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Welcome to the 'Blue Pages'. This is where guest editors from the Editorial Advisory Panel for Building Services Engineering Research and Technology address current developments in building services engineering practice and research. The articles are very short, on one theme of current interest, and do not go through the longer refereeing process for conventional research papers. This is to encourage consultants and contractors to discuss their latest developments in a non-commercial manner. Academics will also be asked to outline current research areas in universities and colleges.

In hot climates ventilation can be a useful means of cooling dwellings, if the outside air is cooler than that inside the dwelling. Often, in hot regions the outside air is so hot during the day that cooling by ventilation is of no benefit until the evening when the outside air cools. Ventilation can then be beneficial, and can be promoted by a sun-warmed cavity or 'solar chimney' added to a building on the sun ward side. The cavity may be of any material of high thermal capacity. Heat from the sun is stored within the walls and heats the air within.

Over the last 15 years, active desiccant systems have become a common component of HVAC systems in commercial buildings needing lower-than-usual humidity levels. Ice arenas, supermarkets and refrigerated warehouses all contain refrigeration systems which cool air more effectively when most of the building's moisture load is removed by an active (heat-reactivated) desiccant system.

Computational Fluid Dynamics (CFO) modelling techniques have been used extensively and with considerable success for many years in providing environmental and physiological flow conditions in applications as diverse as:

In response to an increased awareness of the impact of building related energy consumption on emissions of carbon dioxide, attention has turned to the task of making buildings more energy efficient. Although this is a key element in the design of a new building, it is important also that the occupants' expectations of a comfortable and healthy environment are met. Computer simulations of the airflow and thermal environment within a naturally ventilated building have been made using a finite volume CFD model.

When buoyancy forces, wind forces and envelope heat losses interact in a naturally ventilated building, the behaviour of the flow rate as a function of these parameters can be quite complex. This paper derives the equations for the flow rate in a two-zone building where one zone is above the other, and where each zone has a high and a low opening.

This paper attempts to answer questions like when thermal stratification is important and how to consider it in simple multi-zone models of natural ventilation. Both simple analytical solutions and comparison of CFO and multi-zone analysis suggest that the multi-zone modelling approaches with the assumption of uniform zonal air temperatures can significantly underestimate the neutral levels in buildings with large ventilation openings, indicating that the flow directions through some openings may not be correctly predicted.

In this study, a mixed mode building, namely the Portland Building at the University of Portsmouth is considered. It combines both Natural Ventilation and conventional Heating Ventilating and Air Conditioning systems to maintain the internal comfort. The paper presents the development of Sof1 Computing models to predict the internal temperature in one of the offices using information from neighbouring rooms, corridor and the outside. To derive this model, the so called Adaptive Neuro Fuzzy lnference System method is used.