scholarly journals A review on coupled building physics analyses

2021 ◽  
Vol 2069 (1) ◽  
pp. 012141
Author(s):  
M. Bühler ◽  
T. Bednar
Keyword(s):  
Data Exchange ◽  
Simulation Models ◽  
Limiting Factors ◽  
Building Performance ◽  
Physics Simulation ◽  
Computational Fluid Dynamics Cfd ◽  
Automated Simulation ◽  
Energy Simulations ◽  
Building Physics ◽  
Common Application

Abstract This paper reviews methods and tools for coupled building physics analyses in the context of Building Performance Simulations (BPS) with a focus on Building Energy Simulations (BES) and Computational Fluid Dynamics (CFD) as a common application. Furthermore, requirements regarding the necessary information for simulations, data models and coupling are identified. Possibilities of automated simulation model generation, data exchange and the performance of existing multi physics simulation models are analysed and limiting factors are discussed.

scholarly journals Synthesizing published knowledge of boreal forest cover change for large-scale landscape dynamics modelling

2003 ◽  
Vol 79 (1) ◽  
pp. 132-146 ◽  
Author(s):  
Dennis Yemshanov ◽  
Ajith H Perera
Keyword(s):  
Boreal Forest ◽  
Large Scale ◽  
Forest Canopy ◽  
Forest Cover ◽  
Forest Succession ◽  
Simulation Models ◽  
Limiting Factors ◽  
Sources Of Information ◽  
Forest Cover Change ◽  
Discrete State

We reviewed the published knowledge on forest succession in the North American boreal biome for its applicability in modelling forest cover change over large extents. At broader scales, forest succession can be viewed as forest cover change over time. Quantitative case studies of forest succession in peer-reviewed literature are reliable sources of information about changes in forest canopy composition. We reviewed the following aspects of forest succession in literature: disturbances; pathways of post-disturbance forest cover change; timing of successional steps; probabilities of post-disturbance forest cover change, and effects of geographic location and ecological site conditions on forest cover change. The results from studies in the literature, which were mostly based on sample plot observations, appeared to be sufficient to describe boreal forest cover change as a generalized discrete-state transition process, with the discrete states denoted by tree species dominance. In this paper, we outline an approach for incorporating published knowledge on forest succession into stochastic simulation models of boreal forest cover change in a standardized manner. We found that the lack of details in the literature on long-term forest succession, particularly on the influence of pre-disturbance forest cover composition, may be limiting factors in parameterizing simulation models. We suggest that the simulation models based on published information can provide a good foundation as null models, which can be further calibrated as detailed quantitative information on forest cover change becomes available. Key words: probabilistic model, transition matrix, boreal biome, landscape ecology

scholarly journals Differences in subcortico-cortical interactions identified from connectome and microcircuit models in autism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo-yong Park ◽  
Seok-Jun Hong ◽  
Sofie L. Valk ◽  
Casey Paquola ◽  
Oualid Benkarim ◽  
...  
Keyword(s):  
Data Exchange ◽  
Computational Models ◽  
Simulation Models ◽  
Autism Diagnostic Observation Schedule ◽  
Supervised Machine Learning ◽  
Global Network ◽  
Imaging Data ◽  
Phenotypic Data ◽  
Severity Scores ◽  
High Level

AbstractThe pathophysiology of autism has been suggested to involve a combination of both macroscale connectome miswiring and microcircuit anomalies. Here, we combine connectome-wide manifold learning with biophysical simulation models to understand associations between global network perturbations and microcircuit dysfunctions in autism. We studied neuroimaging and phenotypic data in 47 individuals with autism and 37 typically developing controls obtained from the Autism Brain Imaging Data Exchange initiative. Our analysis establishes significant differences in structural connectome organization in individuals with autism relative to controls, with strong between-group effects in low-level somatosensory regions and moderate effects in high-level association cortices. Computational models reveal that the degree of macroscale anomalies is related to atypical increases of recurrent excitation/inhibition, as well as subcortical inputs into cortical microcircuits, especially in sensory and motor areas. Transcriptomic association analysis based on postmortem datasets identifies genes expressed in cortical and thalamic areas from childhood to young adulthood. Finally, supervised machine learning finds that the macroscale perturbations are associated with symptom severity scores on the Autism Diagnostic Observation Schedule. Together, our analyses suggest that atypical subcortico-cortical interactions are associated with both microcircuit and macroscale connectome differences in autism.

