Fluid Selection and Plant Configuration of an ORC-biomass fed System Generating Heat and/or Power☆

Abstract The aim of the paper is to compare from an energetic, exergetic and economic viewpoint different plant configurations of Organic Rankine Cycles matched with biomass-fired boilers for electricity production or combined heat and power generation. To this purpose, a computer tool able to perform the fluid selection and plant layout optimization has been developed. The devices efficiency charts are used to predict the components performance while the fluid thermodynamic properties have been retrieved from two databases. Results show that Toluene guarantees the highest performance in both cases while the most suitable configuration is the recuperative one

improvement of the energy system of a nepali village through innovative exploitation of local resources

Abstract Nepal is one of the less industrialized Countries and does not have fossil fuel reserves. In this scenario, a better exploitation of energy resources is a key factor to start improving the country's overall energy system. For these reasons, the aim of this work, which is the result of a collaboration between two research groups from different countries, is the design of an ORC which recovers the discharged heat by an existing ICE: the integrated system will supply electricity to a small Nepali village, contributing to a little rise of the life standard of a small and poor community

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Ottimizzazione e analisi in regime dinamico di un ciclo ORC cogenerativo

Lo scopo della tesi è di creare un programma di ottimizzazione che, date alcune specifiche d'input, ricerchi il ciclo ORC e il fluido di lavoro ottimo sulla base di una funzione obiettivo stabilita a priori. Determinata la soluzione migliore, si procede con il dimensionamento dei componenti d'impianto principali e l'analisi in condizioni di off design e in regime dinamico per mezzo del software Dymol

Recovering gas turbine high-temperature exhaust heat using organic Rankine cycle with mixture as working fluid

In the recent years, several studies have been conducted about the possibilities of recovering heat from gas turbine (GT) exhaust gases using Organic Rankine Cycle (ORC) units. However, it is difficult to find out working fluids properly matching with GT exhaust gases. For this reason, the Authors have developed a computer tool able to perform fluid selection and plant layout optimization. The optimum fluid is selected among 81 pure working fluids and their mixtures. The optimization goal is the maximization of the net electric power while the optimized variables are the heat source outlet temperature, the evaporation pressure of the organic medium, the turbine inlet temperature, the fluid or mixture composition, the recuperator efficiency and the condensation pressure. Given that the plant components play a fundamental role in the prediction of the design performance, the efficiency charts of the axial and radial flow turbines are implemented into the tool. Exergetic and economic analyses are also performed. The plant model is built in Matlab environment and the optimization is performed using the genetic algorithm toolbox. The fluid thermodynamic properties have been retrieved from REFPROP and CoolProp database. Results show that hydrocarbon mixtures guarantee better performance than pure hydrocarbons

The ORC-PD: A versatile tool for fluid selection and Organic Rankine Cycle unit design

The ORC (Organic Rankine Cycle) is an emerging and commonly accepted technology for converting medium and low temperature heat sources into electricity. Several ORC units are already in operation but there is a continuous need of new and more versatile computer tools able to perform fluid selection and plant layout optimization. For these reasons, the present work is devoted to present a computer tool able to perform the fluid selection and the plant design of ORC units maximizing, for example, the net electric power for different heat sources' type and temperature (low, medium and high temperature). The optimum fluid is selected among 81 possible candidates. The optimization is performed taking into account a wide range of operating conditions: subcritical and transcritical cycles, regenerative and nonregenerative units and heat transfer made from the hot side and the power cycle (with and without the oil loop). Being the expander a crucial component, the axial and radial efficiency prediction charts are employed to estimate the expander isentropic efficiency. An exergy and economic analysis is also performed. For the selected test case the maximum net electric power can be reached using Toluene with a recuperative subcritical cycle