English

Multizone network models employ several assumptions, such as uniform pressure and quiescent air inside the zone, which may cause inaccurate results in flow calculations.

This paper investigates airflow in an office room with a displacement ventilation system parametrically using three-dimensional CFD. A numerical study is executed for a typical office room with a dimension of 6m by 6m by 3m height according to a variety of supply air velocities, supply air temperatures and heat source conditions. Internal cooling load is given as 28W/m2  to 111W/m2. In CASE1, a heat source is installed at the center of the room. In CASE2, four heat sources are located separately in the modeled room.

This study is focused on the ground heat pump (GHP) used in heating single-family houses. These systems generate a ground heat depletion which decreases its performances after several years of operation. The study relates to the evolution of ground heat pumps performances and on simples solutions to maintain a stable temperature in the ground. The use of GHP in cooling mode during the summer and the coupling of thermal solar collectors with the boreholes is a good solution to complete the natural ground recovery.

Whereas water can frequently come in contact with wood-based building envelope components, little work has tried to measure and model moisture uptake in orthotropic wood. This paper presents experimental results and numerical simulations of water uptake in softwood. Water absorption coefficients were measured and shown to vary according to the orientation of the fiber grain. Helium pycnometry was employed to obtain porosity values with the intention of approximating the capillary moisture content of the wood samples. From these measurements, average diffusivities were estimated.

Increasingly the fire protection concerns at airports are being addressed using computational fluid dynamics and most of these studies have been based on the prescriptive recommendations on design of an airport terminal building given by appropriate standards. However, this study is based on the performance based principles of so called Qualitative Design Review (QDR), introduced by recently adopted fire safety standard (BS 7974: 2003-2004).

This paper deals with the development and the evaluation of hybrid ventilation control strategies, using both natural and mechanical modes, in residential buildings using a graphical simulation tool. The description of a library of airflow components and macroscopic pollutants models used to simulate the demand controlled ventilation based on indoor pollutant concentrations is provided.

Throughout its thirty year history, the transient energy simulation package TRNSYS has been under continual enhancement by an international group of developers and users. This paper briefly describes a subset of the features that were added to the simulation package with the release of its 16th version in November, 2004. 

This paper is part of a larger research to ‘theoretically’ review the application of natural ventilation to commercial buildings, the potential advantages these systems offer, and some pitfalls that must be considered.

A mathematical model applied to building hygrothermal behavior analysis is described in this paper. We have used a lumped approach to model the room air temperature and humidity and a multilayer model in finite volumes for the building envelope. The capacitance model allows studying the dynamic performance of both humidity and temperature of a building zone when it is submitted to the different climatic factors. In the results section, we show the moisture effects on the heat and mass transfer through the floor and ground.

Controlling humidity to prevent moisture and condensation phenomena is a growing problem for building designers nowadays. Ventilation and air conditioning are common solutions to avoid mold and condensation. However, to promote low cost energy buildings, an alternate solution may be to decrease the daily variation of humidity with anti fungi treated absorbing material.