Conference Agenda

Session
Session T2.2: Ensuring high quality building simulations
Time:
Thursday, 02/Sept/2021:
10:30 - 12:00

Session Chair: Frank De Troyer, KU Leuven
Session Chair: Nils Artiges, Univ. Grenoble Alpes, CNRS, Grenoble INP, G2Elab, F-38000 Grenoble, France
Location: Cityhall (Belfry) - Room 2


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Presentations
10:30 - 10:48

Investigation of the temperature-dependent conductivity towards improving energy performance of building

Anna Wieprzkowicz, Dariusz Heim

Lodz University of Technology, Poland

Aim and Approach

(max 200 words)

The aim of the study is to investigate the effect of the temperature-dependent thermal conductivity on energy demand. The analysis was performed for the basic test building composed of a single rectangular zone, based on the Case 900 from ANSI/ASHRAE Standard 140-2011 (ANSI/ASHRAE 2011). The analysis was conducted for three locations characterized by different climate conditions: Norway, Bergen - cold climate without a dry season and with cold summer; Romania, Bucharest - temperate climate without a dry season and with warm summer; United Arab Emirates, Abu Dhabi – hot desert climate.

Ten functions of temperature-dependent thermal conductivity were developed and tested using non-linear properties subroutine implemented in ESP-r. The results were compared with the constant values of thermal conductivity: the maximum and minimum values included in predefined functions.

Results were analysed in terms of heating and cooling energy demand, the temperature of the insulation layer and dynamically changing thermal conductivity values as well as parameters characterizing the dynamics of thermal properties switching.

Scientific Innovation and Relevance

(max 200 words)

Dynamic properties of building components are highly expected regarding overall energy performance (Jelle, Gustavsen, and Baetens 2010) and future construction technology (Berardi et al. 2018). In case of heat transfer through building construction two thermal properties are technically possible to be adjusted: capacity and conductivity, or combined both as a so-called heat retention index

The technical solution of dynamic insulation materials (DIM), also named controllable insulation materials (CIM) is mainly based on pore (gas filles) structures. It should be noted that only radical changes in the conductivity can lead to the reduction in energy consumption.

One of the parameters which determine the overall performance of DIM is control strategies. The initial work e.g. (Park, Srubar, and Krarti 2015) have investigated a binary R-value control in which the thermal resistance of the wall is either “on” or “off”. Further research, (Rupp and Krarti 2019) investigated the improved strategy by using wall surface temperatures, the heating/cooling set-point temperature, and the temperature in the middle of the wall. It is found that adding a period during which the R-value of the wall can vary continuously within a defined range has the potential to modestly decrease the heating and cooling energy consumption.

Preliminary Results and Conclusions

(max 200 words)

The results of building energy performance equipped with dynamic insulation materials were presented in the paper. The numerical model was developed in ESP-r considering the different function of thermal conductivity versus temperature. The sudden and smooth changes in conductivity values were considered in case of heating/cooling energy demand. Analyses were performed for three geographical locations: Bergen, Bucharest and Abu Dhabi. For each location, the energy savings were determined and the best function was finally defined. The biggest difference in cooling demand was 50% for Bucharest and 25% for Abu Dhabi. In both cases, the rapid changes in lambda values gave better energy performance of the dynamic insulation in case of analysed building. It was also concluded that periodic increase of thermal conductivity has no beneficial effect of heating energy demand - in a heating season high thermal resistance is crucial.

Main References

(max 200 words)

Jelle, Bjørn Petter, Arild Gustavsen, and Ruben Baetens. 2010. “The Path to the High Performance Thermal Building Insulation Materials and Solutions of Tomorrow.” Journal of Building Physics 34 (2): 99–123. doi:10.1177/1744259110372782.

Berardi, Umberto, Lamberto Tronchin, Massimiliano Manfren, and Benedetto Nastasi. 2018. “On the Effects of Variation of Thermal Conductivity in Buildings in the Italian Construction Sector.” Energies 11 (4). MDPI AG. doi:10.3390/en11040872.

Park, Benjamin, Wil V. Srubar, and Moncef Krarti. 2015. “Energy Performance Analysis of Variable Thermal Resistance Envelopes in Residential Buildings.” Energy and Buildings 103 (July). Elsevier Ltd: 317–325. doi:10.1016/j.enbuild.2015.06.061.

Rupp, Shawn, and Moncef Krarti. 2019. “Analysis of Multi-Step Control Strategies for Dynamic Insulation Systems.” Energy and Buildings 204 (December). Elsevier Ltd: 109459. doi:10.1016/j.enbuild.2019.109459.



