The energy consumption matter for the building sector has come up again urgently looking for standards, measures, policies and best practices. That is because building sector have direct impact both on energy consumption and environment (cooling, heating, raw materials for construction, consumption of natural sources-water, fossil fuels and emissions of harmful substances). Buildings are responsible for the approximately 40% of the primary energy consumption in EU (164 millions buildings in EU- 15, 193 millions in EU-25) and for about 50% of CO2 emissions.

The use of centralized air-conditioning systems in buildings with fixed windows is becoming an increasingly high-risk strategy in buildings for a number of reasons. These include fuel insecurity and price rises, the need to reduce climate change emissions from the built environment, and the need to make buildings more robust in the face of the extreme weather events that are beginning to characterize climates in a warming world.

This paper challenges the conception that comfort can exist only w/in strict parameters, should be achieved w/o inhabitant interaction, and cannot be achieved w/o mechanical means. A period of research was conducted followed by the redefinition of several standards of practice. A mixed-use adaptive re-use design application was developed and simulated in an effort to combat the perceived necessity of mechanical cooling systems (Fig. 1).

As dry assembled multi-layered walls very often suffer overheating in hot climates because of their low thermal inertia, the appropriate use of Phase Change Materials (PCM) inside the same walls can increase their thermal mass before they reach high temperatures (which they tend to do when irradiated by the sun) avoiding overheating.

Achieving good building energy performance has been a major challenge in architecture but has intensified over the past twenty years. Today, the constant increasing cost of energy and the environmental impact of production and energy use make reduced energy use a significant objective in the design and operation of buildings. This paper addresses the general problem of minimizing building energy consumption and the associated operational costs of HVAC systems in an existing building.

China is rightly regarded as a country in which progress on developing sustainable and low energy solutions for building design is essential. The size of the population, the rapid urbanisation that is taking place, and the reliance on fossil fuel based energy sources, not only make this a priority for China but also for the rest of the world. The concept of zero emissions or zero energy buildings has been in existence for many years in the UK and other developed countries and more recently has evolved to larger scale examples such as the development of complete housing schemes.

A large number of design guidelines and tools are available for the design of passive cooling systems. However, the building engineer should take several uncertainties into account since the actual use of the building, the building physical properties or the user behaviour are uncertain. One promising approach to include these uncertainties in the design procedure is the use of statistical models: The design parameter is defined by a mean value and its deviation.

The insertion of Phase Change Materials (PCM) inside light dry assembled building envelopes seems to be the right way to solve overheating problems usually caused by the low thermal inertia of such walls.

This work aims at applying a numerical analysis methodology, based on CFD techniques, to evaluate the effect of the wind and the temperature over the quality vision of a new telescope in La Palma (Spain). This island constitutes one of the best places in the world to carry out astronomy experiments. However, small variations in the climate conditions, together with the particle dispersion, drastically affect the selection of the best place where this building may be installed.

The paper is divided in two parts: the first is about the microclimatic function of the vegetation in built area. Experimental data in different contexts case studies- are analysed in order to define guide-lines for cooling. The second presents a data base of the ecological, functional, morphological characteristics of trees and shrubs. This data base contains sixty elements and is a useful tool for designers, when they want to put green elements in an urban context.