[Trace-users] Baseline equipment modulation control

[Jason Dietterick]

Hello all,

I'm having some trouble interpreting what is required in regards to
modulation w/ heating and cooling equipment.  I have always trusted the
curves in the Trace ASHRAE library members however, I have recently seen
some conflicting documentation and model reports that are confusing me.
Per Trace curves, all equipment is inherently capable of modulation.  At
100% load, a boiler consumes 100% of the power and at 1% load a boiler
consumes 1% of the power.  It seems like Trace has this wrong.

The only thing I have been able to find in ASHRAE refers to cooling
part-load efficiencies, and states that minimum efficiency requirements
need only be adhered to if the compressors are capable of modulation.
However, there is nothing that defines whether or not compressors should be
modulating, so it would appear that the baseline is on/off.  There are no
specifics outlines in regards to boiler/furnace modulation that I have been
able to find either.

Can you tell me in your experience, what the requirements are for baseline
equipment modulation for all equipments types?  And does Trace really have
this wrong with all their ASHRAE library members or am I missing something?

Best,
Jason


-- 

*Jason Dietterick, CEM*
Associate

The Stone House Group
​
Suite 400

 ​​

301 Broadway
Bethlehem
 ​,​
 PA 18015
tel. 610 868 9600 | dir. 484 548 4007
fax 610 868 2272
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