Search results for "pump"
showing 10 items of 471 documents
A review of 507 off-pump coronary bypass patients: a single center experience.
2007
This retrospective study evaluates perioperative results of 'Off-pump' coronary artery bypass surgery (OPCAB) experience in a single center. Five hundred and seven patients were operated (median sternotomy) from 1998 to 2002 using OPCAB. Patient data were registered and risk prediction calculated using the full logistic version of EuroSCORE. Overall, 1091 distal anastomoses were performed and only five (1%) patients required conversion to cardiopulmonary bypass. The predicted mortality was 3.8+/-4.5%, the observed mortality was 2.37%. OPCAB technique has become a standard approach in our department with low mortality and morbidity rates even in treatment of multivessel disease or high-risk …
Multi-stage Linear Programming Optimization for Pump Scheduling
2014
This study presents a methodology based on Linear Programming for determining the optimal pump schedule on a 24-hour basis, considering as decision variables the continuous pump flow rates which are subsequently transformed into a discrete schedule. The methodology was applied on a case study derived from the benchmark Anytown network. To evaluate the LP reliability, a comparison was made with solutions generated by a Hybrid Discrete Dynamically Dimensioned Search (HD-DDS) algorithm. The cost associated with the result derived from the LP initial solution was shown to be lower than that obtained with repeated HD-DDS runs with differing random seeds. (C) 2013 The Authors. Published by Elsevi…
Load match and grid interaction optimization of a net zero energy building through electricity storage: An Italian case-study
2016
The study aims at applying of Load Match and Grid Interaction indexes to a Net Zero Energy Building in order to optimize the performances of its energy systems. The case study is a modular prefabricated house that uses solar energy (photovoltaic) and natural gas (Fuel Cell) as energy sources and equipped with an Energy Management System addressing the optimal energy use.
Techno-economic analysis of off-grid hybrid renewable energy system for Sri Lanka
2014
Off grid hybrid renewable energy based power systems for rural electrification has become an attractive solution for areas where grid electricity is not feasible. Hybrid systems use several generation technologies, therefore the selection of proper technologies and optimum sizing of the components has become of great importance in reducing the overall cost and increasing the reliability of the service. The focus of this study has been to investigate the optimum configuration of a hybrid system which can supply electricity to a rural community in Sri Lanka. A rural village from the Siyambalanduwa region in Sri Lanka inhabiting approximately 150 households resulting approximate daily electric…
Method for size optimisation of large wind–hydrogen systems with high penetration on power grids
2013
Wind power generation is growing rapidly in many locations around the world. Power systems are able to absorb large amounts of wind capacity, but operational problems arise when the wind power penetration becomes high. Such factors as voltage dips, frequency variations, low power system stability, low reactive power and power flow imbalances reduce the economic value and represent a barrier to the unlimited development of wind energy. Hydrogen production from wind power that is not matched with hourly electricity demand appears to be an attractive storage option capable of providing a balancing service to the electricity generators and suppliers for mitigation of the negative impacts due to…
An optimal operating strategy for combined RES–based Generators and Electric Storage Systems for load shifting applications
2013
This paper focuses on an optimal operating strategy of combined RES-based generators and electric storage systems for small/medium-scale public facilities. The operating strategy can be used in load shifting applications in response to a time-of-use (TOU) rate design with differential pricing for on- and off-peak usage. Load shifting applications can be exploited by customers using battery energy storage systems (BESS) in order to reduce their electricity bill, charging the storage when off-peak time periods are applied and discharging it during on-peak periods, when electricity energy prices are high. The operating strategy is implemented within a bidirectional converter that provides an i…
Wind energy potential assessment in order to produce electrical energy for case study in Divandareh, Iran
2014
This paper evaluates the electricity production at Divandareh, a place located at Kurdistan, Iran through wind energy assessment using wind data of the site recorded in duration of a year at three different heights of 10, 30 and 50 meters. For this purpose, a statistical analysis of the measured wind data is performed. According to the US standards, the site is found to be a class-3 wind power site with power density of 336.18 W/m2 at 50 m height. Moreover, dominant flow direction of wind is checked through wind rose plotting. It has been shown that the site is suitable for wind energy development by installing wind turbines with tall towers. Thereupon, four different commercial wind turbin…
Study and simulation of photovoltaic installation connected to the grid with storage system
2016
In the present paper, a new approach to the management of energy resources in a research laboratory is proposed and evaluated by a simulation for the PV installation realized for the Tunisian-Italian cooperation project DE.DU.ENER.T, using renewable energy and economic criteria. The aim of this project is to improve energy efficiency order to minimize the electricity cost consumed at the laboratory, because according to the bills of electricity received we noticed that there is a high consumption of electrical current, from the STEG grid, and especially by the energy intensive equipment such as drying ovens and all the workstations. So we targeted to install a photovoltaic field of 12KWc to…
Performance of zero energy homes in smart village skarpnes
2016
In Smart Village Skarpnes in southern Norway, five detached houses are designed as zero energy homes. This work reports on the photovoltaic (PV) power production and energy consumption behavior of these homes and discusses whether an annual zero energy budget may be achieved. Results so far indicate that the extremely low annual energy consumption assumed for these types of homes may be difficult to achieve, and also point at a need for better matching between production and consumption power profiles. Performance results are based on monitoring data combined with estimated performances from PVsyst simulations. The work is part of a larger research project that investigates how the introduc…
Classification of pumpkin seed oils according to their species and genetic variety by attenuated total reflection Fourier-transform infrared spectros…
2011
Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), followed by multivariate treatment of the spectral data, was used to classify seed oils of the genus Cucurbita (pumpkins) according to their species as C. maxima, C. pepo, and C. moschata. Also, C. moschata seed oils were classified according to their genetic variety as RG, Inivit C-88, and Inivit C-2000. Up to 23 wavelength regions were selected on the spectra, each region corresponding to a peak or shoulder. The normalized absorbance peak areas within these regions were used as predictors. Using linear discriminant analysis (LDA), an excellent resolution among all categories concerning both Cucurbita species a…