It’s permanent magnet motors for Morrisons

11 February 2011

Refrigeration equipment supplier J&E Hall was recently involved in a project to equip Morrison Supermarkets’ latest distribution centre, choosing a two-pronged approach to optimise the energy efficiency and thus minimise the carbon footprint of the new facility.

J&E Hall's approach was to combine both fixed and variable speed refrigeration packs, the latter being used to regulate compressor output depending on demand. In order to maximise energy savings, the company tried two variable speed pack configurations: one using existing asynchronous induction motor technology and the other one using Leroy Somer’s new Dyneo high-efficiency permanent magnet motor and drive combination. After analysing the performance of these two configurations, Hall’s choice came down firmly in favour of Dyneo. Over a speed range of 1,000-3,600rpm, the difference in the efficiency level between the motors can be as much as 7.5%.

The plant runs seven days a week, 365 days a year.
Depending on the duty cycle, the energy savings achieved by Dyneo over the Eff2 system amounted to £9,473 (Eff2 motor consumption being 2,899,243 kWh at a cost of £231,937 and the Dyneo consumption being 2,780,802 kWh at a cost of £222,464). The total energy consumption of the standard motor includes the 3kW forced ventilation and the calculation is based on a cost of 8p per kWh.

J&E Hall project manager Duncan Aspinall is convinced by the figures. “Our customers are more and more concerned by their energy bills and without doubt, Dyneo is the right solution. This motor will have a bright future, fitted on J&E Hall's screw compressors.”