Feature and walk to that gauge and see the pressure . However , we have seen a steady switch from analogue to digital over the last five to 10 years and that trend is definitely going to accelerate in the future ,” says Townsend .
Rusznyak adds there ’ s nothing wrong with the analogue technology in existing plant and people will carry on using it , as it ’ s human nature for people to want to sweat their existing assets . But when gauges are due for replacement they will most likely opt for a digital alternative .
He says the education map will have to evolve with Industry 4.0 – with less requirement for mechanical engineers and more need of people with certain software knowledge to understand how applications work . There will be need for a quick decision matrix by digital instruments – so there will be a transition in functions .
As an example , Townsend notes that one won ' t need a technician to take a reading from a gauge , jot it on a clipboard and take it back to the control room . Instead , you might need a technician to service the instrument taking the reading . They do not anticipate digitisation replacing a high number of jobs , as people will always want to speak to another person rather than a chatbot .
The impact of digitisation will be lesser for simple on-off valves , but will impact proportional valves controlling airflow , for example , according to the demand for air so as to save energy or redirect it to a high-demand area .
SYSTEM INSTALLATION ERRORS There ' s a lot that can go wrong , says Townsend . “ We ' ve had a few experiences from clients where equipment was selected to measure , say , the airflow in a duct : they want to use a pilot tube and a differential transmitter , and they ended up installing the equipment incorrectly . For example , a pilot tube creates a differential pressure as a negative and a positive , and by mistakenly swapping the measurement sensors connections around they get negative readings .
“ Sometimes the decision on what equipment to use is a problem and causes accuracy issues . When dealing with HVAC systems , we ' re dealing with huge ducts , pipes and valves . These decisions can end up skewing the ultimate operational efficiency . Sometimes contractors may install the element the wrong way around , and sometimes there ’ s a welding error ,” says Townsend .
He adds : “ Maintenance is performed according to set intervals , and these enable one to understand the potential degradation of the system over time .
“ With an air-conditioning system , there would typically be an interval of every six months between each of the first two or three checks . The maintenance checks include : pressure value , air delivery , whether the filter is saturated with dust and more . They clean what needs to be cleaned , and document whatever action has been taken . From these initial checks they can decide
Wika website
WIKA ' s air2guide flowmeter .
whether to extend or shorten the maintenance interval . This can all be digitised ,” explains Townsend . He notes that this can be affected by the external climate when local conditions prove to be much different from what was anticipated at the time of installation , for instance if the air is highly saturated .
Reunert lists common maintenance errors as , “ Not using a spanner but rather using the hands with the result the technician may strip the thread on a gauge . Or the internal device can start twisting inside the case , creating a leak on the gauge itself which can also give an incorrect reading . Dropping the gauge or banging it as you walk past something like a toolbox can bring into question the validity of the gauge readings – there are springs and gears inside which can be dislodged ,” he adds .
In conclusion , smart HVAC coupled with IoT can improve a building ’ s profitability . New and innovative methods of collecting and analysing data will constantly upgrade smart HVAC systems to meet comfort and maintenance benchmarks . Together , HVAC piping , valves and gauges contribute much to smart HVAC having a brighter , more efficient future . RACA
REFERENCES 1 . https :// copper . org / applications / plumbing / benefits /
2 . https :// www . particle . io / iot-guides-and-resources / hvac-iot /
“ While a significant portion of gauges sold in the South African market remain analogue , this reflects the persisting culture in the country whereby technicians still like to see a gauge ’ s reading , but elsewhere the trend is firmly towards digital .”
www . refrigerationandaircon . co . za RACA Journal I April 2023 33