bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards automated stochastic Grey-Box Model Calibration for Heat Transfer Coefficient Inference
Authors: Faure Gaëlle , Juricic Sarah , Rabouille Mickaël , Rouchier Simon , Challansonnex Arnaud , Jay Arnaud 
Published: December 2023

Abstract
An accurate on-site measurement of the intrinsic thermal performance of the building envelope is a strong leverage to promote quality management and energy performance contracting. The building sector expects on-site measurements of the Heat Transfer Coefficient to be as short as possible and highly accurate. Perturbation measurement methods analysed by RC models have been shown to be promising with accurate results within 2 days. However, stochastic RC model calibration is highly dependent on expert knowledge. In particular, model initialisation jeopardises the calibration success if not carefully chosen a priori and all the more so with second or higher order models. This paper proposes and assesses a novel automated initialisation procedure for RC models. After having brought to light that the capacitance initialisation is critical to the calibration success, the paper shows how first-order models are almost always highly identifiable. The first-order model estimated parameters then serve as initial values for all second and higher order models. This novel procedure is in 78 % of the 156 cases tested better than or similar to expert knowledge initialisation. The results are very encouraging and suggest a successful integration in a global RC model calibration and selection workflow for a fully automated process.
Assessment of wind-driven rain (WDR) on buildings in an urban area: comparison of different CFD frameworks
Authors: Gholamalipour P , Ge H , Stathopoulos T 
Published: December 2023

Abstract
The study of Wind-Driven Rain (WDR) loading on building facades is essential to design more sustainable and climate-resilient buildings, as well as to prevent further damage to old and historical buildings. Both WDR loading on buildings and façade responses to impinging raindrops have been studied previously but results for such a multi-parameter problem are not generally conclusive. Thus, the relevant provisions of ISO semi-empirical model cannot be applied with confidence for complex building configurations, such as those in urban areas since the WDR prediction can be more than twice that of the experimental data. In this paper, the Eulerian Multiphase (ME) technique is coupled with the RANS model to simulate the WDR loading on a six-story building under steady rainfall event conditions. Wind and WDR results are compared with the available wind-tunnel and on-site field measurement results, respectively. The field measurements were carried out on a six-story mid-rise residential building, located in Vancouver, Canada. The results show that the Euler-Euler framework (RANS-EM) predicts wind and WDR in such an urban area configuration more rapidly and accurately compared to the more traditional Euler-Lagrange framework (RANS-LPT) for both stand-alone and urban area configurations.
Occupant behaviour and the potential of automating lighting control in terms of energy consumption – is there a link for residential buildings?
Authors: Thillo L Van , Verbeke S , Audenaert A 
Published: December 2023

Abstract
The implementation of occupancy-controlled and daylighting-dimmed lighting systems has an impact on the energy consumption of residential buildings. The BAC factor method of EN ISO 52120-1 estimates that 8% of the lighting energy can be saved compared to conventional manual control. However, it is assumed that their ability to potentially lower the lighting energy consumption is strongly related to external factors, such as the extent of daylight entrance and the behaviour of the inhabitants. By means of simulations in EnergyPlus, the performances of automated and manual lighting control are compared for an apartment and semi-detached building located in Brussels (Belgium) with variation in the occupant behaviour and orientation.
It appears that an automated lighting control including 0-100% dimmer reduces the lighting energy demand for all investigated cases with savings up to 38.4%, whereas a similar control without dimmer does not necessarily reduce the lighting electricity demand. However, the results show a considerable variation, making prediction methods as the BAC factor method highly inaccurate. The actual relative energy performance depends on the automation system, type of building, orientation and occupant behaviour (i.e. number of inhabitants and occupancy rate). Hereby, the number of inhabitants has the most considerable impact on the relative energy performances with differences up to 50%, while the occupancy rate shows a significant correlation, especially for low numbers of inhabitants.
Impact of Positioning Phase Change Materials on Thermal Performance of Buildings in Cold Climates
Authors: Norouziasas Alireza , Yin Hang , Hamdy Mohamed 
Published: December 2023

