This document discusses interoperability challenges in exchanging building information modeling (BIM) data between authoring tools and energy simulation software. Specifically, it finds issues in the exchange of complex geometry, material properties, building systems data, and building operation patterns. It concludes that data exchange standards need to provide more detailed information support to accurately model building energy performance and ensure compatibility between BIM models and building energy models. The IMPRESS research project aims to develop a performance-based retrofit solution for existing buildings using innovative technologies like reconfigurable moulding and 3D printing. It relies on decision support, project management, and data exchange software to handle the large amount of digital information generated.

1. Energy Efficiency and Sustainability (buildings)
Luis Torres Cardona, Laura Carlosena Remirez, Rufino Hernández Minguillón
on behalf of IMPRESS Corresponding author: ltcardona@ahasociados.com
Alonso Hernández Asociados Arquitectura S.L.; Larrascuncea s/n , 31190 Cizur Menor,
Navarra, España. Tel. 948311750 www.ahasociados.com
H 2 0 2 0 I M P R E S S P r o j e c t ;
Challenges of advanced building
retrofitting in the BIM era
This project has received funding from the European Union’s
Horizon 2020 research and Innovation programme under grant
agreement nº 636717
The contents of this publication do not necessarily reflect the Commission’s own posi-
tion. The document reflects only the IMPRESS Consortium views and the European Com-
mission is not liable for any use that may be made of the information contained therein.
Consortium www.project-impress.eu
As a result of the IMPRESS collaboration, which involves 16 organi-
zations from 7 countries across Europe, interoperability came as an
enabling condition to exchange data from very diverse origins. Nev-
ertheless and because of the energy driven approach followed by IM-
PRESS interoperability between BIM authoring tools and energy sim-
ulation software became a critical factor. Despite the fact that IFC and
gbXML standards are intended to allow information transfer, several
interoperability issues continue to hinder a seamlessly data exchange,
sometimes requiring user input, resulting in a duplicity of work and in-
creasing the risk of error.
- Geometry
It has been reported previously in the literature that complex geome-
tries, as curved walls or any other non-planar geometry are prone to
error when exported to IFC format. Nevertheless in some instances,
during the course of the project, pitched-roofs were inconsistently ex-
ported or retrieved and visualized.
- Material properties
Despite the fact that data schemes allow for a very detailed information
about physical properties to be included, evidence suggest that this in-
formation may not be properly exported to the exchange file or this in-
formation is not correctly retrieved into the energy simulation software.
Furthermore, even if IFC and gbXML allow storing the absorptivity, re-
flectance and emissivity of materials, some authoring packages still
lack these parameters. In a different scenario, considering PCM used
for the recladding IMPRESS solution, IFC and gbXML files are unable
to convey heath capacity, therefore requiring the energy modeller to
enter it manually before energy simulation.
- Building systems
As a consensus, energy performance is highly dependant on HVAC
systems and other building equipment; therefore exchange standards
should provide the means to convey very detailed information that re-
sults from real monitoring of existing buildings.
- Building operation
As for the previous dimension, operation patterns are widely acknowl-
edge as a determinant factor in energy simulation results, therefore
software tools and information exchange standards should provide the
means to acquire operation data from data schemes.
Conclusions
Data exchanges standards should grow in depth, so as to support
the complexity involved in an accurate energy performance forecast.
These standards should focus more on the compatibility between BIM
and Building Energy Modelling (BEM). Finally as a suggestion, model
verification routines should be included in authoring tools and the mod-
el check should insure the compatibility of BIM model and BEM.
Acknowledgments:
Adalberto Cabrera and Dimitrios Ntimos from IES
Shirley Gallagher for SIRUS
The whole IMPRESS Consortium partners
EASME; European Commission
The IMPRESS research project, funded by the European
Union under Horizon 2020 programme, aims to develop
an innovative Performance Based Retrofit (PBR) solu-
tion for existing buildings. The methodology proposed
by IMPRESS involves two different approaches; the first
one a recladding option in which the actual façade is
removed and replaced by a sandwich panel incorpo-
rating Phase Change Material on the inner wythe. The
second, an over-cladding option involving two different
alternatives; a lightweight Ultra High Performance Con-
crete sandwich panel or hybrid cement-polymer foam
panels. The production chain of panels and ancillary
elements involves innovative technologies, as Recon-
figurable Moulding and large format 3D printing, which
are not usual in the construction industry; as well as hi-
res scanning coupled with thermography and CNC laser
cutting. The concurrence of all those technologies, as
well as the PBR approach, result in an unprecedented
flux of digital information that should be stored, autho-
rized and exchanged among all parties involved in the
process. In order to deal with these challenges the IM-
PRESS project relies on three software tools; (i) an on-
line Decision Support Software (DSS), which conducts
an early assessment of the energy savings offered by
each one of the retrofitting technologies; (ii) an Online
Management Platform (OMP) for project management;
and (iii) an Interoperable Data Exchange Server (IDES)
for data storage and exchange. The OMP and the IDES
constitute what is referred as the Common Data Envi-
ronment in the BIM context.