Construction World March 2015

CONSTRUCTION WORLD

MARCH

2015

ENVIRONMENTAL ENGINEERING

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

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

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.

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.

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