Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Please note that all times are shown in the time zone of the conference. The current conference time is: 17th May 2022, 06:08:59 CEST

 
 
Session Overview
Session
Session T4.3: Buildings paving the way for the energy transition
Time:
Thursday, 02/Sept/2021:
15:00 - 16:30

Session Chair: Elli Nikolaidou, University of Bath
Session Chair: Vojtech Zavrel, CTU in Prague, Faculty of Mechanical Engineering
Location: Cityhall (Belfry) - Room 3

External Resource: Click here to join the livestream. Only registered participants have received the access code for the livestream.
Show help for 'Increase or decrease the abstract text size'
Presentations
15:00 - 15:18

Validated combined first and last year borefield sizing methodology.

Wouter Peere1, Damien Picard1,2, Iago Cupeiro Figueroa1, Wim Boydens2,4, Lieve Helsen1,3

1Department of Mechanical Engineering, University of Leuven (KU Leuven), Leuven, Belgium; 2Boydens Engineering, Dilbeek, Belgium; 3EnergyVille, Thor Park, Waterschei, Belgium; 4Department of Architecture and Urban planning, University of Ghent, Ghent, Belgium

Aim and Approach

(max 200 words)

This paper presents a new easy to use sizing method for borefields. Starting from the ASHRAE three-pulse sizing method (Ahmadfard, 2018a), there are mainly two variants found in literature: sizing based on the first year of operation (Carcel, 2016) and sizing based on the last year of operation (Ahmadfard, 2018b). In this paper we combine both methods in order to come up with an overall more correct and complete sizing method. This combined sizing method is then validated against an existing sizing method using earth energy designer (Heelström, 2000) and a dynamic simulation in Modelica (Laferrière, 2020) for both a heating and cooling dominated case from the point of view of the borefield.

Scientific Innovation and Relevance

(max 200 words)

The combination of these two sizing methods, using both the first and last year of operation, is novel. The obtained method is fast and easy to implement and gives for specific borefield loads a more correct result than the existing individual methods. The correct sizing of a borefield is relevant due to the high cost associated to these investments. Keeping targets against climate change in mind, geothermal heating and cooling systems, using borefields, are more used nowadays. To make this technology attractive, the cost needs to be correct and not overstated. This method gives designers a new and quick tool to (more) correctly calculate the borefield size.

Preliminary Results and Conclusions

(max 200 words)

This method is thoroughly validated using earth energy designer for both a cooling dominated and a heating dominated case from the point of view of the borefield. The validation results show that the current individual methods do not give the correct result in some cases (typically leading to undersized borefields) while this combined method does so. Moreover, this novel method is validated by a dynamic simulation using the IDEAS-library in Modelica to check whether the fluid temperature restrictions are kept. The presented combined sizing method sizes the field within these limits, whereas in some cases the current sizing methods on either the first or last year of operation don’t.

Main References

(max 200 words)

M. Ahmadfard. A Comprehensive Review of Vertical Ground Heat Exchangers

Sizing Models With Suggested Improvements. PhD thesis, École Polytechnique

de Montréal, 2018.

Mohammadamin Ahmadfard and Michel Bernier. Modifications to ASHRAE’s

sizing method for vertical ground heat exchangers. Science and Technology for

the Built Environment, 24(7):803–817, 2018.

Patricia Monzó Cárcel, Michel Bernier, José Acuña, and Palne Mogensen. A

monthly based bore field sizing methodology with applications to optimum

borehole spacing. ASHRAE Transactions, 122, 01 2016.

