17-12-2012, 06:47 PM
Paraboloidal dish collector
1Paraboloidal dish.ppt (Size: 440.5 KB / Downloads: 29)
Power Generation
The Generation of electrical power is one of the most important application of an energy source.Solar thermal power cycles can be classified as:
Low Temp cycles(Work at max temp of about 100 deg) eg:Solar Chimney
Medium Temp cycles(Work at max temp of about 400 deg) egarabolic Concentrating Collectors
High Temp cycles(Work at a max temp above 400 deg)
Paraboloidal dish collector
Working Principle:
The parabolic reflector functions due to the geometric properties of the paraboloidal shape, if the angle of incidence to the inner surface of the collector equals the angle of reflection, then any incoming ray that is parallel to the axis of the dish will be reflected to a central point.
WORKING
Concentrator tracks the sun by rotating about two axes.
Sun’s ray are brought to a point to focus.
A fluid flowing through a receiver at the focal point is heated.
This heat is used to drive a prime mover.
Typically Stirling engines have been favoured.
Construction
Parabolic dish concentrators offer the highest thermal and optical efficiencies of all the current concentrator options
According to an analysis of normalized dish cost per unit aperture area as a function of dish radius, supports a choice of most cost-effective size b/w 400 and 1000 m2
To be most effective the parabolic-shaped concentrator needs to focus the sunlight on the receiver and hence the shape of the parabola
needs to be relatively precise