The local council at a popular English seaside city wanted to achieve better control of its energy and other public utilities supplied to sea front sites such as public toilets, arches, railway premises and cafeterias.
To this end, Efficiency Direct were approached with a view to examining the possibility of installing Smart Metering which could be connected centrally to a council computer system to provide regular data collection and management reporting functions. It was envisaged that this would give the Local Authority the means to access accurate and reliable consumption information on a daily basis if necessary. This in turn removed any necessity for payment of invoices for utilities which had been based on estimated meter readings as was often currently the case.
During the audit phase, it was noted that the water meter for a particular set of toilets was indicating a large flow.
Simple timing of the flow through the meter established that approximately 6.8 litres per minute (9.8m3 a day) were being used at the site. The system in question fed not only the toilet block comprising a Ladies, Gents and disabled facility, but also a small cafeteria on the beach front which at the time of the initial visit was closed. The toilets, although open, were seeing little use as there were no pedestrians in the vicinity at the time.
A cursory examination of invoices for the cliff top meter showed that normal consumption for the entire site was in the region of 40 m3 for the 6 months (0.22 m3 a day) between July 2008 and January 2009. Consumption from January 2009 to February 2009 however was calculated from available meter data at 4,182 m3 a significant increase.
Following some research into the fitted Cistern Miser equipment fitted to the Gents toilet urinals it was established that the 7 litre cistern unit should only flush every 25-30 minutes(Source CisterMiser Manufacturers Installation Guide). In fact the unit was found to be flushing every 4 minutes and 30 seconds. The consequences of this are:
- 7 litres every 4.5 minutes = 818m3 per annum costing £2,035
- 7 litres every 25 minutes = 49m3 per annum costing £122.
- Annual cost saving of £1,913
Another gent’s toilet which was found to be flushing continuously was wasting large quantities of water. If left unattended, assuming this one toilet was leaking only 3 litres/minute the associated cost of the defect would be:
- 1576 m3 per annum costing £3,926
- Assuming a Smart meter and Exception Reporting took 1 week to highlight this, a water cost of £75 would have been incurred.
- Annual cost saving of £3,851
Clearly, in order to capture problems like this the existing metering system is completely inadequate. A Smart Metering system however, capable of providing half hourly meter reads to a centralised system combined with the system’s ability to monitor current consumption rates compared to preset alert levels would have highlighted the increased levels of water consumption and early action would potentially have saved thousands of pounds.
A regular routine maintenance check of the systems in place in the toilets should have revealed the presence of a malfunction on the urinal Cistern Miser at an early stage. Despite the apparent daily visits to site by the responsible contractor no corrective action was taken and the defect remained unnoticed..
In the longer term, plumbing issues needed to be resolved and corrected and the site needed to be equipped with Smart meters to enable close monitoring of both electricity and water consumption and to allow the provision of Management Reports to the Local Authority on a regular basis.
A further modification might be to install a solenoid operated isolation valve on the water input to the toilets. This could be controlled by a seven day timer unit isolating water to the toilets when they are closed. This would minimise any wastage associated with developing faults remaining uncorrected over long periods.
Automated metering provided the following benefits to the local authority
- Exception Reporting on a smart meter sited in the Gents toilet provides early warning of any developing problems and allows rapid investigation and rectification. Combined with a timer operated solenoid, wastage within the toilet complex is minimised
- A second water meter in the cafe allows for accurate tenant billing.
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