G. Heelström, B. Sanner, Earth Energy Designer (EED), User’s Manual, version 2 (2000).

Laferrière, A., Cimmino, M., Picard, D., Helsen, L. with Cimmino, M. (corresp. author) (2020). Development and validation of a full-time-scale semi-analytical model for the short- and long-term simulation of vertical geothermal bore fields. Geothermics, 86, 101788-101788. doi: 10.1016/j.geothermics.2019.101788 Open Access



15:18 - 15:36

Efficiency of a heated air curtain under cross-jet temperature gradients

Claudio Alanis Ruiz1, Twan van Hooff2,1, Bert Blocken2, GertJan van Heijst3

1Building Physics and Sustainable Design Section, KU Leuven, Belgium; 2Building Physics and Services Unit, Eindhoven University of Technology, The Netherlands; 3Fluids and Flows, Eindhoven University of Technology, The Netherlands

Aim and Approach

(max 200 words)

Air curtains, which are essentially devices that generate an aerodynamic barrier, are used to reduce infiltration through entrance doors where transit is frequent. While isothermal jet air curtains (only driven by momentum) are commonplace, the use of air curtains with buoyant jets is fairly normal for certain applications. An example of the latter are heated air curtains at the entrance of buildings in cold and moderate climates, which are subjected to temperature differences between indoor and outdoor environments. In these air curtains an interaction occurs between natural convection, jet buoyancy and jet momentum. Despite the frequent occurrence of such scenarios, little has been done in investigating this interaction and its influence on air-curtain performance. Therefore, this study aims to provide an analysis of the added effect of jet temperature and ambient temperature on the overall flow behavior and the efficiency of a heated air curtain at the entrance of a building. The analysis is performed numerically using validated computational fluid dynamics (CFD) simulations. Two performance indicators are considered: (1) separation efficiency (related to mass transport), and (2) thermal efficiency (related to heat transport).

Scientific Innovation and Relevance

(max 200 words)

Air infiltration is usually associated with increased energy demand in buildings. Moreover, problems concerning thermal comfort and indoor air quality can in many instances also be attributed to air infiltration. The infiltration of unconditioned air through access doors significantly contributes to these potential problems, especially in buildings where transit through these doors is frequent. For such reasons, air curtains are often implemented at these locations in order to facilitate the transit of people, vehicles and materials while minimizing energy losses, decreasing the transport of outdoor air pollutants to the inside and reducing thermal discomfort (e.g., due to wind draft and vertical air temperature differences). By virtue of the value that air curtains can provide in building applications, understanding their behavior and improving their performance is of great interest. The present contribution provides insights on the interaction of ambient conditions and air-curtain operating conditions, which has not been frequently studied in detail before. The analysis is conducted for a variety of representative combinations of ambient and air curtain operating conditions and overall performance is evaluated in terms of both heat and mass transfer.

Preliminary Results and Conclusions

(max 200 words)

The results indicate that from energy conservation and pollution control perspectives, the use of a heated air curtain is not favorable over the use of an isothermal air curtain, since in every instance the heated air curtain yields additional heat losses and infiltration. Nevertheless, from a thermal comfort standpoint, it could be that the adoption of heated air curtains is beneficial to counteract potential factors of thermal discomfort at building entrances such as cold air drafts.

Main References

(max 200 words)

Alanis Ruiz C., van Hooff T., Blocken B., and van Heijst G.J.F. 2018. CFD analysis of the effect of pressure gradients on the separation efficiency of a generic air curtain. Proceedings of Roomvent&Ventilation 2018, Helsinki, Finland: REHVA, pp. 241-246.

Brinks P., Kornadt O., and Oly R. 2015. Air infiltration assessment for industrial buildings. Energy and Buildings, pp. 663 - 76.

Khayrullina A., van Hooff T., Blocken B., and van Heijst G.J.F. 2017. PIV measurements of isothermal plane turbulent impinging jets at moderate Reynolds numbers. Experiments in Fluids, Vol. 58:31.

Lstiburek J., Pressnail K., and Timusk J. 2002. Air pressure and building envelopes. Journal of Building Physics, Vol. 26(1) pp. 53-91.

Younes C., Abi-Shdid C., and Bitsuamlak G. 2012. Air infiltration through building envelopes: A review. Journal of Building Physics, pp. 267-302.



