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SWANSEA CIVIC CENTRE TURBOMISER CHILLERS SETS NEW PIPE-RUN RECORDThe new Turbomiser chiller installation at Swansea Civic Centre is be-lieved to have the longest pipe work run ever used for a Turbocor com-pressor-based project. Designed and project-managed by the council’s in-house mechani-cal and electrical design and maintenance section, the project uses two 420kW “split” Turbomisers, installed by Cool-Therm’s Wales branch in the building’s plant room. They are connected to two air-cooled condensers some 70m away on the rooftop. The Turbomisers replaced a pair of conventional, aging Carrier chillers based on R22. To avoid disruption, it was essential to use some of the existing refrigeration pipe work. Dave Blackmore, Cool-Therm director, explains: “The internal building pipe work runs through library archives, risers and ceilings, and into office spaces. Replacing it would have been complex and expensive, and would have caused considerable upheaval for the building. “The project manager was understandably keen to retain it and replace the outdoor condensers and chillers in the plant room, resulting in mini-mal disturbance to the operation of the building.” This posed a number of design and installation challenges. The original chillers were based on different pipe sizes to those on the Turbomisers. Integrating the two required careful design and installation onsite.In addition, the original dual-circuit Carrier system had four pipes run-ning through the building per chiller, two liquid and two discharge pipes, compared with Turbomiser’s single circuit. To overcome this, Cool-Therm designed and manufactured its own bespoke Refnet Y-joint pipe connect-ing system. The design for the new chiller system itself posed a particular challenge due to the complex configuration. It required intensive planning as well as detailed flow calculations to ensure it would perform efficiently and as intended. Dave Blackmore says: “We needed to make sure there was no excessive pressure drop across any specific component or pipe length, in order to deliver the correct cooling capacity at the flooded evaporator - rather than in the pipework. “This entailed a forensic focus on pipe sizing, vertical and horizontal pipe lengths. The evaluation had to be right first time, there was no margin for error. Calculations had to take account of all system pressure drops, continued over page

SWANSEA PROJECTData fileIt uses two 420kW “split” Turbomisers, installed by Cool-Therm’s Wales branch. The chillers are connected to two air-cooled condensers some 70m away on the rooftop. The Turbomisers replaced a pair of conventional, ag-ing Carrier chillers based on R22 refrigerant.

“IT ENTAILED A FORENSIC FOCUS ON PIPE SIZING. THE EVALUATION HAD TO BE RIGHT FIRST TIME, AS THERE WAS NO MARGIN FOR ERROR.” DAVE BLACKMORE, COOL-THERM

The condensers are connected to chillers by pipework 70m in length

The coastal location posed challenges around corrosion protection

Unit 5 , Trubody’s Yard, 121 London Road, Bridgeyate, Bristol BS30 5NA

Email: enquiries@cooltherm.co.uk | Tel: 0117 961 006 | Fax: 0117 947 8642 | www.cooltherm.co.uk

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factoring in bends and 45 degree angles, all components and the proper-ties and behaviour of refrigerant via psychrometric charts.” A further issue arose due to the oil-free nature of the Turbomiser chillers, which run on magnetic bearings. The previous chillers, based on recipro-cating compressors, used conventional lubricant and therefore pipe work incorporated oil traps. This meant that all oil residues in existing pipe work had to be flushed out and thoroughly cleaned prior to installation. “We couldn’t allow any oil to remain in the system. This required remov-ing all the oil traps and blowing the pipes out with oxygen-free nitrogen (OFN). As a back-up, we also ran a separate recovery rig with an oil ac-cumulator in series with the chiller to catch any residual oil that remained after treatment with OFN.” The existing chillers were disconnected and dismantled in situ, and taken out in manageable sections through public access areas in the civic cen-tre. The Turbomisers were transported to the plant room in the same way Dave says: “Fortunately, Turbomiser chillers are fully modular so we were able to break them down, bring them in into the building in ‘kit form’ and rebuild them insitu in the plant room.” Cool-Therm fitted new refrigerant leak detection and emergency extract ventilation in the plant room to comply with current F-Gas regulations. The plant room also features a fully integrated compressor input/output board with an RS232 connection to a laptop or building management system. All the controls can be integrated with the Turbocor compressors.

Corrosion protectionGiven the coastal location, the specification of the aluminium condensers required special attention in order to safeguard them against maritime conditions and potential corrosion. The micro-channel condensers are designed to reduce refrigerant charge while, at the same time, increasing the effectiveness heat exchange. However, Swansea Civic Centre is located just 20m from the seafront and is constantly exposed to salt and sand and corrosive sea breezes. To protect against this, the micro-channel condensers were treated with an anti-corrosion coating to protect them from the elements. “The client wanted an extended warranty on the system. To achieve this given the location, we ensured that condensers were galvanised and then epoxy coated and that copper pipe work was PIB (pipe insulation billet), covered with galvanised wrapping on top of that. This ultra-corrosion resistant treatment enables the equipment to withstand the effect of the sea air and coastal weather conditions.” Turbomiser chillers are based on the Turbocor oil-free compressor, which uses virtually frictionless magnetic bearings to produce the most energy efficient product of its type on the market. Turbomiser chillers reduce energy costs by up to 50 per cent compared with traditional chillers.

TURBOMISER CHILLER

In addition to dramatically lower energy use, the main benefits of Turbomiser chillers are reduced refrig-erant leakage; less main-tenance due to the oil-free design; light weight (the compressor weighs 125kg compared with 600kg for traditional compressors); excellent part load efficien-cy; quiet operation, and reduced starting current of around 5Amps compared with some 600Amps for conventional compressors.

“TURBOMISER CHILLERS ARE FULLY MODULAR, SO WE WERE ABLE TO BREAK THEM DOWN AND BRING THEM INTO THE BUILDING IN KIT FORM.” DAVE BLACKMORE, COOL-THERM

The built-in control panel on the front of a Turbomiser chiller

A Turbocor compressor on one of the two Turbomiser machines

Unit 5 , Trubody’s Yard, 121 London Road, Bridgeyate, Bristol BS30 5NA

Email: enquiries@cooltherm.co.uk | Tel: 0117 961 006 | Fax: 0117 947 8642 | www.cooltherm.co.uk