A Trend BEMS supplied and engineered by NEA Teknik AB is helping to ensure the wellbeing of critically ill patients in a recently opened unit at Sweden’s Sahlgrenska University Hospital in Gothenburg via accurate control of environmental conditions.
The system is also ensuring energy-saving, demand-led HVAC control.
The hospital provides emergency and general care to some 700,000 local inhabitants, and specialist treatment for all of western Sweden. The 312-bed unit is part of an ongoing rebuilding and refurbishment programme at one of Northern Europe’s largest hospitals.
The SEK 500 million (£45 m), 24,000 m2, seven-storey unit houses inpatient wards and outpatient and daycare services. Those treated include recent transplant patients, others suffering from serious infections or recovering from strokes, and individuals undergoing renal care.
The building has no boilers, chillers, or radiators; district heating and cooling supplies all hot and chilled water. The entire unit is served by underfloor heating and cooling, and chilled beam ceiling units. Six main air handlers supply tempered air at 18oC all year round. The Trend BEMS controls and monitors all HVAC plant, plus the power plant room cooling and numerous extract fans; switches lighting; monitors medical gases, and has a smoke management role in the event of fire.
On two floors housing patients particularly susceptible to infection, the air supply is HEPA filtered. Here the Trend system keeps the double door entries that act as airlocks positively pressurised.
Despite often high heating and cooling loads, the HVAC services’ design and the BEMS’s control actions are helping prevent excessive energy consumption. For example, the AHUs’ sophisticated heat recovery arrangement reclaims 68% of the heat within the extract air. This equipment is controlled by the BEMS, which also varies the AHU fans’ speed. Control zones make it possible to prevent supply of tempered air to unused areas.
Each floor and corridor has its own, independently controlled, lighting profile. Light levels are set by a DALI lighting system. Sahlgrenska’s aim is that total energy use should not exceed 130 kWh / m2.
In the event of fire, the BEMS would close the appropriate zoning dampers to isolate the affected floor, with the area’s AHU supply fan switched off, and the extract kept running to evacuate smoke. It would also activate a large roof-mounted fan to clear smoke from the stairwell and lift shafts.
The Trend BEMS comprises 23 Ethernet-linked IQ3 controllers, with almost 1,000 input and output points. There are four main plant room control panels, plus a further 12 housing the IQs that undertake lighting control and space temperature measurement. The panels offer sufficient spare capacity to allow for system expansion.
The Ethernet TCP/IP network to which all the IQs connect is interfaced with a fibre-optic LAN that runs around the hospital, supporting a SCADA operator interface comprising two servers, one used for centralised management and monitoring of the HVAC services by providing access to all BEMS monitored data and control settings. The other covers various other systems, including lighting, lifts, power supplies, and utility metering. There are around 100 Trend IQ controllers in other buildings.
NEA Teknik engineered the BEMS, drew up the controls specification, and developed the software driver that enabled the Trend BEMS to be interfaced to the fibre-optic network.
The main contractor on Sahlgrenska’s new care unit was PEAB, who engaged Johan Lidbeck to act as installations coordinator on the BEMS element.
For more information,
NEA Teknik AB, Sweden,
can be contacted on
Tel: +46 31 68 9300
Trend Control Systems Limited
Albery House, Springfield Road, Horsham, West Sussex, RH12 2PQ, UK.
Tel: +44 (0)1403 211888 Fax: +44 (0)1403 241608 www.trendcontrols.com
SA107205 Issue 1
