IBPSA1995

Even at the beginning of the concept and planning phase for low energy buildings co-operation between architect and different engineers is, mandatory. In particular, the climate engineer supports the architect by developing an energy concept for a building. Thus, even in the design phase this new discipline of engineering makes sure that the influences of the climate, of an active or passive use of solar radiation, of zoning and all aspects concerning the thermal behaviour of a building are taken into account.

A new approach for computer-aided thermal analysis of buildings is presented. It is based on an electronic book "Building Thermal Analysis" which operates in a mathematical programmingenvironment (Mathcad). It consists of a set of independent files covering various topics ofbuilding thermal analysis linked together with a hypertext system. Each file integrates "live"equations (the "program "), explanatory text and figures, as well as graphs linked dynamically toequations and data.

This paper presents some results of the development and application work of the Building Equipmentsection at EMPA related to integrated building and HVAC simulation environments. Routines for thermal comfort evaluations with DOE2 are developed and COMVEN, the simulation code of the COMIS multizone air flow program, has been adapted as a type for TRNSYS. The application potential. for this coupling is demonstrated for a retrofit study of a school building, naturally ventilated through a glazed double facade.

New software (BASECALCTM) has been created for modelling heat losses from residential basements and slabs-on-grade. A menu driven interface allows the user to quickly and efficiently describe how the basement or stab-on-grade is constructed, where insulation is placed, what type of insulation is used, and to select ground properties and weather. BASECALCTMthen performs a series of detailed finite-element calculations before presenting succinct, easy-to-read results to the user.

Comprehensive studies of the energy saving potential for buildings will often not be performed in a design phase - especially not for renovation projects. There may be several reasons; for that but it may often be related to the amount of time needed to create models of the buildings and plants. The paper describes a method for auto-generation of complex simulation models for existing, documented and validated simulation programs. An automatic model generator has been developed for Danish conditions and programs.

Analytical solutions to the heat flow equation in a dynamic insulation is presented. A numerical least:squares method, called the gradient method, to estimate the steady state and transient air flow through a dynamic insulation is presented. The method was applied to measurements from a house with dynamicinsulation in the ceiling. The analysis showed that 40% of the total inlet air passed through the insulation. The measured energy efficiency was very similar to the calculated one.

This paper discusses a detailed building energy simulation model that has been made available to thebuilding designer through a graphic user interface. The simulation model uses hourly energy calculationsdriven by an hourly weather data generator. Capabilities of the simulation portion include: monthlyenergy loads and utility bill predictions, peak load analysis, demand charge evaluations, life-cycle cost:analysis, and floating space temperature prediction for comfort analysis in passive designs.

This paper presents an integrated approach for the energy saving, control optimization and BEMS/BMSapplication of centralized air conditioning systems. The approach is based on the field test/monitoring, building realistic performance simulation and emulation. The methods and their roles for improving the operation, the control optimization and EMCS/BMS application are discussed. Examples of utilization are presented.

In order to improve upon previous calibration techniques, this paper presents new calibration methodsincluding a temperature bin analysis to improve hourly x-y scatter plots, a 24-hour weatherdaytype bin analysis to allow for the evaluation of hourly temperature and schedule dependent comparisons, and a 52-week bin analysis to facilitate the evaluation of long-term trends. In addition, architectural rendering is suggested as a means of verifying the building envelope dimensions and external shading placement.

Within the framework of an Anglo-French validation project funded by EDF and the BRE, a building model has been tested using an error analysis method. The first step enabled the identification of the different discrepancy sources. The second step pointed out the way the model should be improved to fit to reality. Presently, the major accuracy gains can be expected from improvements on heat exchange between air and heating system, glazing modelling and solar radiation distribution.