IBPSA1995

Previous work has shown that for saturated air/water vapour mixtures, water vapour transfer in cavities can cause very large increases in net energy transfer due to its effect on natural convection. Given that many materials used in building envelopes adsorb water vapour, then in many situations a water vapour pressure gradient will exist across a cavity, leading to water vapour transfer across the cavity. In these situations the mixture is generally not saturated, but some effect of the water vapour transfer on natural convection can be expected. 

There are two main issues to be resolved in order that design tools can be used in cooperative mode, each communicating with the other. Firstly, there is a need to put in place a consistent product model of a building and its systems from which disparate design tools can obtain their inputs and return their outputs. Secondly, there is the requirement to manage the transactions between users and design tools. Tbese issues were addressed within the European COMBINE project. This paper is concerned with the latter issue.

RADIANCE has emerged as one of the most powerful programs for modelling the luminous environment within and around buildings. It has a large and growing number of users in many countries including the UK. This paper illustrates its use for producing photo-realistic images of proposed building designs and for daylight analysis of a complex atrium building. The results of validation work, using real sky data, are presented and some current UK research involving RADIANCE is described. 

Learning how to model and simulate dynamical systems such as a building does not have to be restricted to specialists who have learned the physics, applied mathematics, and engineering necessary for the task. Modern software tools allow for a new approach to modeling which makes it accessible to a much wider group of scientists, eng neers, and architects. This paper presents an integrated modular method for training students in the methodoIogy of modeling and simulation.

We introduce SEMPER, a computational tool for active and multi-dornain design and evaluation support. We demonstrate SEMPER's unique synthesis of three fundamental system requirements: 1) a methodologically consistent performance modeling approach through the entire design. process; 2) a structurally homologous building representation across multiple dornains; and 3) a "preference-based" performanceto-design mapping technology. 

The fundamentals of a probabilistic approximation in thermal buildings analysis is here briefly presented. However, the principal aim of this paper is to show the advantages of such simulation approach in many applications requiring massive simulations. Several examples are presented to illustrate the relevance of the proposed method as an alternative to deterministic simulations, and to show how it is a powerful tool for analysis. The developed simulation approach appears; as an extremely helpful method for comfort analysis in free-floating buildings.

A collaborative building design environment has been proposed to integrate, together both the heterogeneous applications and the dispersed project particípants. Based on the functional requirements identified, the conventional building product models have been extended to incorporate high-level concepts such as activity and organisation. which are essential for coordination, and a generic humanhuman interaction model has been developed, which could not only make the building domain models interaction-aware, but also serve as a base model for developing general interaction utilities.

Three computer programs have been developed for use in assessing solar heat gain through windows in buildings. SUNSPEC calculates the direct beam and diffuse sky solar spectral and broadband irradiances incident on an arbitrarily oriented plane, for any position of the sun in the sky relative to the receiving plane. The calculations are for a cloudless sky and allow the user to specify the concentrations of various atmospheric gases and particulates. AWNSHADE calculates the unshaded fraction of a vertical window's area when illuminated by direct bearn solar radiation.

Using the Visual Basic development tool kit, the authors have developed a highly interactive graphical interfáce to an hourly energy simulation model for estimating annual energy consumption in buildings. The software, named ENER-WIN, features an interfáce program that calls and controls the execution of the energy simulation model and the weather data processor. The software will run on PCcompatible microcomputers under the Windows operating system. 

A simplified building heat and moisture transfer model has been developed and integrated with relevant air-conditioning system component models for simultaneous simulation of heat and moisture transfer at the building envelope, the indoor air-zone and the aír-conditionin- system. This model requires much less computational effort when compared with other more rigorous heat and moisture transfer modelling methods. The accuracy of prediction of the model hás been compared with some experimental results.