Non-Coincident and coincident Peak Demand

[electrics]

coincident load and peak demand
Non-coincident load and peak demand
What are these?

 

[bob]

Check here
http://www.google.com/search?source...nUS396US396&q=coincident+load+and+peak+demand

 

[electrics]

dear bob I googled it already, I just plead a nice and clear explanation . Thank u..

 

[charlie b]

The notion of coincident or non-coincident has to do with whether two or more loads have the ability to run at the same time. For example, a chilled water system might have four chilled water pumps, but the control system might be set up in such a way as to prevent more than three from running at the same time. That is, if three are running, the fourth is locked out. In such circumstances, the load calculation only needs to account for the KVA associated with three pumps. So three pumps count as ?coincident loads,? and the fourth counts as a ?non-coincident load.? Then if you are using ?coincident? and ?peak demand? together, you must be addressing the total load of the three pumps.

 

[electrics]

Okay guys I see there is something I wanna ask finally, is diversity factor inversely proportinal to the demand factor? Can such an conclusion be arrived?

 

[charlie b]

. . . is diversity factor inversely proportional to the demand factor?

It is not. In fact, I don't think the NEC uses the two word phrase "diversity factor." It speaks of load diversity from time to time, but that is a separate thing entirely.

Article 100 has is a formal definition of ?demand factor.? It is almost word for word the same as the definition in one of my engineering textbooks. Having said that, I just realized that the way the NEC defines that phrase and the way the NEC uses it within article 220 are similar, but not precisely the same. The definition is talking about how much of the total connected load is actually running at the same time. The way the book uses the phrase is to tell us how much of the total connected load we are allowed to consider as being running at the same time, so that our load calculation does not have to account for all of the connected load.

The same textbook has a definition of ?diversity factor.? It has nothing whatsoever to do with the way the NEC speaks of ?load diversity.? It has to do with comparing the maximum demands of portions of a distribution system (e.g., the individual max demands of each building on a university campus) to the maximum demand of the system as a whole.

 

[dbuckley]

In the UK the word 'diversity' has much of the same connotations as coincident loads; a suitably competent person can apply diversity to reduce the calculated load of an installation down from the aggregate of the breaker sizes.

There used to be rules for it, similar to the NEC, but no longer.