simulation

A network approach is chosen for a new building simulation program BUS, and a lumped capacitance method (LCM) is selected for the assessment of temperature levels and energy consumption of a building. An implicit solution algorithm is chosen to solve the energy balance equations and temperatures of network nodes. Both the simulation method and simulation parameters (number of thermal nodes and time-step) needed to simulate thermal behaviour of a single building structure reliably are tested by comparing the results of LCM with an analytical solution of a test case.

The idea that intend temperatures can be reduced by ventilating the air-space between the ceiling and the roof (the attic) of a house, is widely acknowledged by Civil Engineers and Architects. This phenomenon was evaluated through three softwares (CASAMO-CLIM, COMFIE and SPIEL) which were designed for the analysis of the thermal performance of buildings, by comparing the results of all three.

In many design cases, energy as well as occupant comfort are the relevant criteria which are studied using computer simulation programs. Comfort evaluations cover air quality, thermal, visual and acoustical comfort. For all these individual aspects, specific simulation programs are available today, but very few programs allow for the integrated evaluation of several or all relevant parameters. The more, heat transport, ventilation as well as lighting are physically coupled and therefore must be integrally modelled in the simulation process.

Simulation is proving more and more important in building physics. Programs of different levels of complexity are today available for researchers and designers to model and plan buildings. But the accuracy of the output is not usually provided as a common result. This paper is a short summary of a dissertation [1] focused on the accuracy of the simulation outputs as a function of the accuracy of the input parameters.

As proposed in IEA Annex 20, a two dimensional case, for which detailed experimental data are available, has been specified by Nielsen to test different CFD codes. This report presents the results computed by the FLUENT code and he comparison between the computed results of thisreport and Chen and between measured results presented by Nielsen.

This report presents the computational results for the two-dimensional benchmark test case described in research item 1.45. The code used is EXACT3, standing for explicit time marching algorithm for continuous thermal fluid flow. It is a three-dimensional finite difference code for simulating buoyant turbulent airflows within buildings.