bluuebunny/crossref_metadata_2025 huggingface dataset:
Horizontal versus vertical force application: association with the change of direction performance in soccer players.
Authors: Robles‐Ruiz Juan , Baena‐Raya Andrés , Jiménez‐Reyes Pedro , Soriano‐Maldonado Alberto , Rodríguez‐Pérez Manuel A.
Published: December 2021

This study examined which mechanical variables derived from a vertical jump (i.e. concentric peak force [ConcPF] and eccentric peak force [EccPF], flight time [FT]: contraction time [CT], eccentric deceleration rate of force development [EccDecRFD]) and linear sprint (i.e. theoretical maximal force [F0] and velocity [V0], maximal power output [Pmax], the peak ratio of the effective horizontal component [RFpeak], and the index of force application technique [DRF]) determined the change of direction (COD) performance to a greater extent. Sixteen male soccer players (age: 21.8 ± 2.9 years; height: 175.94 ± 6.88 cm; weight: 73.23 ± 9.59 kg) were assessed for a countermovement jump, the horizontal force velocity (FV) profile, and the COD ZigZag test. The horizontal FV profile parameters were significantly associated with COD performance, while jump mechanical variables did not show any significant association (r = 0.08–0.19; p > 0.05). Specifically, F0 (r = −0.56), Pmax (r = −0.68), and RFpeak (r = −0.54) were strongly associated with COD performance. Moreover, a 1 N·kg−1 increase in F0 was associated with −0.11 s to complete the ZigZag test, whereas 1 W·kg−1 and 1% increase in Pmax and RFpeak were associated with −0.05 and −0.03 s, respectively, to complete the COD test. Horizontal force production during sprinting might play a key role in COD performance. Assessing the horizontal FV profile might help coaches to prescribe a specific training programme to maximize sprint acceleration, which might improve COD performance.
Gut microbiota–driven brain Aβ amyloidosis in mice requires microglia
Authors: Dodiya Hemraj B. , Lutz Holly L. , Weigle Ian Q. , Patel Priyam , Michalkiewicz Julia , Roman-Santiago Carlos J. , Zhang Can Martin , Liang Yingxia , Srinath Abhinav , Zhang Xulun , Xia Jessica , Olszewski Monica , Zhang Xiaoqiong , Schipma Matthew John , Chang Eugene B. , Tanzi Rudolph E. , Gilbert Jack A. , Sisodia Sangram S.
Published: December 2021

We previously demonstrated that lifelong antibiotic (ABX) perturbations of the gut microbiome in male APPPS1-21 mice lead to reductions in amyloid β (Aβ) plaque pathology and altered phenotypes of plaque-associated microglia. Here, we show that a short, 7-d treatment of preweaned male mice with high-dose ABX is associated with reductions of Aβ amyloidosis, plaque-localized microglia morphologies, and Aβ-associated degenerative changes at 9 wk of age in male mice only. More importantly, fecal microbiota transplantation (FMT) from transgenic (Tg) or WT male donors into ABX-treated male mice completely restored Aβ amyloidosis, plaque-localized microglia morphologies, and Aβ-associated degenerative changes. Transcriptomic studies revealed significant differences between vehicle versus ABX-treated male mice and FMT from Tg mice into ABX-treated mice largely restored the transcriptome profiles to that of the Tg donor animals. Finally, colony-stimulating factor 1 receptor (CSF1R) inhibitor-mediated depletion of microglia in ABX-treated male mice failed to reduce cerebral Aβ amyloidosis. Thus, microglia play a critical role in driving gut microbiome–mediated alterations of cerebral Aβ deposition.
Dzhanibekov effect in a physics classroom
Authors: Lozovenko O , Minaiev Yu , Lutai R
Published: December 2021

The purpose of this publication is to present a novel approach to the demonstration of the Dzhanibekov effect. The main idea of our version is to use a lightweight spinning top of a spherical external form but distinct principal moments of inertia floating in the upward flow of air. As a result, the Dzhanibekov effect can be easily demonstrated anywhere on Earth: in any classroom, or even in the ‘home-lab’. The proposed demonstration allows one to observe the periodical flipping motion of the asymmetrical top with the clearly seen quasi-stable rotational phase. It may also become the base for various theoretical and experimental research projects for students.
Micro-features of ambipolar snapback behaviour under high current injection to design capacitorless memory device
Authors: Singh Pragati , Dhar Rudra Sankar , Baishya Srimanta
Published: December 2021