Abstract
The building envelope, an essential component of any building, plays a critical role in meeting energy efficiency and thermal comfort requirements. Incorporating phase change materials (PCM) into the building envelope can offer an opportunity to minimize energy usage and enhance thermal comfort by offsetting daily temperature fluctuations. However, the optimal performance of PCM is contingent on the material’s placement and thickness within the building envelope. Therefore, this study investigated the effects of positioning and thickness of PCM on thermal comfort and heating loads in a lightweight timber building in Trondheim, Norway. Four scenarios were considered based on the positioning of the PCM layer in the exterior wall and roof. Using IDA ICE, parametric simulations were conducted for various PCM wallboard positions and thicknesses in the exterior wall and roof. In Nordic climates, adding PCM reduces the risk of annual overheating. The findings of this study showed that installing 75mm of PCM wallboard in the exterior wall’s inner layer reduced the annual heating load by 2.3%. Compared to the base case scenario, increasing PCM thickness reduced zonal maximum indoor air temperatures by up to 6.2°C. This study underscored the importance of carefully considering the placement and thickness of PCM in building envelopes for optimal performance.
Lime-hemp as Wall Insulation - Hygrothermal Performance Analysis by Validated Simulations
Authors: De Mets Timo , Prignon Martin , Knapen Elke 
Published: December 2023

Abstract
The application of lime-hemp as a thermal insulation material is promising: besides its ecological benefits, lime-hemp has a reasonably low thermal conductivity, combined with a good moisture buffering capacity and high thermal inertia. However, adequate design and accurate execution on-site are required, as severe long-lasting moisture accumulation could cause the hemp shives to degrade. In this study, a numerical simulation model is validated using long-term measurements. Then, it is further used to evaluate the hygrothermal performance of lime-hemp as both external and internal wall insulation. The simulations show that high humidity levels are found in lime-hemp as external insulation if an external render with inadequate rain protection is used. If the lime-hemp is used as internal insulation, its high vapour permeability allows the masonry to dry towards the inside, resulting in a drier wall compared to vapour tight materials such as cellular glass.
An influence of temperature on thermal conductivity of loose fill insulations of natural origin
Authors: Kosiński Piotr , Wójcik Robert , Rosiński Arkadiusz 
Published: December 2023

Abstract
Basing the calculations of heat losses of buildings on the constant thermal conductivity calculated for the average temperature of 10°C may be a source of calculation inaccuracies. It may lead to oversizing heating systems or the inability to achieve high efficiency of devices, e.g. heat pumps or ventilation heat exchangers. At the same time, in the summer it may turn out that the rapidly increasing thermal conductivity of thermal insulation will not protect the building against overheating. In the paper, the authors described the influence of temperature on thermal conductivity of loose fill insulations, mineral wool, cellulose, hemp fibers and flax shives. Authors measured the properties of materials under 15 and 20°C temperature differences. The highest effect of temperature was observed for hemp fibers, with up to 18% rise of conductivity in the range from 10 to 40°C with 20°C temperature difference. While 14% rise of thermal conductivity in the range 2.5 to 37.5°C with 15°C temperature difference. The lowest increase was observed in the case of flax shives, 11% and 9% rise, respectively. The measurements were supplemented by thermal simulation performed in the Delphin software. The authors are currently researching the influence of moisture on heat transport and thermal diffusion through the described materials.
Experimental study on the capillary water absorptivity of an aerogel-based coating mortar under subsequent drying and wetting cycles
Authors: Karim A N , Kalagasidis A Sasic , Johansson P 
Published: December 2023