15:36 - 15:54

Development of the hybridGEOTABS design methodology for feasibility study and pre-design

Eline Himpe1, Mohsen Sharifi1, Rana Mahmoud1, Filip Jorissen3, Lieve Helsen3, Wim Boydens2, Jelle Laverge1

1Ghent University, Belgium; 2Boydens Engineering, Belgium; 3KU Leuven, Belgium

Aim and Approach

(max 200 words)

GEOTABS refers to the combination of a geothermal heat pump with thermally activated building systems, and is applied in low temperature heating and high temperature cooling of buildings. TABS is a radiant heating and cooling system and is beneficial in terms of thermal comfort and energy efficiency. When combined with a geothermal heat pump, it allows to make efficient use of low grade renewable energy sources. In order to maintain the thermal comfort when sudden and significant changes in heating or cooling loads appear and to maintain the thermal balance of the geothermal source, a secondary heating and cooling emission and generation system can be added, together with model predictive controls to optimise the operation of the hybrid system. This concept is called 'hybridGEOTABS'. In context of the hybridGEOTABS Horizon 2020-project, we developed a methodology to allow a near-optimal design for such hybridGEOTABS buildings, that is applicable in the early design stages. This paper sets out the main lines of the research study that has been undertaken to arrive to this methodology.

Scientific Innovation and Relevance

(max 200 words)

The design hybridGEOTABS buildings brings along some challenges such as: how to decide on the sizing of the GEOTABS and secondary heating and cooling systems? How to incorporate the effects of the large thermal inertia of the TABS into the sizing of the systems? How to take into account the effect of the control on the sizing of the key components of the system? And most of all, how to do all of this while avoiding excessive engineering costs and detailed simulation studies from the very early design stages onwards?

In this project an integrated design solution is developed, that takes into account the aforementioned aspects to come to a near-optimal sizing result with the precision required in early design stages. Behind the resulting easy-to-use guidelines and materials, is found an intensive study and cooperation that incorporates the use of dynamic building energy simulations of the EU building stock, the development of load splitting algorithms and simulation studies of the effect of control on the design.

Preliminary Results and Conclusions

(max 200 words)

This paper will walk the reader along the set-up and main outcomes of the aforementioned sub-studies and synthesise them into the development of a hybridGEOTABS design methodology. The main findings of this methodology are presented.

The resulting methodology is translated into a tool and guideline and allows the HVAC-designer to assess the feasibility of hybridGEOTABS in time similar to what is required in the design of more classical HVAC-solutions, and to come to a pre-sizing of the main system components. Before GEOTABS was mainly applied into a specific range of building designs and climates, by experienced designers. This newly developed methodology makes it possible to investigate the feasibility of hybridGEOTABS for a much wider range of buildings and building properties across EU, and makes the concept more accessible towards HVAC-designers and policy developers.

Main References

(max 200 words)

[1] W. Boydens, D. Costola, A. Dentel, T. Dippel, L. Ferkl, A. Görtgens, L. Helsen, J. Hoogmartens, B.W. Olesen, W. Parijs, M. Sourbron, C. Verhelst, J. Verheyen, C. Wagner, REHVA Guidebook No. 20: Improved system design and control of GEOTABS buildings: Design and operation of GEOTABS systems, REHVA, Brussels, 2013. www.rehva.eu.

[2] E. Himpe, M. Vercautere, W. Boydens, L. Helsen, J. Laverge, GEOTABS concept and design : state-of-the-art, challenges and solutions, in: Proceedings of the REHVA Annual Meeting Conference Low Carbon Technologies in HVAC, 2018. http://hdl.handle.net/1854/LU-8565219 (accessed March 15, 2020).

[3] Model Predictive Control and Innovative System Integration of GEOTABS in hybrid Low Grade Thermal Energy Systems - hybridGEOTABS (EU H2020 project “MPC-GT” n°723649), Www.Hybridgeotabs.Eu. (2016). www.hybridgeotabs.eu.

[4] M. Sharifi, R. Mahmoud, E. Himpe, J. Laverge, Integrated Sizing Methodology for a hybridGEOTABS Building, ASHRAE Transactions. 125 (2019) 222–230.