This paper presents micro-features of capacitorless memory cells based on snapback phenomenon and modeling of space-charges. 2—Dimensional gate grounded NMOS structure is specified and its operational window of the memory cell is inspected using the Synopsys TCAD tool. This work examines snapback behaviour in one transistor DRAM memory cell in the absence of a storage capacitor under zero gate bias and applied ramp of high current at the drain terminal. Carrier electrostatics and memory cell mechanisms are also explored by adjusting the slope of the high current ramp. The process variation is examined for different parameters in the device. The current crowding phenomenon due to the injection of electrons and holes is investigated, giving rise to ambipolar behaviour. Due to the snapback, redistribution of electron and hole current is investigated. This work also evaluates the impact on electrostatic potential along channel and bulk under the snapback. It explains the dependency of snapback on potential build-up. Post-snapback electron current flipping presents the flow line near the gate region. The bipolar activity is manifested in surface and bulk regions to show its impact through analytics. The effect of gate biasing is also examined under the applied current ramp.
Impact of hot injected beam on whistler mode with alternating electric field (AC) in the magnetosphere of Saturn
Authors: Shukla Kumari Neeta , Singh Devi , Pandey R S
Published: December 2021

Whistlers are believed to be generated by its own and responsible to evolve dynamical properties of magnetized planetary environment. Growing whistler instability can cause other uncertainties in the magnetosphere and evident to be generated by mean of injection events and temperature variance in plasma environment. In this paper the empirical dispersion relation has developed for parallel propagating whistler mode instability in an infinite saturnian magneto plasma in the presence of perpendicular electric field for ring distribution function having non-monotonous nature. Method of characteristics solutions alongside kinetic approach found to be most suitable in order to achieve perturbed plasma states. The perturbed and unperturbed particle trajectories have taken into consideration to determine perturbed distribution function. A remarkable growth rate expression with added hot plasma injection has been calculated in inner magnetosphere near 6.18 Rs. The results obtained using demonstrative value of the parameters suited to the Saturnian magnetosphere have been computed and discussed. Pressure (Temperature) anisotropy is found to be a peculiar source of free energy for whistler mode instability. The AC frequency irrespective of its magnitude, affects the growth rate significantly. The bulk of energetic hot electrons injection influences the growth rate by increasing its peak value. The result obtained provide the important view of wave particle interaction and useful to analyze the VLF emissions observed over a wide frequency range.
Comparative Evaluation of Control Techniques of PMSM Drive in Automotive Application
Authors: Shriwastava Rakesh , Deshmukh Satayjit , Tidke Ashwini , Thakre Mohan
Published: December 2021

This paper deal with comparative evaluation of control techniques of Permanent magnet synchronous motor (PMSM) drive in automotive application is investigated. The FOC, DTC and proposed SVM-DTC with LC-Snubber circuit are presented. In SVM-DTC, this reduces low torque ripple by using space vector modulated. The parameters of FOC, DTC and proposed SVM-DTC with LC-Snubber method are studied by simulation. The simulation analysis of control method is investigated in terms of speed, current and torque ripples It was observed that the proposed method upgrade the performance of PMSM drive in respect to speed, current ripples, and torque responses
Influence of production on hemp concrete hygrothermal properties: sorption, water vapour permeability and water absorption
Authors: Ruus A , Koosapoeg T , Pau M , Kalamees T , Põldaru M
Published: December 2021

Hemp concrete is considered to be a carbon negative material. Hemp absorbs CO2 during the growth and lime needs CO2 for carbonation. The material, which has good thermal insulation properties, is used as a non-bearing wall material or plaster. For such use the hygrothermal properties of a material must be well known especially when indoor insulation is in focus. In the current study hemp concrete produced in two different ways was in focus and following the hygrothermal properties of hemp concrete as a building material were studied: water absorption (EN 1015-18), water vapour sorption (EN 12571), water vapour permeability (EN 12572) and thermal conductivity (EN 12667). The results of the study can be used in hygrotheramal calculations and modelling.
Influence of the mold growth on the crystallographic composition of hemp mortar
Authors: Kosiachevskyi D. , Abahri K. , Daubresse A. , Prat E. , Chaouche M.
Published: December 2021

The use of hemp mortar as a bio-based insulation composite is widely promoted in the construction sector in France due to its environmental and hygrothermal advantages and the availability and low price of hemp fibers. Nevertheless, the use of such materials claims the consideration of the microbiological contamination that could lead to its degradation. Molds are known for their ability to modify locally the composition of hemp mortar by decreasing the pH level. That’s why the main objectives of the present work are, first, to expose the hemp mortar favorable conditions for mold growth, secondly, to investigate the proliferation of the mold filaments inside the hemp mortar sample and, then, to analyze the crystallographic composition. Experimentally, hemp mortar samples were exposed to high level of relative humidity during one year until the mold growth. The SEM observation allowed to follow the internal growth and identify the depth of the mold growth. Finally, the composition of the contaminated hemp mortar was studied by X-ray diffraction. The obtained results reveal that molds growth occurs not only on the surface but also in the depth. Nevertheless, as the mold growth started only after one year of high humidity exposure, a good resistance of studied hemp mortar towards molds was noted. Furthermore, the mineralogical composition analysis of the contaminated samples shows that the hydrates responsible for durability remained. These results provide data to better predict the durability of hemp mortars.
Simplified Infinite Fin Method to Model the Heat Transfer Associated with Slab Edges and Balconies
Authors: Ghobadi Mehdi , Hayes Alex , Moore Travis
Published: December 2021

