SA Affordable Housing July - August 2019 // Issue: 77 | Page 16

FEATURES
Generating heat in your home
Undoubtedly the most expensive running cost for any home is
generating hot water but developers, architects and specifiers have
a wide range of options in water heating technology to choose from.
By Benjamin Brits
T
he amendments to the National Building
Regulations in 2012 stipulates that all hot water
generated annually must comprise a system that
uses 50% of any other heating technology other than
the conventional geyser / element system. These
alternative solutions (in their various forms) continue
to undergo improvements in engineering, technology
as well as efficiency.
In the affordable housing market water heating
solutions are highly important in terms of the
sustainability aspect as typically purchasers or tenants
already have limited financial resources and cannot be
burdened with unnecessary costs or inefficient
systems.
Solar heating technology through flat plat collectors (a
heat exchanger that converts the radiant solar energy
from the sun into heat energy using the greenhouse
effect), can produce up to a 60% saving on a home’s
water heating requirements, while a heat pump that
uses natural ambient air coupled with compressed gas
through a condensing unit, can produce similar
savings. These are both dependant on the time of year
whether it is summer or winter. Gas boilers have the
advantage of supplying instantaneous hot water and
are both energy efficient and water efficient.
Although to be ‘safe’ suppliers specify savings of
between 50 to 60%. “This may also be more – as high
as 90% – as South Africa generally has the ideal
circumstance to be able to maximise our climate
conditions,” says Laetitia Botha, mechanical engineer
at Energas South Africa.
The developments in the solar thermal flat plat
collector models and similar solar technology now
include options to have a back-up system through
both gas and electrical elements, and all depend on
how much sunshine is available at the time. This
allows hot water to be generated even when weather
conditions are not ideal.
“If this technology can work in European countries
where they are on the forefront of these technologies
and have much softer sun, it can work without a doubt
in South Africa. Also, as with products such as the
Viessmann range of solar technology that Energas
supplies, because of the intensity of the sun’s heat in
South Africa there is a likelihood of overheating and
therefore the products have a thermo-protective layer
that will switch the solar collectors off when they
reach a specific temperature. When this temperature
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JULY - AUGUST 2019
ALTERNATIVES GAIN POPULARITY
A typical flat plate collector where the storage cylinder is installed
inside the roof or on the side of the building.
is reached, changes in the crystalline structure of the absorber
layer increases the rate of heat radiation and reduces the
collector output. The Viessmann-patented technology
significantly lowers the maximum temperature inside the
collector and prevents steam formation in the solar circuit,“ adds
Nicole Viljoen, project administrator at Energas South Africa.
QUALITY OUTLASTS PRICE
In our country with the already stressed economy and further
stressed construction industry, developers seek the most
cost-effective solution, however this should not result in
installation of products which are inferior quality.
www.saaffordablehousing.co.za