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13 result(s) for "Naumann, Maik"
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Economic Optimization of Component Sizing for Residential Battery Storage Systems
Battery energy storage systems (BESS) coupled with rooftop-mounted residential photovoltaic (PV) generation, designated as PV-BESS, draw increasing attention and market penetration as more and more such systems become available. The manifold BESS deployed to date rely on a variety of different battery technologies, show a great variation of battery size, and power electronics dimensioning. However, given today’s high investment costs of BESS, a well-matched design and adequate sizing of the storage systems are prerequisites to allow profitability for the end-user. The economic viability of a PV-BESS depends also on the battery operation, storage technology, and aging of the system. In this paper, a general method for comprehensive PV-BESS techno-economic analysis and optimization is presented and applied to the state-of-art PV-BESS to determine its optimal parameters. Using a linear optimization method, a cost-optimal sizing of the battery and power electronics is derived based on solar energy availability and local demand. At the same time, the power flow optimization reveals the best storage operation patterns considering a trade-off between energy purchase, feed-in remuneration, and battery aging. Using up to date technology-specific aging information and the investment cost of battery and inverter systems, three mature battery chemistries are compared; a lead-acid (PbA) system and two lithium-ion systems, one with lithium-iron-phosphate (LFP) and another with lithium-nickel-manganese-cobalt (NMC) cathode. The results show that different storage technology and component sizing provide the best economic performances, depending on the scenario of load demand and PV generation.
Fundamentals of Using Battery Energy Storage Systems to Provide Primary Control Reserves in Germany
The application of stationary battery storage systems to German electrical grids can help with various storage services. This application requires controlling the charge and discharge power of such a system. For example, photovoltaic (PV) home storage, uninterruptible power supply, and storage systems for providing ancillary services such as primary control reserves (PCRs) represent battery applications with positive profitability. Because PCRs are essential for stabilizing grid frequency and maintaining a robust electrical grid, German transmission system operators (TSOs) released strict regulations in August 2015 for providing PCRs with battery storage systems as part of regulating the International Grid Control Cooperation (IGCC) region in Europe. These regulations focused on the permissible state of charge (SoC) of the battery during nominal and extreme conditions. The concomitant increased capacity demand oversizing may result in a significant profitability reduction, which can be attenuated only by using an optimal parameterization of the control algorithm for energy management of the storage systems. In this paper, the sizing optimization is achieved and a recommendation for a control algorithm that includes the appropriate parameters for the requirements in the German market is given. Furthermore, the storage cost is estimated, including battery aging simulations for different aging parameter sets to allow for a realistic profitability calculation.
A PSO-Optimized Fuzzy Logic Control-Based Charging Method for Individual Household Battery Storage Systems within a Community
Self-consumption of household photovoltaic (PV) storage systems has become profitable for residential owners under the trends of limited feed-in power and decreasing PV feed-in tariffs. For individual PV-storage systems, the challenge mainly lies in managing surplus generation of battery and grid power flow, ideally without relying on error-prone forecasts for both generation and consumption. Considering the large variation in power profiles of different houses in a neighborhood, the strategy is also supposed to be beneficial and applicable for the entire community. In this study, an adaptable battery charging control strategy is designed in order to obtain minimum costs for houses without any meteorological or load forecasts. Based on fuzzy logic control (FLC), battery state-of-charge (SOC) and the variation of SOC (∆SOC) are taken as input variables to dynamically determine output charging power with minimum costs. The proposed FLC-based algorithm benefits from the charging battery as much as possible during the daytime, and meanwhile properly preserves the capacity at midday when there is high possibility of curtailment loss. In addition, due to distinct power profiles in each individual house, input membership functions of FLC are improved by particle swarm optimization (PSO) to achieve better overall performance. A neighborhood with 74 houses in Germany is set up as a scenario for comparison to prior studies. Without forecasts of generation and consumption power, the proposed method leads to minimum costs in 98.6% of houses in the community, and attains the lowest average expenses for a single house each year.
