www . refrigerationandaircon . co . za RACA Journal I May 2024 9
Associations
MAXIMISING EFFICIENCY THROUGH VRF BASICS AND PROPER INSTALLATION TECHNIQUES
Edited by Eamonn Ryan
The following article is derived from an ASHRAE Journal public podcast delving into the intricacies of Variable Refrigerant Flow ( VRF ) systems , presented by Kelley Cramm , an ASHRAE Life Member and mechanical engineer with Henderson Engineers .
The presentation explores VRF systems , proper installation techniques , and addresses common misconceptions surrounding compressor failures .
VRF systems represent an innovative approach to all-electric heat pumps , providing remarkable flexibility . These systems may incorporate heat recovery , offering diverse indoor fan coil unit options , from drop-in ceiling cassettes to compact wall-mounted units and concealed ducted units . The unique feature of VRF is the ability to pipe multiple indoor units to a single set of outdoor condensing units , reducing the overall footprint .
They are highly cost-effective , particularly for spaces demanding individual temperature control , such as buildings with multiple enclosed offices . In comparison to hydronic fan coil systems or classic variable air volume systems with reheat , VRF proves to be a more economical solution . Moreover , its capacity for heat recovery makes it an energy-efficient choice . By utilising heat rejection from cooling zones to provide heat to zones in need , VRF ensures optimal performance and resource utilisation .
Supplied by AHI Carriers system design aligns with the building ' s specific requirements . Adequate training for installers and ongoing maintenance are essential components of ensuring the longevity and efficiency of VRF systems .
Multiple VRF heat recovery systems with a central control . Multiple Light Commercial cassettes units , high wall units and ducted units which are also connected to the central controller .
COMMON CHALLENGES AND MISCONCEPTIONS While VRF systems offer numerous advantages , the industry has faced challenges , primarily related to compressor failures . Routine compressor replacements have contributed to a negative perception of VRF in the market . Manufacturers , keen on maintaining customer relationships , often replace failed compressors under warranty without delving into the root cause of the failures . This practice has led to a persistent issue without a comprehensive resolution .
To mitigate the challenges associated with VRF , proper
installation techniques are crucial . It is important to perform a thorough assessment during installation , ensuring that system components are correctly matched and that the
Supplied by AHI Carriers
Numerous Teraco projects ranging from pre-treating fresh air to humidity control hybrid units . These projects utilised Light Commercial outdoor units and VRF outdoor units connected to custom built AHUs .
www . refrigerationandaircon . co . za RACA Journal I May 2024 9