As building codes become more stringent in terms of thermal performance of building envelopes, and higher insulated wall assemblies are becoming more common, the heat flow due to major thermal bridges can contribute to a significant portion of the total heat transfer through a building façade. Characterizing different thermal bridging elements is essential not only to capture the thermal resistance of wall assemblies and understand the thermal efficiency of buildings, but also in terms of understanding the impact of each thermal bridging element and mitigation strategies that can be used. Numerical simulations are used widely to characterize different thermal bridging elements. However, not all designers have access, technical skills or time to complete numerical simulations to calculate the heat transfer loss through thermal bridges. In this study we propose an analytical method to integrate the effect of adding a slab edge/balcony/eyebrow into a clear-field wall assembly. The additional heat transfer due to the slab edge is calculated by considering the slab edge to be an infinite fin. The additional heat transfer is integrated into the clear-field as a quasi-convective heat transfer coefficient. The overall thermal resistance of the wall assembly is calculated by employing the parallel path method. Comparing the results obtained from this method with the numerical simulations which were benchmarked against guarded hot box results, an overall deviation of 1 to 8 percent was observed.
The effect of temperature, humidity and mechanical properties on crack formation on external thin plasters of ETICS
Authors: Volkova K , Põldaru M , Ilomets S , Kalamees T , Talvik M , Heim D
Published: December 2021

External Thermal Insulation Composite Systems (ETICS) are widely used in the northern hemisphere in retrofitted and new external walls. The outer layer of ETICS is usually a thin layer of plaster. The effects of temperature and humidity on the hygrothermal behaviour and mechanical properties of thin plasters have been quantified by conducting several experiments to determine the possibility of crack formation. Combinations of plasters using four types of binders are tested: mineral, polymer, silicate and silicone. Plasters are tested as four systems consisting of a base coat, a glass-fibre reinforcement mesh and a finishing coat. Sorption curves of the plaster systems are determined to gather data for numerical simulations. The coefficients of thermal and hygroscopic expansion are determined. The modulus of elasticity and tensile strength of four different plasters are measured to allow the calculation of crack formation in ETICS and suggest the distances between the deformation joints. The method demonstrated in this paper makes it possible to calculate the crack formation caused by the temperature and moisture shrinkage in the thin exterior plaster of ETICS.
Hygrothermal Monitoring of Two Pilot Prefabricated Exterior Energy Retrofit Panel Designs
Authors: Conley B , Carver M , Brideau S
Published: December 2021

NRCan undertook a proof-of-concept project to retrofit a small building with prefabricated wall panels in 2017 in Ottawa, Canada. The retrofit used two wall panel designs: nailbase and woodframe. The Nailbase panel consisted of fiberglass batt, an expanded polystyrene (EPS) core, oriented strand board (OSB) sheathing, a rainscreen, and cladding. The Woodframe panel also featured OSB sheathing and included a 90 mm stand-off gap filled with dense-packed, fibrous insulation. A side-by-side comparison of cost, constructability, and performance was performed. The wall assemblies were instrumented to monitor the temperature, relative humidity, and moisture content of sensitive layers. The data was used to evaluate the hygrothermal performance, moisture accumulation, and risk of associated problems such as mould growth. This paper presents the monitored hygrothermal data from 2017 to 2021, compares the two approaches and assesses their feasibility. During construction, some of the fibrous insulation may have been wetted by wind-driven snow before completion. The data showed that this moisture was able to dissipate without significant risk. The sheathing of the Woodframe panel experienced a higher peak moisture content during the dry-out period. Otherwise, both panel designs showed limited potential for mould growth on monitored surfaces over the monitored period.
Influences on the drying behavior of a concrete ceiling below a cold attic
Authors: Lewis Thomas , Sarkany Andreas , Heiduk Ernst , Grüner Manfred , Bednar Thomas , Hofbauer Harald
Published: December 2021

