English

Recently, the more accurate comparisons between the existing building behaviour and the simulations have shown that a more realistic model of the whole system has to be considered. In fact, the coupling effects and feedback loops between building, HVAC equipments and the control, are essential and can only be taken into account by a large scale simulation. This observation emerged more and more during the last three years. But, unfortunatly the direct coupling of the existing models in the same simulation software was not often possible.

This paper summarises the objectives and initial achievements of BEPAC, a recently formed club based in the UK which in many respects parallels the stated goals of IBPSA. The mission of BEPAC is "to improve the quality of building performance by encouraging the use and development of environmental prediction methods for buildings".

In recent years. researchers, designers and contractors have begun to investigate the use of new technologies in building construction and operation.The search for more efficient designs has led to complex and difficult to analyze components, systems, and whole building structures. Existing building energy simulation programs were initially conceived in an era when design questions were simpler than they are today. As a result, there are fundamental limitations in the analysis capabilities of these programs.

Today, the development of computer makes the accurate performance analysis of complex system by simulation available for most of the research community, and very soon for every concerned engineer. However, the simulationist approach requires a strong investment on the modelling of the system behaviour. This paper deals with a basic contribution on domestic hot water gas or fuel oil boiler models, usable for large scale simulation involving building and HVAC.

This paper summarizes the results of numerous building energy analysis and design tool evaluation exercises carried out under lEA Task VIII: Passive and Hybrid Solar Low Energy Buildings. These exercises have included: Empirical validation of detailed simulations using passive solar test room data from Canada, Switzerland and the U.S. Code to code comparison of detailed simulations for severa¡ passive solar system types in Copenhagen and Denver.

In order to create a simulation model of a building, it is usually necessary to make a number of assumptions and/or approximations about the building being simulated. Many physical quantities cannot be known precisely when the building is being simulated. For example, the real amount of infiltration is almost never known because it is impossible to predict accurately and difficult to measure. Other examples include quantity and type of internal mass, thermophysical properties of building materials, ground temperatures, and equipment efficiencies.

In thermal simulation codes for buildings, aeraulic transfers are computed either with very simplified models (fixed air distribution) or with sophisticated models (based on the computation of the pressure fields). The simplified models are not accurate enough and the sophisticated models are too complicated for only thermal computations. An intermediate model has been developed. This new model is based on the computation of the temperature fields and on the knowledge of an average air distribution due to air leakage and specific ventilation.

Much research has been directed towards development of software environments that allow easy construction of building simulation models of widely varying structure and purpose. For example, TRNSYS has been in use for a number of years. Recently, several new such environments have been proposed. In spite of a considerable variation in model description formats among environments, the underlying mathematical models of physical processes are very similar.

This papers introduces an emulation system for simulation of the thermal process of building and plant named ESAC (Emulation Set for Air-Conditioning systems) developed in 1984, and a prototype system was presented in 1985 (1), since then a great progress has been made and several applications have been explored.

Simulation of building performance is increasingly being used in design practice topredict comfort of occupants in finished buildings. This is an area of great uncertainty:what actions does a person take when too warm or suffering from glare; how is comfortmeasured; how do groups of people interact to control environmental conditions, etc? Anincreasing attention to model these issues is evident in current research.Two issues are covered in this paper: how comfort can be assessed and what actionsoccupants are likely to make to achieve and maintain a comfortable status.