We are working on a residential project in climate zone 4A served by water loop heat pump system for heating and cooling. The baseline system is PTAC with fans running continuously throughout the year and compressor cycling based on heating and cooling load.
In the proposed case, the operation of the compressor and fan are controlled by cooling and heating load i.e. the compressor and fans will be off when heating/ cooling is not required. Additionally, the fresh air intake is through the unit's HVAC system.
According to G3.1 #4 Schedules "Schedules for HVAC fans that provide outdoor air for ventilation shall run continuously whenever spaces are occupied and shall be cycled on and off to meet heating and cooling loads during unoccupied hours."
Due to intermittent operation of unit's HVAC system, the fan equivalent full load hours (EFLH) are much lower than the baseline case. The schedules for HVAC fans are identical in both the baseline and proposed case.
To meet the ventilation requirement in the residential units when HVAC system is not operating during occupied hours. Can we demonstrate ventilation through suction of toilet exhaust and operable windows. We have exhaust fans in toilets of each residential units which will run continuously. As per EnergyStar Multifamily high-rise program, the continuously operating exhaust fans that pulls fresh air through any opening meet the requirement of "HVAC fan schedule" section.
Will this suffice the requirement of ventilation provision and ASHRAE modelling protocol for LEED EAp2 and c1?