In this paper, we develop a discrete approach to describe the transport of condensible vapors through a microporous substance. We consider only isothermal water migration under uniform atmospheric air pressure, at temperature lower than 100C with negligible gravity. The pore-structure which is supposed to be representative of the material is built on a 2D random network of tubes. The basic phenomena (adsorption/desorption, diffusion, condensation) that occur during the water vapor transport in a single cylindrical pore at the steady state are taken into account.

A set of statistical regression equations was developed to predict relative heating and cooling loads of external zones of commercial buildings. The equations were derived from the coil loads predicted by several thousand DOE-2 simulations.

The topic of this paper is the use of low temperature air (40 F or 5 C) for room cooling. Cold air systems can offer energy and space savings relative to higher temperature cooling systems. As the supply temperature and flowrate are reduced, considerations such as adequate flowrate, jet dumping or separation, condensation on duct walls, and decreased relative humidity become increasingly important. Cold air jet separation from the ceiling can be a problem resulting in unacceptable thermal discomfort in the occupied zone.

With the accelerating use of building performance prediction models in a design context, the need for comprehensive program accreditation procedures is becoming more pressing. This paper recognises the importance of the validation component of such a procedure and makes a case for containing much of the present knowledge about validation within an interactive facility centred on test cells.

This paper deals with the validation methodology used within the PASSYS project focusing on the developed method for empirical whole model validation of building energy simulation programs. The paper further discusses and describes how high quality data sets for empirical whole model validation are obtained within PASSYS.

A "detailed" model of a heat emitter in hot water circulation has been developed considering, two phases (liquid and metal), the non linear heat transfer and the enthalpy transport by the fluid. A reduced order state model ( order two or three) has been then formed, linearising the initial "detailed" model and using a model reduction technique developed in our laboratory which is especially based on modal analysis. The simulated results from both the models for a step input of the inlet temperature have been presented and discussed.

Three complementary approaches may be used in the evaluation of the performance of building control systems-simulation, emulation and field testing. In emulation a real-time simulation of the building and HVAC plant is connected to a real building energy management system (BEMS) via a hardware interface. Emulation has the advantage of allowing controlled, repeatable experiments whilst testing real devices that may contain proprietary algorithms.

This paper discusses the use of the computer program DAYLIGHT, as a method of analysing and evaluating the natural lighting in buildings. The computer's design parameters and outputs are discussed in some detail, and the program is then used to examine some of the standard design criteria. The paper concludes with a case study of a primary school building to evaluate the accuracy and usefulness of the program.

Presently, the building performance analysis requires to take accuratly into account the coupling effects between building, HVAC and control. For large scale systems, this implies the intensive use of the simulation tools.Today, the existing tools are not flexible enough for this purpose. The present paper describes the development of a more adequate tool : CSTBt. This tool is built on the TRNSYS core (University of Madison), but offers a more adapted library of solvers and component models concerning the building envelope and the hot water heating network.

The simplified thermaI simulation of buiIdings is particularly useful for both bioclimatic design and the selection of the most suitable HVAC systems. The LEGO computer program was prepared in order to simulate the conventional HVAC plant-building systems and the complex systems Iike seasonal storage tank and solar collector plants. Therefore, it is possible with this kind of program to study the interaction among the various systems by means of combination of different simulation subroutines. In this way, a more accurate dimensioning of the systems can be achieved.