passive ventilation

Whole-house ventilation systems are becoming commonplace in new construction, remodeling/renovation, and weatherization projects, driven by combinations of specific requirements for indoor air quality (IAQ), health, and compliance with standards, such as ASHRAE 62.2. At the same time we wish to reduce the energy use in homes and therefore minimize the energy used to provide ventilation. This study examined several approaches to reducing the energy requirements of providing acceptable IAQ in residential buildings. Two approaches were taken.

Ventilation towers are often incorporated into the design of naturally-ventilated buildings. These towers increase the physical height of the building and thereby potentially enhance the buoyancy-induced air velocity. However, acoustic baffles, insect meshes, etc., placed within the towers result in pressure losses that effectively reduce the area of the flow path, thereby restricting the rate of airflow.

Recently most houses in northern Japan are highly insulated and air-tight, which can lead to seriousproblems such as indoor air pollution. It is important to evaluate the performance of an air-tight housefrom the viewpoint of ventilation. However, in general, houses consist of multiple rooms and each roomhas airflows in different directions which mix with each other. Therefore it is not easy to measure realventilation rates.The purpose of this paper is to evaluate a simplified method for measuring airflow rates in houseswhich have a basement with outer insulation.

The necessity of focus on more large integration of passive concepts for indoor climate conditioning is today a reality. Through this study, a contribution to fill the lack of useful design guidelines for natural ventilation is proposed, in order to develop the passive ventilation systems implementation. Besides a methodological approach, the paper proposes conceptual tools. The implementation of a natural ventilation strategy includes the envelope building design, the indoor spaces layout and the

Describes a project to develop strategies and dissemination material to assist the efficient application of solar and passive ventilation in urban buildings. Describes the website, aimed at the informed architect and engineers specialising in HVAC. Features design solutions in the form of case study buildings and design components. Also presents a review of how current regulations encourage/restrict the application of solar and passive ventilation in urban buildings.

Currently, in the design of new buildings and retrofit of old buildings, attention is turning towards a more integral energy design with focus not only on thermal insulation and airtightness but also on optimal use of sustainable technologies such as natural ventilation. There is a tendency for buildings to be designed in order to utilise the outdoor environment to create an acceptable indoor environment, whenever it is beneficial. Passive ventilation and natural cooling are sustainable energy efficient and clean technologies.

There has been a growing interest in the use of natural ventilation in buildings to supplement orreplace mechanical air supply systems. However, for buildings in busy urban areas the potentialto use natural ventilation can be limited by excessive noise entering through natural ventilationopenings such as windows and trickle ventilators. Such openings tend to have large open areasto enhance air flow while offering a very low resistance to the transmission of external urbannoise.

Passive solar cooling for hot humid areas represents an important field for innovation, if we want to solve comfort needs in spaces (especially housing) designed to reduce economic, technical and health requirements. In urban areas or deep valleys and rain forests, which are common in most of the tropical equatorial countries, external breeze is not frequent and air speeds are too low to produce cooling, using a simple cross ventilation system. Since 1982 the author has developed new designs and constructions using passive solar techniques.

The feasibility of designing ventilation routes in the house with passive ventilation system is investigated using the numerical experiments and the measurements on its ventilation rates and indoor air quality. As a result, the ventilation design using the used-air in the rooms on the second floor is proved to be one of the simplest ways to keep good indoor air quality. And the required airtight level of the house with the ventilation design is lower than that with the general ventilation design where the air is supplied to every room.