The Solar Furnace
Milner was keenly interested in working not just with academics but also with workshop technicians, engineers (the designers) and industrialists. He was of the opinion that good scientists should not look down upon technologists and engineers but work in partnership with them. His ideal models were MIT and CalTech in the USA and so he thought it was a mistake when the words ‘of Technology’ were dropped from his University’s name in 1959.
The construction of the Solar Furnace in 1962 was a prime example of such a collaborative effort, as was the smaller pilot solar furnace built at the UNSW Broken Hill campus. Under Milner’s direction, the remarkable project involved the School of Physics and its workshop, a team of engineers and manufacturers. A co-sponsor was the industrial firm, Ralph Symonds Limited under the leadership of Ralph Symonds himself. At the time they were specialists in the new medium of plywood (they also contributed to the construction of the Sydney Opera House). Sadly Symonds died in a freak boating accident shortly before completion of the solar furnace which affected the elegance of the final design in many ways.
The main feature of the solar furnace was a 15.2M (50 ft) high tower housing a 3.7M (12 ft) diameter paraboloidal mirror. A flat mirror (heliostat) on the ground reflected light up into the paraboloidal mirror which focused reflected sunlight into the core, producing temperatures as high as 3 000 degrees C.
The School of Physics’ Solar Furnace was completed in 1961 and was used until the early 1970’s for the investigation of materials at very high temperature. It was the first of UNSW’s early projects using solar energy- capturing and concentrating solar radiation for research purposes. Today, the University is a world leader in developing solar technology as a renewable energy source for common use, notably its solar cell research and manufacture.
The opening of the Ralph Symonds Solar Furnace of the School of Physics on 2 November, 1962. It was named in honour of the company owner who tragically died before the furnace was completed. His widow attended the opening as guest of honour. From left, Professor C. J. Milner, Mrs Symonds, Pro-Vice-Chancellor Professor R. H. Myers, Deputy Chancellor Dr R. J. Webster and Mr A. Robb (Managing Director of Ralph Symonds Ltd) standing.
Above: Professor Kit Milner in the cabin of the solar furnace. Solar radiation reflected downwards by the concave mirror above converge on the ‘hot spot’ where samples are heated to temperatures of 3 000 – 4 000oC. The veiling roller blinds control the area of paraboloid in use. Courtesy, UNSW Archives CN485-14
Opening of the solar furnace on 2 November, 1962. From left, Professor C. J. Milner, Mrs Symonds, widow of Ralph Symonds, Pro-Vice-Chancellor Professor R. H. Myers, Deputy Chancellor Dr R. J. Webster and Mr A. Robb (Managing Director, Ralph Symonds Ltd) standing. Courtesy, UNSW Archives CN945-52-1
A heliostatic mirror was controlled by a hydraulic system tilting the flat mirror to track the sun. The heliostatic mirror was composed of aluminium coated resin tiles that reflected solar radiation up into the parabolic mirror above.
The paraboloid mirror (3.7M, 12 ft diameter) was composed of 162 mirror segments arranged in concentric circles to form a concave mirror that concentrated solar radiation to a focal point. The mirror segments were cast from resin and the surface made reflective by a coat of vacuum evaporated aluminium. This technique was patented by UNSW. One of these segments is on display in the exhibit at New College Village.
The Solar furnace is partly completed with the upper laboratory not yet in place. The eye-catching furnace was located at the Western end of the Heffron building (then Chemistry, now the Australian School of Business). The site is now a car park. Photo courtesy of Mitchell Library, State Library of New South Wales
The ‘hot spot’ of the solar furnace where samples were tested in the crucible. Courtesy, UNSW Archives CN1000-6-2
Temperatures in the solar furnace could reach 3 000 - 4 000oC. The furnace enabled the study of samples at very high temperatures with minimal contamination.
Courtesy, UNSW Archives CN1000-6