The article describes the current state of a project examining the influences on the moisture distribution in cold attics above concrete ceilings of residential buildings. Considerable research has been done on moisture damages in cold attics, especially in Scandinavia and North America, focussing on spaces above wooden ceilings. The project (ongoing until Sept 2021) underlying the article deals with cold attics above concrete ceilings resting on masonry walls, a frequent variant in Austria. Research was triggered by a regional Austrian building industry association to shed light onto recent detrimental moisture accumulation in the wooden wall plate (= bearing for the rafters along the eaves) and in the two EPS insulation layers on top of the ceiling. Suspected reasons for the moisture problems and for the local moisture distribution are 1) a too small diffusion resistance of the vapour retarder covering the ceiling, 2) insufficient (natural) attic ventilation and 3) convection, e. g. in the gap between the polystyrene blocks. In order to rank these potential causes by influence and also to find a practical solution a two stage experimental approach was chosen: 1) A handy small scale replica (order of dimension: 1m) of the situation was exposed to the according indoor and outdoor climate in a climate chamber. Different vapour retarders on top of the ceiling were chosen. 2) A larger 1:1 replica has been erected as well but not yet delivered monitoring data. In parallel, a hygrothermic model taking convection into account was established and simulations carried out. The project will deliver a contribution to the Austrian standard on moisture safety 8110-2 on how to judge the moisture safety of joints via simulation.
Thermal insulation of autoclaved materials
Authors: Stepien A , Piotrowski J Z
Published: December 2021

The construction industry relies on the production of building materials, which are created as a result of particular actions of binding materials widely used in construction, and directly condition the quality of life of a society. Following these thesis, one should create possibilities of conscious choice and use of building materials not only among scientists and constructors, but among the whole society. Two types of additives are used in building materials: additives with a crystalline structure (SiO2) and additives with an amorphous structure (fly ash), which affects the properties and durability of materials. In the last decade industry is also moved on the fight against global warming and overproduction of materials. In May 2019, the level of CO2 concentration in the atmosphere exceeded 415ppm, which was the highest result in the last 50 years. Overproduction is, in turn, associated with the excessive use of natural resources (SiO2) and since 2010 there has been talk of the “sand deficit”. One way to combat overproduction is to use and promote recycling to avoid excess waste. The article describes the method of managing recycled glass sand in autoclaved materials and checking their thermal properties. This study describes the relationship between the physical (thermal isolation), mechanical and microstructural properties of autoclaved materials which undergone hydrothermal treatment and consist of lime (7%) and were modified through the introduction of glass components (up to 90%). For this modification, a certain amount of crystalline SiO2 was replaced with amorphous glass sand. Hydrated calcium silicates are formed in building materials (CaO-SiO2-H2O).
The effect of rising damp on heat transfer performance and energy consumption of two kinds of Chinese blue-brick masonry walls
Authors: Kong Z Y , Xie H R , Cai Y K , Tan X , Hokoi S , Li Y H
Published: December 2021

Rising damp is common in brick buildings due to groundwater and natural precipitation, which not only causes deterioration of the walls, but also significantly affects the heat transfer coefficient, thermal inertia, and building energy consumption. In order to clarify the effects of rising damp on the heat transfer through traditional Chinese brick solid wall and cavity walls, two types of wall of 1.2 m wide and 3 m high were built in the laboratory. The heat transfer performance under the influence of capillary rising was tested by Simple heating box – heat flow meter method. Based on the data obtained from the experiment, the Energyplus was used to simulate the energy consumption of a Chinese typical residential building influenced by rising damp. The results proposed 3.67 W/m2·K and 3.61 W/m2·K as the recommended heat transfer coefficient for the moisture affected parts in the experimental solid and cavity wall, and the rising capillary water increased the heat transfer coefficients by 74% and 84%, respectively. The heating and cooling load of the solid-wall building under the influence of capillary water increased by 18.5% and 29.6%, respectively, while of cavity-walls building increased by 6.5% and 11.8%.
The Hybrid-Agile Design of Experiments Methodology
Authors: Gradeci K , Sletnes M
Published: December 2021

A DOE (Design of Experiments) is the laying out of a detailed experimental plan in advance of doing the experiment. Optimal DOEs maximize the amount of information that can be obtained for a given amount of experimental effort. The traditional DOE methodology is waterfall-type methodology implying a sequential and linear life-cycle process. The success of the experiment and usefulness of the results are highly dependent on the initial experimental setup and assumptions, and does not allow to go back and change something that was not well-documented or thought upon in the design stage. The fast-changing software development industry have made it understandable that the traditional waterfall methodology for developing systems, which follows similar patters to the traditional DOE, lacks the agility required for developing robust systems. These limitations have triggered the development of agile: a type of incremental model of software development based on principles that focuses more on flexible responses to change, instead of in-depth planning at the design stage. This paper proposes the hybrid-agile DOE methodology – a methodology that incorporates agile principles in traditional waterfall DOE methodologies – to design effective experimental layouts that allow for improvement during the experimental trial process. The methodology is applied to the natural ageing of adhesives tapes for building applications. This methodology can overcome traditional DOE, by adding agility in the whole process, especially in cases where the investigated products lack prior information and are characterised by large variability.
Damage risk assessment of building materials with moisture hysteresis
Authors: Libralato Michele , Angelis Alessandra De , D’Agaro Paola , Cortella Giovanni , Qin Menghao , Rode Carsten
Published: December 2021

