Hello Everyone,
I have modeled the baseline case using the PIU HVAC system and in the
proposed case, SZR system is considered.
The temperature schedules & fan schedules are the same in both the cases.
When I assigned the night cycle control ?Cycle On Any? to both the cases,
the consumption of fans in the proposed model increased by 2.5 lakh units
whereas in the baseline case, it was increased by 10000 units only.
I have created the customized hourly report for both the cases and it has
been observed that whenever the ?Current hour zone thermostat setting? has
-999 in that case, the fan is not in operation.
This is the case in the baseline model where most of the time in unoccupied
hours, the current hour zone thermostat setting is -999 whereas in the
proposed model, the current hour zone thermostat setting is 82 which keeps
the fan in operation.
Due to this the consumption of proposed fan energy consumption is more
compared to the baseline model.
Can anyone help me how to keep current hour zone thermostat setting in both
the cases same to have the fan power consumption to be increased
proportionate when the night cycle control is assigned in both the cases.
Hello Nitin,
-999 in the context of fan schedules is typically intended for optimized warmup (variable starting times prior to occupancy. You might for simplicity reasons wish to switch to 0?s during unoccupied hours in both models, at least until you resolve this matter of unintuitively larger runtime with the proposed case.
Zone thermostat settings (setpoints) should match for all hours between both models, typically/implicitly, for most prescriptive modeling protocols. Your phrasing suggests the case of 82 F in the proposed case is unique?
Otherwise, the phenomenon of CYCLE-ON-ANY producing more fan runtime in one model vs. another can be directly attributable to how often each model will have one or more zones falling outside of the throttling range. Put loosely, if your proposed model features more unmet hours than the baseline, then that is a likely primary issue that would resolve the secondary matter of night cycling runtime.
I hope these are helpful points to help guide you in the right direction!
~Nick
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Nick Caton, P.E. (US), BEMP
??? ????, P.E. (US), BEMP
Senior Energy Engineer
Energy Manager, Yokota Airbase
ESS - Energy & Sustainability Services
M JP
M US
Email
+81 . 070 . 3366 . 3317
+1 . 785 . 410 . 3317
nicholas.caton at se.com
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