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Sizing optimization of a central chilled water system

Your organization has decided to build a central chilled water plant to supply comfort cooling to several existing and planned future buildings. Among the immediate design decisions as well as siting the facility and distribution system routing, your charge is to size the central plant. While sizing a single building’s in-house chilling system might be fairly routine, the sizing of a central system is a much larger undertaking. Where do you begin?

How can you be comfortable with the capacity of the plant while avoiding the problems associated with an oversized facility.

Immediately it can be seen that designing and constructing a central chilled water system is a major undertaking and there are many decisions that must be made during the design process which play a critical role in the system’s performance, reliability, serviceability, etc. Almost without exception, the primary decision to be made, which will have a significant impact on the economics of the project, is the central plant sizing. The implications of under-sizing a central chilled water plant are evident – unhappy, hot customers whose chilling requirements are not being met. However, not quite as obvious are the implications of over-sizing a central system. The initial capital cost of the facility is tied directly to the capacity of the plant; from the chillers and pumps to the cooling towers, to the distribution system.

Capital expenditure on equipment that will be under-utilized or not used at all will have a detrimental economic effect on the project. Therefore, careful thought and attention must be given to the sizing decision during the design process.

Download the pdf that will offer optimization guidelines for the sizing of a central chilling plant. Information which is normally available at the beginning of such a project will be examined and then sizing experiences of existing central chilled water systems will be reviewed in order to establish “capacity sizing guidelines” for central chilling plants.