scholarly journals A tool for automated detection of hidden operation modes in building energy systems

2021 ◽  
Vol 2042 (1) ◽  
pp. 012071
Author(s):  
Thomas Storek ◽  
Jonathan Kriwet ◽  
Alexander Kümpel ◽  
Dirk Müller
Keyword(s):  
Expert Knowledge ◽  
Renewable Energy Sources ◽  
Energy Systems ◽  
Building Energy ◽  
Knowledge Extraction ◽  
Automated Detection ◽  
Change Points ◽  
Series Data ◽  
Operation Modes ◽  
Building Energy Systems

Abstract The integration of renewable energy sources into building energy systems and the progressive coupling between the thermal and electrical domains makes the analysis of these systems increasingly complex. At the same time, however, more and more building monitoring data is being collected. The manual evaluation of this data is time-consuming and requires expert knowledge. Hence, there is a strong need for tools that enable the automatic knowledge extraction from these huge data sets to support system integrators and favor the development of smart energy services, e.g., predictive maintenance. One crucial step in knowledge extraction is the detection of change points and hidden states in measurements. In this work, we present a tool for automated detection of hidden operation modes based on multivariate time series data deploying motif-aware state assignment (MASA). The tool is evaluated utilizing measurements of a heat pump and compared to two baseline algorithms, namely k-Means and k-Medoids. MASA performs particularly well on noisy data, where it shows only a small deviation in the number of detected change points compared to the ground truth with up to 77% accuracy. Furthermore, it almost always outperforms the baseline algorithms, which in turn require extensive preprocessing.

scholarly journals Grid-Aware Layout of Photovoltaic Panels in Sustainable Building Energy Systems

2021 ◽  
Vol 8 ◽  
Author(s):  
Luise Middelhauve ◽  
Francesco Baldi ◽  
Paul Stadler ◽  
François Maréchal
Keyword(s):  
Energy Demand ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Energy Systems ◽  
Energy Generation ◽  
Building Energy ◽  
Solar Irradiation ◽  
Mixed Integer ◽  
Photovoltaic Panels ◽  
Building Energy Systems

In the context of increasing concern for anthropogenic CO2 emissions, the residential building sector still represents a major contributor to energy demand. The integration of renewable energy sources, and particularly of photovoltaic (PV) panels, is becoming an increasingly widespread solution for reducing the carbon footprint of building energy systems (BES). However, the volatility of the energy generation and its mismatch with the typical demand patterns are cause for concern, particularly from the viewpoint of the management of the power grid. This paper aims to show the influence of the orientation of photovoltaic panels in designing new BES and to provide support to the decision making process of optimal PV placing. The subject is addressed with a mixed integer linear optimization problem, with costs as objectives and the installation, tilt, and azimuth of PV panels as the main decision variables. Compared with existing BES optimization approaches reported in literature, the contribution of PV panels is modeled in more detail, including a more accurate solar irradiation model and the shading effect among panels. Compared with existing studies in PV modeling, the interaction between the PV panels and the remaining units of the BES, including the effects of optimal, scheduling is considered. The study is based on data from a residential district with 40 buildings in western Switzerland. The results confirm the relevant influence of PV panels’ azimuth and tilt on the performance of BES. Whereas south-orientation remains the most preferred choice, west-orientationed panels better match the demand when compared with east-orientationed panels. Apart from the benefits for individual buildings, an appropriate choice of orientation was shown to benefit the grid: rotating the panels 20° westwards can, together with an appropriate scheduling of the BES, reduce the peak power of the exchange with the power grid by 50% while increasing total cost by only 8.3%. Including the more detailed modeling of the PV energy generation demonstrated that assuming horizontal surfaces can lead to inaccuracies of up to 20% when calculating operating expenses and electricity generated, particularly for high levels of PV penetration.

Ontological specification for the model integration in ICT building energy systems

2012 ◽  
pp. 939-950 ◽  
Author(s):  
R Guruz ◽  
P Katranuschkov ◽  
R Scherer ◽  
J Kaiser ◽  
J Grunewald ◽  
...  
Keyword(s):  
Energy Systems ◽  
Building Energy ◽  
Model Integration ◽  
Building Energy Systems

scholarly journals Optimum Renewable Fraction for Grid-connected Photovoltaic in Office Building Energy Systems in Indonesia

2018 ◽  
Vol 9 (4) ◽  
pp. 1866 ◽  
Author(s):  
Ayong Hiendro ◽  
Ismail Yusuf ◽  
F. Trias Pontia Wigyarianto ◽  
Kho Hie Khwee ◽  
Junaidi Junaidi
Keyword(s):  
Carbon Dioxide ◽  
Renewable Energy ◽  
Energy Systems ◽  
Building Energy ◽  
Office Building ◽  
Pv System ◽  
Optimum Result ◽  
Pv Systems ◽  
Building Energy Systems

<span lang="EN-US">This paper analyzes influences of renewable fraction on grid-connected photovoltaic (PV) for office building energy systems. The fraction of renewable energy has important contributions on sizing the grid-connected PV systems and selling and buying electricity, and hence reducing net present cost (NPC) and carbon dioxide (CO<sub>2</sub>) emission. An optimum result with the lowest total NPC for serving an office building is achieved by employing the renewable fraction of 58%, in which 58% of electricity is supplied from the PV and the remaining 42% of electricity is purchased from the grid. The results have shown that the optimum grid-connected PV system with an appropriate renewable fraction value could greatly reduce the total NPC and CO<sub>2</sub> emission.</span>

Expressing the Building Energy Systems Thermodynamic Seasonal Efficiency

2017 ◽  
Author(s):  
Karolis Januševičius ◽  
Juozas Bielskus ◽  
Vytautas Martinaitis ◽  
Giedrė Streckienė ◽  
Dovydas Rimdžius
Keyword(s):  
Reference Conditions ◽  
Energy Systems ◽  
Integrated Approach ◽  
Building Energy ◽  
Simulation Software ◽  
Calculation Procedure ◽  
Thermodynamic Efficiency ◽  
Engineering Practice ◽  
Time Step ◽  
Building Energy Systems

In order to reduce impact to environment, a qualitative approach of energy saving is global aspect that is included in various forms of CO2 emissions, primary energy limitations and benchmarks in EU and member countries policy. Exergy analysis allows expressing the quality of energy flows in comparison to ambient or other reference conditions. Despite of this valuable information, this concept is not widely used in engineering practice. The article suggests the calculation procedure for sessional or periodical thermodynamic (exergy) efficiency in relation to variable reference conditions. Knowledge about defined procedures unlocks the possibility to fill up the implementation gap for building system engineering practice where seasonal performance parameters are widely used to express efficiency. Prepared algorithm allows determining seasonal or periodic thermodynamic efficiency of individual elements and energy transfer chains in building energy systems. Defined calculation procedure workflow is suitable for integrated approach when coupled heat transfer and fluid flow processes are explored in short time steps with dynamic simulation software tools. Presented algorithm ensures result that fits in thermodynamically correct range 0-1 and helps to summarize separate time step results. By adding duration of specific conditions, this analysis enables to identify critical peak periods and base load conditions across operation period. The presented framework fills the gap in lack of systematic expression for seasonal thermodynamic efficiency and suggests the process for calculation procedures workflow.

Sign in / Sign up

Export Citation Format

Share Document