IBPSA1999

It is a basic premise of this paper that accurate earthcontact simulation is important and that the rapid parametric analysis of a structure can help designers pinpoint critical aspects of a structure early in the design stage. Numerical tools are an attractive option for this role in that they are potentially flexible and accurate. However, their application to such a tool is limited by their lack of speed. A new tool for use in paramteric analysis is proposed which incorporates a numerical model with elements of the response factor method.

A nodal model has been developed to represent room heat transfer in displacement ventilation and chilled ceiling systems. The model uses precalculated air flow rates to predict the air temperature distribution and the division of the cooling load between the ventilation air and the chilled ceiling.

Large Eddy Simulation (LES) with a Dynamic Subgrid-scale Model (DSM) is a powerful tool to predict indoor airflow. However, the model needs to average the model coefficient over a homogeneous direction. Since most indoor airflow does not have a homogeneous direction, this study proposed a new Filtered Dynamic Subgrid-scale Model (FDSM) without the need of a homogeneous flow direction. The predicted air velocity, air temperature and turbulence distributions agree reasonably well with the experimental data. The results show that the FDSM can be used to simulate indoor airflow.

Traditional algorithms for the simulation of sound propagation in spatial enclosures include the image source method and the ray-tracing method. These algorithms are computation intensive and take a long time to generate results. In this paper, a new algorithm is proposed for the simulation of sound propagation in spatial enclosures that is relatively fast. This algorithm is based on modeling the surfaces of a spatial enclosure as sound radiators. The purpose of the algorithm is to generate an energy response graph at a certain listening location based on a sound source.

This paper presents the new EnergyPlus HVAC simulation environment, which differs from existing energy analysis programs in three key respects. First, the EnergyPlus HVAC simulation is based on a "manager-interface" protocol that supports multiple solution techniques within the overall context of the simulation. Second, the EnergyPlus HVAC simulation is based on high level component connectivity. Third, the EnergyPlus simulation and component modules enforce a high degree of data encapsulation.

This paper describes a computer simulation model for assessing the potential energy savings in office buildings through the use of daylight and occupancy sensors. Because motion sensors control the lights, special attention is placed on a Monte Carlo approach to establishing lighting schedules for the typical workday. Fixed lighting profiles were shown to generate misleading information regarding electric demand charges and life-cycle costs of the building.

A general method to determine the shading of direct and diffuse radiation is presented. This can handle an almost infinite number building surfaces and screens of any shape. Furthermore, the method can be used to determine view factors in rooms of arbitrarily shape.

A study of the way in which humans visually perceive the motion of high-rise buildings was carried out. In our experiment, an edited movie was projected so that the subjects could observe the motion of the view from a window. The movie was edited by changing the speed of pictures that had been previously recorded by a video camera moving at a constant low velocity. In this way, a visual simulator created a movie replicating a cosine wave. The results of this experiment showed that visual perception is more sensitive than physical perception in the case of torsional motion.

This paper presents a tool, based on a method using IDA for simulation of duct systems and MATLAB as a pre- and post-processor, to study the controllability of VAV-systems. The focus of this paper is on how the data created during the simulations are analysed and how criteria matrices are used to determine the grade of controllability of the systems. The method is tested on a set of different system configurations and the result shows that it, as a whole, appears to be viable. Furthermore, there is a discussion about how MATLAB and IDA are used as an integrated part of the method.