3.7.6.3 Hydronic/Steam Heating Coils

Systems with boilers have heating coils, including baseline building systems 1, 5 and 7.

Heating Coil Capacity
Applicability	All systems with a hydronic heating coil
Definition	The heating capacity of a heating coil at ARI conditions
Units	Btu/h
Input Restrictions	As designed. Adjust the capacity if the number of unmet load hours exceeds 300.
Baseline Rules	Autosize with a heating oversizing factor of 25%. If the number of unmet load hours for the baseline exceeds 300, increase the heating coil capacity as described in Chapter 2.

Systems with boilers have heating coils, including baseline building systems 1, 5, 7, 11 (for climate zones 3B to 8), and system 12. Two-way valves are assumed at the baseline system heating coils with a single three-way bypass valve at the end of the loop.

*Heating Coil Capacity*
Applicability	All systems with a heating coil
Definition	The heating capacity of a heating coil at ARI conditions
Units	But/h
Input Restrictions	As designed. Adjust the capacity if the number of UMLH exceeds 300.
Baseline Building	Autosized, with a heating oversizing factor of 25%. Sizing calculations shall be based on the heating design day and cooling design day conditions, as defined in Section 3.2.3 of this document. Oversizing would be carried out at zone level where the sizing parameters would be applied to the zone design heating loads, but not the airflow rates. If the number of UMLH for the baseline exceeds 300, heating coil capacity may need to be increased along with system airflow as described in Section 2.7.2 of this document.

G3.2 New Construction/Major Alterations

Systems with boilers have heating coils, including baseline building systems 1, 5, 7, 11 (for climate zones 3B to 8), and system 12. Two-way valves are assumed at the baseline system heating coils with a single three-way bypass valve at the end of the loop.

G3.3 Minor Alterations

Hydronic/steam heating coils are applicable to the baseline where they are specified in the proposed design.

Heating Coil Capacity
Applicability	All systems with a heating coil
Definition	The heating capacity of a heating coil at AHRI conditions
Units	But/h
Input Restrictions	As designed. Adjust the capacity if the number of UMLH exceeds 300.
Baseline Building	G3.2 New Construction/Major Alterations Autosized, with a heating oversizing factor of 25%. Sizing calculations shall be based on the heating design day and cooling design day conditions, as defined in Section 3.2.3 of this document. Oversizing would be carried out at zone level where the sizing parameters would be applied to the zone design heating loads, but not the airflow rates. If the number of UMLH for the baseline exceeds 300, heating coil capacity may need to be increased along with system airflow as described in Section 2.7.2 of this document. G3.3 Minor Alterations Heating coil capacity for the baseline design shall be sized proportionally to the capacities in the proposed design based on sizing runs—i.e., the ratio between the capacities used in the annual simulations and the capacities determined by the sizing runs shall be the same for both the proposed design and baseline building design.