scholarly journals Guidelines to Calibrate a Multi-Residential Building Simulation Model Addressing Overheating Evaluation and Residents’ Influence

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 242
Author(s):  
Christoph Schünemann ◽  
David Schiela ◽  
Regine Ortlepp
Keyword(s):  
Simulation Model ◽  
Time Window ◽  
Residential Building ◽  
Simulation Models ◽  
Building Simulation ◽  
Night Time ◽  
Building Performance Simulation ◽  
Starting Point ◽  
3D Simulation Model ◽  
Building Physics

Can building performance simulation reproduce measured summertime indoor conditions of a multi-residential building in good conformity? This question is answered by calibrating simulated to monitored room temperatures of several rooms of a multi-residential building for an entire summer in two process steps. First, we did a calibration for several days without the residents being present to validate the building physics of the 3D simulation model. Second, the simulations were calibrated for the entire summer period, including the residents’ impact on evolving room temperature and overheating. As a result, a high degree of conformity between simulation and measurement could be achieved for all monitored rooms. The credibility of our results was secured by a detailed sensitivity analysis under varying meteorological conditions, shading situations, and window ventilation or room use in the simulation model. For top floor dwellings, a high overheating intensity was evoked by a combination of insufficient use of night-time window ventilation and non-heat-adapted residential behavior in combination with high solar gains and low heat storage capacities. Finally, the overall findings were merged into a process guideline to describe how a step-by-step calibration of residential building simulation models can be done. This guideline is intended to be a starting point for future discussions about the validity of the simplified boundary conditions which are often used in present-day standard overheating assessment.

scholarly journals The building performance gap: Are modellers literate?

2017 ◽  
Vol 38 (3) ◽  
pp. 351-375 ◽  
Author(s):  
Salah Imam ◽  
David A Coley ◽  
Ian Walker
Keyword(s):  
Physics Education ◽  
Energy Demand ◽  
Building Performance ◽  
Performance Gap ◽  
The People ◽  
Great Utility ◽  
Input Variables ◽  
Definition Of ◽  
Building Physics ◽  
First Time

One of the most discussed issues in the design community is the performance gap. In this research, we investigate for the first time whether part of the gap might be caused by the modelling literacy of design teams. A total of 108 building modellers were asked to comment on the importance of obtaining and using accurate values for 21 common modelling input variables, from U-values to occupancy schedules when using dynamic simulation to estimate annual energy demand. The questioning was based on a real building for which high-resolution energy, occupancy and temperature data were recorded. A sensitivity analysis was then conducted using a model of the building (based on the measured data) by perturbing one parameter in each simulation. The effect of each perturbation on the annual energy consumption given by the model was found and a ranked list generated. The order of this list was then compared to that given by the modellers for the same changes in the parameters. A correlation analysis indicated little correlation between which variables were thought to be important by the modellers and which proved to be objectively important. k-means cluster analysis identified subgroups of modellers and showed that 25% of the people tested were making judgements that appeared worse than a person responding at random. Follow-up checks showed that higher level qualifications, or having many years of experience in modelling, did not improve the accuracy of people’s predictions. In addition, there was no correlation between modellers, with many ranking some parameters as important that others thought irrelevant. Using a three-part definition of literacy, it is concluded that this sample of modellers, and by implication the population of building modellers, cannot be considered modelling literate. This indicates a new cause of the performance gap. The results suggest a need and an opportunity for both industry and universities to increase their efforts with respect to building physics education, and if this is done, a part of the performance gap could be rapidly closed. Practical application: In any commercial simulation, the modeller will have to decide which parameters must be included and which might be ignored due to lack of time and/or data, and how much any approximations might perturb the results. In this paper, the judgment of 108 modellers was compared against each other. The results show that the internal mental models of thermal modellers disagree with one another, and disagree with the results of a validated thermal model. The lessons learnt will be of great utility to modellers, and those educating the next generation of modellers.