10:48 - 11:06

3D drone-based time-lapse thermography: a case study of roof vulnerability characterization using photogrammetry and performance simulation implications

Tarek Rakha1, Yasser El Masri1, Kaiwen Chen1, Pieter De Wilde2

1Georgia Institute of Technology, United States of America; 2University of Plymouth, United Kingdom

Aim and Approach

(max 200 words)

This paper investigates airborne time-lapse thermography using drones as a method of translating 3D envelope CAD models generated via RGB and IR photogrammetry into whole Building Energy Modeling (BEM) software. The goal is to develop a novel 4D approach that incorporates defects detected at varying situations and instances of time into comprehensive thermal profiles for envelopes. We propose the development of novel 3D thermography models constructed from time lapse IR image data collected using UAS to inform BPS envelope modeling inputs. A case study is presented for a courtyard building on a North American campus, where the research team employed a drone to fly in two path types, perimeter polygon and in a strip. The flights repeated in 2-hour intervals starting at 9 AM until 5 PM (5 flights). In this work, we are focusing on the roof as a building element that is typically assumed to perform uniformly and is neglected in as-built inspections due to the impossibility of perceiving the entire component without being significantly higher than it.

Scientific Innovation and Relevance

(max 200 words)

Multiple built environment applications have made use of thermography, mainly focusing on defect identification using perspectives from the IR spectrum. However, standard IR readings are typically undergone in singular points in time, when in several cases, such as varying pressure differences or latent heat gain, anomalies can only be revealed at specific times of the day, possibly in different seasons of the year. The pursuit of a time-series based envelope diagnosis is not new; it started in the early 80’s under the terminology “Transient Thermography,” which evolved into “Time Sequential Thermography” in the late 90’s, and finally to “Time Lapse Thermography” in the mid-2010’s onward. Therefore, this paper’s scientific contribution is evolving this concept through two proposed innovations: 1) developing a novel Time Lapse Thermography inspection methodology that employs drones to inspect building envelopes at different times during the day that characterize an envelope’s performance comprehensively without being constricted spatially; 2) employing drone-collected and geolocated RGB and IR images to build 3D envelope CAD models using photogrammetry, and introducing the concept of 3D thermography to identify envelope defects. The work’s relevance is the translation of such models into simulation software for more accurate and faster existing building envelop modeling.

Preliminary Results and Conclusions

(max 200 words)

We presented in this paper a novel workflow for 3D envelope modeling using aerial time-lapse IR data collection using UAS. A comprehensive roof thermal profile was developed for a case study building employing photogrammetry software Agisoft Photoscan, which generated temporal IR inspections of a building’s roof using multiple 3D thermography CAD models. The goal was to develop a building inspection framework that utilizes drones equipped with IR cameras to collect data time series, which in turn informs envelope performance modeling to accurately depict thermal resistance as well as anomalies for more accurate BPS. The paper concludes that on-site building envelope inspections are significantly enhanced by a time-based passive thermography audit approach that has spatial liberty due to the use of UAS and discussed the potential for integrating this technology effectively in BEM to inform both facilities management and retrofitting design. Future work should explore full envelope 4D CAD modeling in concert with thermography. Advances in this field are expected to leap the process of building envelope energy audits forward to become ubiquitous and informative to decision makers aiming to retrofit and manage our existing built environments to become significantly more highly performing.

Main References

(max 200 words)

Edis, Ecem, Inês Flores-Colen, and Jorge De Brito. 2015. “Time-Dependent Passive Building Thermography for Detecting Delamination of Adhered Ceramic Cladding.” Journal of Nondestructive Evaluation 34 (3): 1–16. https://doi.org/10.1007/s10921-015-0297-5.

Fox, Matthew, David Coley, Steve Goodhew, and Pieter De Wilde. 2015. “Time-Lapse Thermography for Building Defect Detection.” Energy and Buildings 92: 95–106. https://doi.org/10.1016/j.enbuild.2015.01.021.

Gharawi, Mohanned Al, Yaw Adu-Gyamfi, and Glenn Washer. 2019. “A Framework for Automated Time-Lapse Thermography Data Processing.” Construction and Building Materials 227: 116507. https://doi.org/10.1016/j.conbuildmat.2019.07.233.

Grinzato, E., V. Vavilov, and T. Kauppinen. 1998. “Quantitative Infrared Thermography in Buildings.” Energy and Buildings 29 (1): 1–9.