Abstract
Aerogel-based coating mortars with thermal conductivities ranging from 30 to 50 mW/(m·K) are an emerging type of thermal insulation coating mortar. They are intended for retrofitting uninsulated building envelopes due to their thermal performance which is comparable to conventional thermal insulation materials such as mineral wool. Meanwhile, their long-term hygrothermal performance and the reliability of the material properties are not fully demonstrated since these normally are declared based on single-cycle laboratory measurements. This paper presents laboratory measurements to determine the capillary water absorptivity of a commercial aerogel-based coating mortar after three consecutive wetting and drying cycles. The effect of the chosen drying (elevated versus room temperature) and sealing condition (sealed versus unsealed samples) on the measurement results were also assessed. The results show that the capillary water absorptivity of the samples increased after each repeated wetting and drying cycle regardless of the drying and sealing conditions. After three cycles, the measured capillary water absorption was more than five times higher than the initial measurement. Future research should investigate the causes of the observation and whether it applies to other aerogel-based coating mortars.
Evaluating the indoor radon concentrations in the Swedish building stock using statistical and machine learning
Authors: Wu Pei-Yu , Johansson Tim , Mangold Mikael , Sandels Claes , Mjörnell Kristina 
Published: December 2023

Abstract
Exposure to excessive indoor radon causes around 500 lung cancer deaths in Sweden annually. However, until 2020, indoor radon measurements were only conducted in around 16% of Swedish single-family houses and 17% of multifamily houses. It is estimated that approximately 16% of single-family houses exceed the indoor radon reference level of 200 Bq/m3, and the corresponding situation in multifamily houses is unknown. Measuring indoor radon on an urban scale is complicated and costly. Statistical and machine learning, exploiting historical data for pattern identification, provides alternative approaches for assessing indoor radon risk in existing dwellings. By training MARS (Multivariate Adaptive Regression Splines) and Random Forest (RF) regression models with the data labels from the radon measurement records in the Swedish Energy Performance Certification registers, property registers, soil maps, and the radiometric grids, the correlations between response and predictive variables can be untangled. The interplay of the key features, including uranium and thorium concentrations, ventilation systems, construction year, basements, and the number of floors, and their impact magnitudes on indoor radon concentrations, are investigated in the study. The regression models tailored for different building classes were developed and evaluated. Despite the data complexity, the RF models can explain 28% of the variance in multifamily houses, 24% in all buildings, and 21% in single-family houses. To improve model fitting, more intricate supervised learning algorithms should be explored in the future. The study outcomes can contribute to prioritizing remediation measures for building stocks suspected of high indoor radon risk.
Local control of near-field diffusion of infected respiratory cloud in a room by air-blades
Authors: Rasam Hamed , Gentile Vincenzo , Simonetti Marco , Tronville Paolo 
Published: December 2023

Abstract
The respiratory cloud of an infective subject contains droplets of mucosalivary fluid carrying pathogens. As this cloud spreads at a certain distance from the emission point, the droplets accumulate and their volume concentration increases in the room unless dilution, adequate ventilation, or filtration reduce it. A susceptible subject, standing a short distance away can be exposed more easily to the infected respiratory cloud, thus inhaling a higher dose of pathogens than someone breathing the mixed air in the room. A local airflow pattern can be employed to reduce this short-distance risk of inhalation and potential contagion. We present experimental and numerical investigations of a novel device acting as a barrier to airborne pathogen diffusion at a short distance. This portable device generates V-shaped air blades in front of the subjects, shifting the respiratory clouds. The air blades are generated by 12 small fans, three on each side of the cube. The air is sucked into the small plenum inside the device body through the bases. By being positioned obliquely on a meeting table, the device acts as a direct barrier to virus-laden aerosols without any filtration. The experimental tests show that the system can reduce the local concentration of aerosol by 63 to 84% at the respiratory position of a subject sitting at a table in front of an infective person. CFD simulation outputs using the Multiphase Eulerian-Lagrangian model show a good agreement with the experimental results. The validated model will be used to extend the range of investigation to different settings and to perform a parametrical analysis of the main design conditions.
Openings in ventilated Attics
Authors: Møller E B , Morelli M , Hansen T 
Published: December 2023

