Water, water everywhere — but where is it really going?
Published: 05 July, 2012
What happens to a building’s or site’s water after the water company’s meter. And can you rely on that meter being accurate? How can you go about reducing the consumption and costs of cold water and hot water? Michael Farnon of Micronics has the answers.
The costs relating to water consumption and the energy associated with domestic how-water services are significant. The first step in bringing them under control is effective metering using the correct type and quantity of meters with an automatic means of reading and analysing the metering data. These data can then be used to provide management information on consumption and consumption trends with respect to time of day and usage patterns.
Irrespective of the size and diversity of building types and occupation, making information available, combined with establishing individual or group ownership and responsibility for consumption, is the key to reducing consumption and costs.
The starting point is the water-company utility meter. Is it correctly sized, and is it accurate? Without sub-metering that meter is the only source of information regarding the consumption of the site; in most circumstances, it also determines the sewage charge for the site.
It is clearly important that the utility meter is working correctly. With the addition of automatic half-hour meter reading, considerable information regarding the consumption patterns and trends for the building can be available.
For example reviewing half-hourly consumption data can identify peak consumption periods for investigation, and the night-time consumption profile can be used to identify water leaks or the operation of automatic functions using water that may be reduced.
The accuracy of the main utility meter can be established using a check meter, which could be a temporary inline meter or a portable or fixed clamp-on ultrasonic flow meter such as the Micronics U1000, which can be quickly installed to shadow the meter and provide half-hourly consumption information.
|A clamp-on ultrasonic flow meter such as Micronics’ U1000 (in the yellow case) can be used to check the water company’s meter and provide half-hourly data that can help identify periods of peak consumption and night-time consumption to detect leaks and unwanted automatic use of water.|
Having addressed the incoming water supply, the next task should be to consider the potable and DHWS consumption by water accountable areas (WAA). A WAA is an area of the building or a specific task or process that represents a significant proportion of the overall consumption for the building. An area could be the water demand related to a specific business function or department, which is in an area where the potable and/or DHWS water pipe-work lends itself to being metered as a WAA or the individual water supplies to kitchens or leisure facilities in a building as examples of building processes.
The key point is that these individual WAAs make up the whole. If they are monitored with individual or specific group responsibility they can be managed so, hopefully, waste can be minimised, usage optimised and overall consumption reduced.
Benefits such as reduced consumption and costs, can be derived from temporary and/or fixed sub-metering of water services. Temporary sub-metering of WAAs can be easily achieved using a portable clamp-on ultrasonic flow meter such as our PF330 with an integral logger to profile consumption patterns and provide information to identify waste and enable corrective action — e.g. automatic urinal that are continuously flushing or not-so-automatic taps or showers.
As an example of temporary monitoring, Network Rail used our flow-measurement and analysis services to help survey water services at Paddington Station.
Having been established for many years and subject to considerable development over the years, Paddington Station’s water-supply network is understandably vast, complex and, to some degree, uncharted. The task of surveying the site to establish what was flowing where was challenging. However, faced with higher than expected water bills the Paddington building-services team of Network Rail was presented with the daunting task
The management team opted for our flow measurement and analysis services using time-of-flight portable flow and logging instruments. Six instruments were used in two surveys to gather 24-hour consumption/load profiles for selected hot- and cold-water services, including supplies to public conveniences. The information gathered provided a valuable insight into what was being used and where across the station.
Fixed or permanent sub-metering of water services as part of an aM&T or BEM system can provide such information and check incoming water services on a continuous basis and should be part of the original design brief for new build or major refurbishment. If installed with the general works, given the relatively small size of potable and DHWS pipework, in-line mechanical meters will probably be the most cost-effective option. However, the potential for retrofit of sub-metering in existing buildings is extensive, and fixed clamp-on, ultrasonic flow meters will probably provide the most effective solution and have additional benefits such as no pipe cutting and dry servicing.
|Temporary sub-metering of water accountable areas can be achieved using a portable clamp-on ultrasonic flow meter such as the Micronics PF330.|
Percy Albuquerque the managing director of PA Energy, a company specialising in flow-metering retrofit installation and remote flow monitoring, says, ‘We have found that applying the Micronics U3000 and U1000 Ultrasonic flow meters has made implementation of retrofit critical flow measurement straightforward. Often the more innovative energy and environmental managers in our customer base want to understand more about thermal flows in renewable such as solar thermal or general water flow volumes, for example rain water harvesting, or check the water supply company's own meters for accuracy. Using non-invasive technology makes retrofit flow metering a much more practical proposition by avoiding the need and associated costs of draining down systems that would otherwise result from the use of in-line meters.’
The benefits of temporary and fixed meter sub-metering of potable and DHWS are clear; the tools to do the job are available. And reductions in water consumption and the energy related to potable water and DHWS are achievable with WAA and an effective management system.
Michael Farnon is managing director of Micronics.