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Saving 294 CO2 tonnes a year and £46,480 financial savings

Overview and challenge

Manchester Metropolitan University’s John Dalton Tower contains 48no fume cupboards that were in operation 24 hours a day 365 days a year. The fume cupboards were Constant Air Volume units, continuously sucking air out of the building to be replaced with conditioned air, a system costing approximately £50,000 per month in electricity costs alone to operate. Managers commented “it was worse than having the heating on with the windows open.”

MMU Environment Team and Property Services looked at the operating costs and how to make MMU more energy efficient. TEL were commissioned to devise a retrofit solution to convert MMU John Dalton Tower’s fume cupboards into a Variable Air Volume scheme.

The solution

The upgrade plan allowed the installation of a controls system to recognise when the cupboards were not in use, which would ramp down the use of the fans and result in massive savings on both fans and heating/cooling. The project focussed on 32 cupboards across two floors, modifying the existing constant air volume (CAV) system to a variable air volume (VAV) without compromising the safety of laboratory users.

The project was successfully completed in short timescales and importantly with only minor disruption to laboratory use including teaching, exams and research functions.

The benefits

The benefits of the retrofit for MMU have been immediate, with fan electrical usage reducing by 62% during term time and 77% during vacation periods and gas consumption drop by 23%.

Pre project electricity consumption was 320 kWh/day/fan and post project that consumption was halved to 118kWh/day/fan. There was also a considerable reduction in gas for heating the air supply. Pre project boiler consumption stood at 7,247 kWh a day but post project dropped to 5,909 kWh a day. This reduction in energy usage is estimated to reduce MMU’s CO2 emissions by nearly 300 tonnes a year and in the early stages of the project going live they were seeing cost savings of £1,104 a week!

Such was the success of the carbon reduction and cost saving initiative, Manchester Metropolitan University was nominated at the Green Gown Awards in 2011. If replicated across English institutions, it could represent over 26,400 tonnes or nearly 5% of HEFCE’s 2020 target.