Chilled water systems are a significant portion of a building’s energy picture, sometimes accounting for up to 40% of peak demand and 15% – 25% of annual energy usage for a large building. That makes efforts to reduce the amount of energy used by a chilled water system worthwhile.

Control sequences in the Building Automation System (BAS) are written to identify and respond to many variables that impact chilled water system energy.  Engineers write, and BAS vendors implement, control sequences that are intended to meet the system demand, operate within safe parameters, protect the equipment, and perform those tasks as efficiently as possible within the capability of the BAS.

Another software tool for controlling system operation is a Chiller Energy Optimization System (CEOS). Consulting engineers hear, from the CEOS vendors, that the CEOS not only meets system demand and protects the equipment but doe it more efficiently. They also hear, from many BAS vendors, that “we can do that.”

So, what’s the difference? And is a separate CEOS worth the investment?

In a recent article for Consulting-Specifying Engineer, Rick Wood, PE, explains the nuances and specifics between how a CEOS operates vs a BAS and what a CEOS claims to do that a BAS cannot do. The article also shows the relationship between the CEOS, which “sits on top of” and gives direction to the BAS, and how that relationship is crucial to realizing the value of a CEOS. (The article begins on page 6.)

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