Please wait, while we are loading the content...
| Content Provider | The American Society of Mechanical Engineers (ASME) Digital Collection |
|---|---|
| Author | Siros, Frédéric Campos, Gonzalo Fernández |
| Copyright Year | 2017 |
| Abstract | The Levelized Cost of Electricity (LCOE) of Concentrated Solar Power, referred to in this document as Solar Thermal Electric (STE) is no match for that of Photovoltaic (about one third in similar conditions). However, the future electrical grids dominated by intermittent renewables (in 2030 and beyond) will value the firm capacity provided by STE that integrate a massive thermal storage. The molten salt solar tower is, beyond any doubt, the best technology to provide this firm capacity at reasonable cost for the 10–15 years to come. We believe that the next generation of STE plants will keep the molten salt tower architecture, but with novel solar loop, storage medium and power block that will allow for higher working temperatures and conversion efficiency, thereby downsizing the solar field that accounts for ∼40% of the plant’s LCOE. Among the three power block technologies that can make good use of the high temperatures allowed by the new storage medium (probably fluidized particles) — supercritical steam Rankine cycle, supercritical CO2 Brayton cycle and combined cycle gas turbine (CCGT) — the latter is a good candidate. In order to achieve today’s impressive efficiencies of state-of-the-art gas-fired CCGTs (up to 62%), the manufacturers relied on continuous improvements — including Turbine Inlet Temperatures (TIT) increases up to ∼1500°C — without modifying the architecture. Our problem is quite different: we consider that our TIT is limited to 1,000°C. Therefore, new architectures must be contemplated in order to reach a ∼50% efficiency that would be a significant improvement compared to the ∼42% obtained with current subcritical steam cycles. The objective of this study is to define the optimal configuration of a CCGT working with an external heat input provided by heat exchangers that collect the heat from a storage medium. The study was conducted as follows. The bottoming cycle’s power output per unit of GT exhaust gas mass flow was defined as a function of the exhaust gas temperature thanks to several simulations performed with Thermoflow’s GT-PRO software and a linear regression. Our efforts were then focused on the gas turbine. Four gas turbine configurations were optimized and compared: with/without reheat, with/without intercooling. Single and double reheat were also compared. For each configuration, three TIT values were considered: 800°C, 900°C and 1,000°C. A supplementary combustion that entails a 6% pressure drop was considered after the external heat and reheat(s). These calculations were performed twice: first using an analytic model, then with the Thermoflex software. Both results were always very consistent, which is no surprise: since the gas turbine is uncooled, the analytical model is straightforward. The single reheat cycle without intercooling is the most efficient one if TIT ≥ 900°C. The double reheat increases the efficiency for TIT = 800°C. The gross efficiencies of the combined cycle power blocks with single reheat GT with additional combustion are as follows: 46.8% if TIT = 800°C (49.7% with a double reheat and no additional combustion), 50.3% if TIT = 900°C and 53.1% if TIT = 1,000°C. The reheat (or second reheat if applicable) poses a considerable challenge because the low working air pressure entails a high relative pressure drop of the heat exchanger that is highly detrimental to the cycle efficiency. According to expert opinion, a train of reheat exchangers with the pressure drop considered in this study (6%) and a ∼50 K final temperature difference can be manufactured at reasonable cost. The Capital Expenditure (Capex) of the CCGT plus its trains of heat exchangers must be assessed in collaboration with manufacturers but should be reasonable, lower anyway than that of a supercritical steam cycle with similar efficiency. In conclusion, a low TIT, externally heated CCGT with single or double reheat (depending on the TIT) is a good option for the next generation of high temperature solar towers. There is no major hurdle for manufacturing such a power block right now, other than convincing a manufacturer to do it. |
| Sponsorship | International Gas Turbine Institute |
| File Format | |
| ISBN | 9780791850831 |
| DOI | 10.1115/GT2017-65227 |
| Volume Number | Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration Applications; Organic Rankine Cycle Power Systems |
| Conference Proceedings | ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition |
| Language | English |
| Publisher Date | 2017-06-26 |
| Publisher Place | Charlotte, North Carolina, USA |
| Access Restriction | Subscribed |
| Subject Keyword | Trains Cycles Temperature Computer software Thermal energy storage Combustion Power grids High temperature Optimization Exhaust systems Gas turbines Supercritical carbon dioxide Solar thermal power Engineering simulation Manufacturing Turbines Combined cycle gas turbines Architecture Combined cycles Heat exchangers Brayton cycle Flow (dynamics) Pressure Renewable energy sources Heat Storage Simulation Pressure drop Concentrating solar power Collaboration Particulate matter Solar energy Steam Rankine cycle |
| Content Type | Text |
| Resource Type | Article |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|