College high achiever builds on its success
An automatic meter reading and data analysis system are helping Lewisham College in S.E. London to achieve even tighter control of its energy bills. The college is also benefiting from a hi-tech upgrade of its energy saving BMS.
One of the largest further education colleges in the country, Lewisham has some 11,500 students and offers over 500 different courses. It comprises two campuses - a long-established site near the centre of the town and a newer one in nearby Deptford.
In recent years, the main campus's energy consumption has actually fallen, and this despite the installation of hundreds of computers and the consequent large increase in cooling demand.
The commissioning in 1995 of a building management system designed and supplied by AES Control Systems has resulted in significant energy savings.
The BMS closely controls and monitors the HVAC services in both the main buildings on the Lewisham campus, the larger of which is fully air-conditioned. It was extended to Deptford in 1996, the year the site opened.
The college's building services and energy manager, Mike Gayle, has made the most of the BMS's ability to prevent energy wastage, centrally managing its settings to ensure that heating, cooling and ventilation plant only operates when necessary. In its first year of operation the system was able to make a saving of around £70,000. Though the price the college pays for energy has gone up considerably (gas increasing by 60% in the last 3yrs), improved control of energy usage has meant that its total utility spend has remained virtually the same. It is currently some £450,000/yr.
However, the energy savings being made were not always reflected in the college's utility bills, which were frequently inaccurate - even including readings from non-existent gas meters. In one year alone, the total overcharge on gas and electricity was approximately £80,000.
It was against this background that Mike Gayle obtained approval to install a new metering system and associated M&T software. Like the BMS they were supplied by AES Control Systems.
Intelligent terminal units collect pulse readings from ten electricity and gas meters at the Lewisham campus (there is separate metering of gas used by the boilers, kitchens and the engineering school's forges). At the end of every day, the readings are automatically uploaded to the M&T package. This is able to generate critical reports, consumption profiles and billing information. The latter is produced in the same format as the invoices received from the utility companies, which has greatly simplified checking for errors.
The data yielded by the M&T software is also used for maximum demand control, checking of plant performance and accurately allocating costs when parts of the college are let out for evening and weekend functions.
In addition, the system meters and creates bills for the power used by mobile phone transmission equipment on the college roof. Deptford, which has a further six meters, will be added to the system shortly.
While working on the metering project, AES was also incorporating state-of-the-art communications and operator interfaces within the BMS. Part of this has involved the fitting of equipment that allows alarm messages generated by the system to be retransmitted to the mobile phones of engineering staff, who can thus be alerted of any problems as soon as they occur. Previously, alarms would just come up at PC-based system supervisors.
At present, all alarms are relayed to the mobile of a specialist maintenance contractor and any critical ones (such as a boiler or chiller failure) also go to Mike Gayle. If he is off site he can remotely interrogate the system - and possibly even correct the fault - using the PC Anywhere program loaded on his laptop.
System communications have been further improved by making use of the college's Ethernet-based Intranet to connect the BMS networks at the two campuses. These had been linked by modem. Now, when say an engineer at Lewisham wants to monitor the operation of building services plant at Deptford, connection is instant and the data is immediately transmitted. Unlike with modems, there are no dropped lines or dialing delays to contend with - nor are there call costs.
The other main element of the BMS enhancement has entailed updating the system supervisors (the PC-based interfaces through which monitored data is displayed and control settings entered). New and more user-friendly supervisor software has been loaded on to two PCs at Lewisham and one at Deptford. There are schematic displays incorporating live data for all building floors and items of plant. To aid operator understanding, AES has made extensive use of animated graphics. One of the Lewisham supervisors connects to the BMS via the college Intranet, which means it could easily be moved to another part of the site if the engineer who uses it moves offices.
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