General Task Publications

Quasi-Monte Carlo based uncertainty analysis: Sampling efficiency and error estimation in engineering applications
November 2019
By: Tianfeng Hou, Dirk Nuyens, Staf Roels, Hans Janssen
Publisher: Reliability Engineering & System Safety, Volume 191

In probabilistic assessment via Monte Carlo sampling efficiency is of high importance. It is shown that Quasi-Monte Carlo mostly performs better than standard Monte Carlo. Depending on the smoothness of the function and the number of dominant parameters. Randomization techniques on Quasi-Monte Carlo allows assessing sampling accuracy.In probabilistic assessment via Monte Carlo sampling efficiency is of high importance. It is shown that Quasi-Monte Carlo mostly performs better than standard Monte Carlo. Depending on the smoothness of the function and the number of dominant parameters. Randomization techniques on Quasi-Monte Carlo allows assessing sampling accuracy.

 

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Trilemma of historic buildings: Smart district heating systems, bioeconomy and energy efficiency
November 2019
By: Andra Blumberga, Ritvars Freimanis, Indra Muizniece, Kriss Spalvins, Dagnija Blumberga
Publisher: Energy, Volume 186

Novel insulation material made from pine needles based on bioeconomy principles is tested. Insulation material without/with lime treatment was tested for application as internal insulation for historic buildings. Insulation material is highly porous, has high moisture transfer and storage capacity, and is good hygric regulator. No mold growth was detected at 85% relative humidity for lime treated samples.

 

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Neural networks for metamodelling the hygrothermal behaviour of building components
September 2019
By: Astrid Tijskens, Staf Roels, Hans Janssen
Publisher: Building and Environment, Volume 162

A metamodel with a memory mechanism is required to accurately predict hygrothermal time series. Recurrent neural networks and dilated causal convolutional networks are able to capture the complex patterns of the hygrothermal response. To predict the relative humidity, dilated causal convolutional neural networks perform significantly better than recurrent neural networks. Dilated causal convolutional networks are 10 times faster to train on the current example, compared to recurrent neural networks.

 

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The effects of wind-driven rain on the hygrothermal conditions behind wooden beam ends and at the interfaces between internal insulation and existing solid masonry
August 2019
By: Tessa Kvist Hansen, Søren Peter Bjarløv, Ruut Peuhkuri
Publisher: Energy and Buildings, Volume 196

Wind-driven rain (WDR) quantification performed experimentally on 2 case buildings. Effect of WDR on hygrothermal conditions in internally insulated masonry studied. Numerical simulations to determine WDR effect on hygrothermal performance. WDR models were found to overestimate WDR deposition. Direct influence of WDR events on RH behind insulation was not detected.

 

The full publication can be found here.

Hygric properties of porous building materials (IV) Semi-permeable membrane and psychrometer methods for measuring moisture storage curves
April 2019
By: Chi Feng, Hans Janssen
Publisher: Building and Environment, Volume 152

Two novel methods for measuring the moisture storage curves are proposed. They feature in wide applicable range, low cost, simple handling and efficiency. Both adsorption and desorption in the over-hygroscopic range can be measured. Tests on 3 representative porous building materials are performed and validated.

 

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Task 59 Highlights 2018
Task 59 Highlights 2018
April 2019 - PDF 0.22MB
Publisher: Task 59

Historic buildings represent a large share of the existing building stock. They are the trademark of numerous cities, and they will only survive if maintained as a living space. In order to preserve this heritage, we need to find conservation compatible energy retrofit approaches and solutions, which allow maintaining the historic and aesthetic values while increasing comfort, lowering energy bills and minimizing environmental impact. 

In the last 10 years a shift in paradigm could be observed: While in times of the first EPBD, a strong opposition from conservators and architects could be observed – “don’t touch these buildings” – there is growing a new openness, a much more constructive approach – “let’s find the right solutions together”. Now is an important moment to identify and promote good approaches and solutions.

Effect of temperature and relative humidity on algae biofouling on different fired brick surfaces
February 2019
By: Enrico Quagliarini, Andrea Gianangeli, Marco D'Orazio, Benedetta Gregorini, Andrea Osimani, Lucia Aquilanti, Francesca Clementi
Publisher: Construction and Building Materials, Vol. 199

Microalgae biofouling on different porous and rough fired brick surfaces was studied. Its growth under different values of relative humidity and temperature was tested. At relative humidity lower than 98% no growth was present. Temperature influenced algae growth rate and covered area as a function of time. Biofouling experimental results were modelled by a modified Avrami’s law.

