Turbomiser chillers chosen for R22 replacement at Salisbury Hospital
The installation of four R134a Turbomiser chillers to replace R22 units at Salisbury Hospital includes connecting them to remote air-cooled condensers by refrigerant pipework up to 75 m long and up to 92 mm on the discharge and 67 mm on the liquid lines. These copper tubes run beneath a road in a concrete-lined culvert.
The installation took nine weeks to complete and 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 previous chillers had screw compressors and were believed to be up to 20 years old. The Turbomiser chillers were installed on the existing mounting points, but occupy only two-thirds of the space.
Cool-Therm provided a complete turn-key installation, including design, supply, installation and commissioning. The company has secured a 5-year service and maintenance contract for the chillers.
In a previous project at the site, Cool-Therm supplied a packaged air-cooled Turbomiser chiller, complete with integral condenser, enabling it to be located in a restricted space in an enclosed area of the hospital.
The new chillers have an economiser based on a plate heat exchanger and provide cooling for the air-handling units that serve wards, administration areas and waiting rooms. They are linked to the hospital’s BMS. Control is based on return-water temperature. The BMS controls chiller sequencing and run-time to even out operational hours and prolong working life.
Rob Young, Cool-Therm’s project director, explained, ‘Due to the need to maintain continuity of cooling throughout, it required a carefully managed staged approach. Because of the time of year, we were able to remove three of the original chillers and leave one operational — after ensuring it was capable of meeting all anticipated demand.
‘When two of the three new systems were operational, the fourth original unit was decommissioned and removed, and the final chiller and associated condenser installed.’