English

Describes an improved form of the standard k-epsilon model for buoyant room flows and gives an assessment of the results. The improved model is based on the generalized gradient diffusion hypothesis of Daly and Harlow. Compares the results from the computations for three-dimensional flow with temperature measurement performed by the authors in a laboratory room with displacement ventilation. A good agreement is shown by the numerical results, better than the results from the standard model.

Presents the design of latent heat storage with small polyethylene spheres with encapsulated PCM, forming porous media inside the duct of the building ventilation system. The study assumed that ambient air is first heated in the solar roof, then passed through latent heat storage and finally enters the living spaces as preheated ventilation air. This latent heat storage serves to prevent overheating and prolong ventilation system operation till the evening or even the night. The authors have taken a numerical approach to transient heat transfer and melting process calculation.

Natural cooling has an important role in decreasing fuel consumption in buildings. The design is mainly directed at reducing heat gains. The following elements are part of the passive precautions taken: window direction, type of fenestration, window surface areas, outside wall construction, inside thermal mass, thermal insulation, shades, and building configuration. The evaluation of these parameters and of natural cooling's feasibility is done by computer simulation. The article describes a computer program devised for this purpose.

States that natural ventilation systems do not sometimes perform well in conditions of high wind and/or low external temperature. Occupants shut down the system to prevent draughts. In contract, in warm summer weather the lack of air movement is a problem. Hybrid ventilation helps mitigate some of these problems. The paper outlines problems in connection with hybrid systems and indicates solutions for them. Gives examples of hybrid system, some in use and some under construction.

Describes studies undertaken at an office development. The first study aimed to outline a calculation method to estimate the allowance to be made for heat gains from the building fabric, especially the slab to the supply air in the design of an underfloor air conditioning system. Quantifications had not previously been made of the allowances necessary in the initial calculations as a result of the heat gains. Also gives an overview of the principle of integrating overnight ventilation using fresh air with underfloor air conditioning for so-called 'free' cooling.

Residential apartments in Hong Kong are usually equipped with up to three window-type air conditioners, placed in living rooms and bedrooms, operated over seven months of hot and humid weather. Analyses the arrangement of room furniture to minimise cold air draughts. The performances were modelled using FLOVENT.

Investigates the possibility of limiting ventilation in archival storage areas when the outside conditions would have a detrimental effect on the humidity. Conducted measurement-based simulations on the Vaud state archives in Lausanne, Switzerland, with a continental mild climate. Recommends good insulation and high thermal mass.

The study developed a method to assess the capability of outdoor air utilized for summer cooling in urban apartments in the hot, humid climate of Taiwan (average yearly temperature 23 Deg C, average humidity 85%). The assessment method is approached using three aspects of identifying the maximum comfort room temperature, estimating the cooling capacity of applied outdoor air volume, and calculating the required outdoor air and pre-cooled outdoor air volumes for cooling through cooling load calculations.

Presents the main features of a preliminary HVAC system project relative to a university complex, based on principles of sustainability. The design involves installation of a cogeneration system. It is proposed to incorporate hybrid and natural ventilation for energy efficiency. Gives examples of architectural designs for the various areas.

Describes best practice for energy labelling for existing residential buildings in four countries. Also describes the specific features of a Belgian procedure for on-site evaluation of both equipment and building envelope. The results can be used by other countries as general guidelines to develop or optimise efficient and effective energy labelling procedures.