Letter to the editor
HEAT PUMPS/REVERSE CYCLE SYSTEMS
I don’t want to go into details of reverse cycle systems and
restrict my comments to the use of cooling only functions.
Just to mention here, the biggest sales pitch rubbish is that
the systems are advertised with power savings, which are
only possible when heating is unlikely to be needed. Outside
conditions are never quoted in wet-bulb temperature (WBT)
and so on – another subject for another day.
VRV SYSTEMS
It is interesting to note that VRV systems became very popular
using indoor units as discussed above, but they have the
same shortcomings. The advantage lies in the outdoor unit
having better power factors and that they can be installed at
distances where noise and serviceability is improved. Zoning
is possible when typically interior zones require cooling while
exterior zones require heating with excellent power savings in
such cases.
ZONING
The only advantage of split systems could be zoning? In short,
the engineering science has left the industry and has been
replaced by the ‘bakkie and ladder brigade science’.
SERVICE/MAINTENANCE/INSTALLATION
The tools and quality of the ‘bakkie and ladder brigade
(technicians)’ arise as a result of the split system dilemma.
How and when the systems are installed can or can’t make it
possible for them to be serviced or repaired.
Condensing or outdoor units are sometimes installed
at 10 or more metres above the ground and indoor units at
heights over permanent seating arrangements like conference
centres or cinemas, where the floor can be at an angle. Such
installations are a nightmare to get to.
Outdoor units installed inside are sometimes hidden away
in spaces with very limited ventilation. I could go on and on
with examples of crazy installations – enough to fill up books.
Pipe sizing does no longer consider oil return, distance,
height of indoor unit above the condensing unit, or pipe wall
thickness when using R410.
Lifetime of equipment depends on the usage, installation
and environment it’s operating in. If it fails or it was bought in a
supermarket, obtaining spares or lack of knowledge of how to
repair can be greatly problematic too.
These above points only touch on the subject, which is in
fact enormous, leading to the question – “What has become of
our industry?” RACA
www.hvacronline.co.za RACA Journal I October 2020 47