Getting Technical
circuits installed for heat recovery, heat pumps and solar energy
collection and transmission.
Water treatment in HEVAC installations has also become far
more advanced in automated control and monitoring systems.
Water treatment providers have had to become more service
focused but still generate most of their revenue from chemical
sales. This will only change when traditional steel pipework and
other potentially corrosive wetted steel surfaces are replaced
with non-corrosive substitutes which will undoubtedly take many
years to eventuate. Water treatment of heating and cooling
water circuits is a large worldwide industry. It seems, therefore,
inconsistent compared to so much other technical progress that
no new chemicals for this purpose have been developed since
1984 which is curiously similar to the fact that no completely new
antibiotics have appeared from the much larger pharmaceutical
industry for the same period. (At the time of writing – the
coronavirus outbreak is still making headline news. Thankfully
there are no reports of any cases reaching Southern Africa as yet
– mid-February).
During the 30-year period from 1980 until 2010, many
laboratory scale experiments were conducted to determine
and measure what happened when various strengths of hard
water solutions were subjected to electrolysis. Published results
universally agreed that dissolved hardness salts, particularly by
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RACA Journal I April 2020
far the most common one, calcium carbonate, were precipitated
out of solution and migrated in ionic form to cathode electrode
surfaces where they accumulated as scale deposits. Some
development work was done in Israel primarily for agricultural
applications, but commercial electrolysis installations on cooling
water systems began only during 2004 in Singapore, Malaysia
and Japan.
In summary, side-stream electrolysis installations on
evaporative water circuits control scaling by precipitating
scale-forming substances which automatically remove them
from the water circuit. In the process, circulating water becomes
partially softened allowing gradual re-dissolving of existing scale
deposits as well as higher cycles of concentration to be used with
commensurate reduction in supply water demand. In addition,
polluting chemical content due to the lower amount of bleed-off
water is minimised or even possibly reduced to zero. Some of
the suppliers of these electrolysis units claim additional benefits
relating to reduction of corrosion and suppression of growth of
bacteria and other micro-organisms.
Water treatment companies have been anxious for a real
technical step forward for many years. On the evidence to date of
effective scale control, water savings and compliance with anti-
pollution regulations provided by electrolysis installations, this
could well be what they have been waiting for. RACA
www.hvacronline.co.za