The Association for Decentralised Energy
The site which contains 24 wards and seven surgery theatres as well as maternity, physiotherapy, radiology and outpatient services, updated its energy centre to include Viessmann low temperature gas boilers and a combined heat and power (CHP) unit.
The significant heating system overhaul has led to savings of approximately £500,000 per year on fuel bills alone, with a projected 25 per cent reduction in carbon emissions per year.
Founded in 1969, Airedale general hospital in Keighley had been serviced by four 3.5 MW steam boilers for more than 45 years. Despite many years of reliable performance, the ageing system’s efficiency was around 65 per cent, and accompanied by an expensive and time consuming maintenance programme.
Airedale General Hospital enlisted the help of construction company Interserve to present a way of improving energy efficiency, whilst providing essential guarantees of reduced carbon emissions throughout the site. Viessmann was chosen as the technology supplier whose calculations could be trusted and therefore could provide the highest level of confidence that targets would be met. Interserve’s 15 year service contract put equipment reliability high on the list of priorities, further positioning Viessmann as the manufacturer of choice.
Initially, Interserve and Airedale General Hospital considered biomass, however this was discounted due to access restrictions, making deliveries to the energy centre difficult. A low temperature gas boiler system with CHP was chosen to supply the site within the existing plant room. Martin Quirk, head of technical services at Airedale said, “The system Interserve recommended had to guarantee savings. We knew from the industry that Viessmann is a well-recognised, reliable manufacturer. We felt confident they could deliver the energy savings.”
Installed in stages by Vital Energi, work began in December 2013 and finished in October 2014. The new heating system is led by a 90 kWel 840 kWth CHP unit, which is controlled by a management system. This ensures high run hours from the unit, achieving high efficiency and low maintenance, delivering 80 °C as a minimum flow temperature.
There are three Viessmann low temperature gas boilers used as back-up for the hospital, including a 3 MW Vitomax unit, a 2.5 MW Vitomax unit and a 560 kW Vitoplex unit.Three low temperature heat exchangers integrate the system with the Vitomax and Vitoplex boilers, along with an inverter driver which monitors pressure. The boilers are integrated with existing pipework throughout the hospital, which resulted in fewer downtime periods during the phased replacement process.
The heating system is one part of the energy efficiency improvements across all hospital wards, including new lighting and air handling units. David Moss, assistant director of estates at Airedale NHS Foundation Trust, said “The new heating system is generating significant financial savings and reducing the hospital’s carbon footprint. The new infrastructure is a more energy efficient way of heating the hospital – we are taking advantage of advances in technology to provide a better environment for our staff and patients.”
“The latest installations are expected to save around £500,000 a year, before capital repayment, which will be reinvested in improving services,” he added.
Project year: October 2014
Equipment: 2 x Vitomax gas boilers
1 x Vitoplex gas boiler
1 x CHP unit
Rated output: 3 MW gas boiler 2.5 MW gas boiler 560 kW gas boiler 90el 840th CHP unit
Location: Airedale Hospital, West Yorkshire
Contractor: Interserve
