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.
