brief intro to solar electricity production with organic rankine cycle turbines
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Solar electricity production with Organic Rankine Cycle turbines[INTRO-DRAFT]
Maria Kaninia27/05/2011
PATW - 27.05.2011 Kaninia Maria 2
“Standard” technologies for solar electricity - 1 Photovoltaics: dominant “mainstream” technology
(large-scale plants, roofing)
Feed-in tariffs decreasing to reach grid parity
flat crystallic
panels
thin-film (roofing)
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“Standard” technologies for solar electricity - 2
“Standard” solar thermal plants = optical concentrators + mechanical heat engines + storage option
(molten salt) large-scale (~ 10-100 MWe)
power tower
linear Fresnel array
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“Innovative” thermal small-scale technologies for solar electricity - 3
parabolic dish concentrator (tracker) + Stirling heat engine high direct normal insolation required (arid regions, no clouds) not yet widely deployed commercially in Europe
dish Stirling (25 kWe)
Plataforma Solar de Almería
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Resource: low grade solar heat (harvested with solar flat plate
collectors)
Business opportunity: feed-in tariffs for solar thermal power plants (Greece: €250/MWhe)
Financial constraint: medium-scale installation + size of investment (~100 kWe , ~100 k€)
Proposed conversion technology: Organic Rankine Cycle
Specific project location and environment conditions: Western Greece
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Organic Rankine Cycle thermodynamic cycle
similar to “classical” Rankine cycle of steam turbines “inverse” refrigeration cycle
working fluid: organic substance (e.g. refrigerant fluid) low vaporisation temperature low pressure
binary ORC cycle: established commercial application for power generation from geothermal low-enthalpy resources (e.g. ORMAT, TURBODEN)
ORC system prototyped in
1961 by Harry Zvi Tabor
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ORC sub-cycle #1: hot “resource” thermal oil
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ORC sub-cycle #2: organic fluid
typical
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ORC sub-cycle #3: cooling water
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Solar collectorsno optical concentrators
array of series-connected flat plate solar collectors thermal oil (low pressure) at temperatures above 100oC intermediate storage
design approach•Overdimensioning of the solar collectors array
•Implement storage
•Achieve maximum nominal output from ORC system
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Equipment: ORC system, Purecycle® Nominal net output: 260 kWe
Reversed centrifugal chiller Refrigerant R245fa
CF3CH2CHF2 pentafluoropropane
(boiling point @1 atm = 14.9oC)
centrifugal compressor centrifugal
“expander” (+generator)
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Project data Project assumptions:
location: Messologhi, Western Greece solar resource: TH = 100oC
(overdimensioning) additionalstorage to “stabilise” output heat sink temperature: TL = ~ 25oC
(seawater) low ratio direct / global irradiation
Resource: Approximately 4kWh/m2/day =
1460kWh/m2/yGlobal irradiance - fixed plance
0
100
200
300
400
500
600
700
800
900
4:48 7:12 9:36 12:00 14:24 16:48 19:12
W/m2 JAN
JUL
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Location of intended project•actual project
•“soft version” presentation
•“test-drive”
•comments