Techno-Economic Evaluation of Energy Storage Systems Built from EV Batteries – Prospective Revenues in Different Stationary Applications
Battery energy storage systems (BESSs) are already being deployed for several stationary applications in a technically and economically feasible way. This paper focuses on the revenues of industrial BESSs built from electric vehicle lithiumion batteries with varying states of health. For this analysis, a stationary BESS simulation model is used, that is parameterised with parameters of a 22-kWh automotive battery. The comprehensive model consists of several detailed sub-models, considering battery characteristics, ageing and operating strategies, which allow technical assessment through time series simulation. Therefore, capacity fade and energy losses are considered in this techno-economic evaluation. Potential economically feasible applications of new and second-life batteries, such as photovoltaic home storage, intraday trading and frequency regulation as well as their combined operation are compared. The investigation includes different electricity price scenarios. The combined operation, followed by frequency regulation, is found to have the highest economic viability for the specified electric vehicle battery.
The impact of the tumor microenvironment on the survival of penile cancer patients
PeCa is a rare entity with rising incidence rates due to increased infections with human papillomaviruses (HPV). The distinct subtypes of PeCa with an individual pathogenesis demand biomarkers for a precise patient risk assessment regarding disease progression and therapeutic susceptibility. We recently identified promising candidates associated with an HPV-instructed tumor microenvironment (TME) using HPV-positive PeCa cell lines and tissue microarrays (TMA). The capacity of HPV + p63 + PeCa cells to release neutrophil-attracting CXCL-8 provided a molecular link explaining the infiltration of CD15 + myeloid cells in PeCa specimens. The candidate biomarkers HPV, p63, CD15, DKK1, and CD147 linked a tumor-promoting TME with a higher TNM classification reflecting more aggressive and metastasizing cancers. Based on immune-reactive scores (IRS) from TMA staining for these biomarkers, we calculated correlations and conducted association analyses to assess the degree of relationship between all biomarkers. We then conducted Kaplan–Meier survival estimates and Cox regression analyses to delineate the impact on PeCa patient survival. There is a notable predictive potential regarding the survival of patients with biomarker profiles beyond the potency of the individual biomarker. From all candidate biomarkers and biomarker profiles, the combination of CD147 and infiltrating CD15 + cells linked to an active HPV-driven transformation displayed cancer-immune dynamics with dismal prognosis for patients. After deciphering relevant interdependencies, the HPV + CD147 + CD15 + status was the most potent profile predicting metastasis-free survival of PeCa patients. The results of this report underscore the need for analysis of the TME and the development of multi-parameter composite scores that reflect fundamental cancer-immune relationships to tailor therapeutic interventions based on actual cancer immune dynamics.
A study on the value of computer-assisted assessment for SPECT/CT-scans in sentinel lymph node diagnostics of penile cancer as well as clinical reliability and morbidity of this procedure
Background Because of the increasing importance of computer-assisted post processing of image data in modern medical diagnostic we studied the value of an algorithm for assessment of single photon emission computed tomography/computed tomography (SPECT/CT)-data, which has been used for the first time for lymph node staging in penile cancer with non-palpable inguinal lymph nodes. In the guidelines of the relevant international expert societies, sentinel lymph node-biopsy (SLNB) is recommended as a diagnostic method of choice. The aim of this study is to evaluate the value of the afore-mentioned algorithm and in the clinical context the reliability and the associated morbidity of this procedure. Methods Between 2008 and 2015, 25 patients with invasive penile cancer and inconspicuous inguinal lymph node status underwent SLNB after application of the radiotracer Tc-99m labelled nanocolloid. We recorded in a prospective approach the reliability and the complication rate of the procedure. In addition, we evaluated the results of an algorithm for SPECT/CT-data assessment of these patients. Results SLNB was carried out in 44 groins of 25 patients. In three patients, inguinal lymph node metastases were detected via SLNB. In one patient, bilateral lymph node recurrence of the groins occurred after negative SLNB. There was a false-negative rate of 4 % in relation to the number of patients (1/25), resp. 4.5 % in relation to the number of groins (2/44). Morbidity was 4 % in relation to the number of patients (1/25), resp. 2.3 % in relation to the number of groins (1/44). The results of computer-assisted assessment of SPECT/CT data for sentinel lymph node (SLN)-diagnostics demonstrated high sensitivity of 88.8 % and specificity of 86.7 %. Conclusions SLNB is a very reliable method, associated with low morbidity. Computer-assisted assessment of SPECT/CT data of the SLN-diagnostics shows high sensitivity and specificity. While it cannot replace the assessment by medical experts, it can still provide substantial supplement and assistance.
