Canberra's Afterlife. Highpressure Crystals and the Bush Capital Dream

Canberra, the ?Bush Capital? of Australia, was a project torn between ambition and avoidance. For fear of upsetting Sydney or Melbourne, its location avoided larger territorial aspirations but its crystalline winning scheme was bold, and contained the promise of enlightened irradiation. Postwar Canberra, like so many other cities at the time, let its future be designed by Cold-War traffic engineers, who confidently turned dream into sprawl and highways. Although Canberra s mix of ambition and banality, of symbolic desire and structural normalcy, may be precisely what a good city is all about, it probably contains these in defective proportions. What Canberra needs is just a little more of itself, in different amounts, to a higher pressure from the inside. We can easily imagine the multiplying of the original Griffin plan, adding the city onto itself, organizing the recent sprawl with new nodes and public transport with more urban streets between them. With this reclaimed space for higher density, Canberra can then grow from the inside instead of sprawling away, lowering its expenditure on transport and its carbon and sustainability footprint. The new nodes will be denser and allow for variety and change in its programmatic design. Minor but detailed changes in street and public space design will also allow for easier multi-species (people, animals?) access to urban and natural resources. Video brief of the project: http://vimeo.com/45799435

Effect of soiling in CPV systems

The effect of soiling in flat PV modules has been already studied, causing a reduction of the electrical output of 4% on average. For CPV's, as far as soiling produces light scattering at the optical collector surface, the scattered rays should be definitively lost because they cannot be focused onto the receivers again. While the theoretical study becomes difficult because soiling is variable at different sites, it becomes easier to begin the monitoring of the real field performance of concentrators and then raise the following question: how much does the soiling affect to PV concentrators in comparison with flat panels?? The answers allow to predict the PV concentrator electrical performance and to establish a pattern of cleaning frequency. Some experiments have been conducted at the IES-UPM and CSES-ANU sites, consisting in linear reflective concentration systems, a point focus refractive concentrator and a flat module. All the systems have been measured when soiled and then after cleaning, achieving different increases of ISC. In general, results show that CPV systems are more sensitive to soiling than flat panels, accumulating losses in ISC of about 14% on average in three different tests conducted at IESUPM and CSES-ANU test sites in Madrid (Spain) and Canberra (Australia). Some concentrators can reach losses up to 26% when the system is soiled for 4 months of exposure.

Feature issue introduction: light, energy and the environment, 2014

This feature issue highlights contributions from authors who presented their research at the OSA Light, Energy and the Environment Congress, held in Canberra, Australia from 2-5 December, 2014.