Prison laundry operation goes greener

A 3-year payback is expected to be delivered by energy savings of nearly 70% being achieved in the running of the Laundry at HMP Wormwood Scrubs following a major audit of the air-handling units and the installation of higher-performance main supply and extract fans. The work was carried out by Efficient Air following the introduction of a new sustainable-development policy in the Prison Service. The original arrangement for air handling in the prison laundry had old-generation backward-curved centrifugal fans. Their total motor power was 23.2 kW, leading to an annual running cost of over £8100. The replacement system installed by Itchen Mechanical Services comprises four new high-efficiency RZR 15,400 aerofoil-bladed backward-curved centrifugal fans driven by ABB Efficiency Class One motors controlled by matched ABB ACH 550 inverters to adjust the ventilation supply. Measurements on completion recorded a 69% reduction in power at maximum flow, representing a saving of over £5500 a year. Annual carbon-dioxide savings are 61.4 t. The installation also enabled a heat-recovery system to be re-used; it had been out of action due to motor overload.