Professionals who care
MICHAEL YOUNG
Michael Young is a trainer , coach and mechanical engineer in the HVAC industry . He graduated from the University of the Witwatersrand in the field of Mechanical Engineering ( B . Sc . Mech Eng .) in 2008 and qualified as a Professional Engineer ( Pr . Eng ) in 2013 . Michael is passionate about promoting knowledge and helping other young engineers grow within the industry through his training workshops and coaching sessions .
HOW GEOGRAPHICAL LOCATION AND APPLICATION CAN AFFECT THE DESIGN OF AN HVAC SYSTEM :
By Michael Young
Temperature , humidity and Covid 19 – what do they have in common ?
PART 2 had an interesting discussion on a Linkedin group to learn
I how the HVAC industry is currently dealing with the Covid-19 pandemic .
The discussion moved from filtration , to the use of UV-C lamps , to 100 % fresh ambient air flushing of an entire building . After delivering my fair share of recommendations , one person reached out to me and asked about the impact of using a 100 % fresh air system as a viable solution .
The discussion actually turned into a full- blown interview with many questions being asked and I thought I would share the results of this interview with you in this month ’ s publication .
Q : Michael , what do you think is the best option to deal with the Covid-19 pandemic ? A : I consulted with some publications from the ASHRAE website and unfortunately there is no clear way forward . Right now , the industry is implementing the use of primary and secondary filters as one solution . Use of UV-C lamps is another solution while the final solution is to provide 100 % fresh air flushing of the room . I personally feel that 100 % fresh air flushing is not the best option .
Q : Why would you say 100 % fresh air flushing of a building is not the right way forward ? A : Well , when we flush 100 % fresh air into a building , we need to condition all the air to a specific setpoint . So , if we were dealing with a very hot and humid climate we would have to sensibly cool and dehumidify the air in summer conditions . For winter operations , we would have to heat and possibly humidify the air depending once again on the ambient winter conditions . a temperature that is below its wet bulb temperature . In some instances , the dew point temperature is so low that you can ’ t introduce the air into a room as occupants within the room will complain that the air is too cold . So , we will need to first dehumidify the air then reheat it to a temperature that is comfortable .
Q : Does this not this result in more energy being used ? A : Absolutely ; so when working with a 100 % fresh air system , sensible , latent and possibly heating loads increase . This results in a cooling system that consumes more high cost energy .
Q : In your opinion , should we not introduce fresh air into our HVAC system ? A : We must introduce fresh air in accordance with SANS 10400 standards and according to the application . For comfort cooling such as offices and gyms , consult with SANS 10400 standards . If you are positively pressurising a room for a data centre , then you will have to introduce fresh air to maintain a 5Pa pressure difference . So , I would recommend that fresh air be introduced according to the desired outcome and application .
It was great sharing this interview with you . Join us next month where we will discuss how ambient air conditions can generate critical alarms within your HVAC system . You won ’ t want to miss it !
Wishing you a successful month ahead and chat soon . RACA
Michael can be contacted on michael @ myhvaccoach . com or 073 171 2311 for any questions or HVAC training needs .
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Q : Why is dehumidification so important and what impact does it have on the design of the cooling system ? A : To dehumidify the air , we first need to sensibly cool the air to
RACA Journal I January 2021 www . hvacronline . co . za