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--- design [2016/04/12 19:08] – created 24.229.224.101
+++ design [2020/10/04 15:41] (current) – old revision restored (2020/09/30 22:02) frozenlock
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-====== Sequence of Controls ======
+====== Design ======
-There are probably hundreds of thousands of sequences of controls that have been written to control everything from a simple pump or fan operating on a schedule to very complex (and often proprietary) chiller plant optimization algorithms.  Among the multitude of sequences written and implemented to date, these sequences offer a broad spectrum of reliability, functionality, ease of implementation, energy efficiency, alarms/notification, etc.  In the interest of gathering the best practices of firms for control of the most common types of HVAC systems, ASHRAE formed a committee to author Guideline 36.
->Guideline 36 was created by ASHRAE’s Technical Committee 1.4, Control Theory and Application to maintain and publish best-of-class control sequences that meet or exceed the requirements of published ASHRAE standards such as 90.1, 62.1 and 55. These sequences are intended for use with fully programmable DDC BAS systems controlling variable speed/capacity equipment.
+===== Control Sequences =====
-As of April 2016, the committee has addressed the most common types of air-side HVAC systems.  Their work is [[http://gpc36.savemyenergy.com/public-files/|published for free download]] as part of the public review process.
+A poor control sequence can completely neuter the best equipment selection, layout, and painstaking coordination.  On the other side of things, a great Sequence can sometimes mask design deficiencies.  Along with specifications and control diagrams, the [[.:design:control-sequences|control sequences]] is where the rubber meets the road, so to speak in an HVAC design.  It is through a Sequence that all of the required and desired functionality is conveyed to the BAS contractor.  This includes different modes of operation (think heating versus cooling), allowable operator overrides, alarms, etc.  It can be a time-consuming process to write a robust Sequence that delivers the strikes the right balance between useful functionality & frivolous modes, actionable notifications & nuisance alarms, robust operation & susceptibility to getting caught in logic loops.