FEATURES
47
“Mines utilise
extremely
large heat
pumps due to
the demand
for substantial
volumes of hot
water in their
staff shower-
houses.”
Large heat pump located at Sun City.
an existing geyser, it can be retrofitted to accommodate a
heat pump. Although the savings on monthly electricity mean
the residential pay-back period may be 18 to 26 months,
the retail market tends to find this too long. Furthermore,
it requires annual maintenance which adds perhaps
another month a year to the pay-back. With Eskom’s rebate
programme that had temporarily reduced.
Performance criteria
“The most important effect of the performance of a heat
pump is the planning and design of a heat pump system,”
says Sascha Altmann, managing director: Stiebel Eltron
Southern Africa. “In a proper heat pump plan, you have
to consider two very important facts: the input- and the
August 2019 Volume 25 I Number 6
output-parameter. The input parameter consists, for
example, of the ambient conditions that the system has to
operate within, such as temperature and humidity, which
have a great impact on performance. The output parameter
describes the requirements of the specific project, like the
amount of domestic hot water required; is space heating
or space cooling required via the heat pump; or does the
client want to heat his pool with the same device? Also the
intelligence of the heat pump controller is important. You
need an intelligent controller that runs the system in the
most effective way. And last but not least, the installer has
a significant influence on the performance. A heat pump
is only as good as its installation: Pipe distances must be
kept as short as possible; and the pipework needs a proper
www.plumbingafrica.co.za