Mooring Integrity Management through Digital Twin and Standardized Inspection Data

2021 ◽  
Author(s):  
Shunsaku Matsumoto ◽  
Vivek Jaiswal ◽  
Tadashi Sugimura ◽  
Shintaro Honjo ◽  
Piotr Szalewski
Keyword(s):  
Simulation Models ◽  
Sensitivity Analyses ◽  
Maintenance Cost ◽  
Digital Twin ◽  
Diagnosis And Prognosis ◽  
Twin System ◽  
Physics Simulation ◽  
Integrity Management ◽  
Risk Visualization ◽  
Inspection Data

Abstract This paper presents a concept of a mooring digital twin frameworkand a standardized inspection datatemplate to enable digital twin. The mooring digital twin framework supports real-time and/or on-demand decision making in mooring integrity management, which minimizes the failure risk while reducing operation and maintenance cost by efficient inspection, monitoring, repair, and strengthening. An industry survey conducted through the DeepStar project 18403 identified a standard template for recording inspection data as a high priority item to enable application of the digital twins for integrity management. Further, mooring chain was selected as a critical mooring component for which a standard inspection template was needed. The characteristics of damage/performance prediction with the proposed mooring digital twin framework are (i) to utilize surrogates and/or reduced-order models trained by high-fidelity physics simulation models, (ii) to combine all available lifecycle data about the mooring system, (iii) to evaluate current and future asset conditions in a systematic way based on the concept of uncertainty quantification (UQ). The general and mooring-specific digital twin development workflows are described with the identified essential data, physics models, and several UQ methodologies such as surrogate modeling, local and global sensitivity analyses, Bayesian prediction etc. Also, the proposed digital twin system architecture is summarized to illustrate the dataflow in digital twin development andutilization. The prototype of mooring digital twin dashboard, web-based risk visualization and advisory system, is developed to demonstrate the capability to visualize the system health diagnosis and prognosis and suggest possible measures/solutions for the high-risk components as a digital twin's insight.

Upgrading the Building Facades in Low-Density Residential Areas

2020 ◽  
pp. 216-243
Author(s):  
Katerina Tsikaloudaki ◽  
Dimitra Tsirigoti ◽  
Stella Tsoka ◽  
Theodore Theodosiou
Keyword(s):  
Energy Performance ◽  
Building Envelope ◽  
Building Performance ◽  
Residential Areas ◽  
Energy Needs ◽  
Building Facades ◽  
Thermal Bridging ◽  
Negative Impacts ◽  
Building Physics ◽  
Common Action

The most common action for the buildings' energy upgrade across Europe is the addition of thermal insulation on the external walls. Such interventions, although simple on their construction, cause significant changes on the building's behavior, not only on its energy needs, but also on the hygrothermal and visual performance. The effects are not always positive; for example, thicker insulation may result in lower thermal transmittance and better thermal energy performance, but on the other hand the thermal bridging effect is amplified, and the daylight levels are decreased. This research intends to quantify these impacts by analyzing the relevant parameters for different regions of Europe. The analysis aims at explaining the complicated interrelationships on the building physics' aspects encountered through interventions on the building envelope, but also at identifying appropriate measures that could counterbalance the negative impacts and enhance the overall building performance.

scholarly journals Simulation of Coal Gasification in a Low-Temperature, High-Pressure Entrained-Bed Reactor with a Volatiles Condensation and Re-Evaporation Model

2019 ◽  
Vol 9 (3) ◽  
pp. 510
Author(s):  
Ming-Hong Chen ◽  
Yau-Pin Chyou ◽  
Ting Wang
Keyword(s):  
High Pressure ◽  
Coal Gasification ◽  
Simulation Models ◽  
Operating Pressure ◽  
Synthetic Natural Gas ◽  
Gasification Process ◽  
Exit Temperature ◽  
Computational Fluid Dynamics Cfd ◽  
Lower Temperature ◽  
Entrained Flow Gasification

