The Stirling engine as an alternative for energy ... · PDF fileTarget function used by our GA...
Transcript of The Stirling engine as an alternative for energy ... · PDF fileTarget function used by our GA...
The Stirling engine as an alternative for energy production from biomass
Stirling Engine - 2006© Enernova Stirling
Enernova Stirling Srl
● Enernova Stirling profile.● The Stirling Cycle.● The Enernova Stirling Project:
● Project phase.● Construction phase.● Main Characteristics.
● Market.● Conclusions.
The Stirling Engine – 2006© Enernova Stirling
Index
● Founded in 2003.● Has 2 main shareholders:
– Sanitaria Scaligera Srl, Italy– Beniamino Benato, physicist.
● Mission: highly optimizing the Stirling engine, to economically produce electric power from biomasses (predominantly wood).
The Stirling Engine – 2006© Enernova Stirling
Enernova Stirling Srl
● 2 full-time employees:– Dr. Beniamino Benato, physicist – Dr. Francisco Yepes, programmer
● 1 part-time employee – Alessandro Zuccato, general manager
● External consultants :– Engineer Gianantonio Cestari (mechanical designer).– Engineer Dr. Carlo Sordelli (agricultural agent).– Engineer Simonetti, (special materials expert).
The Stirling Engine – 2006© Enernova Stirling
Enernova Stirling SrlManagement Team
● First patent in 1816 by Robert Stirling.
● Made of two parts, with different temperatures.
● In the hot part the working fluid expands, while it is
compressed in the cold part.
● Isothermal expansion and compression (t=constant).
● The mechanical work done equals the net difference
between the heat absorbed in the hot part during
expansion and the heat released to the cold part during
compression.The Stirling Engine – 2006
© Enernova Stirling
The Stirling Engine
● High efficiency: an ideal Stirling Cycle has a maximum theoric efficiency.
● Low emissions.● No dependency upon particular fuel characteristics or
particular fuel quality.
● Silent.
● Reversible.● It is one of the few possibilities for the
economically convenient production of electric power from biomass.
The Stirling Engine - 2006© Enernova Stirling
Advantages of the Stirling Cycle
● Use of advanced optimization techniques (genetic algorithms) for dimensioning.
● Configuration study for maximum
thermodynamic efficiency.● Designed explicitly to use biomass fuel. ● Advanced technical and design solution (operating
conditions, material research).● Thermodynamically- optimized design.
The Stirling Engine - 2006© Enernova Stirling
Enernova Stirling’s Project
● Use of Genetic Algorithms to study the mathematical space of the parameters governing a Stirling engine.
● Steady-State Genetic Algorithm.
● Multi-Objective Genetic Algorithm with two objectives:– Minimizing the difference between the power generated
by candidate solutions and the desired solution given as an input;
– Maximizing thermodynamic efficiency.
The Stirling Engine - 2006© Enernova Stirling
Genetic Algorithm Dimensioning
● Target function used by our GA is given by Martini’s isothermal sizing procedure (Stirling Engine Design Manual, William R. Martini, University Press of the Pacific, 2004).
● Our GA has been applied to the example given by
Martini, obtaining efficiency improvements during
sizing exceeding 6% for the same output power and
using the same working fluid.
The Stirling Engine - 2006© Enernova Stirling
Genetic Algorithm (GA)Target Function
● Enernova Stirling proposes an Alpha configuration which ensures, in principle, an high thermodynamic efficiency.
● For this purpose, two cylinders are used, a hot one and a cold one, to reduce as much as possible the inefficiencies due to the proximity of hot and cold parts.
The Stirling Engine - 2006© Enernova Stirling
Maximum Thermodynamic Efficiency
● The Enernova Stirling engine structure has been expressly designed to use biomass as fuel.
● For this purpose combustion chamber conditions and heat exchanger configuration have been expressly designed to work with biomass combustion exhaust fumes.
The Stirling Engine - 2006© Enernova Stirling
Biomass-Fuel optimized
● Enernova considers 3 engine configurations:
– ~3-5 kWe: Home use ;
– ~20 kWe: Residential / Condominial use (first prototype engine will be a 20 kWe unit)
– ~160 kWe: Industrial applications.
The Stirling Engine - 2006© Enernova Stirling
The Enernova StirlingProject
● Working temperatures: 650-800°C● Mean pressure: 19.7 atm @ 800°C● Extreme pressures: 13.8 atm-28.8 atm● Speed: 600 rpm● Electric power: > 20 kW● Fluid temperature in the hot part: 782 °C● Fluid temperature in the cold part: 85 °C● Carnot’s Limit: 66%● Real Engine Efficiency: > 32%
The Stirling Engine - 2006© Enernova Stirling
The Enernova Stirling Engine
Il motore Stirling – luglio 2006© Enernova Stirling
The Enernova Stirling Engine Design Phase
Fully CAD designed.
