[Equest-users] Boiler HEAT-EQUIP-CTRL for accurate part-load performance

[Brian Fountain]

If you set up a heating equipment control with all the boilers with the same
sequence priority (probably 1) then they will all fire simultaneously and
ramp down to handle the load.

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Bishop,
Bill
Sent: Thursday, February 21, 2013 10:27 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Boiler HEAT-EQUIP-CTRL for accurate part-load
performance

 

I have been experimenting with Equipment Control on a hot water loop to try
to maximize the benefit of multiple condensing boilers, but I can't seem to
reduce gas consumption below that using no equipment control (and for most
of my experiments it actually increases). Condensing boilers are most
efficient at part load. Obviously the first things to do to accurately
capture the energy savings potential of condensing boilers (after setting
BOILER:TYPE to "Condensing." is to enter the following values:

BOILER:CAPACITY

BOILER:HEAT-INPUT-RATIO

BOILER:MIN-RATIO (a 20:1 turndown would be .05)

HW loop DESIGN-HEAT-T

HW loop LOOP-DESIGN-DT

HW loop HEAT-SETPT-CTRL to "OA Reset" with assigned HEAT-RESET-SCH

HW loop LOOP-OPERATION to "Demand" (if appropriate)

 

Is there a way to use Equipment Control to keep multiple boilers at part
load while minimizing cycling losses from BOILER:START-UP-TIME and
STANDBY-TIME, or does eQUEST stage the boilers efficiently automatically?

I have observed multiple old, large HW and steam boilers on a single loop
running simultaneously when one boiler could clearly satisfy the load. Can
anyone suggest a HEAT-EQUIP-CTRL to represent this? Does anyone have
different START-UP-TIMEs or STANDBY-TIMEs suggestions based on field
observations? Anyone know of any white papers or IBPSA presentations on the
topic?

 

Thanks,

Bill

 

 <mailto:wbishop at pathfinder-ea.com> Senior Energy Engineer 28Jun2012

 

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