The type of HVAC system assigned to each thermal block of the reference building shall be determined based on each thermal block's building or space type using Table 8.4.4.7.A. with the corresponding descriptions in Table 8.4.4.7.B. The following table provides a description of the NECB Reference building HVAC system types:
A reference HVAC selection dialog based on Table 8.4.4.7.A has been included to help the user choose which system is appropriate for their particular building configuration.
While the selection dialog takes into account the selection criteria from Table 8.4.4.7.A the following additional considerations should be noted when selecting the reference system:
·Spaces generally located in the same vicinity shall be grouped together for the purposes of selecting the reference building's type of HVAC system.
·Small individual spaces in the proposed building that are located among larger spaces of another space type shall be considered ancillary to that larger space: for example, a conference room serving office spaces would be grouped with the office spaces as one space type. The HVAC system serving that space in the reference building shall be the same as the one for the larger space type.
·If the building or space type of a thermal block of the proposed building is not listed in Table 8.4.4.7.A., the type that most closely corresponds to that thermal block shall be used for the reference building.
·Where the area of a building or space type in the proposed building accounts for 10% or less of the total area of conditioned spaces, it is permitted to be excluded from the energy model, provided its area is added to an adjacent building or space type having similar space loads as those listed in Sentence 8.4.2.2.(1) and similar operating schedules as those determined in Sentence 8.4.3.2.
·For each thermal block of the proposed building having an HVAC system that includes a heat pump, the corresponding thermal blocks of the reference building shall be modeled with a type of HVAC system determined in accordance with Article 8.4.4.12.
It should also be noted that as per note to Table 8.4.4.7.B that, where present, humidification systems shall use the same energy source as the heating system.
