analysis of building exterior walls including thermal  bridges. TB3D/FDM  has a tool forming input data set for 3-D computations from DXF file, and employs TRAC3D (Thermal Radiation and Air-Convection in 3-Dimensional Air Cavity) computing thermal resistance of 3-D air cavities.

THERM  2.0  is  a  state-of-the-art  software  program, available without cost,  that uses the finite-element method to model steady-state, two-dimensional heat- transfer problems. It includes a powerful simulation engine combined with a simple, interactive interface and graphic results. Although it was developed primarily to model thermal properties of windows, it is appropriate for other building components such as walls, doors, roofs, and foundations, and is useful for modeling  thermal  bridges  in  many  other  contexts, such as the design of equipment.

The  traditional  methods  for  the  evaluation  of  the thermal performance of buildings are appropriate to winter conditions and are often used in standards that regulate energy consumption.

The  successful  application of  moisture  simulation models to building envelopes requires accurate values of material transport properties. Unfortunately, although the presently-available database is reasonably voluminous, much of the information given is of limited use.