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Aufsatz
Time Series Optimization-Based Characteristic Curve Calculation for Local Reactive Power Control Using Pandapower-PowerModels Interface
(2023-05-29)
Local reactive power control in distribution grids with a high penetration of distributed energy resources (DERs) will be essential in future power system operation. Appropriate control characteristic curves for DERs support stable and efficient distribution grid operation. However, the current practice is to configure local controllers collectively with constant characteristic curves that may not be efficient for volatile grid conditions or the desired targets of grid operators. To address this issue, this paper ...
Aufsatz
Allocation of carbon dioxide emissions to the by-products of combined heat and power plants: A methodological guidance
(2023-10-07)
Cogeneration has higher efficiency than separate heat and power generation. Since both are generated in a single process, it is necessary to allocate the emissions to by-products for comparing their environmental performance. Numerous methods exist resulting in very different allocations. There is no consensus regarding the method choice. The main objective of this article is the development and implementation of an evaluation scheme allowing the choice of an appropriate method for specific applications. This scheme ...
Aufsatz
Determination and Modeling of Proximate and Thermal Properties of De-Watered Cassava Mash (Manihot esculenta Crantz) and Gari (Gelatinized cassava mash) Traditionally Processed (In Situ) in Togo
(2023-09-27)
The roasting process of Gari (Gelatinized cassava mash), a shelf-stable cassava product, is energy-intensive. Due to a lack of information on thermal characteristics and scarcity/rising energy costs, heat and mass transfer calculations are essential to optimizing the traditional gari procedure. The objective of this study was to determine the proximate, density, and thermal properties of traditionally processed de-watered cassava mash and gari at initial and final processing temperatures and moisture contents (MCwb). ...
Aufsatz
Technoeconomic analysis of standalone hybrid renewable energy systems for telecommunication sector under different climatic conditions in Saudi Arabia
(2024-04-05)
Reliance on conventional fossil fuels to fulfil the extensively increasing energy demands due to industrial development is becoming a financial burden and a huge source of global warming. Saudi Arabia, possessing nearly 15% of the world's oil reserves, confronts an intricate scenario where approximately 53% of government revenue is oil-dependent, rendering it the 11th largest global emitter of carbon gases. This proclivity underscores the urgent need for transitioning towards renewable energy sources to alleviate ...
Aufsatz
PrOuD: Probabilistic Outlier Detection Solution for Time-Series Analysis of Real-World Photovoltaic Inverters
(2023-12-21)
Anomaly detection methods applied to time series are mostly viewed as black boxes that solely provide a deterministic answer for the detected target. Without a convincing explanation, domain experts can hardly trust the detection results and must conduct further time-series diagnoses in real-world applications. To overcome this challenge, we mathematically analyzed the sources of anomalies and novelties in multivariate time series as well as their relationships from the perspective of Gaussian-distributed non-stationary ...
Aufsatz
Analysis and Optimization of the Loss Distribution for a Two Stage AC/DC Power Supply
(2023-12-12)
This paper presents the analysis and optimization procedure of a two-stage bidirectional AC/DC power supply. The exemplary power supply consists of a silicon carbide based active front end and a dual active bridge DC/DC converter. It is designed to supply 600 V DC applications from universal low voltage AC grids with a power up to 6 kW. The paper includes the topology and design considerations, as well as an in-depth loss distribution analysis based on a validated loss model. The loss model is then utilized for an ...
Aufsatz
Peak shaving at system level with a large district heating substation using deep learning forecasting models
(2024-05-20)
The decarbonisation of urban district heating (DH) systems requires increased heating grid flexibility. Therefore, this article examines the optimised operation of a tank thermal energy storage (TTES) on the secondary side of a new DH substation for an industrial site in a German city, in order to shave the peaks of the whole DH system and thus reduce the need for heat-only boilers (HOB). The accuracy of heat load and return temperature forecasts for both the industrial consumer and the DH grid is critical to the ...
Aufsatz
Mathematical modelling of a latent heat storage: Influence of PCM thermal conductivity and enthalpy-temperature relationship
(2024-06-08)
Mathematical modelling of latent heat storage units is useful to calculate their thermal performance for integration in larger systems. This requires the input of thermophysical properties of the phase change material (PCM) used, but data provided by manufacturers or published in the literature is often incomplete and/or varies between sources. However, it is not clear to what extent an accurate knowledge of these properties, including their phase dependency, is necessary to obtain reliable calculations, especially ...
Aufsatz
Self-generation and outage losses: A firm-level analysis for emerging and developing Asian countries
(2024-02-26)
Access to reliable and affordable electricity is critical to economic development in emerging and developing Asia. However, many firms in these regions face challenges in obtaining consistent and affordable electricity from the grid, leading them to invest in self-generation technologies. This paper examines the strategic decision of firms to self-generate electricity and the economic losses incurred during power outages. Using survey data from the World Bank Enterprise Survey (WBES) of 5639 manufacturing firms in ...