EC Fan Upgrade at NHS Hospital.

The Project.

The Croydon Health Services engineering team, along with Carbon Architecture, who manage Energy projects for the Trust, were keen to explore the possibility of upgrading the tired, old, belt driven fan in one of its AHU’s. The aim was to reduce energy consumption and increase the available airflow capacity. In the height of summer, the existing AHU was not delivering adequate airflow, leading to overheating problems in the hospital. Carbon Architecture had a full validation of the existing AHU carried out and supplied this information to Airedale International Air Conditioning. As a long-term partner of Airedale, ebm-papst were contacted for their expertise and gladly assisted to produce an outline proposal. A detailed site survey was then carried out to confirm the mechanical solution as well as record the unit‘s power consumption. The existing DOL motor was found to be drawing 9kW and delivering approx. 15,000 m3/h at matched original performance .

Old / New Installation


The Solution.

Utilising its in-house design and manufacturing facilities, ebm-papst UK produced a bespoke fan and bulkhead solution that allowed simple installation and connection via pre-wired extended control and mains cables. The technology at the core of the solution is the ebm-papst EC RadiPac centrifugal fan; a direct drive EC external rotor motor, with aerofoil backward curved impeller and onboard control electronics including integral variable speed drive. Each component of the fan system, i.e. impeller, motor and VSD are optimised to work with one another allowing for peak efficiency. The onboard electronics also allow for alarm outputs/condition monitoring, simple analogue speed control, closed loop sensor control (demand ventilation) and MODBUS communication/control, ideal for integration to the hospitals planned BMS upgrade works.

The Results.

A professional installation was carried out with little fuss and minimum downtime by Airedale over an 8-hour period. After the on-site team carried out some minor alterations to the electrical panel, which included the addition of its own sub-meter, the unit was back up and running in no time. The installation was a complete success, achieving its two primary objectives as well as providing additional benefits listed below.


– Increase in available airflow (25%)

– 40% reduction in power consumption (at matched duty)

– Maintenance free, no more belt changes!

– Increased control and monitoring options

– Increased system resilience


Find Out More

Carbon Architecture can provide assistance in the upgrade of AHU to save energy. If you would like any further information or advice please contact Tim Roebuck (

About Dan Jackson

Dan Jackson is a process and sustainability consultant. He has experience in helping clients reduce energy and cost in the NHS and across the hospitality supply chain, from breweries to pubs.