15:54 - 16:12

To be or not to be a hybridGEOTABS: energy performance of hybridGEOTABS buildings in the EU

Rana Mahmoud, Mohsen Sharifi, Eline Himpe, Jelle Laverge

Ghent University, Belgium

Aim and Approach

(max 200 words)

HybridGEOTABS technology plays an important role in providing clean energy for the building sector due to its high performance and use of renewable energy sources. However, for a building to be elected for the use of this technology it needs to follow a strict criterion in terms of energy performance. As stated by the GEOTABS guidebook [1]; it shall be a high insulated building with reduced window to wall ratio, using suitable orientation, with installed shading system and low internal heat gains. Therefore, limiting the implementation of this technology on buildings with different configurations.

In this paper we investigate the feasibility of hybridGEOTABS for a much wider range of configurations. We propose design guidelines for the possible building configurations that can allow higher shares of GEOTABS (primary system) and the residual can be covered by a secondary system. As a result, we can support the designer in the preliminary design stages to identify the eligibility of his building to be a hybridGEOTABS building or not. Our approach [2], [3] is based on the analysis of building stock dynamic simulations. We investigate the energy demand of a large spectrum of building geometrical and building physical properties combinations covering EU climatic zones.

Scientific Innovation and Relevance

(max 200 words)

Our main focus is on non-residential buildings typologies namely offices, schools and elderly homes. One of the main difficulties faced when studying non-residential building stock is the scarcity of the available data. Our methodology allows the using of linear data found in the building energy certificates and transform these data into multi-zone energy models that can be dynamically simulated. The approach adopted in this research considers the different functions requirements and profiles based on extensive research regarding each typology. By implementing this method [3], we are able to obtain an hourly estimation of the energy demand of the buildings. The building energy models vary in terms of geometrical characteristics such as; surface area, volumes, window to wall ratios, as well as physical properties such as; internal heat gains profiles, possible orientation, thermal mass materials, varying the use of shading systems and the thermal performance of the envelope. The analysis is based on 40,000 cases of offices, 50,000 cases of schools and 5000 cases of elderly homes.

The output of this research shall support designers and policy makers identifying the potentials of building ranges that can benefit from this technology.

Preliminary Results and Conclusions

(max 200 words)

The first step is to transform the linear building stock data into building energy models using a geometrical fitting process. A tool has been developed in python to transform the fitting geometries into multizone building energy models, while incorporating the building physical variables. An automatization process was implemented to simulate thousands of cases of the different typologies.

The Second step is analysing the estimated heating and cooling demand output simulations. By implementing a baseload algorithm developed by [4], this algorithm is able to define the shares of the GEOTABS (primary system) and secondary heating and cooling system.

The preliminary results show that 50% of cases have more than 50% of GEOTABS share while achieving balance in the ground (where heating and cooling demand covered by primary system are equal).

The paper will further identify the building design properties that leads to the highest environmental performance with hybridGEOTABS for different EU climates.

Main References

(max 200 words)

This work is performed under the EU-Horizon 2020 hybrid GEOTABS project (MPC-GT) with project number 723649. Project: website: http://www.hybridgeotabs.eu

[1] Improved system design and control of GEOTABS buildings Design and operation of GEOTABS systems, Guidebook no.20, REHVA, 2013.

[2] R. Mahmoud, M. Sharifi, E. Himpe, M. Delghust and J. Laverge, "Estimation of load duration curves from general building data in the building stock using dynamic BES-models," in E3S Web of Conferences, vol. 111., Bucharest, 2019.

[3] R. Mahmoud, E. Himpe, M. Delghust and J. Laverge, "A modelling approach to reduce the simulation time of building stock models," in Proceedings of the 16th IBPSA Conference, Rome, 2019.

[4] M. Sharifi, R. Mahmoud, E. Himpe and J. Laverge, "Integrated sizing methodology for a hybridGEOTABS building," in ASHRAE TRANSACTIONS, Kansas City, Kansas, USA, 2019.



