SA Affordable Housing September / October 2020 | Page 31

ENVIRONMENT & ENERGY
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“Communication and DSTV connections, for instance, will
need UPS and back-up systems. UPSs will be important
for things that cannot be cut off, such as DSTV and Wi-Fi.
“To save money on back-up, you can include split
distribution between essential and non-essential
systems in your planning,” he says.
NON-ESSENTIAL LOADS
“Non-essential loads include those systems for which you don’t
need backup in any form. It is the part of your load that the
premises can do without while remaining operational during
mains fail conditions. An example of this might be geysers,
heaters, air-conditioners, pool heating, and pool pumps, which
are not essential.” However, if you lose your utility supply for
long periods, the situation might change, as will the definitions
of the non-essential loads.
“Lifts in a housing estate, for example, provided they are
not higher than two to three stories, and water heating geysers,
would typically be seen as non-essential, but again this will
be determined by the duration of the power outage. With
dual systems, where the distribution of power can be split:
Paraplegic lift can be seen as essential and the other lifts as
non-essential, for example.”
“To assist in understanding electrical load
needs, Oosthuizen explains that there are
at least five different segments to consider:
essential loads, critical no-break loads,
non-essential loads, energy-inefficient
loads in existing complexes, and your total
load profile over time.”
ENERGY-INEFFICIENT LOADS
According to Oosthuizen, energy-inefficient loads include
electrical elements which can be replaced by more efficient
alternatives to make the load less bearing. You can implement
energy saving with heat pumps and/or solar for geysers. If
using all roofs, you can have a great solar power element for
renewable energy.
“This lends itself to energy saving in day-to-day operations.
For example, all new geysers must comply with the new
minimum standard as set by the Department of Energy,
namely Class B, as specified in SANS 151, to ensure less
pressure on your electrical load,” he explains. In various
premises, the replacement of air conditioners and electric
heaters with the latest state-of-the-art low energy and
higher power factor technology will have quite an impact
on energy consumption. Changing older light fittings to the
newest technology LED fittings will also have a significant
impact on energy usage. Water and sewage pumps are other
considerations. In general, pumps have a very low power
factor, which means they draw higher current than necessary.
“Where premises have many pumping systems, it is worth
considering power factor correction to these loads to increase
the power factor, which will decrease the reactive power with
various cost benefits, such as lower demand charges, avoiding
reactive power penalties and freeing up distribution system
capacity,” advises Oosthuizen.
LOAD PROFILE
“When determining a development’s power supply needs,
some forethought can go a long way in ensuring appropriate
systems,” says Oosthuizen. “You should determine your total
load profile for at least a year, bearing in mind that loads are
seasonal and are changing from day to day. When determining
your load profile of existing premises, don’t only use utility
account information – this normally only provides monthly
maximum demand where applicable and energy usage.
Additionally, it is important to understand which parts of
your load can be moved to non-operational times when total
consumption is less. There are many timer and automation
technologies on the market that can help with load shifting in
order to spread the usage curve,” says Oosthuizen.
“Investing in an alternative power supply system for
a development is a good idea, but for it to be a feasible
investment you must clearly understand your load
requirements before making any decisions. Knowing what you
have is the critical first step to knowing what you need next.
Analysing this resultant need for alternative power supply
solutions against your potential loss/increase of sales for the
developer and energy savings for the buyer forms the essence
of your business case for investment,” says Oosthuizen.
www.saaffordablehousing.co.za SEPTEMBER - OCTOBER 2020 29