English

The HVAC BESTEST has been developed within the framework of the IEA (International Energy Agency) It is a comparative test method developed for estimating the ability of whole building simulation programs to model the performance of unitary space cooling equipment.

The potential offered by computer simulation is often not realized: Due to the interaction of system vari- ables, simulation users rarely know how to choose input parameter settings that lead to optimal perfor- mance of a given system. Thus, a program called GenOpt® that automatically determines optimal pa- rameter settings has been developed. GenOpt is a generic optimization program. It min- imizes an objective function with respect  to multi- ple parameters. The objective function is evaluated by a simulation program that is iteratively called by GenOpt.

A  structured,  generalized  modeling  and  simulation software is described that enables development and analysis of control algorithms and systems and pre- diction of thermal performance and energy use in buildings. The  basis for this tool is the  state-space technique, which casts differential and algebraic equations describing the system into a vector-matrix form. An automated building modeling capability generates detailed and simplified models directly from building plans by using a library of construction element models (walls, floors, etc.).

To provide practitioners with the means to tackle problems related to poor indoor environments, building simulation and computational fluid dynamics can usefully be integrated within a sin- gle computational framework. This paper describes the outcomes from a research project sponsored by the European Com- mission, which furthered the CFD modelling aspects of the ESP-r system. The paper sum- marises the form of the CFD model and describes the method used to integrate the thermal and flow domains.

A flow responsive algorithm was devised and implemented within the ESP-r simulation program to advance the modelling of internal surface convection. Empirical methods were extracted from the lit- erature and a new method for characterizing mixed flow was created to provide the algorithm with a basis of 28 convection coefficient correlations. Col- lectively these methods can calculate convection coefficients for most flows of practical interest.

Buoyancy driven flows have always been, and still are, difficult to model using CFD programs. Much validation work is required along with guidelines for the CFD practitioner about how to model such flows. This paper makes a contribution to these two areas by considering buoyancy driven displacement ventilation in a very simple geometry. The nature of buoyancy driven displacement ventilation is briefly described and guidance offered on how to represent the problem in a CFD program. Simulations were carried out using two eddy viscosity turbulence models.

This paper presents the results from the experimental and numerical study of a room with mixing ventilation, focused on the local mean age of air (LMA). The measurements were performed using the tracer gas concentration decay method.  The numerical predictions were obtained from the computational fluid dynamics (CFD) module of the latest version of the ESP-r software. In order to address the requirement for a proper choice of the number of control volumes in CFD, the analysis is made by comparing the results from two consequently finer numerical grids.

Computer  simulation  Of  measurement  methods  can give in-depth information on the possible effect of a wide variety of parameters on measurement results. Examples for computer simulation of simple U-value measurements of building components for  the appraisal of retrofit measures and more complex examples of building airtightness measurements with the blower door method are given. The simulation models used are described in detail and results for example cases are given.