From model validation to production of reference simulations: how to increase reliability and applicability of building and HVAC simulation models

Validation of simulation models appears from a long time as a key issue in order to promote
a more intensive and more efficient use of simulation models in the field of building and
HVAC simulation. IEA Annex 34/43 originally targeted a number of specific applications
where a more advanced validation was required: ground coupling problems, multizone
building, shading, day lighting and cooling load interaction, HVAC components and
ventilated facades. These validation exercises were built on the large methodological
experience obtained in previous projects and address sometimes very fundamental
problems of heat transfer in buildings. Consulting engineers and practitioners might see
these exercises as a bit too far from their objectives and it is the reason why an additional
activity was proposed with the specific aim of producing, based upon the results of the
validation of models, a set of reference simulations. These applications cover a range of
building types (residential, commercial) and systems (production, distribution emission) and
run in a variety of climates. The paper will describe how models dedicated to these applications
were developed, starting from validation results, going through the selection and
consolidation of simulation hypothesises and ending with a number that might be considered
as reference for the concerned applications. The paper will concentrate on models
required by a residential building application (multizone building equipped with a heat pump
or a condensing boiler, heat emitted by radiators or floor heating systems). Simulations
make use of both EES and TRNSYS software and both software are applied in parallel as far
as possible in the different applications in order to get a better judgment of their potential
advantages and drawbacks. The use of reference simulations in view of qualifying
normative methods currently in development in the frame of the European Energy
Performance in Buildings Directive is also addressed and demonstrated in the paper.