Meeting increasing heat loads and rising fuel costs head on, the Yorkshire Building Society (YBS) has worked with Airedale, to reduce building energy costs by replacing an existing, less efficient chiller with Airedale’s low energy free-cooling technology in its main call centre offices.
YBS is the fourth largest building society in the UK, with 1.8 million members, assets of £16.3 billion and 131 branches across the UK. It prides itself on being one of the most cost-efficient building societies with an on-going commitment to the environment. Based in Bradford, West Yorkshire, the YBS head office and main call centre are part of two purpose-built £40 million developments, employing over 1000 staff.
Representing £10 million of this investment, the four storey call centre accommodates workstations for 300 people; refreshment and staff comfort zones and a data centre cooled by two AlphaCool close control units. The 3,200 m² of operational space in this sealed building is now fully utilised, with people and computers creating a high heat gain. In this busy, business critical application, calls are constantly received from branches, investors and borrowers twelve hours a day, six days a week and during this time, continuous business operation is crucial.
With the call centre at full capacity, the existing, standard chiller was unable to cope with the increasing heat load and maintain temperatures at the required 23ºC setpoint, leading to uncomfortable working conditions for the staff.
Yorkshire Building Society Premises Engineer Steven Ward wrote the specification for an Ultima FreeCool (UFC) 500 kW dual-circuit Chiller: “Quality was important but energy efficiency was the crucial factor and Airedale proved that its free-cooling chiller can save energy and is the right system for us. The initial purchase price is far outweighed by the savings we can make on running costs. Anything that improves payback is of interest to the Society.”
Typically saving 35% of the energy used by a conventional air-cooled liquid chiller, the UFC uses a free-cooling cycle to reduce the need for mechanical cooling, giving priority to free-cooling as soon as the ambient temperature is 1ºC less than the return water. In the evenings when the call centre is open until 8pm and ambient temperatures are lower, energy consumption can be reduced further. During the coldest part of the year, free-cooling can totally satisfy the cooling load, saving energy otherwise used in the mechanical operation of the compressors, evaporator and fans. For maximum energy saving the UFC can operate on simultaneous mechanical and free-cooling for up to 50% of the year and only needs to operate completely on mechanical cooling for about 38% of the year.
With the minimum of interruption to the operation of the call centre, Mitton Mechanical Services conducted the lifting operation and installation work after temporarily removing structural steelwork and extracting the old chiller.