English

Increases in the levels of thermal insulation required in the walls and roofs of houses in the U.K. in recent years have meant that heat losses through floors now assume greater significance, as a proportion of the total heat loss from a dwelling. To effect further reductions in the energy consumption of houses, the thermal performance of floors needs to be examined to assess the most cost effective insulation strategy.

The major objective of the IEA task XIII project is to design and construct low energy dwellings which should be technically and economically realistic in the period 2000-2010. The design criteria for the Belgian dwelling are the following: - low energy demand for heating purposes; - good thermal comfort conditions, as well in winter as in summer with attention to the problem of overheating; - very good airtightness (n50 <= 1 h^-1); - good indoor air quality conditions; - attractive design for majority of potential clients; - only use of realistic technical solutions.

This paper shows the extensive influence of humidity on comfort, cooling load and refrigeration capacity. Modern computer programs allow an effective consideration of humidity in systems.

The growing diffision of small power, gas-fired individual units for space heating and service hot water production, as well as concern about operational safety issues, has promoted greater attention to the understanding of ventilation mechanisms in the dwellings equipped with such units. Within a joint research project between Politecnico di Torino and Italgas, an experimental campaign has been conducted in order to investigate the influence of purpose-provided ventilation openings (sized according to the national UNI-CIG 7129-72 standard) on air changes and IAQ.

The number of smokers differs mainly with age, sex, education, profession, and cultural background. The change in habits from the 2nd World War till today in form of increasing number of female smokers and decreasing number of male smokers is significant. The smoking of tobacco causes pollutants in the form of volatile organic compounds, particles, and carbon monoxide. Many of the pollutants are carcinogenic. In some cases the concentration of specific tobacco smoke related pollutants in room air may be higher than the maximum allowable concentration.

A combined thermal and ventilation model has been used to investigate the seasonal variation of air infiltration rates and ventilation heat losses in modern industrial buildings. The model was initially compared to measurements of ventilation rates, temperatures and heating loads in such a building, and was found to agree well. The model was then used to predict infiltration rates, temperatures, ventilation heat losses and space heating loads for a standard heating season for that building.

Many modern office and residential buildings in Sweden include an atrium. The atria are often mechanically ventilated and sometimes they are heated. Very little is know about the ventilation and air infiltration in built atria. These issues were examined in an apartment building with a non-heated and mechanically ventilated atrium, built in 1986 in Sweden. The ventilation of the atrium is coupled to the apartments.

A test room which was built at a scale 1:5 to the original one has been used to investigate air-conditioned rooms. The original room was specified by the international project IEA ANNEX 20. A lot of experiments were made on different inlet geometries and air change rates. Velocities and turbulent quantities were measured not only in the inlet plan but also in the room itselfby means of hot wire anemometry. The ammonia absorption method according to Kruckels has been applied to determine the heat transfer coefficients at the walls. Qualitative results were obtained by laser light sheets.

This paper presents the results of monitoring the ventilation in Netley Infants School in Hampshire. The study was carried out on behalf of the Department of Trade and Industry as part of the Energy Performance Assessment Project, as managed by the Energy Technology Support Unit. The school was designed so that during the summer the solar heating of a south facing conservatory would enhance the stack effect and induce ventilation in the adjacent classrooms. It was expected that ventilation rates would be adequate to maintain comfort conditions and air quality.

The efficiency of removing excess heat by employing mixing ventilation is based on the properties of jets. Therefore the behaviour of jets in enclosures is important. A correct supply design is essential otherwise the jet will separate from theceiling and drop into the occupied zone. This will give rise to unacceptable high velocities. the basic properties of jets in ideal situations like an infinite space are well known. However, in a room the jet interacts with the room air and the room surfaces.