English

In France there is an increasing demand for energy efficient and environmentally friendly buildings of high thermal comfort. Balanced ventilation systems with heat recovery on the exhaust air and earth to air heat exchangers (EAHEX) are interesting techniques which can reduce the heating and cooling demand of buildings, and improve internal thermal comfort. A numerical study was carried out to evaluate the impact of these two systems on the energy performance and internal thermal comfort of a dwelling, with respect to the French climate characteristics.

The objective of heating, ventilating and air conditioning (HVAC) systems is to satisfy users when it comes to health, indoor air quality (IAQ), and thermal comfort. Air conditioning systems employed to provide thermal comfort and indoor air quality consume a significant part of building energy requirements. Any effort to minimise energy consumption improves cost effectiveness and economics. A variable air volume (VAV) system is a choice in that direction. In this research, a relative energy consumption analysis of a constant air volume (CAV) system and VAV system has been performed.

Natural ventilation using open windows is an energy efficient and effective method of providing a good indoor air climate in schools. However, open windows not only let fresh air into the building but also external noise. The availability of automatically controlled windows enables precise control over the window opening distance in comparison with manually operable windows. This paper considers the benefits of using small opening distances to provide sufficient ventilation for a good indoor climate as well as attenuation of external noise.

Active thermal mass strategies can be used to enhance the performance of thermal mass through integration with the heating, ventilation and air conditioning (HVAC) systems. Dynamic thermal modelling is required in most cases to accurately determine the performance of its integration with the environmental systems of the building. This paper describes the use of a commercially available dynamic building thermal program to construct models for active thermal mass strategies and compare the results with monitored temperatures in buildings incorporating the strategies in the UK.

The purpose of this work is to present a study of the indoor environmental conditions of an office which is fully occupied and naturally ventilated by window and door opening. In order to investigate the mechanisms controlling the indoor environmental conditions, as well as the processes acting indoors, the CFD model PHOENICS and the numerical mass balance Multi-chamber Indoor Air Quality model (MIAQ) were applied. Model inputs were based on input data obtained from extensive experimental measurements that took place in the office.

The authors outline the knowledge they have gained through their design experience on the efficacy of natural ventilation in non-residential buildings in Japan. They also describe the various challenges which must be overcome to deploy natural ventilation. It is hoped that the knowledge presented in this paper will be of reference in the drafting of guidelines for the research and design of future natural ventilation systems.

To evaluate wind pressure distribution on a building by using CFD (computational fluid dynamics), it has been general practice to use k-e models. However, it is known that the use of the standard k-e model has disadvantages such as overestimation of wind pressure coefficient and turbulent kinetic energy on the windward surface where wind impinges on the building. To overcome these problems, various modifications of the k-e model have been proposed.

This paper addresses the applicability of passive and low energy cooling technologies in the Czech Republic. The main research methods are climate analysis and buildings and systems analysis, both with the objective to assess the building performance potential of passive and low energy cooling technologies. The analysis is based on case studies, which include building performance simulation as well as in-situ monitoring. The role of computer simulation in low energy building design and optimisation is briefly discussed.

Sustainable architecture design for tropical climates requires the use of natural ventilation combined with other strategies including: the use of appropriate materials, site location, orientation of faades and solar shading, etc. Requirements for thermal performance and indoor thermal comfort also depend on the geographical site where the building is located. The new Brazilian standard Norma ABNT NBR 15220-3 has established seven bioclimatic zones and some architectural guidelines for low-income houses.

In this study, the evaluation of cross ventilation is presented based on the simultaneous analysis of inside and outside conditions and for wind directions other than 0 degrees (i.e. for wind flow that is not aimed directly or normally to the inflow opening). The first part of the paper considers a conventional CFD analysis and compares the performance of the widely used k-e turbulence model as well as the modified Durbin k-e turbulence model. While a CFD approach can give good results it is very labour and computationally demanding.