PLEA

We report on a detailed monitoring exercise and an analogue experimental study of a naturally ventilated theatre in operation in the UK which can take audiences up to 300 people. The theatre has a raked seating area, and two outflow stacks, with a ring of air inflow vents on the floor which supply air naturally from an underfloor plenum. Detailed temperature measurements over a period during the winter 2003/2004 broadly indicate that the air within the theatre is stratified in temperature, with a relatively cool zone near the lower inflow vents and a progressive increase in temperature up to the roof space, where the temperature decreases again. A series of analogue laboratory experiments designed to simulate the natural convective flow, to help understand this thermal profile and the air flow pattern, identifies a series of fascinating flow regimes which depend on the inflow opening area at the base of the theatre. In general, the raked seating leads to a large scale circulation upwards and backwards across the audience which then spreads across the roof space and partially vents. The remaining flow rising from the seating zone recirculates in the upper part of the air space creating a weakly stratified upper layer. Lower in the theatre, the inflow of relatively cold air through the floor develops small inflow jets which mix with some of the warm air in the theatre and then spread laterally to form a cooler lower layer of air. This is mixed by the convective plume rising over the raked seating area and heated up as it is then carried into the upper part of the theatre. The experiments point to some design rules in order to achieve satisfactory ventilation within the space, without leading to excessive or insufficient cooling.

Since April of 2003, a group of students from Concordia University and Université de Montréal has been preparing their entry to the Second Solar Decathlon competition to be held in September 2005. Their goal is to design, build and operate the most attractive and effective solar-powered house that also sets a considerable standard in sustainable design. Some of the technologies to be integrated into the architectural design include solar electricity (photovoltaics), advanced windows, solar domestic hot water and battery storage; at the same time, other less high tech concepts (such as buffer zone spaces, Trombe wall, thermal mass, and natural daylighting) are to be transparently incorporated. Additional ecological strategies include the attempt to reduce embodied energy, recuperate and recycle rainwater, and design for growth and change. This paper will present the experience from the first year design process. The complexity of bringing together students from totally different backgrounds and institutions is not unlike the situation of some architect-engineer forced-relationships found in practice, and the interaction process will be described and analyzed.

The use of cooling in buildings is continuing to increase in Europe. This is raising concern that it will undermine the European Community’s drive toward reducing CO2 emissions. To counter this trend, there is increasing interest in evaporative cooling in general and passive downdraught evaporative cooling (PDEC) in particular. However, there are many locations in southern Europe where the relative humidity is sometimes too high for evaporative cooling to be viable. This in turn has led to the proposal for energy efficient hybrid cooling systems. This paper will present a case study of a hybrid downdraught cooling system within the new Malta Stock Exchange.

A novel approach is developed for modeling the influence of street canyon geometry on microclimatic conditions within the urban canopy. A physical scale-model of an urban roughness array was constructed in open-air conditions to enable the measurement of climatic parameters with natural turbulence effects, potentially overcoming some of the limitations common to more conventional research techniques. Energy balance in the urban canopy is quantified using a pedestrian-centered model which allows for the computation of energy exchange between a hypothetical human body and the urban environment, based on data measured within the scale-modeled street canyons and taking into account the effects of dimensional scaling. The proposed technique is demonstrated under typical hot-arid summer conditions in a desert region, and relative pedestrian energy exchanges are compared with previous findings from full-scale measurements in a climatically-similar actual urban setting. Results show that a compact street canyon geometry may reduce pedestrian heat gain during most summer hours, if attention is paid to design aspects such as street axis orientation. The model shows the ability to reproduce patterns observed in full-scale, and to reveal distinctions which are impractical to quantify using field studies alone.

This paper presents the preliminary results of the first stage of a research grant from SSHRCC (Social Sciences and Humanities Research Council of Canada) on the control of physical ambiences and the nature of internal-external transactions in a Nordic climate. The main objective of this research is to investigate the impact of environmental step-changes on the sensation of comfort in order to diminish the thermal gradient between indoor and outdoor in Nordic climate without sacrificing comfort. This, in parallel with the recent adaptive model for thermal comfort, could serve reducing further the energy consumption in buildings. The first stage of research consisted in the development of the combined quantitative and qualitative method for the assessment of global environmental comfort in transient conditions based on previous work by the author. The quantitative measurement of ambient conditions is assessed by a portable array whilst the qualitative aspects of comfort are assessed via an extensive WEB based questionnaire. The theoretical background behind that research and the development of the portable array and electronic questionnaires are the main subject of this paper.

The aim of this paper is the architectural analysis of natural ventilation devices developed by architects. The technical solutions adopted are exposed through some examples of naturally ventilated buildings. The natural ventilation principles and design challenges are discussed. The necessity of taking into account simultaneously both the natural ventilation strategy and the design of the building in order to improve the natural ventilation is underlined. The morphological analysis of a corpus of naturally ventilated buildings allows us to define various space organisations in adequacy with specific natural ventilation strategies. In conclusion, this study proposes a conceptual data model to support the integration of natural ventilation concept in the building envelope design.