Getting Technical
CHARLES NICOLSON
Charles Nicolson has a physics and chemistry degree from Natal University which he subsequently put to
good use by applying speciality chemicals in mining and industrial processes where water is a major factor.
This created an enduring interest in water technology, a passion that expanded to the HVAC industry
in 1984 when he joined BHT Water Treatment. Since then, water technology in HVAC water circuits has
continued to be an abiding interest.
PROGRESS OF NON-CHEMICAL
WATER TREATMENT [NCWT]
FOR CONTROLLING SCALING
By Charles Nicolson
Almost ten years ago, an article updating the status of NCWT appeared
in a previous issue of RACA.
T
he final paragraph read:
In South Africa, the successes and failures over the past
30 years of non-chemical water treatment (NCWT) for controlling
scaling correspond to those in other countries with similar ranges
of available water quality. One new factor is the rapidly growing
number of supplementary hot water circuits heated by solar energy,
heat pump and/or condenser heat recovery which will need scale
control wherever only ‘hard’ supply water is available. This could
well be a future for non-polluting, non-toxic water treatment units
developed on the technology of those which have showed promise
and successes in this area in the past.
Since 2011, the number of companies promoting NCWT
products on the internet has increased by around 80% with a
corresponding increase in the number of actual products offered.
All of these products still generate magnetic, electromagnetic or
electrostatic fields and from the technical data on their websites,
it would seem that most of the products that were on the market
in 2011 have been improved by the incorporation of electronic
developments for increasing the scope and complexity of the
electromagnetic or electrostatic fields they generate. However, as
yet, not many of these improved products seem to be appearing
on the increasing number of heated water circuits in HVAC
installations in South Africa.
NCWT works in alkaline conditions of non-corrosive but
potentially scale-forming water chemistry so the primary task
of NCWT is to control scale. Controlling scale effectively directly
correlates with improved heat transfer. The basic technical
premises of non-chemical water treatment for prevention of
scaling are the same as they were forty years ago, but there is
www.hvacronline.co.za
now a much more transparent attitude by those companies
who present their latest research results in an open manner. The
starting point remains that magnetic or electromagnetic fields
applied to water containing dissolved calcium and magnesium
carbonate salts can modify the structure of the crystals formed
when these salts precipitate out of solution.
This ‘crystal modification’ begins when crystals start forming
at the molecular level and continues as the crystals proliferate
and enlarge. Most of the recently published experimental results
continue to refer to work published in 1997 by Cho, Fan and Choi
who proposed that a form of ‘controlled precipitation’ occurs
when suitable electromagnetic fields ‘agitate’ calcium and
magnesium cations as well as carbonate radical anions in water
thereby increasing the number of ‘collisions’ between the cations
and anions and consequently the rate of crystallisation as well as
faster growth of the crystals. The experimental results also noted
that the accelerated crystallisation is not confined to heat transfer
surfaces but occurs throughout the bulk of the water volume.
Whether ‘collisions between ions’ is indeed a cause of
precipitation of dissolved salts out of solution in water has not
yet been scientifically proven. Stephen Lower, retired faculty
member of the Department of Chemistry at Simon Fraser
University, Vancouver, Canada, states in his informative and
amusing website concerning magnetic and electromagnetic
effects on water that, “This is not surprising; the entire process by
which ions form precipitation nuclei is poorly understood. ‘Bare’
ions do not exist in solution but are protected by a hydration
shell of loosely attached water molecules and surrounded by an
electric double layer of counter-ions. They do not simply come
RACA Journal I February 2020
45