SOLAR FURNACE

SF-60 SOLAR FURNACE

In operation since 1991, the 60 kW power solar furnace SF60, is the oldest in service of the three PSA solar furnaces.  It consists essentially of a 120 m2 flat heliostat and a 100 m2 surface reflection parabolic concentrator.

It is mainly devoted to surface heat treatment of materials, both metallic and ceramic. Some of the treatments carried out are: hardening, sintering, nitriding, coatings, carburizing or foaming.

Other research lines are aimed at solar chemistry experiments and the production of process heat by using receivers.

The parabolic concentrator is the main component of the solar furnace.  Its function is to concentrate incident sunlight from the heliostat, multiplying the radiant energy in focus. Its optical properties especially affect the flux distribution at the focus.

It consists of a facetted parabolic reflection surface in which focus sunlight is concentrated. Each facet is adjusted independently -canted- to reflect sunlight into the focal point of the parabola.

The optical axis of the concentrator is aligned with the center of rotation of the heliostat, forming a solar furnace type "on axis", in which the concentrator, the focal point and the heliostat are aligned on the optical axis of the paraboloid. It is composed of 89 facets of spherical shape with five different curvature radii grouped from low to high in concentric circles around the vertex of the parabola. Facets are sandwich type, silvered, and are made from two sheets of very thin glass -0.7 mm-thick of 1222.3 mm x 917.4 mm and reflectivity r = 92%, stuck in a rack metallic spherical shape.

The structure consists of a set of vertical trusses curved in arc and interconnected by horizontal beams also curved so as they configure the surface of revolution; the radius of curvature of both trusses and beams is about 15 m, double the focal length. The set, with the facets aligned, works as a paraboloid of revolution.

Tecnichal caracteristics:

  • Dimensions: 11.05 m x 10.24 m
  • Total reflections surface: 99,8 m2
  • Focal distance: 7,45 m
  • f/d ratio: 0,64
  • Rim angle: 38º
  • Focal heigth: 6,12 m
  • Focus diameter -90% power-: 26 cm
  • Total power: 69 kW
  • Peak concentration: 3000
SF-60 Solar Furnace: Concentrator (left) and receiver in operation at the focus (right).