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Strategies enhancing efficiency of cavity receivers

Uhlig, Ralf and Flesch, Robert and Gobereit, Birgit and Giuliano, Stefano and Liedke, Phillip (2014) Strategies enhancing efficiency of cavity receivers. Energy Procedia, 49, pp. 538-550. Elsevier. DOI: 10.1016/j.egypro.2014.03.058 ISSN 1876-6102

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Introducing solar energy into the gas turbine of Combined Cycle systems (CC) offers significant advantages over other solar power plant concepts. A promising way to introduce solar power is solar preheating of the compressor discharge air before it enters the combustor of the gas turbine using a receiver built consisting of several metallic tubes. The main challenge during the design of such a receiver is the low solar flux capability caused by the limited convective heat transfer. To ensure a sufficient efficiency, the receiver is usually located in a cavity. The heat losses by conduction through the (insulated) cavity walls can be reduced by increased insulation thickness. Heat losses by radiation and convection to ambient depend strongly on the aperture area, receiver inclination and the receiver temperature. The receiver temperatures can be reduced by increasing the cavity si ze, as the flux distribution gets more homogenous and the overall flux density is reduced. Following heat losses by radiation and convection to ambient are reduced. On the other hand additional costs for the cavity walls have to be considered. The paper deals with the comparison of two different strategies to increase the receiver efficiency of a cavity receiver used to heat the compressed air of a 4.7 MWel turbine from 330°C up to 800°C, with a mass flow of 15.9 kg/s at 10 barabs. The influence on the levelized cost of energy (LCOE) of different receiver sizes and one design option (transparent covering of aperture) for reducing the convections losses were analyzed and compared. The thermal and hydraulic layout was done for a thermal heat of 8.4MWth and 250 mbar pressure drop using thermal finite element (FE) models considering the local heat flux distribution, heat transfer to working fluid, radiation exchange between components and ambient as well as conduction and convection losses of the cavity. As the convective losses play a significant role, CFD models were used to evaluate the convective heat losses.

Item URL in elib:https://elib.dlr.de/91849/
Document Type:Article
Title:Strategies enhancing efficiency of cavity receivers
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Uhlig, Ralfralf.uhlig (at) dlr.deUNSPECIFIED
Flesch, RobertRobert.Flesch (at) dlr.dehttps://orcid.org/0000-0003-2725-8039
Gobereit, BirgitBirgit.Gobereit (at) dlr.dehttps://orcid.org/0000-0002-1952-9209
Giuliano, Stefanostefano.giuliano (at) dlr.deUNSPECIFIED
Liedke, PhillipPhillip.Liedke (at) dlr.dehttps://orcid.org/0000-0003-3391-8638
Journal or Publication Title:Energy Procedia
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
DOI :10.1016/j.egypro.2014.03.058
Page Range:pp. 538-550
Series Name:Elsevier Ltd.
Keywords:lar tower; Combined Cycle, Tubular receiver; Convection losses; Window
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Concentrating Solar Systems (old)
DLR - Research area:Energy
DLR - Program:E SF - Solar research
DLR - Research theme (Project):E - Point-Focusing Systems (old)
Location: Stuttgart
Institutes and Institutions:Institute of Solar Research > Punktfokussierende Systeme
Deposited By: Uhlig, Tamara
Deposited On:11 Nov 2014 16:26
Last Modified:06 Sep 2019 15:22

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