PROJECT |
INCORPORATING COLD CHAIN |
|||
|
this in mind that the design of the coolers was consistently refined to ensure that they satisfied the load requirements while utilising available resources and fitting within the overall design philosophy applied throughout the entire facility .
The coils are built to work at relatively elevated fluid temperatures which adds size but improves long term plant energy efficiency and therefore operating cost and viability . The detail design done by AMC Engineers was focused on the best overall site solution . Having a view of each part working in conjunction with the others in the system allowed HC Heat Exchangers to design coils that overcame challenges related to pressure drops , laminar flow regimes and defrost energy considerations without compromising on performance .
Based on the scale of the project , the tender for the cooling coils invited submissions from international suppliers but local supply was secured based on product design coupled with the most attractive offering .
Van Rooyen says the coils defrost regime was the subject of much discussion and a crucial factor in the design of the units . In place of typical electrical defrost systems these coils make direct use of warm glycol heated by the waste heat recovery from the ammonia plant . This allows for quick defrosts with minimum energy spilled into the cooled space while eliminating risks from possible element failures .
Further to this the cooling units were supplied with ebm Axicool EC fans . This
|
premium range of fans allows for low noise , ultra-efficient operation with long term monitoring and real time feedback on fan data points with protections built in to minimise down time and optimise operating points . There being a total of 104 blower coils and 416 fans with a total peak power consumption of 650 kW , it was important to optimise the fan speed and control to reduce power consumption to an absolute minimum .
“ The efficiency of the fans is beyond the current regulatory requirements , even in Europe : for instance , providing for a IE5 energy rating when an IE3 or IE4 rating is sufficient at the moment . The detailed design calls for monitoring , tracking for errors , for restarting and for warning upfront of any maintenance problems ,” van Rooyen adds .
THE CHALLENGE OF STOCKHOLDING RAMP UP “ As a manufacturer of multiple cogs of the cooling machine that is implemented in various aspects throughout the HVAC & R space , the HC Group is always aware of the role that its units must play and their ultimate wider societal impact .”
The group is comprised of several companies that are all interlinked in the HVAC-R space . HC operates as a product supplier ( as in this case ) or also as a full solution provider , partnering with contractors to add value to the end users by means of full project implementations . The Pick n Pay distribution centre represents one of its larger contracts .
|
“ We had a design which we tweaked as far as we could to make sure that it satisfied the requirements . The selected coils were efficient units that would last long and be efficient in terms of the operation , accounting for all the various issues such as temperatures and flows in addition to whatever other challenges every specific design comes with ,” says van Rooyen .
“ We went to extremes to ensure that the materials we brought in were correct as to gauges , pricing for the specific job , and the correct stockholding – given work commenced just after Covid . We had to increase our stockholding by approximately 40 % over our norm to ensure sufficient stock on hand given the various logistics issues , the fact the construction industry was ramping up and there were also strikes in various sectors .”
Van Rooyen points out that projects such as this have many different moving parts , “ and you don ' t want to get caught without even the smallest part as it can delay the entire project ”.
“ By the time our manufacturing component was complete , due to the nature of such a massive project there was still a fair amount of work happening on site : electrical work , installation work , fitting various components , adjusting various things during commissioning .
“ Having increased our stockholding proved a good move , but coordinating stock levels and work with all the other contractors is the core of managing such a large project . Its scale required intense engagement with
|
Gert van Rooyen , HC Heat Exchangers mechanical engineer .
all parties . For instance , there was strike action and materials delays in between , affecting a range of items such as tubing and fittings – while ports were closed for several weeks . Even though we pre-ordered supplies of fans , for instance , they still took longer than initially expected . Coordinating all these issues to get them complete at the same time was quite a challenge , requiring constant dialogue with the main refrigeration contractor MRE .
“ We were already busy , so taking on another large project was a challenge . We increased manpower in various parts of the factory , and managed the shifts accordingly . On the other hand , the benefit of being a large project was that it was quite repetitive enabling one to get into a routine to run things smoothly : plug in , play and repeat .” CLA
|