English

The Air Infiltration and Ventilation Centre was established as a jointly funded International Energy Agency activity in 1979. This paper seeks to describe some of the work of the AIVC and outline its evolving structure which is aimed at strengthening the link between research and application.

A major concern of those wishing to limit the energy use in buildings is the growing trend towards installing air-conditioning in new and refurbished  buildings. The Airlit - PV project has taken this challenge and has designed a novel fa9ade unit incorporating the latest thinking in solar control, natural ventilation, daylighting and photovoltaic power. By careful design and intelligent control the goal is to reduce the impact of solar and internal gains to such an extent that mechanical cooling is not required to maintain comfort conditions.

The inherent unreliability of the forces which drive natural ventilation can make such systems unattractive for the designer. Developing interest in mixed-mode ventilation is prompting difficulties in sourcing components suitable for ultra-low velocity flow generation in large ducts. This work examines the possibility of using air induction. A theoretical analysis generates equations which assist the designer in sizing a suitable inducer for ventilation purposes. Preliminary tests which verify the theory are described.

Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilizes and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation. Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC.

An historical background of fluid mechanics used in computation of natural ventilation is provided. Unresolved issues in computation of natural ventilation for thermal comfort are discussed. These issues include the influence of building porosity on wind pressure difference coefficients; wind shelter effects; indoor air flow resistance; air flow for thermal comfort and heat stress relief; air flow computation techniques; and natural ventilation in home energy rating schemes.

This paper summarises the planned redevelopment of Webber's Yard industrial estate on Dartington Estate in Devon. It discusses the needs of different stakeholders involved in the project and outlines how the design team responded. It argues that this approach to building design and development is particularly sustainable and could be used as a model for the development of other light industrial estates.

This paper describes the current government activities relating to Photovoltaics in buildings as implemented in tbe DTI New and Renewable Energy Progranune. To set the context the paper starts with a brief review of the overall prospects for renewable energy in global, European and UK contexts. This is based on work previously undertaken for the DTI1. For comparison, the current state of deployment of renewable energy in the UK is reviewed. This then leads into a brief description of the UK government's programme on new and renewable energy.

The on-the-ground experience of a domestic design and construct company (Ecobuild Pty Ltd, for which the author is the designer and director), is illustrated as a case study for the application of domestic natural ventilation in the temperate climate of Sydney. Factors limiting the general domestic application of natural ventilation are discussed. Requirements of a domestic ventilation system in Sydney are listed. Examples of domestic natural ventilation designed the company are illustrated. Preliminary results are discussed. The need for domestic IAQ research and standards is stressed.

This paper reports on research into the fundamental fluid mechanics mechanisms that lead to thermal stratification in a naturally ventilated room containing sources of heat, or cooling. This aspect of natural ventilation has an important influence on both air exchange rates and thermal comfort in a naturally ventilated space. Particular attention is paid to the situation where the major source of heat is a vertical surface, such as a wall heated by solar insolation, for example.

Unsteady wind effects can be important in natural ventilation, but their treatment requires knowledge of instantaneous surface pressure distributions which are extremely difficult to obtain. The paper describes a theoretical investigation aimed at determining the effects of unsteadiness and, perhaps more important, the conditions for which it may be worth accounting for them in the design process. For generality the study uses nondimensional parameters. The effects of unsteadiness on both mean and instantaneous flow rates are covered.