Abstract
How big should ventilation openings be in ventilated attics? In Denmark, guidelines describe what is sufficient to remove excess moisture penetrating through the ceiling. These guidelines are based on many years of experience. An important parameter is the tightness of the ceiling. With current regulations for the airtightness of buildings, convection through the ceiling is reduced compared to older buildings. Therefore, it is relevant to review these old rules of thumb and maybe revise them. In this two-year study, tests with different sizes of ventilation openings were conducted in a test house with 18 separate ventilated attics and airtight ceilings. One third of the attics were ventilated according to the guidelines, one third’s ventilation was reduced by one third and the last third had 50 % ventilation of the recommendations. Hourly measurements of temperature and relative humidity in the attics were conducted. Rafters in the attics were tested for mould growth. Six different types of insulation systems were used in the attics (with and without a vapour barrier, different insulation materials, and insulation thickness), therefore, the study also includes these differences. Earlier investigations, with full ventilation in all attics, showed no significant hygrothermal differences between them; consequently, it was assumed that the amount of ventilation would be decisive for the hygrothermal performance. This study follows up on this assumption. Results show little differences between the attics, mainly that having a vapour barrier becomes more important with reduced ventilation, and the insulation thickness and thereby U-value is of less importance. Reducing the requirements for ventilation of attics could be relevant, provided that the ceiling is airtight.
Thermal performance of two different PV-ETICS integration solutions in a real environment
Authors: Heim Dariusz , Knera Dominika , Krempski-Smejda Michał , Wieprzkowicz Anna , Kalamees Targo 
Published: December 2023

Abstract
The main aim of the paper was to experimentally investigate the thermal performance of the newly developed concept of building integrated photovoltaics. The first experimental results were obtained for the two proposed techniques of direct integration of photovoltaic panels (PV) with an external thermal insulation composite system (ETICS). Both systems were developed, described in detail, and constructed on a south-oriented building wall, and the main novelty was the introduction of an additional layer with increased heat capacity in one of the variants. Components were equipped with temperature and heat flux sensors connected to the datalogger system. The measurement period was from July to December, while the temperature of the PV panels was measured and analysed. The results were statistically analysed, and the main differences were emphasized. Moreover, the advantages of the case with a higher mass were listed and recommendations were formulated. The obtained results of the possible temperature of exploitation allow one to determine the risk of damage or loss of performance.
Innovative Integration of Phase Change Materials and Conceptional Design of Test Cases – New Products for the Building Envelope
Authors: Ali Asmaa , Kieseritzky Esther , Bogacz Anna , Tsiokou Vaia , Susana P.B. Sousa 
Published: December 2023

Abstract
The building sector contributes to a great part of energy consumption and has a major impact on climate in Europe. Development of climate-friendly and energy-efficient products is required to reach low and net-zero energy buildings and to facilitate the energy transition. The building envelope is critical in defining the demand for space heating and cooling as well as ensuring thermal comfort and indoor environmental quality through proper ventilation. This paper presents the conceptual test cases integrating phase change materials (PCMs) in the building envelope. PCM absorbs, stores, and releases the heat energy in a controlled manner taking advantage of the temperature difference between night and day. Hence PCM can support the thermal management of the building by minimizing unwanted heat gains and losses while integrated into walls or support the energy efficiency of ventilation while supplying fresh air. Smart ventilated heat harvesting windows and multifunctional sandwich panels are developed within the EU-funded iclimabuilt project. Additionally, commercial air-guided PCM storages are presented as ready-to-install products for decentralized ventilation and heat recovery systems.
Impact of indoor humidification on hygrothermal performance of building envelope in Northern Finland
Authors: Schroderus S , Kuurola P , Haverinen-Shaughnessy U , Fedorik F 
Published: December 2023

