During the past three years, BRE has conducted winter and summer occupant surveys on satisfaction with environmental conditions in 23 buildings. These were a mixture of naturally ventilated and air conditioned buildings. The results presented in this paper are based on a secondary analysis of 5136 completed questionnaires. The aim of the analysis was to determine the effect of ventilation type and season on occupant satisfaction with key environmental parameters: thermal sensation, thermal comfort, humidity, air movement, stuffiness, air quality, lighting and noise.

In recent years there has been a gradual re-emergence of the use of passive or 'low energy' ventilation and cooling techniques including mixed mode application. It is apparent that many clients developers and agents are reluctant to make a commitment to such 'low energy' buildings due to concerns, albeit unsubstantiated by hard evidence, that such buildings will provide acceptable comfort levels for occupants.

This paper proposes a definition of integrated design in order to improve use and understanding of the term and the concept throughout the construction industry. In particular, the paper considers the topic from an energy efficiency perspective as this plays a central role in design. The definition is supported by a discussion on the design process, and developing a design strategy. This is based on work carried out in editing the CIBSE Guide: Energy efficiency in buildings that will be published in the future.

This paper describes an innovative experimental technique that accurately reproduces natural ventilation flows, driven by the combined effects of stack and wind, at small scale in laboratory models of rooms or buildings. This technique provides a powerful tool for examining the performance of naturally ventilated buildings at the design stage as it may be used to predict quantitatively ventilation flow rates and temperature stratification under a wide range of climatic conditions.

In recent years, increases in pollution emissions resulting from an increase in vehicular traffic have caused great public concern regarding the quality of urban air and its impact on those working in these areas. In buildings this has led to an increase in the installation of air conditioning systems to 'clean' the incoming air. However, with environmental issues in mind such as high energy costs, the related C02 emissions and global warming, designers are increasingly being encouraged to consider natural ventilation as the primary design option.

As experience with assisted naturally ventilated buildings has increased designers have extended the approach to larger and more demanding building types. This paper looks at two very different theatre projects where assisted natural ventilation systems have been designed, examines the design tools used, illustrates the solutions and shows how the built form was influenced.

Air conditioning, as we know it, providing thermal comfort by mechanical means, first appeared in buildings about one hundred years ago. During that time it has had major influence on the evolution of the design buildings. This paper reviews the development of providing cool comfort in office buildings from the pre-active era of the middle of the 19th century through the rise of air conditioning in the mid 20th century to the current state of the art.

There is increased interest in using chilled ceilings and beams for cooling in UK buildings, on account of their perceived advantages over traditional air or chilled water based systems. However, there is currently limited knowledge or experience of the use of chilled ceiling and beam systems in the UK, and there is no proper professional guidance. Designers are particularly concerned to avoid condensation occurring on the exposed cold surfaces that could cause a health problem or lead to the so-called "office rain" effect.

This paper critically reviews current and previous research into the use of displacement ventilation in commercial offices with and without supplementary static cooling devices. It also reports the findings of a preliminary study of a displacement ventilation technique that may increase the scope of application for displacemelllt ventilation systems without the need for supplementary static cooling.

Providing people with a quality indoor environment means full air conditioning with an energy use tag that we would rather not mention in the debate about environmental impact and sustainability. But is this really the case? Is it not possible to design mechanical systems so they use less energy than their naturally ventilated counterparts? The law of conservation of energy means we can use the same energy repeatedly. As long as we are aware of how energy is degraded in quality and temperature terms, we can design systems that repeatedly recover and reuse energy.