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winter. Too small and your customer’s room will struggle to
reach operating set point during the warmer ambient periods.
Here are some additional tips from Van der Merwe:
• Budget for regular maintenance.
• Consider installing mobile racking to ensure that the
size of the cold store is minimised for the pallet holding
capacity with the subsequent reduced running costs
associated with a smaller cold store.
• Be careful of going for the lowest cost solution without
considering the possible differences in equipment
capacities/ specifications and the effect on the running
cost. The short-term benefit of a low first cost can be
quickly overcome by high running costs and poor plant
performance or production or product losses.
• Consider the contractor’s track record and the calibre of
clients that he serves regularly.
Ammonia refrigeration plants are common options for a cold
store, but come with strict regulations and requirements in terms
of health and safety.
No matter your choice in refrigeration solution, maintenance is
key to ensure the plant runs as it was designed.
cost vs. maintenance cost is becoming more widely used to
compare installations,” says La Grange.
Another crucial factor is to ensure your heat load
calculations are correct, says La Grange. “Few things can
save or waste more energy than heat load calculations that
don’t consider all relevant factors.” Also, use well-established
guidelines like the Total Equivalent Warming Impact (TEWI) to
compare alternatives.
Size also matters – especially when it comes to the
refrigeration plant. If you are too conservative and the plant
ends up being oversized you might adversely affect the
viability of the project, explains La Grange. A system that is
oversized for the application might end up being less reliable
when it is required to operate at part-load conditions in the
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RACA Journal I June 2019
Ford advises the following:
• Either you know how to do it or you don’t — don’t
overcommit.
• Updated and correct qualifications are a must.
• Ensure that the correct design is done for the required
plant output.
• No shortcuts.
• Make sure you account for more than enough capacity.
• Don’t compromise on insulation.
• Understand the mandate.
These are Smith’s tips:
• Make sure that piping and equipment are kept dry and
clean when being stored prior to installation.
• Ensure that pipe insulation is glued and joined correctly.
• Ensure that free air movement is allowed for around all
insulated piping.
• Ensure piping is installed for effective oil return to the
refrigeration plant.
CHALLENGES
It’s never quite as easy as it looks. What are the possible
challenges of working on a cold storage refrigeration project?
“Energy savings vs. price is a major challenge,” Ford says.
People generally want the most efficient plant but have a very
tight budget, so the more expensive units are cheaper to run
and have a high return on investment. “The cheaper system
may not offer long-term running and energy savings. Clients
want a Rolls Royce for the price of a Citi Golf.”
Then of course, the time frame allocated for the
completion of the project is a major consideration. La Grange
explains that often good solutions aren’t considered because
they can’t be installed within the tight project schedule.
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