Abstract
Dry indoor air is known to increase the risk for respiratory infections, viability, transport of influenza virus and intensifies sensitivity of nasal systems. The aim of this study was to investigate the effect of humidification on the hygrothermal performance of the common timber wall structure of a day care building located in Northern Finland. Hygrothermal performance of structures under different indoor moisture loads was analysed. Numerical simulation and the Finnish mould growth model were used to evaluate the impact of humidification on moisture safety of the envelope. Largest impact of indoor air humidification is observed in the low humidity ranges on inner side of water vapour barrier. At the outer side of the water vapor barrier the indoor humidification has no effect on the hygrothermal conditions or mould growth risk. The most favourable conditions for mould growth are obtained at the corner of the building envelope, at the interface of load bearing timber and windshield where hygrothermal conditions are almost 60% of the time over 80% of relative humidity. However, the Finnish mould index does not indicate any mould growth risk. The study demonstrates that the indoor air can be humidified to RH of 35% during the cold dry period.
Moisture Performance Requirements for Insulation in Exterior Wood-Frame Walls without a Vapour Barrier
Authors: Leszmann Anna E. , Morelli Martin , Rasmussen Torben Valdbjørn 
Published: December 2023

Abstract
An increased interest has been observed, especially among architects, in constructing the building envelope without using a vapour barrier membrane of polyethene (PE) foil. An increasing interest in biogenic building materials has also been expressed, as their use, besides storing embedded carbon, can reduce greenhouse gas emissions, replacing nonrenewable building components. Further, building envelope construction without a vapour barrier reduces expenses and the difficulty of the work process, especially around joints and penetrations. This study aims to determine the most important material properties of biogenic thermal insulation materials that influence the moisture-robustness of exterior wood-frame walls constructed without a vapour barrier. A literature study was performed to examine which material parameters have the most influence on the moisture conditions in an exterior wall without a vapour barrier. Hygrothermal simulations of lightweight exterior walls were performed to investigate the significance of variations in material properties (e.g., equilibrium moisture content and vapour diffusion resistance) and determine their necessary characteristics when used as thermal insulation material in an exterior wall without a vapour barrier in internal humidity class 3 (defined in EN ISO 13788). The moisture-robustness of the construction is assessed based on the risk of mould growth in the layer between the thermal insulation and wind barrier. The study suggests that the moisture capacity of the available common biogenic thermal insulation materials does not significantly affect the overall moisture performance of the wall. Simulations demonstrate that, for the thermal insulation layer in internal humidity class 3, at least one of the following requirements must be met to ensure moisture-robustness in exterior walls without a vapour barrier: (I) high diffusion resistance of the thermal insulation and (II) high moisture capacity of the thermal insulation material at relative humidity between 60% and 90%. Commercial biogenic thermal insulation materials on the market do not meet the latter requirement.
Numerical and experimental estimation of building wall heat flux in presence of moisture transfer
Authors: Assaad M El , Colinart T , Lecompte T 
Published: December 2023

Abstract
Insulating building envelope is an efficient way to increase building energy efficiency and minimize greenhouse gas emissions related to heating. After building refurbishment, on-site measurements are suitable for verifying the actual thermal transmission properties of plane building components. For instance, the standard ISO 9869-1 describes a HFM method based on the measurement of surface heat flux with heat flow sensor (HFS). This method has been extensively investigated in the literature and successfully applied on vapor tight building walls. Nevertheless, hygroscopic building insulation materials (like biobased materials) are increasingly used, and heat transfer are coupled to moisture transfer within the wall. In this case, the HFS acts as a vapor barrier: it modifies the local moisture transfer and the associated latent heat flux. In this view, this study aims to clarify what it is measured with HFS in presence of moisture transfer. The question is first treated by numerical simulation of heat and moisture transfer within hygroscopic building wall. Then, experiments are carried out on hygroscopic building insulation where the moisture effects are exaggerated.