thermal comfort

This paper tries to give a reasonable description of the state of the art of the Belgian building stock with regard to ventilation. The Belgian research projects on ventilation in buildings, which were carried out recently, enable a precise overview of the quality of the Belgian building stock to be gained. It shows that airtightness varies a great deal from one building to another. Very leaky as well as very airtight buildings are frequently found. Notable is the near absence of controllable ventilation provisions.

This paper presents an analysis of indoor climate in buildings with forced air heating systems. The results is based on indoor climate measurements and extensive interviews with the occupants. The analysis shows that design criteria is of great importance for the occupants conceptions of thermal comfort in buildings with air heating systems. Forced air heating systems could be a way to provide mechanical supply air with less problems with the thermal comfort, such as draught, than in ordinary supply- and exhaust air ventilation systems.

In displacement ventilation systems, air flow rates, temperature and the design of the air supply device strongly influence the parameters which decide the thermal comfort. This paper reviews experiments and theoretical models which show the connection between t.hese parameters. It is indicated that the Archimedes number of the supply air is the parameter which decides the air velocity in the area close to the floor. (The Archimedes number is the ratio between buoyancy and inertia forces).

Since thermal comfort on human body is influenced by the local air flow speed, it is needed to estimate the distribution of air flow speed in a room for the "effective ventilation". Numerical solution of the equations for the motion of 3-dimensional turbulent air flow and model experiments are conducted for this purpose. The experiment model is a single room model house with 2 windows on the opposite walls. It is actually ventilated by the natural wind. Non-directivity thermistor anemometers are used to measured the 3-dimensional distribution of indoor air flow speed.

There are reputed to be only ten examples of the thermal manikin (a computerized doll) in the world at present. Here, the author discusses their potential in microclimate research, and describes experiments with a thermal manikin at the Hungarian Institute for Building Science (ET/) to identify the quality of indoor comfort conditions. One study revealed that the correct heating system would yield better results than extra thermal insulation.