English

The authors' previous analysis of dynamic insulation is extended to include the inner and outer air film resistances with the objective of modelling the variation in surface temperature with air flow. The boundary condition that comes closest to predicting the variation of the surface temperature with air flow is one which assumes that the conduction heat flux at the wall surface, rather than the net heat flux, is equal to the flux incident on the wall from global environmental temperature, T.;.

This paper is concerned with the numerical modelling and investigation of the performance of air curtains employed to reduce air flow and heat transfer across open doors and between conditioned and unconditioned spaces. It has been found that the model based on a commercial Computational Fluid Dynamics software package can successfully predict the critical velocities and efficiencies of air curtains and the influence of external parameters such as wind speed.

A new thermal simulation model, QUICK II, is presented and numerous verification case studies performed on naturally ventilated buildings are discussed. Four new case studies performed on two buildings located in the Negev desert in Israel are discussed in detail. All the measurements pertaining to these new case studies were taken independently by the Desert Architecture Unit of the Jacob Blaustein Institute for Desert Research. These measurements are provided, along with a description of the buildings.

A numerical calculation procedure for an air flow window (AFW) system integrated with a roll screen is presented. Both beat and air flows within the window elements such as the outside pane of glass the outside air space, a venetian blind, the inside air space and a roll screen, are taken into account by considering the thermal and air flow networks. Agreements between measured and calculated results of temperatures and pressure differences through a series of experiments carried out in an environmental test chamber were observed.

Draughtproofing the doors, windows and other sources of excessive air leakage of a dwelling can be an effective and relatively inexpensive means of improving comfort and reducing heat loss by natural ventilation. The doors and windows considered in this digest are existing components not originally designed for draughtproofing. Products for general use on these components have to fill a wide range of gap sizes, be durable and retain the ease of opening and closing.

The need to conserve energy in buildings of all types has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest discusses the properties required of thermal insulation in flat and low-pitched roofs with continuous waterproof coverings. It reviews the wide range of products available and suggests criteria for selection.

Computational fluid dynamics may be used to predict the details of airflow in rooms served by displacement ventilation systems, provided a suitable turbulence model can be found. Since buoyant plumes are central to the displacement ventilation strategy, four turbulence models - three eddy-viscosity models (the 'standard' k-s model, a modified k-s model, and an RNG k-s model) and the Reynolds stress model - were applied to simulate airflow in a turbulent buoyant plume.