Heat and Moisture Transfer (HMT) simulations are used to evaluate moisture related damage risks in building envelopes. HMT simulations are commonly performed accepting the hypothesis of not considering the moisture hysteresis of materials. The results of HMT simulation of a timber wall with hysteresis are presented, and compared to the results of three simplified models, showing the effects of hysteresis on the simulation results and on the assessment of the risk of decay. Moisture content is the most influenced variable, while temperature and relative humidity are slightly affected. The wood decay risk analysis is performed using the simplified 20% moisture content rule. Similar temperature values and relative humidity values are calculated as simplified models, while the moisture content annual average values have differences up to 2.3%. The wood decay risk obtained with the simplified models could be overestimated if the simulation is performed using the desorption curve, while it could be underestimated with the adsorption curve. The best approximation is obtained with the mean sorption curve, while the desorption curve and the adsorption curve could be used to calculate the upper and lower boundary of the moisture contents respectively.
The effect of silanes as integral hydrophobic admixture on the physical properties of cement based materials
Authors: Grabowska K , Wieczorek A , Bednarska D , Koniorczyk M
Published: December 2021

The paper explores the possibility of using organosilicon compounds (e.g., poly(dimethylsiloxane) and triethoxyoctylsilane) in commercial admixtures as internal hydrophobization agents for porous cement-based materials. The study involved the cement mortar with five different hydrophobic admixtures. Four of them is based on triethoxyoctylsilane, but with various concentration of the main ingredient, and one of them on poly(dimethylsiloxane). Mechanical properties, capillary water absorption, as well as microstructure were investigated. The organosilicon admixtures efficiently decrease the capillary water absorption even by 81% decreasing mechanical strength of cement mortar at the same time even by 55%. Only one admixture, based on poly(dimethylsiloxane) caused significant changes in microstructure of cement mortar.
Built-in moisture in cross-laminated timber roofs – a field study
Authors: Gaarder J E , Pettersen T D
Published: December 2021

Cross-Laminated Timber (CLT) elements have had a growing popularity in recent years due to i.e. low carbon footprint, low weight and efficient construction time. However, the elements are sensitive to moisture and prone to organic growth if not treated properly or if used incorrectly. Roof slabs are particularly exposed, as they have a large area of exposure and the horizontal orientation doesn’t allow rainwater run-off. The efforts made to protect CLT-roofing elements by Norwegian contractors vary widely, as there are few guidelines and little long-term experience. A field study of CLT-roofs on existing buildings was conducted to investigate the conditions after some years in service. The study includes inspection and moisture measurements of CLT elements from the exterior side in 10 building projects 1-9 years old from two regions of Norway. The contractor of each project was interviewed in order to assess the extent of climate exposure and protection measures during construction. The results indicate a correlation between water content, building age and exposure level during construction. There is a clear indication that the drying time for built-in moisture in CLT roof constructions are slow. Keeping built-in moisture to a minimum is therefore paramount.
Impact of climate change on the wind-driven rain exposure of a historical building
Authors: Bourcet J , Kubilay A , Derome D , Carmeliet J
Published: December 2021

Due to climate change, considering future rain event patterns and increased average temperatures, wind-driven rain exposure of buildings can increase. In order to assess the future damage risk related to moisture, it is essential to take the future wind-driven rain load into account. Computational fluid dynamics simulations of wind-driven rain are performed on a historical building located in Victoria, BC, Canada using the current and future weather data. The results show an increased wind-driven rain exposure of the building by up to 20%, especially in façade regions which are already exposed to a higher amount of rain.
Multivariate analysis of the influence between building design and energy performance, socio-demographic metrics, and the intra-urban environment
Authors: Llaguno-Munitxa M , Shu X , Mistry B
Published: December 2021

Through advancements of direct and remote sensing technologies, we have recently learned that urban microclimate and air quality gradients can often be more significant than city to rural differences. However, the urban design parameters that are most critical to improve environmental health and reduce building energy consumption, are yet to be identified. This research makes use of air quality datasets collected through a dense stationary sensing network in New York City, remote sensing datasets for land surface temperature and normalized difference vegetation index, building usage metrics, building and urban design metrics, and socio-demographic datasets including population and health metrics. Through a neighbourhood-scale footprint-based regression analysis, the correlation between the air quality, land surface temperature, building usage and urban metrics has been studied. Highest correlations have been observed between air quality and land surface temperature and urban design and socio-economic metrics. The results show that building usage metrics such as the energy use intensity or electricity purchase, are mainly affected by building design characteristics. On the other hand, significant correlations have been observed between the urban design, socio-demographic and contaminant concentration gradients, addressing the critical role the planning and design of our cities plays in the environmental well-being of citizens.
The impact of the spatio-temporal morphology of urban green infrastructure on urban building energy consumption: A case study in the hot-summer-cold-winter climate
Authors: Zhu Sijie , Li Yanxia , Wang Chao , Zhang Xingkai , Shi Xing
Published: December 2021