Rakha, T., & Gorodetsky, A. (2018). Review of Unmanned Aerial System (UAS) applications in the built environment: Towards automated building inspection procedures using drones. Automation in Construction, 93, 252-264.

Hobbs, Chris. 1992. “Transient Thermography.” Sensor Review 12 (1): 8–13.

Hoyano, Akira, Kohichi Asano, and Takehisa Kanamaru. 1999. “Analysis of the Sensible Heat Flux from the Exterior Surface of Buildings Using Time Sequential Thermography.” Atmospheric Environment 33 (24–25): 3941–51.

Ibarra-Castanedo, Clemente, Stefano Sfarra, Matthieu Klein, and Xavier Maldague. 2017. “Solar Loading Thermography: Time-Lapsed Thermographic Survey and Advanced Thermographic Signal Processing for the Inspection of Civil Engineering and Cultural Heritage Structures.” Infrared Physics and Technology 82: 56–74.



11:06 - 11:24

Dynamic modelling and comparison between transient step response of capacitive hygrometers and chilled mirrors

Ettore Zanetti, Rossano Scoccia, Marcello Aprile, Mario Motta

Politecnico di Milano, Italy

Aim and Approach

(max 200 words)

This manuscript presents the results of an experimental study carried out to compare the transient responses of three capacitive hygrometers with respect to three chilled mirrors. Several experiments were carried out changing the values of air flow rate, temperature, and relative humidity in the test chambers. The results of these experiments were used to derive different models of the sensors, from black box data driven models, to grey box models. These can be used to check and eventually reconstruct transient data operation of desiccant evaporative cooling heat exchangers which are inherently transient. The sensors were tested in the ReLab research group facility [1], two climatic chambers were used to simulate the different conditions, the sensors were installed in a long cylindrical duct with a 16cm diameter. The step analysis was carried out by having a fan actively driving air inside the duct and by rapidly moving one end of the duct from one chamber to the other at different conditions until a steady state was reached.

Scientific Innovation and Relevance

(max 200 words)

Desiccant Evaporative Cooling (DEC) systems have seen an increased interest in academia [2] and commercial applications [3] for Heating ,Ventilation and Air Conditioning (HVAC) applications. The core components of these systems are the direct or indirect evaporative cooler coupled with a desiccant component. Traditionally the process air goes through the desiccant component, which can be a rotary enthalpic wheel filled with silica gel or other desiccant materials, and after being dehumidified and heated up is cooled via the direct or indirect evaporative cooler [4]. However, in the last years more compact solutions that incorporate the evaporative cooling and the desiccant action at the same time were developed as shown in [5],[3]. These new heat exchanger designs do not allow a continuous operation as the enthalpy wheel, they are transient systems where the silica gel dehumidify the air moisture until being full of water, then they are regenerated and the cycles can repeat. This transient behavior on a macroscale raises the problem of having a reliable measurement of the moisture content at the outlet of the heat exchanger. This manuscript shows the transient response of capacitive and chilled mirror hygrometers, trying to develop a dynamic model to simulate the transient response.

Preliminary Results and Conclusions

(max 200 words)

The experiments were carried out for three air flow rates (100-360-500 kg/h), three values of temperatures (20-30-35) and three (20-35-60) values of relative humidity. The preliminary result analysis shows that the chilled mirrors are faster for coupled Temperature and relative humidity step changes, while for just a relative humidity change the two instruments perform in a similar fashion. This is due to the type of capacitive hygrometer tested that has a heavy metal head, drastically increasing its thermal inertia. Starting from the experimental data the dynamic models for the instruments will be developed and validated against experimental data.

Main References

(max 200 words)

[1] P. di M. Department of Energy, “ReLab.” [Online]. Available: http://www.relab.polimi.it/laboratorio/laboratorio/.

[2] Y. Yang, G. Cui, and C. Q. Lan, “Developments in evaporative cooling and enhanced evaporative cooling - A review,” Renew. Sustain. Energy Rev., vol. 113, no. May, p. 109230, 2019.

[3] M. Beccali, P. Finocchiaro, M. Motta, and B. Di Pietra, “Monitoring and Energy Performance Assessment of the Compact DEC HVAC System ‘Freescoo Facade’ in Lampedusa (Italy),” Eurosun Conf. Proc., pp. 1–8, 2018.

