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Replace R11 Chillers

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  rev. 2008-12-07        

Existing Conditions

The facility has an R11 chiller plant at the end of its useful life (xxx years old).  Legislated CFC phase-out has caused it to become increasingly difficult to operate an R11 chiller.

In Canada , production of CFC refrigerants has been phased out since 1996.  As of January 1, 2005, owners were no longer allowed to replace the refrigerant after a chiller overhaul, defined as the following:

•  Maintenance requiring the replacement of any internal sealing devices;

•  Maintenance requiring the replacement of any internal mechanical parts, other than oil heaters, oil pumps, float assemblies, and vane assemblies in the case of chillers with single-stage compressors; or

•  Maintenance resulting from the failure of evaporator or condenser heater exchanger tubes.

Because building owners have been very slow to respond to this deadline, an exemption to allow for the charging of a chiller and its continued operation with CFCs following an overhaul is available on the condition that the system is converted, replaced or removed from service no later than 12 months from the date of the charge.  This exemption involves significant documentation, and it is our expectation that the 12-month grace period will be vigorously enforced.

The R11 chiller owner can choose to wait until there is a significant failure before addressing the issue.  However, any investment in the repair at that point will probably be lost, because once an exemption has been granted, replacement of the machine or an expensive upgrade to change refrigerants will be the only options.

Retrofit Conditions

We recommend that the R11 chillers be replaced with more efficient R134a chillers, with a variable speed compressor for optimized part-load operation.  The chillers will have to be resized based on current cooling loads and operating experience.  The average chiller efficiency must be 0.56 kW/ton or less in order to achieve desired energy savings.  There will be a trade-off between chiller cost, chiller flexibility and chiller efficiency.

Based on site observations, it appears that the remaining major equipment (cooling towers, pumps, and controls) are in reasonable condition so we have not included replacement of those components in the pricing.  A life cycle costing analysis of these components is recommended at design time to determine if it makes sense to replace them at the same time as the chillers.

< Based on site observations, it appears that the remaining major equipment (cooling towers, pumps, and controls) are also nearing the end of their useful lives, so they should be replaced at the same time.  Chiller plants involve complex interactions among components, and replacing the entire plant at once will result in better optimization and overall efficiency.>

Further Benefits

R11 is a restricted substance with highly-regulated handling procedures.  It has become very expensive to procure and work with.  Maintenance contracts and emergency repair work for the new chillers will be less expensive.



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