Dimensioning optimized using genetic algorithms.
Design phase fully completed in Q2/2006.
Il motore Stirling – luglio 2006© Enernova Stirling
The Enernova Stirling Engine construction
20 kWe prototype almost 100% complete as of Q2/2006.
Full prototype tests will be completed by Q3/2006
The Province of Mantova has already ordered a complete 80 kWe plant
The Stirling Engine - 2006© Enernova Stirling
A Possible Scenario
Module type (power) 161kWeBiomass consumption 160 Kg/hFuel to electricity efficiency > 22%
Working hours per year 7500kWhe produced per year 1,207,967 kWhe/yearkWhe produced during plant life 6,039,833Biomass consumption per year 1200 tons/yearBiomass productivity 35 tons dry substance per hectareCultivated hectares for biomass production 34
● High fuel-to-electricity transformation efficiency (>22%).
● Unsupervisioned, automated working mode possible
● Transportability ( 2 x 40’ containers).● Low maintenance costs.● Does not require expensive and complex auxiliary
systems.● Limited system costs (< 2000 € per installed kWe )
The Stirling Engine - 2006© Enernova Stirling
Competitive advantagesof our system
● No significant environmental impact:– Conforms to low atmopspheric emission laws– Low quantities of inert residues (ashes), – Silent running, – Small size
● Can use other combustibles:– Biogas,– Painting plant residual gases, – Refuse Derived Fuels, – Oils
The Stirling Engine - 2006© Enernova Stirling
Competitive advantagesof our system
● Possibility to locate the plants near biomass production sites (small and medium agricultural industries, wood industry, etc.)
● Long service life thanks to low rpm working regimes and high quality, high-tech materials.
The Stirling Engine - 2006© Enernova Stirling
Competitive advantagesof our system
● The system helps transforming food farming in non-food farming,so farmers can increase their income.
● It favors the development of local resources and makes territory less dependent on non-renewable energies.
● It can be used in underdeveloped countries ● It may allow the development of small and medium
technologically advanced industries for the production of system parts and components.
● It creates diffused occupation for production, sale and assistance of the systems
The Stirling Engine - 2006© Enernova Stirling
Added Social Value
● Enernova Stirling is now completing and testing the prototype.
● All tests and experimentation are expected to be completed by Spring 2007
● Production is scheduled to begin in Spring 2008.
The Stirling Engine - 2006© Enernova Stirling
Actual state of the development process
● We expect a market for transformation of farming from cultures food to energetic cultures.
● As an example, if the 35% of food production in province of Verona was transformed to energetic cultures, there would be the possibility to install about 700 160-Kwe plants in 10 years.
● Said plants would produce about 110 MWe, corresponding to the power used in residential district of Verona.
● It is reasonable to believe that the same proportion is valid on a national and European scale.
The Stirling Engine - 2006© Enernova Stirling
Market dimension
● The short-term market is composed of medium agricultural industries that want to convert part of their productions to energetic cultures.
● The long-term market remains related to the conversion of biomasses to energy, (e.g. residues of agro-industrial productions and wood industry).
● An important part of the market will be composed of other industries (such as painting plants, and ceramic tile industry) which want to recycle their high temperature gas residues, valorizing them.
The Stirling Engine - 2006© Enernova Stirling
Market targets
● Fine-tuning a Stirling engine is a very complex task, both scientifically and from an engineering standpoint;
● Designing an efficient Stirling engine allowing an economically-interesting use of biomass is still an open problem.
● Solution requires state-of-the art knowledge of physics, engineering, material science and toolworking.
The Stirling Engine - 2006© Enernova Stirling
Stirling & Research
● From an economic standpoint, a project to design and build a Stirling engine requires adequate financing to conclude all prototypal phases and appropriately resolve all engineering problems.
● This perspective includes the study of different sizes and assembly configurations.
The Stirling Engine - 2006© Enernova Stirling
Stirling & Research
● Stirling technology is greatly interesting from the technical standpoint.
● Upon market liberalization, it could become a suitable candidate to produce energy from renewable sources (e.g. biomass)
● As of today, there is no definitive “Stirling solution”. This makes it an interesting investment, but requires an economical and technical research effort.
The Stirling Engine - 2006© Enernova Stirling
Conclusions