Feature
Continued from page 25
but nevertheless , a mode that would be more necessary in certain geographical regions above others during seasonal fluctuations .
The major advantage of unitary systems is that , above the ease of installation of such units today , all components can be contained in one “ cabinet ” ( eg : a rooftop unit ) or they can be housed in two “ cabinets ” ( eg : a split system ). The indoor unit of a split system contains the space conditioning , filtration , and air movement components , and the outdoor unit houses the heatrejection devices .
Some other features of unitary systems may include any of the following :
• A smaller equipment footprint than central air handlers , chillers , or boilers .
• The ability to install heat rejection units outdoors , which reduces indoor space requirements ( although depending on environmental and security factors this may open possible vulnerability to severe weather conditions or vandalism ).
• One also has the ability to install heat rejection units in smaller indoor spaces ( attics , ceiling voids , etc .) or on rooftops ( here service accessibility / maintenance must be considered ).
• Further , this system type may be used for installations with many individual spaces requiring individual control .
• New technology today also allows the use of multiple indoor units to a single outdoor unit – similar to the variable refrigerant flow technology , but on smaller scale .
• Certain models of unitary equipment have special coating to mitigate the effects of corrosive or chemical impacts .
• Unit finishes come in a wide variety of styles and colours to meet aesthetic appeal or requirement .
When considering the installation of unitary equipment , the engineer or contractor would , as with other HVAC systems , need to consider the application . Here a determination of what type of conditioning is required would be established as well as the service space , so for example cooling only is required for 12 hours a day to a 36m 3 space – or five private offices located amongst an open plan setting or central closed off boardroom amidst spaces using natural ventilation , and so on .
Also , depending on location and thus humidity levels , as the natural refrigeration cycle “ dries ” the air – unitary equipment may be selected to combat humidity and address one of the most impactful elements in occupant comfort .
Unitary equipment , for the record , is not only about comfort cooling – they have several applications in a range of sectors that could include :
• Singular or remote spaces requiring control for comfort conditions of occupants
© RACA Journal | Benjamin Brits © RACA Journal | Benjamin Brits © RACA Journal | Benjamin Brits
• Certain medical or examination rooms
• Data centres , server or interchange rooms
• Libraries and document storage rooms
• Wine cellars or enclosed specialised produce rooms
AIR FILTRATION AND UNITARY UNITS Air conditioners don ' t only perform the function of keeping occupants cool - they further play a major role , in both summer and winter months , by filtering the air . In summer conditions it is common for pollen and spores to be prevalent in air and during dry winter times dust is more common as well as other particulates such as dry skin flakes . New technology has enabled unitary equipment , also referred to “ ductless ACs ” to include
A set of split units installed in a building control room .
Some applications require split unit installation as no other options are suitable or where a building structure cannot be altered .
A unit installed in a document storage room located in an underground basement .
www . refrigerationandaircon . co . za RACA Journal I November 2022 27