English

Established methods of computational fluid dynamics (CFD) have been applied to predict the details of airflow, contaminant dispersal and thermal transport within isolated zones, yet zone transport processes do not occur in isolation. They result from and interact with the bulk airflows from the larger whole-building systems in which they are embedded.

This paper presents an assessment of indoor air quality and various ventilation strategies inside a school building located in the south of Portugal. In the first phase, ventilation rate was experimentally evaluated using the tracer gas method. In the second part, different airflow typologies were investigated and, after calculating the air exchange and flow rates for each of them, the evolution of metabolic carbon dioxide inside the spaces was numerically estimated.

The interaction of turbulent plumes is examined in the context of building ventilation flows. Recent models for natural ventilation have been based on simplified treatment of the heat sources in a ventilated enclosure. These models treat buoyancy sources as plumes and assume that they do not interact. To improve the applicability of these models to buildings we examine the effects of plume-plume interaction on the ventilation flow. We present experimental results for the flow in a ventilated enclosure where two plumes in close proximity to each other coalesce to form a single plume.

Desiccant cooling is a potentially environmentally friendly technology which can be used to cool buildings without the use of traditional refrigerants. We have studied the operation of a desiccant cooling system in France. It is used to meet the cooling demand of a training room containing 40 persons. In order to decrease the system primary energy requirement, free cooling techniques are used. Models are implemented in SimSPARK a simulation environment able to solve complex problems. Simulations are run for several French cities.

This paper presents steady-state energy and exergy analyses for dwelling ventilation with and without air-to-air heat recovery, and discusses the relative influence of heat and electricity on the exergy demand by ventilation airflows. Energy and exergy analysis results for De Bilt, NL, are presented in terms of heat and electricity use, on an instantaneous and a daily basis. The amount of electricity input to fans and the heat recovery unit (HRU) is much more significant in terms of exergy than of energy, due to the higher exergy value of electricity.

A model has been proposed for evaluating the discharge coefficient according to the flow angle at an inflow opening for cross-ventilation. This model is based on the fact that the cross-ventilation flow structure in the vicinity of an inflow opening creates dynamic similarity under the condition that the ratio of cross-ventilation driving pressure to dynamic pressure of cross flow at the opening is consistent. It was confirmed from a wind tunnel experiment that the proposed model can be applied almost regardless of wind direction and opening position.

In recent years, the quest has been focused on energy efficient building design. To achieve this in terms of high efficiency air conditioning schemes for hot climate cooling, the combination of variable refrigerant volume (VRV) with variable air volume (VAV) systems have become popular. In this paper, attention is focused on achieving good thermal comfort and indoor air quality (IAQ) combined with energy savings by using multi-zone VAV air conditioning (A/C) that incorporates a genetic based fuzzy logic controller (FLC).

The Local Dynamic Similarity Model (LDSM) is a ventilation model for predicting the discharge coefficient and the inflow angle at the opening of a cross-ventilated building. This model requires a dynamic pressure generated by the wind velocity component tangential to the opening in addition to wind pressure. Also, total pressure, wind pressure, static pressure, room pressure and inflow velocity components are needed for model validation.

The design of a building should provide the flow paths needed for natural ventilation. Therefore, the decision to apply natural ventilation should be taken early in the building design process, when little information is available for airflow estimation. To deal with this lack of data, a semi-qualitative method to assess the potential of an urban site to host a naturally ventilated building is proposed. First, natural ventilation driving forces and constraints are assessed by using comfort criteria, statistical meteorological data and userprovided information.

Previous research has shown that air movement has a significant influence on humans’ thermal comfort. For persons feeling cool, air movement tends to be perceived as draught, whilst when feeling warm air movements may provide a desired cooling effect. In the transition zone it therefore seems difficult to use constant air velocity as a tool for cooling without creating draught problems.