Studies have confirmed that urban green infrastructure (UGI) profoundly impacts urban building energy consumption by regulating urban microclimate, providing shading to buildings, and other mechanisms. This impact is largely dependent on the morphology of UGI. Although this conclusion is widely accepted there lacks a systematic approach to quantify the impact and thus the knowledge regarding its magnitude. This paper discusses the influencing mechanisms of UGI on urban building energy consumption. The city of Nanjing, a Chinese city in the hot-summer-cold-winter climate, is morphologically analyzed to extract prototypes of UGI forms. These prototypes are simulated for their microclimate and urban building energy consumptions using a co-simulation technique, which links ENVI-met to EnergyPlus. The simulation results are statistically analyzed to quantify the impact of UGI morphology on urban building energy consumption. The energy consumption of different morphological groups in summer and winter is compared to determine the impact of UGI morphological features on urban building energy.
Assessing the climate change adaptation over four European cities
Authors: Yang Yuchen , Nik Vahid M.
Published: December 2021

In recent years, climate change has been widely recognized as a potential problem. The building industry is taking a variety of actions towards sustainable development and climate change mitigation, such as retrofitting buildings. More than mitigation, it is important to account for climate change adaptation and investigate the probable risks and limits for mitigation strategies. For example, one major challenge may become achieving low energy demand without compromising indoor thermal comfort during warm seasons. This work investigates the future energy performance and indoor thermal comfort of four European cities belonging to four different climate zones in Europe; Barcelona, Koln, Brussels, and Copenhagen. An ensemble of future climate scenarios is used, including thirteen climate scenarios considering five different general circulation models (GCM) and three representative concentration pathways (RCP 2.6, RCP 4.5 and RCP 8.5). Through simulating the energy performance of the representative buildings in each city and considering several climate scenarios, this paper provides a comprehensive picture about the energy performance and indoor thermal comfort of the buildings for near-term, medium-term, and long-term climate conditions.
A comparative benchmarking study of multi-storey residential buildings in two periods of energy saving efforts: the 1980s and the 2010s
Authors: Jensen O M , Rose J , Kragh J , Christiansen C H , Grimmig M , Hvenegaard C M
Published: December 2021

In 1990, Technological Institute (TI) in Denmark made a benchmarking study of 92 typical multi-storey buildings covering 23 000 dwellings. The study included measurement data from the 1970s and the years after the energy crises. This study showed that over a period of less than 20 years a significant reduction in energy consumption took place. In a new similar study, TI and Aalborg University have analysed 62 buildings covering 18 000 dwellings including measurement data from the last 20 years. This time, the data covers a period with an increasing focus on the carbon-emission impacts of energy consumption. As opposed to the first benchmarking study, the new 20-years study shows that the heat consumption has been almost constant over the last 20 years. This paper presents a comparative study of the two sets of measurements and evaluates energy saving efforts and individual building energy performance. Furthermore, the paper compares two different ways of deriving benchmarks from the data and demonstrates how utilizing change-point models/energy signature as opposed to the more traditional mean annual values per heated area, significantly increases the usability.
Recent progress of SPIDER: Aspects of subtractive approaches to existing building’s performance improvement
Authors: Sommer B , Pont U , Moncayo G , Bauer P , Braun J , Sommer-Nawara M , Prieler I , Brus T , Mahdavi A
Published: December 2021

This contribution reports about methodology, progress and preliminary findings of a recent exploratory Research and Development project, pertaining to the (semi-)automated thermal retrofit of existing building’s envelopes. Thereby, the potential of robots, which autonomously identify areas of facades that can be used for inserting openings into the existing wall material, is examined. The idea is based on the fact that masonry walls of historic masonry walls (especially of Gründerzeit buildings built between 1850 and 1918) often have been structurally over-dimensioned. As such, the spare thickness of the walls could be used for thermal insulation purposes. The initial idea to implement air cavities for insulation purposes is in correspondence with the predominant functional principle of most insulation materials.
The effect of weighting factors on income-related energy inequalities: The case of Sweden’s new building code
Authors: Platten J von , Mangold M , Mjörnell K
Published: December 2021

