Modelling of District Heating Systems: Comparative Evaluation of White-box Modelling Approaches

District heating systems are prevalent in most European countries, and such energy delivery methods can be crucial to decarbonisation objectives. To appropriately size and design the control of such networks, the modelling of district heating networks should have a good representation of the demand-side, which is the set of buildings connected to the network. In-stead of simplified modelling of the demand, whole-building simulation tools can be invoked in this case, like EnergyPlus. More recently, equation-based libraries have been developed in Mod-elica for component-based simulation of HVAC systems. Modelica-based libraries offer easier model composability and are particularly interesting for control fine-tuning; on the downside, the model setup can be more complex, with more validation needed. This paper conducts a comparative study of the Modelica LBNL Buildings library against Ener-gyPlus, based on an archetype-based hypothetical case in the UK with a small-scale district heating system. The methodology resides on models developed in the two tools with the same level of modelling detail. The comparison helps understand software differences in the model-ling procedure, computational time, relative accuracy of energy predictions and heating system variables. The results indicate Modelica Buildings library yields similar accuracy in terms of heat transfer calculation through thermal zones as EnergyPlus, whilst capturing additional en-ergy consumption caused by the dynamic changes at system startup and the realistic controllers used in the Modelica district heating models. Meanwhile, the Modelica Buildings library’s out-puts show the fluctuations of system variables, indicating different operation patterns and con-trol effects against EnergyPlus. This study also proves that the Modelica Buildings library is the better tool for district heating simulation in the context of dynamic performance evaluation and control testing, based on overall capabilities, limitations, and prediction differences

A Photocatalytic Organic Wastewater Disposing System Based on Solar Energy

AbstractThe paper presents a photocatalytic organic wastewater disposing system, with functions of automatic examination and drainage, for disposing organic wastewater. It is based on photocatalysis and oxidization of complex TiO2 nonmaterial, the system is made up of complex TiO2 nonmaterial carrier units, examining and controlling unit, solar energy unit and auxiliary magnetic field unit. Light absorption diagram shows the vanishing of impurity after adequate time

Data-driven smart buildings: Narratives of drivers and barriers from real-world implementations

Progress in the digitalisation of building services has been slow. Data-driven insights combined with innovative business models have the potential to unlockvalue. Yet barriers associated with implementing smart building technologies in the real worldinclude an unclear value proposition, differing stakeholder perspectives, and limited evidence of the benefits and disbenefits. This paper reports ongoingwork within the International Energy Agency Annex 81, “Data-driven smart buildings, ”to understandthe current technology landscape and opportunities by implementingdata-driven building servicesin non-domestic buildings. Several case studies were collected fromaround the world, contributed by Annex81 participants. This paper discusses stakeholder narratives on the value proposition and lessons learnt from the case studies collected and gives practical suggestions to overcomedigitalisation barriers

Electronic Information Major Practice Teaching Reform Concentrated Research and Innovation

AbstractBringing forward the concentration of practical teaching system reform ideas are based on product-oriented, hierarchical progressive. The idea associates all parts of practice, establishing a large framework system. This approach reflects the intrinsic link between knowledge, reached through the practice of teaching will be the focus of a comprehensive knowledge of the purpose. Its implementation will help to change the traditional teaching mode, and to further promote the theory of teaching, thereby raising the overall quality of training

Fabrication and evaluation of polyurethane-based asymmetric membranes

Abstract For preparation of an ideal wound dressing, a series of novel polyurethane-based asymmetric membranes with acetic starch and poly (ethylene glycol) as fillers were successfully fabricated by a combination of polymer-filler hybridization and immersion precipitation phase inversion. These resultant polyurethane-based asymmetric membranes consisted of an integral and dense skin layer supported by a porous sublayer as designed. The porosity and internal substructure of asymmetric membranes could be controlled by adjusting species and amount of fillers. The polyurethane-based asymmetric membranes showed promoted fluid absorption capability and controlled water vapor transmission, but could inhibit exogenous microorganisms invasion deriving from its dense skin layer. In vitro biodegradation assay indicated that the polyurethane/acetic starch composite membrane exhibited faster degradation behavior. These results indicated that the polyurethane-based asymmetric membranes prepared in this study has potential for application as an ideal wound dressing

Positional multi-length and mutual-attention network for epileptic seizure classification

The automatic classification of epilepsy electroencephalogram (EEG) signals plays a crucial role in diagnosing neurological diseases. Although promising results have been achieved by deep learning methods in this task, capturing the minute abnormal characteristics, contextual information, and long dependencies of EEG signals remains a challenge. To address this challenge, a positional multi-length and mutual-attention (PMM) network is proposed for the automatic classification of epilepsy EEG signals. The PMM network incorporates a positional feature encoding process that extracts minute abnormal characteristics from the EEG signal and utilizes a multi-length feature learning process with a hierarchy residual dilated LSTM (RDLSTM) to capture long contextual dependencies. Furthermore, a mutual-attention feature reinforcement process is employed to learn the global and relative feature dependencies and enhance the discriminative abilities of the network. To validate the effectiveness PMM network, we conduct extensive experiments on the public dataset and the experimental results demonstrate the superior performance of the PMM network compared to state-of-the-art methods

Research on Axial Mechanical Properties of the Grouted Connection Section Considering Installation Errors

[Introduction] With the development of offshore wind turbine works to deep sea areas, the challenging construction environment tends to result in errors in the installation of the grouted connection for the jacket foundation. These errors can subsequently affect the axial mechanical properties of the grouted connection. Therefore, it is necessary to study the impact laws of installation errors on the axial mechanical properties of the grouted connection section. [Method] The study was commenced by conducting axial static loading tests on reduced-scale test piece of the grouted connection section, which was followed by simulating the axial loading process of the corresponding test piece using the finite element analysis method. The simulation results were found to align well with the experimental data, indicating a successful outcome. [Result] According to the research findings, the increasing in longitudinal and transverse installation errors can lead to an increase in the axial stiffness of the grouted connection section. This, in turn, further alters the longitudinal strain distribution of the casing and pile pipe. Additionally, the increase in installation errors can lead to an increase in the maximum value of the third principal stress in the grouting materials during the axial loading process, as well as changes in its distribution location. [Conclusion] In conclusion, the influence of installation errors on the axial mechanical properties of the grouted connection section for the jacket foundation can cause alterations in failure modes of the grouted connection section. Therefore, it is needed to consider and evaluate the harm caused by the impact laws of installation errors based on their influence rules

The effect of Matmo typhoon on mixed zone between the Yellow sea and Bohai sea

The results of remote sensing, buoy and profile based on measured data indicate that the wind speed, H-1/3 and salinity increased, sea surface temperature declined, and wind direction changed greatly during the transit of the Matmo typhoon on July 25. It was found that the typhoon transport the Yellow Sea Cold Water Mass into the the Yellow and Bohai seas mixed zone