[Bldg-sim] unmet load hours of VAV+baseboard system

[Jessica XP]

Dear folks,

I am simulating an office building to be LEED-certified.

The system for the proposed design is VAV+baseboard radiation. The system
contains no reheating and preheating.

The system for the baseline is VAV with reheat, but without preheat.

The unmet load hours for both models are significant and sim file outputs
warnings as below:

"Warning message"

 **WARNING**********************************************************************
             PREHEAT/HEATING-CAPACITY in SYSTEM E1 Sys1
(VAVS)
             is too low to provide the requested supply temperature for
             the calculated mixed air temperature using total ZONE loads
             (on LS-A/B) and SYSTEM design parameters, plus outside air
             conditions (on LS-C), and specified capacities & air flows.
             Requested temperature is  52.00 calculated is  48.87
             Check HEATING-CAPACITY, HEAT-SET-T, PRE-HEAT-T, MAX-SUPPLY-T,
             DESIGN-HEAT-T, and ZONE loads for consistency.


I am wondering if any expert could tell me what accounts for warnings and
the high unmet load hours, and how to reduce it.

Thank you

Jessi Xu
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