 

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Task 59 Renovating Historic Buildings
Task 59 Renovating Historic Buildings
Task Flyer
January 2019 - PDF 0.85MB
Publisher: Task 59
Historic buildings constitute a considerable part of our building stock and are the trademark of numerous cities.  Historic buildings will, however, only survive if kept in use. To save this heritage for future generations, we need to find conservation compatible, renovation approaches and measures that preserve the heritage values of these buildings while improving user comfort, lowering energy bills and minimizing environmental impacts.
Building Retrofit Measures and Design: A Probabilistic Approach for LCA
October 2018
By: Claudio Favi, Elisa Di Giuseppe, Marco D’Orazio, Marta Rossi and Michele Germani
Publisher: Sustainability

This paper presents a new and structured approach to address uncertainty and sensitivity analysis in Life Cycle Assessment (LCA) to support the decision-making process in building renovation. This “probabilistic” approach to LCA allows for the obtaining of results expressed as ranges of environmental impacts and for alternative solutions, offering an idea of the meaning of input parameters’ uncertainties and their influence on the result. The methodology application is illustrated through a case study where three building retrofit measures were assessed. Results provide an insight about the uncertainties of LCA indicators in terms of climate change and non-renewable energy.

 

Please visit MDPI for the full publication.

Energy savings due to internal façade insulation in historic buildings
September 2018
Editor: Tor Broström, Lisa Nilsen and Susanna Carlsten
Publisher: Uppsala University, Department of Art History

The paper presents desktop analyses of potential energy savings in historic buildings, carried out using standard boundary conditions for calculation of energy savings, as prescribed in the European building energy performance certification schemes. Internal insulation of the building’s façades can potentially reduce the theoretical energy demand for space heating by 9 to 43 % compared to the energy demand of the original building if installed moisture-safe. Combined with other commonly used energy saving measures, 43–78 % reduction of the energy demand was estimated.


For the full paper, please visit the EEHB2018 website.
 

How to estimate material properties for external walls in historic buildings before applying internal insulation
September 2018
Editor: Tor Broström, Lisa Nilsen and Susanna Carlsten
Publisher: Uppsala University, Department of Art History

Before deciding how to improve the energy efficiency of historic buildings by applying thermal insulation, an estimation of consequences, e.g. changes in heat and moisture flux, must be made. In the EU-project RIBuild, attempts have been made to cluster historic building materials; enabling a user to choose an appropriate material and include uncertainties. Unfortunately, the decisiveness of properties depended on whether e.g. conditions at external or internal surface of the brick wall were considered.

 

Visit the EEHB2018 website to download the full report.

Outlining a methodology for assessing deterioration threshold criteria
September 2018
Editor: Tor Broström, Lisa Nilsen and Susanna Carlsten
Publisher: Uppsala University, Department of Art History

This paper describes a methodology for assessing damage threshold criteria. The methodology includes a survey and determination of threshold values for deterioration, which can then be used to evaluate the risk in specific structures of external walls. The work includes summarizing existing knowledge and adapting and developing models for failure modes based on field and laboratory testing. Failure modes include frost damage of the exterior façade layer, rot and mould growth within the building envelope and adjoining structures, as well as discolouring of façade surfaces due to biological growth.

 

Please visit the EEHB2018 website for access to the full report.

Laboratory Investigation of Latvian Historic Brick and Measurements of Water Movement in Historic Masonry Walls
May 2017
By: Reinis Purvins, Edite Biseniece, Andra Blumberga
Publisher: Energy Procedia

Experimental laboratory tests including density, water absorption, soluble salts, compressive strength and freeze-thaw resistance have been done on clay, concrete and silicate bricks from 6 masonry buildings in Latvia following CEN standards with adjustments for historic bricks. In addition, in-situ measurements of moisture content in brick masonry walls were done over a 5 month period using Trotec micro-wave apparatus.

 

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State of the art on historic building insulation materials and retrofit strategies
March 2016
By: Andra Blumberga, Kristaps Kašs, Edite Kamendere, Gatis Žogla, Agris Kamenders, Dagnija Blumberga, Armands Gravelsinš, Reinis Purvinš, Marika Roša, Lelde Timma, Hans Janssen, Peggy Freudenberg, Fredrik Stahl, Ruut Peuhkuri, Pierryves Padey, Sebastien Lasvaux, Elisa di Giuseppe, Ernst Jan de Place Hansen
Publisher: RIBuild Deliverable D1.2

This report provides an analysis and evaluation of a state-of-the-art of internal insulation materials and methods for application in historic buildings, and review on methods, tools and guidelines used as decision-making tools for implementation of internal insulation in historic buildings. The survey is limited to buildings with heavy walls (stone, brick, timber framing), thus excluding wooden buildings.

 

For the full report, please visit the RIBuild project website.