Simulation is useful in many aspects of the design, control, and evaluation of buildings and their associated heating and cooling equipment. Pure experimental studies are often limited by the bounds of cost and measurement techniques, whereas simulation studies are limited by theoretical understanding and computational constraints. In particular, experiments are needed to develop the fundamental understanding necessary to create new mathematical models and to validate larger scale simulation models.

A first question attendees from oversees may ask is: what is meant by building physics? In fact, the name is hardly used in the Anglo-Saxon and Roman countries. In Northern Europe instead, the indication building physics points to the discipline which covers all physical aspects of influence on building performance and building use. Three main fields of knowledge are involved: (1) heat and mass, (2) sound, (3) light. Energy for example belongs to the first. Room acoustics is part of the second. Day-lighting takes a big share in the third.

In this session 14 papers are discussed covering a wide range of topics, applications and aggregation levels. Besides papers using different simulation tools, several field tests, experiments and theoretical approaches are discussed. The majority of the papers present applications in dwellings, but also industrial and agricultural environmental issues like those in greenhouses for the production of crops and livestock buildings (pigs) are discussed.

This paper reflects the research presented in session 1 "Indoor Environment" of the present CLIMA 2000 Congress. Design and assessment of the indoor environment, mainly its thermal component, is discussed. The steps of the design process as well as the model prediction and the field assessment of the indoor environment are included in the discussion. Special attention is paid to the correct application of the requirements specified in the present indoor climate standards. Examples from research presented at this congress are used.

It is well-known that there exist indoor temperature distributions. To have more precise predictions of indoor thermal comfort and better control of indoor thermal conditions, a both detailed and fast model of the dynamic indoor temperature distributions is needed. Unfortunately, very few papers studied such models due to the complexity of fluid (air) flows. CFD can be used as a detailed model. But it is too time consuming. This paper discusses two models in this respect, the fixed-flow-field model and air-zonal model. Both models are validated with experimental results.