Dear Collegue,

I have some questions for Baseline model's System control

The project has the baseline system (System-7 VAV Reheat, Climate Zone 4A)

The ASHARE 90.1 2010 G3.1.2.11 states that "Exhaust air energy recovery shall be modeled for the budget building design in accordance with section 6.5.6.1 ", but 90.1 2010 User manual stage that "Exhast energy recovery is required for fan systems that are lager than 5,000 cfm(2,360 l/s) that also require a significant amount of outdoor air (70% or more of

1. Which criteria should be considered first?

secction 6.5.6.1 or G3.1.2.11

I wonder if ERV is not applied regardless of the climate zone if the ratio of the calculated OA/SA  does not exceed 70%.

2. Baseline System-7 heating 

the project located in the region has the summer and winter seaon(cooling design OA :  34 ℃/ heating design OA :  -10 ℃)

and the indoor temperature set-point is (cooling :  26 ℃, Heating : 20 ℃). 

In accordance with  the ASHRAE 90.1 2010 G3.1.2.9.1, the baseline cooling SA temperature was modeled at 15 ℃

If so, how should the heating supply air temperature be set in this case? 

3. The electric preheat coil in the hotwater coil AHU

The project has the electric heating coil for de-frost in winter season but the system's main heating coil use the hot-water.

In this case, the electric preheat coil was modeled as a process load or as a another electric heat soure for preheat coil in the baseline model?

Thanks for answers.