To ensure building construction with low heating demand, efficient use of sustainable energy carriers, and neutrality between heating technologies, Sweden recently introduced weighting factors (WFs) for different energy carriers which are now used in Energy Performance Certificates (EPCs). As EPC ratings are gaining increased influence in Swedish energy policy and regulation, with recent examples of buildings’ EPC rating acting as base for imperative regulatory requirements, the introduction of WFs is likely to have significant effects on how policy and regulations are distributed in the multifamily building stock. As residents often are directly or indirectly affected by policy that either impose or trigger measures to be undertaken in their building, the aim of this paper is to analyse how WFs affect the assessed energy performance of buildings in different resident income groups. The results show that overall, reduced energy performance from WFs was more common in high-income areas than in low-income areas. However, although the total number of buildings in the lowest EPC ratings was reduced after introducing WFs, the resulting income distribution among worst-performing buildings was more skewed towards low-income households than before introducing WFs. As imperative regulatory requirements previously have targeted worst-performing buildings, these results indicate that energy-related inequalities in the housing stock have become more prominent and should be considered as to not disproportionately burden low-income residents in the energy transition of the housing stock.
Energy and Environmental Evaluation of Retrofitting Facades for Zero Energy Buildings: The Case of an Office Building in Greece
Authors: Giama Effrosyni , Kyriaki Elli , Antoniadou Panagiota , Symeonidou Maria , Papadopoulos Agis M.
Published: December 2021

Energy and environmental targets are expressed clearly by the EU policies setting ambitious goals for 2030 and 2050 considering energy intensive sectors such as buildings. Pursuing high energy performance with the least environmental impact of a building, along with ensuring the well-being of the occupants, is the ultimate goal of an institutional framework that addresses energy efficiency and environmental sustainability. Part of this effort is the improvement of the building envelope’s thermal performance, along with the respective one of HVAC systems, as those determine thee energy performance of buildings in their use phase. Main scope of the paper is to evaluate and analyse different scenarios considering the retrofitting of facades as part of the refurbishment towards Zero and Positive Energy Buildings, but also in connection with the strive for Net Zero Energy, Net Zero Cost Energy and Net Zero Emissions goals. The paper also discusses energy and environmental evaluation of refurbishing an office building in Greece, examining the performance of different envelope construction typologies and alternative insulation scenarios. These scenarios include state of the art insulation techniques, but also innovative design elements such as the use of different final coating materials for ventilated façades like the use of phase-changing materials (PCMs). The results of the assessment undertaken are used to rate the construction solutions by means of energy and environmental parameters proving the environmental impact of concrete and insulation materials in construction phase but also the reduced primary energy consumption and thus the CO2 emissions in the life cycle of the building. Considering the environmental evaluation, the carbon footprint analysis was used according to Greenhouse Gas Protocol focusing mainly on CO2 emissions, which is the main emission target of EU policies. The impact assessment followed demonstrated that the most significant impact categories are global warming, acidification and eutrophication.
Evaluation of the performance of enclosed balconies based on temperature monitoring
Authors: Grudzmska Magdaleńa
Published: December 2021

Enclosed, glazed balconies influence the energy balance of the flats thanks to the temperature rise caused by solar gains in unheated sunspaces. The potential benefits, however, may differ depending on the inhabitants’ behaviour. To evaluate these effects, internal temperature in multi-family buildings located in Zamość (a city in the eastern part of Poland) was monitored at the turn of the years 2017 and 2018. The temperature was registered with the use of iButton sensors located in flats and sunspaces. Three dwellings with the same orientation were included in the research – two with glazed balconies, differing by the area of the living space, the number of the inhabitants, and their behaviour (flats no. 1 and 2), and one with an open balcony, used for comparison (flat no. 3). Air temperature within the glazed balconies was usually higher than the external air temperature, and the sunspaces helped to reduce heat losses from the adjoining rooms by 10.7% (flat no. 1) and 26.6% (flat no. 2). The apartments also showed some differences as far as the comfort of use during summer is concerned, flat no 1 being the most prone to overheating.
Semi-automatic geometry modelling: faster and streamlined building simulation models
Authors: Svane N D , Pranskunas A , Lindgren L B , Jensen R L
Published: December 2021

The architecture, engineering, and construction (AEC) industry experiences a growing need for building performance simulations (BPS) as facilitators in the design process. However, inconsistent modelling practice and varying quality of export/import functions entail error-prone interoperability with IFC and gbXML data formats. Consequently, repeated manual modelling is still necessary. This paper presents a coupling module enabling a semi-automated extract of geometry data from the BIM software Revit and a further translation to a BPS input file using Revit Application Programming Interface (API) and visual programming in Dynamo. The module is tested with three test cases which shows promising results for fast and structured semi-automatic geometry modelling designed to fit today’s practice.
Validation of the simplified heat conduction model of EN ISO 52016-1
Authors: De Luca G , Ballarini I , Bianco Mauthe Degerfeld F G M , Corrado V
Published: December 2021