The objective of this study is to implement a tar condensation and re-vaporization sub-model in a previously established Computational Fluid Dynamics (CFD) model for the Entrained Slagging Transport Reactor (E-STR) gasifier, modified from the existing E-Gasifier simulation models in previous studies. The major modifications in E-STR, compared to the existing E-GasTM design, include higher operating pressure and lower temperature, with the aim of achieving a higher H2/CO ratio of syngas, which is more favorable for synthetic natural gas (SNG) production. In this study, the aforementioned sub-model is described by the UDF (User-Defined Function) and incorporated in a previously developed computational model for entrained-flow gasification process, to study the syngas composition without implementing a tars-cracking catalyst in the E-STR gasifier. The results show that incorporating the tar condensation model leads to a formation of approximately 6.47% liquid volatiles and an exit temperature increase about 135 K, due to the release of latent heat. These sub-models have been successfully implemented and will be useful in the condition that the gasifier temperature is intentionally kept low, just as the E-STR gasifier. The results indicate that high pressure and less oxygen feed produce a higher H2/CO ratio, more favorable for SNG production.

scholarly journals A tool for Danish buildings energy retrofit design and evaluation using dynamic energy simulations

2020 ◽  
Vol 172 ◽  
pp. 18008
Author(s):  
Muhyiddine Jradi ◽  
Henrik Engelbrecht Foldager ◽  
Rasmus Camillus Jeppesen
Keyword(s):  
Assessment Tool ◽  
Dynamic Performance ◽  
Building Energy ◽  
Building Performance ◽  
Single Family ◽  
Design Development ◽  
Energy Retrofit ◽  
Energy Simulations ◽  
Family House ◽  
Retrofit Design

In general, static tools and simplified assessment approaches are still dominating the Danish building energy retrofit market. These static tools are generally associated with a large number of assumptions and tend to neglect the overall building dynamics. This leads to major uncertainties and substantial gaps between the predicted performance, promised before retrofitting, and the real building performance after carrying out the retrofit project. To overcome these challenges, this work presents the design, development and demonstration of DanRETRO, a tool for Danish buildings energy retrofit design and evaluation. The tool uses a large database of dynamic performance simulations employing EnergyPlus, for different building types, ages and sizes, allowing a preliminary assessment of the technical, economic and environmental impacts of various retrofit measures. In this regard, the tool provides a large selection of retrofit techniques and measures along with retrofit packages. DanRETRO is intended to be a comprehensive building energy retrofit assessment tool, but at the same time being simple to use with minimal inputs. The demonstration of the tool in an office building, a single-family house and an apartment in Denmark is presented and assessed. DanRETRO evaluation results are aimed to serve as a basis to aid energy retrofit projects decision-making.

Development and Preliminary Verification of a Thermal-Hydraulic Multi-Scale Coupled Code

2010 ◽  
Author(s):  
Yu Liu ◽  
Hong Zhang ◽  
Baoshan Jia
Keyword(s):  
Nuclear Power ◽  
Data Exchange ◽  
External Control ◽  
Coupled Analysis ◽  
Time Step ◽  
Multi Scale ◽  
Coupling Strategy ◽  
Computational Fluid Dynamics Cfd ◽  
Integral Structure ◽  
Future Work

On the basis of best estimate thermal-hydraulic system code RELAP5, sub-channel code COBRA-1V, and commercial Computational Fluid Dynamics (CFD) code CFX, a thermalhydraulic multi-scale coupled code RECOX has been developed. The coupling strategy was designed to keep the integral structure of each code and minimize modifications of code source. Under the Parallel Virtual Machine (PVM) environment, an external control code has been developed to perform codes spawn, data exchange and mapping, time step coordination, etc. Two test cases including single phase blowdown and temperature fluctuation transient have been carried out to evaluate the coupling between codes. Compared with stand-alone simulations very good agreement was achieved. Then in order to demonstrate the coupled analysis capability of RECOX, an asymmetry transient in a simple two loops system which is similar to the nuclear power plant was simulated. The result is correct and reliable, although further verification of coupled code with related experiment is needed. Finally, some potential improvements of coupling and future work were presented.

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