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W AT E R T R E AT M E N T
Don’t muddy the water
By Steve Cupples, managing director of Industrial Purification Systems
From our experience, it is not annum for a nine hour
uncommon to see large operation, five days a week.
commercial buildings lose Many systems are running
between 15-20% of its total continuously to minimise
heating energy input just energy losses so this figure
because the water is dirty. could be as high as 870,000kW
The discoloration is a product hrs per annum.
of the corrosion which is taking Assuming the losses are only
place naturally within the 15%, this means a loss of
system, and this corrosion 35,000kW per hour per annum.
reduces the heat transfer from If the system is on 24 hours a
the heat source to the water, day this cost increases to over
and then from the water to the 130,000kW per hour per
heating/cooling outlet. A double annum, all of which could be
energy whammy. recovered through investing in
In addition, if chemicals are proper filtration which could
used to treat this dirty water, give a return on investment in
then the effectiveness of the less than 10 months.
chemical treatment will be The Government has a big
reduced because of the high part to play if it is serious about
solid load within the water. Past reducing energy use and
examinations of this process minimising the impact on the
have shown filtration to remove environment. But many
particulates down to 10 micron potential ‘energy savers’ are
can improve heat transfer being put off investing in
significantly, but our tests on these technologies through
I
n many operations, within hour operation, the water bill for and process issues. However, heating in winter and so use a many systems also shows that lack of support funding
the industrial, construction this modest operation could by installing the correct combined system of chilled the majority of this and awareness of the true
and commercial sectors, well be in the region of six technology over 90% of the water and hot water. On the hot contamination is between 1.0 situation as illustrated in this
the use of water is often an figures. Yet having the ability to UPVC industry now has better water systems this would be micron and 10 micron. We article.
accepted process cost. remove solids of 1.0 micron quality products with a near connected to the hot water believe that a saving of 15-20% Yet the consequences of
There is scant attention paid to and less, plus any additional zero loss water system. Taking boiler, very often driven by oil or in total energy costs in this taking positive action by the
reducing such a significant treatments, to enable process the following into account, a gas. On the cooling side there is process can be readily achieved Government, for what can only
service cost with fixing leaking water re-use would cost just return on investment was a cool water circuit, connected The solution is to clean up the be described as responsible
taps often being the extent of £30,000 to £40,000 giving a achieved in less than six to refrigeration chillers to heating/cooling water using usage of water by industry,
energy saving in this area. payback within six months. months: enable cooling to occur. reliable filtration to less than 1.0 would not only reduce energy
Industry uses water in many Even with today’s interest rates • Reduced use of potable The energy input by the boiler micron connected to both the consumption significantly but
different ways and in different this is a fantastic return on water (evaporation and or the chiller is significant hot and cold water system. If also make huge cost
amounts, therefore water investment. spillage only) whether using gas, oil or the water in the system is reductions, and at the same
saving technology, in many • Reduced effluent charges electricity to achieve the anything but clear then energy time reduce the use of this
cases, is used in multiple Case Study 1 • Reduced product scrap due heating/cooling. is being wasted. The darker the valuable resource - drinking
applications. The A plant manufacturing UPVC to better product finish Ask any maintenance water the more it is costing a water.
commonalities however are that window sections typically uses • Less energy expended on engineer what colour the water business. The answer is in fact clear.
highly efficient water saving 200,000 litres of water for the reworking scrap is in this system and this will The Government has to
techniques are proven to not manufacturing process every • Reduced chemical use range from pale straw (usually Making savings recognise water as a direct
only reduce an organisations hour which is traditionally • Reduced electrical energy found in a new system) to black So what are the savings against energy resource and bring the
carbon footprint but to also treated with chemicals and (chilling water) (found in a typical system). This the cost of the technology? use of innovative water saving
make huge savings on energy chilled to 12-14ºC. With such a discoloration is not just ‘yucky’ A typical system using a solutions into the funding
bills. volume of water being used, a Case Study 2 it is actually having a major 100kW chiller and equivalent stream. Everyone and the
The simple fact is if an large recirculation tank and In the commercial sector, for negative effect on the system. heater can use 250,000kW per environment will benefit.
organisation can clean up this larger water chiller (2000 kW is businesses that have large
process water and re-use it just not uncommon) is normally space cooling or heating
one more time it will effectively employed. systems the cost reductions are
reduce its process water costs However, this process not based on the cost of the
by a staggering 50%. generates water contamination. water, so much as the cost of
Yet, interest in this area of In order to try and control this electricity. These systems are
‘process’ is given little attention. contamination many plants often closed loop water heating
True, the re-use of process undertake an overflow of 20% or cooling systems. Typically, a
water involves the installation of of the volume every hour. This chiller for a medium sized
additional filter technology to means paying for new fresh building with computers may
provide the necessary clean water at a rate of 40,000 litres well have installed refrigeration
water. However, modern every hour and at the same time chillers which have 200-300kw
technologies and techniques paying for disposal of the same. of electrical energy. Larger
can provide a significant return This approach however still buildings with high populations
on investment. didn’t solve the process of personnel and computers
If a process only uses 10 problems, as the remaining can be much bigger.
m³/hr (10,000 litres) and is a 24 contamination still gave quality Many public buildings require
26 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JUNE 2009
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