The issue of improving the building energy efficiency led to the development of calculation methods for the building energy performance assessment. To overcome the low accessibility to detailed input data, the recently introduced EN ISO 52016-1 hourly method is based on assumptions and simplifications chosen to allow a sufficient accuracy in the outcomes with a low amount of input data. Among these assumptions, a simplified mass distribution in the envelope components is considered. In the present work, the hypothesis of the simplified heat conduction model introduced by the EN ISO 52016-1 technical standard and an improved solution provided by its Italian National Annex were evaluated. In particular, the accuracy in the prediction of the internal surface temperature was assessed in comparison with a detailed finite difference conduction algorithm. The validation was performed for 5 opaque component test cases, covering a wide range of areal heat capacity values, by considering both internal and external thermal constraints (e.g. variation of the air temperature). For the structures and boundary conditions considered, results reveal that the standard algorithm allows to predict the internal surface temperatures with a valuable level of accuracy compared to the finite difference algorithm.
A case study on the impact of fixed input parameter values in the modelling of indoor overheating
Authors: Petrou G , Mavrogianni A , Symonds P , Davies M
Published: December 2021

Global efforts to reduce greenhouse gas emissions from buildings while also improving their environmental resilience have intensified. These efforts are often supported by building stock models which can inform policymakers on the impact of policies on energy consumption, greenhouse gas emissions and the indoor environment. The input values of such models are commonly informed by reference tables, which can result in inaccurate specification and incomplete representation of the distribution of possible values. In this modelling case study of a semi-detached dwelling archetype, the influence of using a reference U-value (2.1 W/(m2K)) for solid walls in England on heat-related mortality rate is compared to a probabilistic specification based on empirical evidence (median = 1.7W/(m2K)). Using the theoretical reference U-value generally resulted in a lower indoor overheating risk compared to the use of the empirically derived U-values pre-retrofit, but a larger increase in heat-related mortality rate following internal wall insulation (1.20%) than the use of the empirical median (0.94%, 95 % Confidence Interval = 0.87–0.99 %). This highlights the potentially significant implications of using fixed reference values. Future work will employ this probabilistic framework on multiple influential parameters.
Develop a New Approach to Evaluate Energy Savings, Thermal Comfort and IAQ from Occupant-Centric Building Controls
Authors: Kong Meng , Dong Bing , Zhang Jianshun , Wang Xuezheng
Published: December 2021

Occupant behavior is identified as one of the key factors influencing the energy use and indoor environmental quality of the building. Occupancy-centric control is famous for its potential to save building energy without sacrificing occupants’ comfort. This study utilized two identical lab spaces, configured as typical open-plan offices, to investigate the performance of the occupancy-centric control in terms of energy-saving, indoor air quality, and thermal comfort. The results have demonstrated that occupancy-centric control could save around 28% total energy, including fan, cooling, and heating energy, with minimal impact on the air quality and thermal comfort.
Acoustic design and optimization of an organic architecture, a cross disciplinary design of an open-space airport case study
Authors: Carlucci F , Tiano W
Published: December 2021

Architectural innovation, both at morphological and technological scale, have increased the importance of new methodologies and tools for the building performance analysis. New organic shapes have decreased the reliability of traditional specialistic knowledge, highlighting the importance of new methodologies to manage complex models and analyse the indoor comfort. The aim of this paper is to present a case study of the acoustic design of an organic open-space airport, realized integrating architectural and acoustic concepts in the design workflow. The building, characterized by a curvilinear plan, a wavy suspended ceiling, and a tilted façade, behave as a single tall, large volume containing different small low-height closed service boxes. This architectural approach leads to a mixture of functions in the same large volume with a resulting complex problem of acoustic optimization. To that end, different studies have been conducted from the protection from external noise to the optimization of the reverberation time, and to the design of the speakers. Considering the geometric complexity, different tools and a particular methodology have been used to properly model the building and to optimize the use and the placement of acoustic absorbing materials.
Airborne sound insulation of single-leaf partitions under hygric load
Authors: Hermes M
Published: December 2021

In buildings of all types the use of single-leaf partitions are recommended, not least for reasons of cost efficiency and possible resource optimisation. In addition to the familiar building physics topics they play also a particularly important role in noise protection. Numerous factors influence the acoustic properties of single-leaf, plate-shaped and dry partitions. These include the mass, the bending stiffness, the position of the critical frequency and the total loss factor of the partition as well as the stimulating frequency of the airborne sound, the sound incidence angle or the characteristic impedance of the air. Each mineral wall-building material has its own product-specific pore structure. In the usual calculation of the airborne sound insulation of single-leaf, airtight and dry partitions, this has so far not been taken into account. It is precisely in these building material pores that a hygrothermal, continuous adjustment of the moisture content takes place in addition to the production-related water quantities. This changes the mass of the building component and thus the airborne sound insulation of the wall. In addition to this well-known mass effect, a further mechanism, which has not yet been considered, increases airborne sound insulation: the smaller the pore sizes in the building material, the greater the mechanical forces caused by stored pore water. The existing equations for airborne sound insulation do not take these effective forces into account and must therefore be extended. The wall building material is considered as a porous medium with solid and fluid components. The new calculation approach allows the calculation of the airborne sound reduction index for single-leaf partitions under hygric load for saturated and partially saturated moisture conditions with high accuracy. The calculation results provide valuable information for the planning and product development of new building materials.