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in a building there is nowhere to put it, because you have to
reject and expel the cold air from the evaporator.
“Separating the evaporator means it can be put anywhere
– up to 50m away from the condensing unit. The design for
these evaporators is also flexible – they can be either vertical
or horizontal discharge, standing or hanging from the soffit.
Fan motors are all fitted with speed control devices which
not only help with electrical savings but also increase the
lifespan of the motors. These units have also been designed
with a wider fin spacing than the imports allowing us to run
at lower ambient temperatures without having to defrost an
iced-up coil,” says Lowe.
“We have been experimenting with various additional
energy-saving and efficiency increasing designs – one of
which is the sub-cooling of the hot refrigerant using the
evaporator coil – removing heat from the liquid line and
transferring it to the evaporator is a win–win, increasing
efficiency of the evaporator functioning and adding up to
35% capacity to the output of the heat pump. We have also
replaced these air / refrigerant type evaporators with water/
refrigerant designs – this gives us the ability to install a fully
self - contained unit in a basement boiler room and then
have many options for harvesting heat from other sources –
such as AC or refrigeration plants or solar heating systems.
“The heating component of these ‘split units’ have an
exceptionally small footprint – a single unit that is 3m x 1m
wide for units up to 500Kw, allowing us to find space in
any building.”
The Bramley system also requires a pressure pump set to
boost the pressure of municipal water to the development,
because of frequent pressure drops within the Bramley area.
“The municipal water is fed into a holding tank, and then
pumped out at the correct water pressure to supply both
hot and cold water to the entire development. The capacity
of the tanks at the moment is 12 000ℓ, but we are adding
an additional 40 000ℓ outside. The 12 000ℓ is sufficient for
the existing units, while the additional 40 000ℓ will provide
for Phase 2 as well as reserves. This means if the municipal
water supply goes down, the complex has 52 000ℓ litres to
keep it going.”
The system brings a number of efficiencies to the
development, says Lowe, primarily constant hot water at a
considerably lower cost. PA
April 2020 Volume 26 I Number 02
The rooftop evaporator at The Village, Bramley.
www.plumbingafrica.co.za