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.

Passive cooling techniques such as night time cross ventilation can potentially provide substantial cooling energy savings in warm climates. The efficiency of night cooling ventilation is determined by three main factors: the external airflow rate in the room, the flow pattern and the thermal mass distribution. The aim of this paper is to analyse the effect of the enclosure shape and the situation of inlet/outlet openings on the total cooling energy stored in the structure.

The possible benefits of automatic ventilation control of trickle ventilators in dwellings are investigated. Such ventilators could offer an improvement in performance over fixed ventilators, due to their ability to adjust to environmental conditions without occupant interaction, thus improving energy efficiency and providing adequate indoor air quality.

Among the tools which serve to predict heat and mass transfer in a mechanically ventilated room, CFD is increasingly used. However, this type of tool needs a correct description of the boundary conditions, especially concerning the air inlet. The ventilation inlet is often geometrically complex and many models exist in order to simplify their equivalent boundary conditions included in CFD codes. Nevertheless, none of these simplified models can predict the correct behaviour of flows issuing, for example, from a T-pipe, a bend or a more complex ventilation system.

The effectiveness of various methods for saving energy and improving the indoor environment in buildings depends upon the building conditions under which those methods are applied. To find better design solutions in such situations, designers or building owners need to make reference to quantitative information so that they can choose appropriate methods, which fit to the design conditions. These include data such as climate, surrounding environment, construction, occupants lifestyle and economic constraints.