A major R22 chiller replacement project at Salisbury Hospital has set what is believed to be a new industry record for underground refrigerant pipework on a Turbomiser installation.
Four new chillers, with a combined cooling capacity of some 1.4 MW, are connected to air-cooled condensers by DX pipework up to 75 m long.
The large-gauge copper tube runs beneath a road in a concrete-lined culvert.
The installation, which took nine weeks, required refrigerant pipe to be mounted on custom-fabricated brackets every 1.5 m along the length of the underground structure. Each chiller and condenser is on an independent circuit.
The high-efficiency R134a-based chillers replace four ‘ageing’ R22-based Hitachi units, on dual screw compressors. The Turbomisers were installed on the existing mounting points, but occupy just two-thirds of the space, ‘due to their high performance relative to their size’. Fitted with an economiser based on a high-efficiency brazed plate heat exchanger, they provide cooling for the hospital’s air-handling units, serving wards, administration areas, and waiting rooms. They are linked to a hospital-wide building energy management system (BMS), with control based on return water temperature. The BEMS controls chiller sequencing and run-time to even out operational hours and prolong working life.
Cool-Therm’s complete turnkey service included design, supply, installation, and commissioning. The company also secured a five-year service and maintenance contract for the chillers.
