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An extra large supermarket in Wisbech, Cambridgeshire, is on course to achieve impressive savings of £52,000 over an eight year period following its decision to install a KalGUARD/CTU water treatment system from Sentinel. The hypermarket, which is part of one of the world’s largest multinational retailers, opened in February 2014 and Sentinel’s technology is successfully protecting the store’s equipment against limescale formation, even in the most unfavourable water-side conditions of very hard water at high temperature. The store’s bakery manager says that the ovens are the cleanest he has ever seen, with no limescale issues occurring since installation.
Sentinel’s KalGUARD, an electrolytic scale inhibitor kit for commercial hot and cold water systems, is independently proven to protect premises against the damaging and expensive impact of limescale in hard water areas (around two thirds of mainland England is served by hard water). Once installed, the device is extremely low maintenance; the unit’s zinc anode last up to 12 years, while servicing is recommended just twice a year. Furthermore, KalGUARD does not waste water. Consequently, KalGUARD offers a typical return on investment of just 12 months in contrast to some alternative Part L-recommended limescale treatment devices.
A single 54 mm KalGUARD unit was fitted on the store’s incoming main at ground floor level. This feeds the plant room cold water storage (CWS) tank at roof level. In turn, this is boosted to outlets and feeds an ACV calorifier, which meets the store’s hot water requirements. As a result, KalGUARD protects both hot and cold water supplies from limescale deposition.
Sentinel’s Calcium Treatment Unit (CTU) is located at roof level, in the plant room. Following a monitoring programme, cartridge changeover frequency has been established as six-monthly, based on average water use and unit capacity. The treated water feeds bakery equipment that includes a deck oven, two rack ovens, two provers, one confectionary oven and a dishwasher. All of the bakery equipment has been inspected quarterly since installation, and even after more than a year of daily baking, the internal conditions remain free of limescale deposits.
The hypermarket’s bakery manager says these are the cleanest ovens he has seen, and is extremely pleased that no limescale issues have arisen since installation. This is vital because in cases where limescale control is inadequate in bakery equipment, problems include the blocking of steam nozzles, which leads to inconsistent steam distribution, poor baking outcomes and bread wastage.
The principal savings for the store at Wisbech, in comparison to some other Part L-recommended limescale treatment technologies, are derived from two sources, maintenance and water. Consumables required to maintain such alternative Part L-recommended technologies to the 54 mm KalGUARD unit (based on pipe size and flow demand) could cost around £5,365 per annum.
With regard to water, a pulse output water meter has been monitoring use at the store in Wisbech over the past 12 months, recording water consumption of 4752 m³. The retailer group’s UK water-use intensity average is 0.12 m³/ft², but at the extra large Wisbech store it is just 0.077 m³/ft². This is very pleasing and KalGUARD will have made a contribution as it reduces overall water usage. Using equivalent data for the 54 mm diameter KalGUARD unit, up to 840 m³ of water per annum can be saved. The store costs its water at £3 per m³, so the use of KalGUARD saves up to £2,520 a year.
Adding the water and maintenance savings delivers an impressive yearly reduction in costs of £7,885, a figure that excludes ‘soft’ savings in maintenance, labour, and management. This amount exceeds the total investment in the KalGUARD and CTU from Sentinel (including two canister exchanges), so payback was achieved within one year – 10.6 months to be precise. Furthermore, as there is no requirement to invest any more on KalGUARD for up to 8 years, the net hard savings in years 2 – 8 could be over £55,000. A small amount (£2,450 total over 7 years) needs to be subtracted for CTU canister exchange. As a result, the net 7 year total savings to the retailer could be a staggering £52,000, just from one store.
As a point of note, the retailer boasts around 240 of these extra large hypermarket stores in the UK, 65% of which are in hard water areas. If Sentinel’s KalGUARD technology was deployed in these 156 stores, based on data from Wisbech, an opportunity exists for the retailer to save up to £8 million over 7 years. Of course, the retailer’s superstores (standard large supermarkets) could also benefit. The retailer has around 450 of these, some 290 of which are in hard water areas. What’s more, the additional benefits of water savings and CO2 emissions reduction all contribute towards corporate sustainability goals, which is definitely food for thought!
Sentinel is a company with a clear goal: we offer water treatment products and services that provide the best lifetime protection for heating and hot water systems. Originally launched in the UK by Grace Dearborn in 1988 and subsequently a subsidiary of the leading multinational General Electric, Sentinel has operated independently since 2005, expanding its international reach and range of innovative solutions. As of 2021, Sentinel is owned by Aalberts N.V., and sits in the hydronic flow control cluster.
