SFERA summer school 2014 Building a Fresnel solar plant : a simulation tool for dimensioning. Dipl-ing Raphaël Alliotte
CNIM company Medium sized company, 2772 employees, operating in 15 countries, Listed on the Euronext exchange in Paris, family based. shareholding. Consolidated sales in 2013 : 782 M (59% export) Three sectors of activity with a dominant: the energy Waste-to-energy and biomass plants Steam generation using fossil fuels Concentrating solar power plants Nuclear energy 2
Environment in pictures Bakou waste to energy power plant (Azerbaïdjan) 3
Environment in pictures Biomass plant, Nesle (France) 4
CNIM Industrial Systems in pictures Modular assault bridge Landing Catamaran 5
Energy sector in pictures Babcock Wanson boiler house in the food industry, France Refurbishment of a sugar refinery, Morocco 6
Solar Energy Division Thermodynamic solar power plants CNIM acts as a main contractor, providing turnkey solar thermodynamic power plants. As a main contractor, CNIM is in charge of: The overall project design, its construction and its. commissioning, and provide technical support for operation. The detailed design of the main elements of the plant using its own processes, in particular for: the solar radiation the receiver the recovery of thermal energy (thermal cycles) 7
CNIM solar power plants
CNIM development in Fresnel technology Characteristics of the CNIM Fresnel technology Direct steam generation without harmful heating fluids for environment such as thermal oils. Easy local implementation, all main components available in local industries: favors local jobs and local economic development Optimized cost Easy implementation even on sloped land Better landscape insertion Low environmental impact Innovating design (patents pending) High development potential (high steam characteristics, heat storage, hybridization, ) Automatic cleaning of the mirror with a robot
Our projects : ecare ecare : Fresnel CSP industrial pilot plant Project awarded in the framework of the French Energy Agency 10 hours energy storage in order to run 24h/24 (10 800 m² of mirror). Start-up: end 2014. Localisation : France. 10
Our projects : ello ecare : Fresnel CSP commercial power plant Project awarded in the framework of a French national solar tender : 20 years PPA 9 MW with 3 hours energy storage (142 000 m² of mirror). Start-up : end of 2016. Localisation : France 11
Dimensioning of a solar plant The optimal global design cannot be based on one theoretical nominal loadpoint. The thermal output of the solar field has important variation through the day and through the year The solar field surface, and thermal energy storage size cannot be decided on a peak point that almost never happens. On a smaller scale, each component of the power plant must be able to work properly even during highly instationnary regimes (start-up, loading, unstoring, shut down) Each component has to be dimensioned based on a worst case scenario which usually corresponds to a transient regime. 12
Dimensioning of a solar plant Large scale dimensioning : for a given steam turbine, how large should be the solar field? The thermal storage? Economical optimization based on annual performance. The power plant is always in transient regime. An accurate performance estimation can only be led with a dynamic software Small scale dimensioning : pumps, tanks, pipes, etc. Technical dimensioning based on worst-case scenario. Worst case scenarios can be very diverse : cold start of the turbine, clouds, most intensive loading, defocussing, long shut down of the plant, 13
APROS (advanced process simulation) Developpers Fortum Nuclear Services Ltd. VTT Technical Research Centre of Finland Designed for study of nuclear plants. APROS: dynamic simulation tool for transitory processes: eg: start-up/shut down of power plants (emergency shut down is also possible) 06.03.2013 14
Fields of application for APROS 06.03.2013 15
APROS structure GRADES (grafical user inteface, flowsheet): drag and drop of elementary components Drawing of connections Input of all parameters Résults : process flow diagramm Output of all variables at any time possible Flow Diagram: usual procedural components (heat exchangers, piping, pumps, turbine, compressor, valves,... Electrical component (motors, generators, transformers,...) Automation: Regulator Check controll system 16 06.03.2013 APROS enables the modeling of small subsystems to complete systems
APROS structure 17 06.03.2013
APROS skills Apros options: Simulation of flow and heat transfer processes and combustion processes 6-equation model (water / steam) for 2-phase flows Solution of momentum, mass and energy balance for each phase Fluids (air, various gases, steam / hot water, solid fuels) 19 different component materials Interactions between the wall and phases between both phase (heat transfer, friction, flow patterns)) Time course of the physical variables (p, v, T...) at any point in the network Local spread of disturbances within the system Long duration simulation Simulation speed Real time (complex 2-phase systems) 30*real time (quasistatic evolution) 18 06.03.2013
Results in APROS 19 06.03.2013
Results in APROS 20 06.03.2013
Modeling : solar receiver Receiver = simple heat pipe Injection of solar power minus heat losses, which depend on wind, tube temperature & air temperature. Flow model : 6 equations 21
Optical & thermal performance Optical performance calculated with an internal software developed by CNIM Thermal losses were calculated with a CFD simulation on Starccm++ 22
Modeling : solar field 23
Modeling : recirculation boiler 24
Example of a simulation on APROS Simulation led for a theoretical 9MW power plant in Llo (~5km south from Odeillo) Saturated steam at 70 bar, with an air condenser as cooling source. 1h storage consisting of 3 steam drums. Turbine works in sliding pressure. Fixed price of electricity -> we store only what can t be sent to the turbine. 25
Flow diagramm of example solar plant 26
Input data 2 7 1-3 july : CIFRE #7
Results : pressure in power plant 2 8 CIFRE #7
Results : steam mass flows 2 9 CIFRE #7
Results : liquid water mass flows 3 0 CIFRE #7
Results : mass flow from turbine extractions 3 1 CIFRE #7
Results : mass flows in solar field 3 2 CIFRE #7
Results : valves positions in solar field 3 3 CIFRE #7
Results : temperatures in solar field 3 4 CIFRE #7
Results : Pressure at turbine outlet 3 5 CIFRE #7
Results : water levels CIFRE #7
Results : power consumption 3 7 CIFRE #7
Results : turbine power 3 8 CIFRE #7
Conclusion APROS is a performant simulation tool for dimensioning a solar plant and validating its regulation. But it can be a helpful tool for research & development too : Direct superheated steam generation Thermal Energy Storage 39
Flow diagramm of superheated cycle 40 Sensible storage Superheater latent storage boiler CIFRE #9
Superheating field in Apros 41
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