[4] X. N. Wu, T. S. Ge, Y. J. Dai, and R. Z. Wang, “Review on substrate of solid desiccant dehumidification system,” Renew. Sustain. Energy Rev., vol. 82, pp. 3236–3249, Feb. 2018.

[5] T. S. Ge, Y. Li, R. Z. Ã. Wang, and Y. J. Dai, “A review of the mathematical models for predicting rotary desiccant wheel,” vol. 12, pp. 1485–1528, 2008.



11:24 - 11:42

Improving the Reliability of theoretical approaches for hygrothermal characterization and modeling of building envelopes

Imane Oubrahim1,2,3, Thierry Duforestel1,3, Rafik Belarbi2,3

1EDF R&D, TREE EDF Lab Les Renardières, 77818 Moret-sur-Loing, France; 2LaSIE UMR 7356, CNRS, La Rochelle Université, Avenue Michel Crépeau, 17042 La Ro- chelle Cedex 1, France; 34ev Lab CNRS, Université de La Rochelle, Electricité de France EDF, Avenue Michel Cré- peau, 17042 La Rochelle Cedex 1, France

Aim and Approach

(max 200 words)

The prevailing thermal methods turned out to be insufficient to deal with recent hygrothermal development in the building industry. Furthermore, the recent advances in dynamic modeling and advanced hygrothermal measurements also show their limitations when applied to these problems (Duforestel 2015). To summarize the situation, the simulated results have been in disagreement with the ones measured, chiefly in dynamic configurations. The analysis of these results led us to two essential weaknesses in the current methods: an underestimation of the vapor permeability of materials (linked to an experimental bias), and ignoring the hysteretic nature of moisture sorption in hygrothermal models. Therefore, a national project (SmartRéno) aims to complement our theoretical and experimental background to produce reliable tools for hygrothermal simulation, by investigating and redefining four main characteristics of building materials: The water vapor diffusion coefficient, the gas and liquid relative permeabilities and the sorption hysteresis.

Accordingly, this article will, first, present the precedent works that led us to this project. Then, the problematics to which we expect to respond and the methodology to be used to achieve the objectives will be detailed. Finally, we will put forward the first results of the work in relation to the objectives of this project.

Scientific Innovation and Relevance

(max 200 words)

All of the work in this paper must lead to a complete corpus of hygrothermal characterization methods, accurate enough to meet the needs of hygrothermal studies, and to an updated heat and mass transfer simulation tool (SYRTHES, developed at EDF R&D) integrating these changes.

We will investigate the impact of changing each coefficient at a time in order to analyze and explain the impact of all individual changes on the overall behavior of the simulation tool. Then, we will integrate all the coefficients revisited in the tool and finally validate the latter by comparing it to existing static and dynamic experimental results.

Preliminary Results and Conclusions

(max 200 words)

A sorption hysteresis model has been progressively identified based on the literrature. It has been integrated into the simulation tool SYRTHES for coupled heat and mass transfers. A comparison between experimental and simulated results has been carried out with various versions of the SYRTHES model:

- With an average curve of the mais sorption curves;

- Pure Mualem model;

- Pure linear model;

- Mixed model.

This comparison made it possible to highlight the impact of taking this phenomenon into account on the different calculated potentials.

A new experimental method for measuring water vapor diffusion coefficient is being tested on a varied range of materials used for the construction and renovation of building envelopes.

It is based on the principle of the cup test method with an adaptation to measure the difference in gas pressure between the two faces of the tested sample.

These tests are also being simulated in order to estimate the impact of the transfer characteristics on the expected results. It is expected that this new testing process will allow to determine the water vapor diffusion coefficient with an higher accuracy and will also allow the measurement of the gas relative permeability.

Main References

(max 200 words)

-Mualem, Y. (1973). Modified approach to capillary hysteresis based on similarity hypothesis.

Water Resources Research, Vol. 9, No. 5.

- Mualem, Y. (1974). A conceptual model of hysteresis. Water Resources Research, Vol. 10, No. 3.

- Duforestel, T. (2015). Des transferts couplés de masse et de chaleur à la conception bioclima-

tique : recherches sur l’efficacité énergétique des bâtiments. Habilitaion à diriger des recherches, Faculté des Sciences et Technologies, Département de Mécanique.

- EDF, I. Rupp, C. Peniguel, Syrthes, version 4.3.6: https://www.edf.fr/groupe-edf/qui-sommes-nous/activites/notre-communaute-scientifique/syrthes.

- Projet SmartRéno (mars 2019 – juin 2021): https://smart-reno.recherche.univ-lr.fr/.