IBPSA2001

The paper discusses the technical features of the physically based computer simulation/visualization techniques for architectural lighting research. Potentials and limitations are evaluated in terms of input, algorithms, output, and analysis tools. The physically based simulation/visualization, supplemented with numeric information, is a promising tool for evaluating the luminous environment. The deficiencies are discussed to provide means of improving the usability and trustworthiness.

An indirect control technique using a single-zone space model is presented. The practice of adjusting temperature of heat supply medium inversely to outdoor air temperature (basic open-loop approach) was replaced with a flux control mechanism and facilitated with Takahashi algorithm1. In thismodel a coupling Laplace equation was applied with a noncapacitive nodal net of conductance and the hemisphere surface envelope concept in long-wave radiation calculations.

THERM is a freely available, user-friendly twodimensional heat transfer model for analyzing the impacts of thermal bridges in building components such as windows and doors. This paper begins by describing THERM as a tool for analyzing individual building components as well as envelope assemblies. The significance of THERM’s detailed radiation heat transfer model, which incorporates a view factor based radiation heat transfer algorithm, is then presented in detail.

Little work has been done on the closed loop response of refrigeration plant using the new chlorine-free refrigerants. A simulation model of a water-water refrigeration plant using R134a is developed for the purpose of investigating control system performance. The well-established problem of coupling between the two main regulatory control loops governing evaporator degree-of-superheat and plant capacity is recognised and the two control loops are tuned in harmony using an optimisation technique.

In this paper we report the findings of a survey conducted to evaluate the energy-conservation performance of an office building some time after construction, and present the results of a simulation that was performed to identify possible improvements to the building’s cogeneration system. The indoor thermal environment was monitored over winter and summer, recording temperature and humidity variations and the vertical distribution of indoor air temperature.

The paper uses the latest state of the art dynamic simulation software to analyse and present design information for building design engineers on current design questions in both Dublin and Boston. The design questions analysed include the options for office perimeter HVAC in Boston e.g. VAV with terminal reheat versus VAV with terminal reheat and trench heating. This is explored with full height glazing and 50% glazing to façade ratio.

Building geometry is essential to any simulation of building performance. This paper examines from the users’ point of view the importing of building geometry into simulation of energy performance. It discusses the basic options in moving from two- to three-dimensional definition of geometry and the ways to import that geometry into energy simulation. The obvious answer lies in software interoperability. With the BLIS group of interoperable software one  can interactively import building geometry from CAD into EnergyPlus and dramatically reduce the effort needed for manual input. 

Hong Kong is the most densely populated city in the world. The Building Regulations of Hong Kong pre- scribe a minimum distance between buildings for light- ing and ventilation. Lately, designers are testing the prescribed requirements with a  performance based ap- proach using computational simulations. Doubts have been cast as to their validity and accuracy. This study compares results obtained by on-site measurements, calculation  and simulated results using Radiance and Lightscape.

This paper describes a strategy to provide computational support for the selection of energy saving building components. The strategy rationalizes a small but significant part of the building design process by providing a clear procedure for a decision making process in which the use of computational tools is embedded; it is based on systems engineering, engineering design and decision theory. Consequences for the embedded computational tools of using this strategy for the selection of energy saving building components are discussed; a prototype providing process support is presented.