In cold and moderate climates, improvements in building shell insulation and air-tightness imply a shiftin heating loads from transmission and infiltration towards ventilation. Heat recovery from the ventilation airflow plays an increasingly important role in minimising energy needs. Such heat recovery systems rely on the input of electric power (to drive fans, heat pumps, etc.) in order to recover thermal energy. Since electricity input is relatively small compared to the amounts of thermal energy recovered, such systems are efficient from an energy viewpoint.

Although the concept of ventilation has been around for several thousand years, the application of ventilation to overcome low productivity in warm to hot climates has been neglected over the last few decades. Since the advent of relatively cheap air conditioning owners have been seduced into installing air conditioning in the belief that the supposed increase in productivity will offset the high capital installation cost as well as the operation and maintenance expense. Local limited research has indicated that this is not the case. In fact, anecdotal evidence suggests the opposite.

Sustainable architecture design for tropical climates requires the use of natural ventilation besideseveral strategies, as appropriated materials, site location, faade orientation, solar shading, etc. Theindoor thermal comfort and thermal performance of the building depends on the bioclimatic zonewhere is located. The new Brazilian Norm ABNT NBR 15220-3 has established bioclimatic zones and guidelines for low-income houses. Due to the lack or scarcity of meteorology wind data, certainregions as Amazon and Northeast coast were inserted in a same zone.

The passive cooling techniques such as night time cross ventilation is potentially an interesting strategy to provide substantial cooling energy savings in warm climates. The efficiency of the night cooling ventilation is determined by three main factors: the external air flow rate in the room, the flow pattern and the thermal mass distribution. Most of the software used to simulate building thermal performance assumes natural convection in the enclosure; therefore the convective heat transfer coefficients for internal room surfaces are underestimated.

Natural ventilation driven by the combined forces of wind and buoyancy has been studiedexperimentally for a building flanked by others forming urban canyons. The steady ventilationestablished in an isolated building was observed to change dramatically, both in terms of the thermalstratification and airflow rate, when placed in the confines of an urban canyon environment. Theresulting ventilation flows and internal stratifications are presented for different combinations of windspeed, opening area and location, and canyon width (building density).

Cross ventilation is one of the most important techniques for maintaining a comfortable indoorenvironment in hot and mild seasons with less cooling energy. But, at present, it is difficult to designindoor environment under cross ventilation because there is insufficient knowledge to evaluate theeffect of cross ventilation quantitatively. Thus the full-scale model experiment has been done in a large wind tunnel to examine the airflow property in the cross-ventilated space.

Ventilation is essential for health and comfort of building occupants. It is particularly required to diluteand/or remove pollutants emitted by occupants metabolism. The concentration of metabolic CO2 iswell correlated to metabolic odor intensity. Therefore CO2 concentration can be efficiently chosen asan indoor air quality indicator when occupants are the main pollution source inside the buildings.

Dynamic analysis is very useful to obtain thermal properties of building components. However different methodologies can be applied, and several software tools based on these methodologies are available which application requires certain degree of experience. The main differences between methodologies are the numerical procedure and the model assumed to estimate the required parameters. Different approaches can lead to different and even wrong estimations of the parameters.

The use of electricity in buildings constitutes around 16% of Singapore’s energy demand. To incorporate energy efficiency measures is one of the key mission to ensure that the economy is sustainable. The recently launched building energy efficiency labell

The process of implementation of the EPBD in Austria is now carried out for several years. Thecalculation scheme for asset rating is finished, the operational rating procedure is still being discussed.One of the major problems in Austria is the fact that most building laws are under the responsibility ofthe nine Austrian provinces. Therefore all political decisions like baseline and limits of the energydemand for the building codes are difficult to achieve. These values are therefore still underdiscussion.