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Total pipe length increases, including the height difference
between indoor and outdoor units.
Reduced installation space for outdoor units.
Continuous heating during defrost mode.
Incorporation of heat recovery technologies.
Simultaneous heating and cooling.
Variable refrigerant temperature technology.
Improved oil management systems.
Auto dust removal from the Condensing units.
High Corrosion Resistant outdoor units.
Diverse control options, including the incorporation of 3rd
party controls.
Hybrid VRF using H 2 O in lieu of refrigerant in occupied
spaces.
New R32 refrigerant with reduced GWP.
All VRF brands have included Air Handling Unit (AHU)
solutions within their product offering allowing the clients
to have custom designed AHUs by using the VRF electronic
expansion valve kits (EEV) with their matching control
modules to achieve the required capacities. This has
allowed local manufacturers like HC Heat Exchangers to
take advantage of the latest VRF technologies within their
AHUs and hybrid rooftop packaged units. “This is one of
the new technologies that the engineers like,” says Thomas
Aphane, sales engineer at Johnson Controls.
Dedicated Outdoor Air Systems – (DOAS) Rooftop units
with VRF are also available.
Technological
improvements
around the
system have
led to an
enhanced
operation.
40
CHOOSING VRF
The performance and efficiencies of these types of systems
are some of the reasons why such systems are popular,
VRF systems are installed in varied applications like office
spaces, lobbies, auditoriums, hospitals, banks, retail,
technical facilities, etc. Brotherhood unpacks this, “typically,
many buildings today rely on several separate systems for
heating or cooling for year-round comfort, ventilation for
high quality environments, and efficient production of hot
RACA Journal I April 2020
Feature
A hybrid double door VRF unit.
water. As a result, energy is wasted. To provide a much more
efficient alternative, VRF technology has been developed
into a total solution managing up to 70% of a building’s
energy consumption giving large potential to cost saving
with advanced controls for maximum operating efficiency”.
He adds, “all indoor units have VRT which modulates the
saturated evaporating temperature according to the load and
certain indoor units have motion sensors that detect human
occupancy which will automatically shut down the unit when
no occupants are detected in a room. This unique mechanism
achieves more sustainability in the long run, as end users
save on energy costs while reducing their system’s carbon
emissions. The outdoor units have a very good power factor
which results in less reactive power being drawn from power
transformers. This, importantly, does not mean that a system
will use less power, but rather it reduces the strain on the
supply transformer”.
Chettiar argues, “the popularity of this technology can
be attributed to advanced controls philosophy coupled with
great training provided to consultants and contractors by
the different VRV/F brands. The majority of the brands have
excellent training facilities and have become key stakeholders
in industry training and overall upliftment of skills”. Daikin
is one such brand as it believes that this raises the level of
competence in the industry and ensures the end user can be
confident that installers have been professionally trained.
“Further to this and for more peace of mind, Daikin technicians
work closely with installers by doing pre-commissioning checks
during the installation and prior to Daikin commissioning of the
systems. Installation of VRF systems can be implemented floor
by floor, so that sections of the building can be put into use
very quickly thereby enabling the air conditioning system to
be commissioned and operated in stages, rather than on final
completion of the project,” Brotherhood says.
Looking at the quality of the systems, Chettiar adds that
VRF condensing units are designed and manufactured in world
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