CHILLED BEAMS GOING TO ANY LENGTH Limited space and the need for flexibility helped drive the specification of chilled beams at Lambeth Civic Centre. Frengers Michael Ainley explains T he need to supply fresh air over a large open-plan office with limited space and locations for the service risers and bulkheads led to the specification of 778 multi-service chilled beam (MSCB) sections, and 39 ceiling-integrated chilled beam (CICB) units, at Lambeth Councils new 45m civic centre. Frengers prefabricated MSCBs, which incorporate cooling, heating, lighting and ventilation, were connected in a series across the 11,000m2 of office space over six storeys. The civic centre building has an energy centre on the roof and district heating and cooling networks that serve the site. It features an open-plan office, central atrium, meeting rooms and cellular offices. Limited space and locations for the service risers meant that, to achieve adequate distribution of fresh air over the floor space, the design team and Frenger used long runs of MSCBs, with the fresh air connected in series. The air chambers effectively became the distribution ductwork, eliminating the need for ventilation ducts. The ability to partition office space and maximise ceiling heights were two of the key benefits of the specification of MSCBs. Low-temperature hot water (LTHW) and chilled water (CHW) circuits from the energy centre as well as tempered fresh air is distributed around the building via dedicated risers, and routed to chilled beams using high-level distribution bulkheads on each floor. The MSCBs use Frengers patent-protected burst-nozzle design a multi-layered nozzle strip that enables a highly accurate and evenly distributed supply air volume at a given pressure at any point along | CASE STUDY the length of the active chilled beam air discharge. This means each unit is able to deliver correct fresh air volumes for each specific control zone, based on the upstream static pressure. With the burst nozzles factory set to the exact air volume and pressure (also allowing for pressure drop from one MSCB section to another), this eliminated the need for dampers to site set each beam to the design air volume, apart from one damper to the first beam in the run. The large open-plan areas meant the chilled beams had to be designed to accommodate higher-than-normal fresh air volumes of up to 150Ls-1 per MSCB run of five separate units in series (totalling 15m each) a rate of 10Ls-1m-1. This was requested at the early design stage to future-proof the system for maximum occupancy of one person every 3.5m2 each person with 12Ls-1 and the required design static pressure for that air volume being The chilled beams distribute lighting, chilled and hot water and fresh air www.cibsejournal.com March 2019 53 CIBSE Mar19 pp53-54 Chilled beam Lambeth.indd 53 22/02/2019 17:01