www . refrigerationandaircon . co . za RACA Journal I November 2023 27
Feature chiller ’ s operational life ,” says Bands . However , he notes that there is still a section of the market that prioritises low upfront costs over long-term performance and maintenance .
Trane is at the forefront of these technological advancements and has dedicated itself to reducing carbon emissions from its products . It has been actively promoting and implementing these new generation chillers in their product lineup in recent years . “ The industry is moving towards the use of refrigerants with lower GWP . In Europe , there is legislation in place to phase out HFC refrigerants in favour of HFO refrigerants . In addition , in countries like South Africa where such legislation is not yet as aggressive as Europe , some environmentally conscious organisations nonetheless choose to adopt more environmentally friendly options voluntarily .”
Regarding chiller types , there are two main options : watercooled chillers and air-cooled chillers . Water-cooled chillers employ cooling towers to reject heat by circulating water and using evaporation and a fan for cooling . On the other hand , aircooled chillers rely on condenser coils , similar to car radiators , to exchange heat with the ambient air .
In terms of pros and cons , water-cooled chillers are generally more energy efficient due to the superior heat transfer properties of water . However , they require additional equipment and maintenance , which can result in higher operational costs . They also consume more water , which may be a concern in certain environmental contexts .
“ On the other hand , air-cooled chillers have a simpler design and lower maintenance requirements . They do not rely on water resources and are generally easier to install . However , their efficiency may be lower , especially in warmer climates where ambient air temperatures are high . In recent years , there has been a trend towards designing systems with air-cooled chillers instead of water-cooled chillers , particularly in Johannesburg . This shift is driven by considerations of environmental impact , maintenance costs and energy efficiency . Air-cooled chillers can be more efficient in low ambient temperatures and require less water consumption over a 20-year span .”
CHILLERS AS OPPOSED TO A VRF SYSTEM The choice between a chiller and VRF system depends on the specific requirements of the project . For smaller buildings , like
© RACA Journal
Chillers vs VRF : VRF systems require small plantroom spaces and can easily by hidden behind facades , within service levels or on small platforms .
two- or three-story structures of individual offices and retail centres , a VRF or individual units may be more cost-effective .
Chilled water systems , on the other hand , are better suited for larger commercial and industrial applications , such as manufacturing facilities and hospitals , where a higher capacity for cooling is required .
In addition , for larger buildings with diverse cooling loads and requirements , such as ones with double or triple volume spaces – like a big reception area or conference facility – then a chiller is more accurate and efficient in meeting specific cooling requirements . Despite being more expensive to install , chilled water , running steel pipes and pumping water around the building is easier , compared to running copper pipes and pumping refrigerant . Furthermore , for hospitals , hotels or larger office complexes , running water becomes more feasible as it is easier to repair and handle a water leak compared to a refrigerant leak .
“ One key difference between VRF and chilled water systems lies in their primary purpose . VRF systems are primarily focused on providing comfort cooling and heating for people in an environment ,” adds Bands . Chilled water systems can be used for a wide range of applications beyond comfort cooling , including industrial processes and data centers .
AHI Carrier
Some chillers can use free cooling with seasonal conditions – such as during winter times when ambient temperatures are normally lower .
www . refrigerationandaircon . co . za RACA Journal I November 2023 27