ASHRAE-90.1-2022- - Page 199
Extracted Content
11.5.2.8.3 G03: Automated Shading Load Management. To achieve this credit, movable exterior shading devices shall be installed to reduce solar gain through south-oriented and west-oriented fenestration by at least 50% with load management controls that operate during peak summer electrical price periods.
Informative Note: This credit can be met by exterior roller, movable blind, or movable shutter shading devices; however, base overhang, screen or shutter, shading will not meet the requirement. Roller shades that reject solar gain but still allow a view are allowed as long as they provide an effective 50% reduction in net solar gain—e.g., have a shading coefficient of less than 0.5 for the shading material itself. Interior shading devices will not meet the requirement.
11.5.2.8.4 G04: Electric Energy Storage. To achieve this credit, electric storage devices such as batteries or flywheel devices shall be charged by load management controls to store electricity during off-peak periods and use stored energy during on-peak periods to reduce building peak period demand . Electric storage devices shall have a capacity between 0.5 Wh/ft [2] and 15 Wh/ft [2] based on project gross floor area . For capacity other than 1.0 Wh/ft [2], credits can be prorated as follows:
Installed electric storage capacity, Wh/ft [2]
--------------------------------------------------------------------------------------------------- G04 table credits 1.0
11.5.2.8.5 G05: HVAC Cooling Energy Storage. To achieve this credit, ice or chilled-water storage equipment shall be installed and load management controls configured to reduce electric cooling peak demand . Storage tank(s) shall be demonstrated through analysis to have less than 2% loss of stored capacity over a 24-hour period for the cooling design day.
Base energy credits in Section 11.5.3 are for storage capacity of 1.0 ton-hours storage per ton of designday cooling load with a 1.15 sizing factor. Prorate energy credits for other installed storage systems sized between 0.5 and 4.0 ton-hours storage per ton of design-day cooling load. Larger storage shall be permitted; however, credits are limited to 4.0 ton-hours storage per ton of design-day cooling load. Energy credits shall be determined as follows:
1.44 SR + 0.71
EC G05 _ adj = EC G05 _ base ---------------------------------------------2.15
where
EC G05_adj = energy credits achieved for HVAC cooling energy storage
EC G05_base = G05 base energy credit for building use type and climate zone based on ton-hours storage per
ton of design-day cooling load
SR = storage ratio in ton-hours storage per ton of design-day cooling load, where 0.5 ≤ SR ≤ 4.0
11.5.2.8.6 G06: Service Hot-Water Thermal Storage. To achieve this credit, where service hot water is heated by electricity, automatic controls activated by utility demand response signal, peak price period time control, or local building demand monitoring shall preheat stored service hot water before the peakprice period and suspend electric water heating during the period of peak prices coincident with peak build- ing load. Storage capacity shall be provided by either of the following:
a. Preheating water above 140 F delivery temperature with at least 1.2 kWh of energy storage per kW of
water heating capacity. Tempering valves shall be provided at the water heater delivery location. This option is not available where heat-pump water heating is used. b. Providing additional heated water tank storage capacity above peak service hot-water demand with
equivalent peak storage capacity to item (a).
11.5.2.8.7 G07: Building Thermal Mass. To achieve this credit, the project shall have both additional passive interior mass and a night flush control of the HVAC system . The credit is only available to projects that have at least 80% of gross floor area unoccupied between midnight and 6:00 a.m.
a. Interior to the building envelope insulation, provide 10 lb/ft [2] of project conditioned floor area of passive
thermal mass in the building interior wall, the inside of the exterior wall, or interior floor construction . Mass construction shall have mass surfaces directly contacting the air in conditioned spaces with directly attached gypsum panels allowed. Mass with carpet or furred gypsum panels, or exterior wall mass that is on the exterior of the insulation layer (e.g., the portion of CMU block on the exterior of insulation filled cell cavities), shall not be included toward the building mass required. b. HVAC units for 80% or more of the supply airflow in the project shall be equipped with outdoor air
economizers and fans that have variable or low speed capable of operating at 66% or lower airflow and be included in the night flush control sequence.
ANSI/ASHRAE/IES Standard 90.1-2022 (I-P) 197