A new high concentration solar furnace has been designed and built at Plataforma Solar de Almeria –from now on PSA- and is fully operative. This system has been designed for the testing of materials at high temperatures, at room conditions, controlled atmosphere and vacuum. This new solar furnace called SF40 –Solar Furnace 40- adds new capacities to the PSA’s High Concentration Facility, as nowadays at the PSA three solar furnaces are in operation, which cover a wide range of tests concerning thermal treatments of materials under extreme conditions and tests of small scale’s reactors and receivers.

The new SF40 solar furnace has a power of 40 kW reaches a peak concentration over 7000 suns, its optical axis is horizontal, and is of the “on-axis” type, that is heliostat, parabolic concentrator and focus are aligned on the optical axis of the parabola. Its rim angle is α= 50.3º.

It basically consists of a flat heliostat with 100 m2 reflecting surface, a parabolic concentrator with 56.5 m2 projecting area, slats shutter or attenuator, and test table with three axis movement.

Since the SF40 is a horizontal axis solar furnace, the focus is arranged on the vertical plane, and so we need to rotate 90º the beam rays incident in focus, in such a way that the tests can be carried out on the horizontal plane. That is why the facility is completed with a tilted mirror, placed in the focal area, which turn the beam to the horizontal plane, and with a vacuum chamber connected to a gas system and a vacuum unit, allowing testing in controlled atmosphere and vacuum, to prevent oxidation of the specimens during tests. 

As concentrator for the SF40, a Eurodish parabolic concentrator was chosen because of the power and high concentration achieved by these systems and their availability in the PSA.

The Eurodish concentrator consists of 12 sectors or petals of bent glass fiber to obtain the desired parabolic shape, and coated with 0.8 mm thick adhesive glass mirrors on its front surface. The sectors are joined together in such a way that they shape a surface of revolution.

The main technical characteristics of the concentrator are:

  • Surface: 56,5 m2
  • Diameter: 8,5 m
  • Focal distance: 4,5 m
  • f/d ratio: 0,53
  • Rim angle: 50,5º
  • Focal heigth: 5,55 m
  • Focus diameter -90% power-: 12 cm
  • Total power: 40 kW
  • Peak concentration: 7000
Interior of the SF40 solar furnace in its final stage of construction