Advances in chiller technology will improve energy efficiency and drive down lifetime costs says Martin Storey (right), Tricool Engineering's sales director
The market for chillers has never been so good. The benefits of free cooling and government-backed initiatives driven by the Carbon Trust and its Energy Technology List (ETL), combined with Energy Efficiency Loans, have helped boost chillers sales.
Major advances in compressor technology and a shift in focus on lower-sized systems that can offer improved energy efficiency will offer even greater rewards and spell good news for the industry as a whole.
Free cooling was without doubt a major leap forward for the chiller industry. With environmental considerations high on the agenda for everyone these days, free cooling provides a major opportunity to save energy and money - good news for any facilities manager looking to cut costs and get more bang for his bucks.
The colder the climate, the greater the savings, although you can achieve partial free cooling during summer months too. Although free cooling systems can be up to 30% more expensive than standard chillers, they can offer short payback periods. Savings of £20,000 a year and a payback of less than 12 months can be achieved (depending on the application) with a total recovery of the cost of the chiller within three years (based on 450kW of cooling with water glycol required at 15ºC and electricity costs of 0.05p/kWh and 24/7 operation).
Chillers are energy demanding, and although free cooling goes a long way to reduce costs, the latest advances in technology will reduce overheads further, cut carbon emissions and deliver long-term business benefits.
The major advance is in compressor technology with increasing use of digital scroll compressors. These variable-speed and highly efficient generation of compressors offer huge energy savings over conventional scroll compressors. The digital scroll differs from an inverter type where the speed of the compressor varies with the changing load. A digital scroll switches between loaded and 100% unloaded. As a result, the compressor can offer better part-load efficiency than alternative compressors, generally a 20% improvement.
Scroll compressors are becoming the standard compressor at smaller capacity end of the market because of their better volumetric efficiency with the new refrigerants and screws or centrifugal will take over in the higher-capacity range.
The latest development from Tricool is its Turbocor oil-free compressor. Magnetic bearing technology, variable-speed centrifugal compression and digital electronic controls combine to save energy. A low start-up current (2A) reduces energy consumption and Tricool says the Turbocor can reduce maintenance bills too.
An oil-less compressor requires no lubrication, and contaminated oil is major reason why chillers fail. The compressor is also inverter-driven with only one moving part, reducing maintenance to one 15-minute operation every five years to change the capacitors.
Noise emissions are reduced as a result of magnetic bearings and on a practical front the overall size and weight of the compressors are five times lighter and half the size in design. An equivalent 300kW screw compressor would weigh about 600kg, whereas a chiller using Turbocor technology weighs 120kg.
Research consultancy BSRIA indicates a growing trend towards smaller chillers. This is as a result of decentralised systems combined with increasing concerns of building designers to provide partial back-up or 100% redundancy, particularly where critical applications are involved. As a result, manufacturers are looking to provide free cooling at the lower end of the scale with 10-100kW chillers. Even here, significant savings in electricity costs can be achieved, although the payback maybe slightly longer. Pricing is key with manufacturers having to achieve the right balance between initial costs and savings.
Other advances on the horizon include the size of condensers and evaporators, refrigerants and HFCs, micro-bore heat exchangers and more adaptive control algorithms.
The ETLs displays a considerable number of chillers. The list is constantly evolving as more manufacturers seek to get a listing. Those not listed are at a distinct commercial disadvantage. Customers have been galvanised into action, and energy efficiency and reducing carbon footprints are rapidly becoming a way of life. For many, the ETL is their first port of call. Being on the list signifies that products meet specific criteria, have endorsement by a government body and thereby gives a competitive edge over those not featured.
Although a powerful tool, the ETL is only a small part of the equation. Customers need to understand the carbon footprint of their whole plant and business. Anything we as manufacturers can do to improve the specification of our products and simplify that process can only help to drive technology forward and create new markets.