Feature
The electrical supply available on the planned site is becoming
more relevant too, according to La Grange. Expanding the
electrical distribution network requires long-term planning
in most cases. In some cases customers pay for transformer
upgrades at huge cost before considering a more energy
efficient system. “Good empirical evidence can help many a
customer not make that mistake. Electrical upgrades are very
costly,” he says, and can cause major delays.
Another challenge is designing a system that can match the
part load conditions closely as well as the full load conditions
required, says La Grange.
Ford says it can be tricky satisfying customer needs as
well as incorporating their needs into a practical design.
“Sometimes the customer wants one thing but the product
being stored has other requirements.”
A big concern in our local market is that R22 (an HCFC)
is still almost half the price of most HFCs in spite of the fact
that it is a refrigerant with an ODP and illegal to use in new
installations, says La Grange. One factor seems to be the very
low purchase cost of R22 from the manufacturers in the east by
refrigerant importers.
LOOKING AT MAINTENANCE
A refrigeration system (usually) works 24 hours a day. If you
drove a car at 100 km/hr for 24 hours a day, then you would
cover ± 70 000km per month. This gives an indication of
how hard a compressor works and the need to maintain it
before it breaks down, Van der Merwe explains. “Planned
maintenance is critical to ensure the plant operates reliably
and at peak efficiency.”
If you consider the value of product that is being stored
in a freezer store, the potential loss of product, and the
implications of finding alternative storage costs at short notice,
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then it is a better bet to carry out the scheduled maintenance,
Van der Merwe says. “Scheduled maintenance is generally
a predictable cost with reliable operation at expected
temperatures as opposed to running until the equipment fails
and then scrambling to sort out the problems and potentially
dumping spoiled product.”
According to Ford, it’s key that service contacts are put
in place to maintain the system. “It is important to note that
operation costs can increase due to unmaintained systems.”
“Maintenance is an ongoing process and aims to prolong
plant life and reduce down-time resulting from breakdowns,”
explains Merrick Smith of Pro Active Refrigeration. The
maintenance programme should, amongst other duties,
include leak checking, oil changes, filter changes, and
condenser/evaporator cleaning, he advises. Mechanical and
electrical checks must also be conducted so that worn parts
can be replaced.
La Grange shares some maintenance essentials:
• Having qualified technicians with the required South
African Qualification and Certification Committee for Gas
(SAQCC Gas) licence.
• Having extensive commissioning information to refer to.
• Minimising leakage rates and doing regular refrigerant
checks.
• Minimising downtime that would result in stock losses
with planned maintenance.
• Keeping records.
ENERGY EFFICIENCY
Energy efficiency is a massive consideration for most HVAC&R
projects and cold stores are no different. “Energy saving
has become very important for all users of refrigeration of
late,” says Smith. Energy saving does come at a cost and the
RACA Journal I June 2019
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