Variable speed drives mean big savings for Plymouth’s National Marine Aquarium

ABB is saving the National Marine Aquarium in Plymouth over £15 000 per annum in electricity by supplying nine variable speed drives, ranging from 7·5 to 18·5 kW.

The aquarium features Britain’s largest seawater tank, which holds up to 2·5 million litres of water and requires constant pumping to keep its fishy inhabitants healthy.

Although the original pumps were operated by an automatic control system using PLCs, flow and pressure were controlled by a manual throttle valve.

This resulted in a substantial amount of surplus energy as the pumps were running at 100% speed.

Drew & Co chose ABB drives for their reliability, and because their interchangeable keypads allowed for a hot changeover. Each drive took just two hours to install.

Single drives now control the duty and standby pump sets, changing automatically to the duty pump as required.

Pressure transducers in the pump output provide a feedback signal to the drive, allowing the throttle valves to be kept completely open. This lets the VSD determine the correct pump speed for the desired flow rate.

Source

Electrical and Mechanical Contractor