Economics of Residential Photovoltaic Battery Systems in Germany: The Case of Tesla’s Powerwall
Residential photovoltaic (PV) battery systems increase households’ electricity self-consumption using rooftop PV systems and thus reduce the electricity bill. High investment costs of battery systems, however, prevent positive financial returns for most present residential battery installations in Germany. Tesla Motors, Inc. (Palo Alto, CA, USA) announced a novel battery system—the Powerwall—for only about 25% of the current German average market price. According to Tesla’s CEO Elon Musk, Germany is one of the key markets for their product. He has, however, not given numbers to support his statement. In this paper, we analyze the economic benefit of the Powerwall for end-users with respect to various influencing parameters: electricity price, aging characteristics of the batteries, topology of battery system coupling, subsidy schemes, and retrofitting of existing PV systems. Simulations show that three key-factors strongly influence economics: the price gap between electricity price and remuneration rate, the battery system’s investment cost, and the usable battery capacity. We reveal under which conditions a positive return on invest can be achieved and outline that the Powerwall could be a worthwhile investment in multiple, but not all, scenarios investigated. Resulting trends are generally transferrable to other home storage products.
Effects of Glucose and Amino Acids on Free ADP in βHC9 Insulin-Secreting Cells
Effects of Glucose and Amino Acids on Free ADP in βHC9 Insulin-Secreting Cells Peter Ronner , C. Maik Naumann and Edward Friel From the Department of Biochemistry and Molecular Pharmacology, Thomas Jefferson University College of Medicine, Philadelphia, Pennsylvania. Address correspondence and reprint requests to Dr. Peter Ronner, Department of Biochemistry and Molecular Pharmacology, 233 South 10th St., 245 BLSB, Thomas Jefferson University, Philadelphia, PA 19107-5541. E-mail: peter.ronner{at}mail.tju.edu . Abstract Stimulation of insulin release by glucose is widely thought to be coupled to a decrease in the activity of ATP-sensitive K + channels (K ATP channels) that is caused by a decreased concentration of free ADP. To date, most other investigators have reported only on total cellular ADP concentrations, even though only a small fraction of all ADP is free and only the free ADP affects K ATP channels. We tested the hypothesis that amino acids elicit insulin release via a decrease in the activity of K ATP channels owing to a decrease in the level of free ADP. We estimated the concentration of free ADP in βHC9 hyperplastic insulin-secreting cells based on the cell diameter and on luminometric measurements of ATP, phosphocreatine, and total creatine. The concentration of free ADP fell exponentially as the concentration of glucose increased. A physiological mixture of amino acids greatly stimulated insulin release at 0-30 mmol/l glucose but affected the concentration of free ADP only to a minor degree and significantly so only at ≤2 mmol/l glucose. In the presence of 2-deoxyglucose and NaN 3 , amino acids were unable to stimulate insulin release. When K ATP channels were held open with diazoxide (and the plasma membrane partially depolarized with high extracellular KCl), amino acids still stimulated insulin release. We conclude that amino acid—induced insulin release depends on two components: a yet-unknown amino acid sensor and K ATP channels, which serve to attenuate hormone release when cellular energy stores are low. We propose that glucose-induced insulin release may be regulated similarly by two components: glucokinase and K ATP channels. Footnotes GLP, glucagon-like peptide; IBMX, isobutyl methyl xanthine; K ATP channel, ATP-sensitive K + channel. Accepted October 11, 2000. Received February 23, 2000. by the American Diabetes Association, Inc.
