Construction World March 2015

ENVIRONMENTAL ENGINEERING

Before setting out to design a ‘solar-friendly’ building, it is important for architects as well as the contractor, engineers, electricians, roofers and other installers associated with the project to have a clear understanding of the responsibilities of each party in the building process.

Integrating solar panels into the design of a building.

Nonetheless, the advantage of BIPV systems over more common non-integrated alter- natives is that the initial cost can be offset by reducing the amount spent on building materials and labour that would normally be used to construct the part of the building that the BIPV modules replace. BIPV modules should be situated towards the north side of the main building. Siting is obviously best confirmed at the design phase which should also address any shading obstacles (neighbouring buildings and trees, for example) that might prejudice the final installation. There is a logical combination between shading a building in summer and producing electricity at the same time. Architects who recognise this have produced examples of BIPV shading systems for entrance protec- tion, and many analogous systems for similar applications. PV systems can also be part of the thermal envelope of a building. One of the by-products of solar energy production is heat radiating from the back of the solar cells which can be channelled and put to good use for winter heating, particularly if provision is made at the design phase. While the use of solar energy during daylight hours is becoming more cost-ef- ficient as electricity prices climb – with paybacks for a complete installation of between three to four years – its use during the hours of darkness (or on cloudy days) presents a number of challenges. Assuming excess solar energy is not returned to the national grid (unapproved as yet in South Africa) it can be stored on-site in battery packs to obviate loss. While a simple procedure, this tends

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industry once incentives become available to consumers, perhaps there is a challenge for South Africa’s training institutions to establish some sort of formal installers’ accreditation or certification programme to help newcomers to this fledgling industry gain knowledge and experience. There is also a challenge for law-makers to mandate distinct electric circuitry spec- ifications for solar PV installations which should incorporate safety elements such as accessible isolation switches which can be thrown by anyone in the event of faults. Solar PV technology is seen an ideal hedge against electricity price rises which seem inevitable in South Africa. There remain countless new ways for solar PV to be developed and optimised. Many are sure to lead to new architec- tural concepts, many in combination with other types of renewable energy resources, going forward.

to be one of the more costly elements of a comprehensive solution. This is because solar PV systems require more robust deep-cycle batteries which have a different physical construction for longevity compared to conventional automotive batteries because of the nature of the charging and discharge profile. Retro-fitting batteries Retro-fitting batteries to a solar installa- tion is not as straightforward as it may appear. Ideally batteries should be stored in an outdoor-facing, well-ventilated battery enclosure and not simply placed haphaz- ardly in the building. So energy storage is best addressed at the design and implemen- tation stage. Towards incentives With the expected mushrooming of the

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