BSEE BUILDING CONTROLS A


The safe and eecve control of the movement and temperature of cold water in a building’s storage tanks is a fundamental requirement. David Meacock, Technical Director for water eciency specialist Keraflo, explains the benefits of intelligent electronic tank management systems over ‘old technology’.


lthough we live in technology-rich times, the electronic control of cold water storage in


commercial premises


and major public buildings is still relatively new.


With ‘traditional’ purely mechanical systems long-established, people have grown to trust them. But they are no longer state-of-the-art.


As legislation has moved on, as cost pressures have grown and as sustainability has risen up the corporate agenda, so this reliance on ‘old technology’ is being questioned. There is a perception that there are more potential failure problems with an electronic management system than a mechanical one. This simply isn’t true. Electronic management systems are robust, much more dynamic, prevent issues arising in the first place, increase efficiency and pay for themselves in a relatively short period.


Not only do they deliver on the efficiency front, they are relatively quick and easy to install and programme, always a plus for building services engineers.


Before looking at an electronic management system, let’s first consider some of the issues that can be found particularly in older properties. Purely mechanical solutions, such as ‘old school’ equilibrium float valves, provide no external warning signs. This leaves the storage system open to issues such as too little water in the tanks or sometimes too much, leading to large quantities needing to be dumped. Or, occasionally, flooding. In addition, poor temperature control can lead to maintenance problems such as freezing water causing stress damage in the tank. There’s also the potential health risk, from the build-up of harmful bacteria, if the water is allowed to get too warm.


So, let’s quickly run through what an electronic tank management system is and what the benefits are when retrofitted to pre-existing cold water storage tanks.


Tailored to the building’s needs


uThe new Keraflo Tanktronic selfcleaning servoceramic valve.


Able to send alarms to a Building Management System, Keraflo’s Tanktronic, for example, features an intelligent control unit that is linked to a sensor assembly suspended at full depth inside the water storage tank. The sensor monitors water levels AND temperatures. It continuously feeds


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ELECTRONIC TANK MANAGEMENT SYSTEMS An ‘intelligent’ soluon to cold water storage


data back and automatically opens and closes valves as required, thereby maintaining stored water levels in line with pre-set operating parameters tailored to the building’s needs. The control unit’s user-friendly interface allows engineers to easily set the filling valve close level, fill delay, alarm high/low and temperature high/low specifications.


The unit can control and monitor water and temperature levels in single or multiple tanks, with each unit managing up to four sensors and two filling valves. Expansion modules can be added if additional valves are needed. In addition, should the water level drop below, or rise above, the assigned parameters, a two-stage precaution process takes place, firstly raising an alarm to the user, then launching an automatic over-ride function if the alarm is not responded to.


Another intelligent feature is a holiday schedule to match fluctuating demand. This is particularly relevant to educational establishments such as schools, which have long summer breaks, and universities, that can be closed for up to three months.


Significant savings


The significant savings that can be made by adding an electronic management system to existing cold water storage tanks can be increased further if considered at the specification stage, before a brick is even laid.


Tanks are expensive. In calculating the overall cost, the size and depth of foundations to support these large and heavy structures should also be taken into account, along with maintenance costs.


With an electronic management system more efficiently matching tank capacity to demand, the level of maintained water can be reduced. As a direct result the tanks can be smaller! Not only will you save on the tank size but the foundations will also be less, with the bonus of the arising unused space being available to put to other, productive use.


If an electronic management system is not considered at the specification stage, there is the danger of ending up with what is, in effect, an oversize tank. This brings with it the risk of slow- moving water in the centre, a rise in temperature and the potential for harmful bacteria, such as legionella, to proliferate.


With an incorrectly set up system cold water enters the tank and, being denser than warmer water, sinks straight to the bottom. But being at the bottom it is the first to be drawn out. This creates a ‘warm zone’ in the middle where the water stagnates and the temperature creeps up. Best practice dictates that to maintain the quality of the water it needs to be churned regularly. This is a particular issue in, for example, sports stadia that are relatively unoccupied for almost an entire week, with heavy demand only on weekend match days.


Aggressive fill and churn


With a system such as Tanktronic, the turbulence is good. Turning the water is


12 BUILDING SERVICES & ENVIRONMENTAL ENGINEER MAY 2018


managed automatically and if a delayed action valve is deployed its aggressive fill actively churns the water. Our most recently introduced delayed action valve, the innovative Tanktronic SCV, is a Servo Ceramic Valve that takes tank management to an even higher level.


Unlike other filling valves, it is able to maintain itself with self-diagnostics. Its auto-clean function resists the build-up of debris, while it also notifies the user of any potential issues.


Ideal for pumped systems, the adjustable delayed action and the smooth open-to-closed valve operation, driven by a highly efficient high-torque electric motor, ensures that no incidence of hydraulic shock or water hammer will occur.


The durable and robust ceramic disc mechanism means there is no seal or washer wear and tear, keeping maintenance to a minimum. The Tanktronic SCV is WRAS-approved and fully compliant with Water Regulations. Five models are available to cater for varying pipe sizes, ranging from ¾ inch up to 2 inches.


www.keraflo.co.uk


uTop: An electronic tank management unit in situ.


uAbove: The aggressive fill from delayed acon valves ensuring strong churn in the stored water.


‘


Electronic management systems are robust, much more dynamic, prevent issues arising in the first place, increase eciency and pay for themselves in a relavely short period.


’ VISIT OUR WEBSITE: www.bsee.co.uk


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