Effects of Glucose and Amino Acids on Free ADP in BetaHC9 Insulin-Secreting Cells
Stimulation of insulin release by glucose is widely thought to be coupled to a decrease in the activity of ATP-sensitive K+ channels (KATP channels) that is caused by a decreased concentration of free ADP. To date, most other investigators have reported only on total cellular ADP concentrations, even though only a small fraction of all ADP is free and only the free ADP affects KATP channels. We tested the hypothesis that amino acids elicit insulin release via a decrease in the activity of KATP channels owing to a decrease in the level of free ADP. We estimated the concentration of free ADP in betaHC9 hyperplastic insulin-secreting cells based on the cell diameter and on luminometric measurements of ATP, phosphocreatine, and total creatine. The concentration of free ADP fell exponentially as the concentration of glucose increased. A physiological mixture of amino acids greatly stimulated insulin release at 0-30 mmol/l glucose but affected the concentration of free ADP only to a minor degree and significantly so only at < or = 2 mmol/l glucose. In the presence of 2-deoxyglucose and NaN3, amino acids were unable to stimulate insulin release. When KATP channels were held open with diazoxide (and the plasma membrane partially depolarized with high extracellular KCl), amino acids still stimulated insulin release. We conclude that amino acid-induced insulin release depends on two components: a yet-unknown amino acid sensor and KATP channels, which serve to attenuate hormone release when cellular energy stores are low. We propose that glucose-induced insulin release may be regulated similarly by two components: glucokinase and KATP channels.
Value and efficiency of sentinel lymph node diagnostics in patients with penile carcinoma with palpable inguinal lymph nodes as a new multimodal, minimally invasive approach
Purpose The international guidelines recommend sentinel lymph node biopsy (SLNB) for lymph node staging in penile cancer with non-palpable inguinal lymph nodes (LN) but it is not recommended with palpable inguinal LN. The aim of this study was to evaluate the reliability and morbidity of SLNB in combination with an ultrasound-guided resection of suspect inguinal LNs as a new multimodal, minimally invasive staging approach in these patients. Methods We performed SLNB in 26 penile cancer patients with 42 palpable inguinal LNs. Prior to the combined staging procedures the patients underwent an ultrasound examination of the groins as well as planar lymphatic drainage scintigraphy and SPECT/CT scans. During the surgical procedure, the radioactive-labelled sentinel lymph nodes and, in addition, sonographically suspect LNs, were resected under ultrasound guidance. Follow-up screening was done by ultrasound examination of the groins according to the guidelines of the European Association of Urology. Results Nineteen groins of 42 preoperatively palpable inguinal findings were histologically tumor-positive. SLNB alone showed lymphogenic metastases in 14 groins. Sonography revealed five further metastatic groins, which would not have been detected during SLNB due to a tumor-related blockage of lymphatic drainage or a so-called re-routing of the tracer. During follow-up, none of the 28 groins with tumor-negative LN status showed any LN recurrence in this combined investigation technique. The median follow-up period was 46 (24 to 92) months. Morbidity of this procedure was low at 4.76 % in relation to the number of groins resp. 7.69 % in relation to the number of patients. Conclusions The results show that this combined procedure is a reliable multimodal diagnostic approach for treatment of penile cancer patients with palpable inguinal LNs. It is associated with low morbidity rates. SLNB alone would lead to a significantly higher false-negative rate in these patients. The encouraging results of this work can extend the range of indications for nuclear medicine in the form of SLNB using radioactive tracers in this patient group.