16:12 - 16:30

BIM2SIM - Development of semi-automated methods for the generation of simulation models using Building Information Modeling

David Jansen1, Philipp Mehrfeld1, Dirk Müller1, Eric Fichter2, Veronika Richter2, Jérôme Frisch2, Christoph van Treeck2, Christian Warnecke3, Andre Barz3, Mike Dahnke3, Jesse Brunkhorst3, Pooyan Jahangiri3, Bruno Lüdemann3

1RWTH Aachen University, E.ON Energy Research Center, Institute for Energy Efficient Buildings and Indoor Climate; 2RWTH Aachen University, Institute of Energy Efficiency and Sustainable Building (E3D); 3Rud. Otto Meyer GmbH & Co. KG

Aim and Approach

(max 200 words)

High complexity of buildings and their energy systems in today’s construction projects requires advanced tools for predicting their behavior even before the planning phase. Dynamic simulations can ensure the optimum functionality of such complex systems in advance by analyzing various variants and identifying their optimization potentials. However, such simulations and the creation of the models are highly complex, time consuming and costly. Automated model generation based on already available building information modeling (BIM) models can significantly reduce the time and effort of dynamic simulation while at the same time increasing their precision.

The aim of this paper is to highlight the development of the methods and tools to derive descriptions to gain ready-to-simulate models for the improved design and optimization of building energy systems from BIM. This approach should significantly reduce the manual effort for model creation and thus support the dissemination of modern simulation applications in the building sector.

Three different topics are addressed, namely, Building Performance Simulations (BPS), Heating, Ventilation and Air Conditioning (HVAC) simulations and Computational Fluid Dynamics (CFD) simulations. The basis for all simulation types is the open exchange format IFC. The information hold in an IFC file are analyzed by topological and semantic algorithms.

Scientific Innovation and Relevance

(max 200 words)

The BPS simulation is addressed by two different simulation approaches: using the open-source Modelica library AixLib and the open-source Python-based tool TEASER, as well as EnergyPlus. The goal of both tools is the calculation of dynamic heating and cooling demands, which can then be used in HVAC simulations to calculate the final energy requirements of a building and to compare different system variations. This information can then be coupled with a CFD simulation for simulating air flow behaviors, comfort, or smoke extraction.

The HVAC simulation models are created in Modelica using two different libraries: an inhouse library of the industry partner and the open-source library AixLib.

For analysis purposes, the energy system including the hydraulics, coming from the IFC file, is transferred into a graph network. This way the semantic studies can be extended by topological analyses.

The tool also serves as an interface program for CFD (Computational Fluid Dynamics) simulation. For this purpose, it offers functions for opening, viewing, filtering, simplifying and exporting IFC building models using a graphical user interface.

Preliminary Results and Conclusions

(max 200 words)

The analysis and transfer of the data from the IFC file is performed in Python. For this purpose, in the scope of this work a comprehensive tool has been developed that serves all the simulation areas. The BIM2SIM tool is implemented as a console-based program but comes with a web application to make it more user-friendly. The tool allows simulations to be carried out quickly and simplifies the use of dynamic simulations in all phases of a construction process, from planning phase with only abstract data to the operation phase with complete data sheets and components.

Besides the automated creation of simulation models, the project deals with the identification of gaps in the IFC standard by close collaboration with IFC developers and software vendors. Especially, prescribed entities and property sets of HVAC systems are still missing in the IFC standard, which are not only necessary for the parameterization of simulation models, but also are requirements to achieve the goal of gathering all the building information in a standardized model.

Main References

(max 200 words)

No papers are cited in this abstract. They will be part of the paper.



 
Contact and Legal Notice · Contact Address:
Privacy Statement · Conference: Building Simulation 2021
Conference Software - ConfTool Pro 2.6.143+TC
© 2001–2022 by Dr. H. Weinreich, Hamburg, Germany