ASHRAE-90.1-2022- - Page 378
Extracted Content
- Electrical input power for fans and pumps (before any speed or frequency control device ) at design condition and calculation of input value (W/cfm or W/gpm) d. A floor plan of the building identifying how portions of the building are assigned to the simulated blocks
(See Section L2.2.1) and which areas of the building are served by HVAC systems required to meet the requirements of Section 6.5 or Section 6.6.1.
Informative Note: The items listed under items (b) and (c) may either be included in the report generated by the simulation program or submitted separately. The compliance report required by Section L3.4 includes the composite systems entered into the program for the blocks. These may differ from actual sys- tems and may be based on capacity efficiency weighting per Section L2.2.3.1. The simulation program may allow input of individual actual systems and perform the weighting, or it may require the user to perform that weighting separately and input the weighted efficiencies . In the second case, the weighted efficiency calculation would be included under item (c) here.
L2.2 Proposed Building Information Required. The simulation of HVAC systems and the HVAC zones they serve shall be modeled based on building information required by this section.
L2.2.1 Simplified Block Approach. The geometry of buildings shall be configured using one or more simplified geometric simulation building blocks, referred to as “blocks” in this appendix. Each block contains one or multiple thermal blocks . A more complex zoning of the building shall be allowed where all thermal zones in the reference and proposed model are the same and rules related to block geometry and HVAC system assignment to blocks are met with appropriate assignment to thermal zones .
L2.2.1.1 Block Geometry. Each block shall define attributes including block dimensions, number of stories, floor-to-floor height, and floor-to-ceiling height. The simulation program is permitted to allow the use of simplified shapes (such as rectangle, L-shape, H-shape, U-shape, or T-shape) to represent blocks. Where actual building shape does not match these predefined shapes, simplifications are permitted providing the following requirements are met:
a. The gross conditioned floor area and volume of each block shall match the actual proposed design within
10%. b. The area of each exterior building envelope component from Tables 5.5-0 through 5.5-8 is accounted for
within 10% of the actual proposed design . c. The area of vertical fenestration and skylights is accounted for within 10% of the actual proposed design . d. The orientation of each component in items (b) and (c) is accounted for within 45 degrees of the actual
proposed design .
The user shall create multiple blocks , if necessary, to meet these requirements.
L2.2.1.2 Number of Blocks. One or more blocks shall be created per building based on the following restrictions:
a. Each block shall have only one building use type. At least one single block shall be created for each
unique use type, including where one HVAC system serves two different use types. b. Each block shall be served by only one type of primary or zonal HVAC system . A DOAS system shall be
permitted to serve blocks served by other systems . A single block shall be created for each unique primary or zonal HVAC system type and building use type combination. Multiple HVAC units of the same type are permitted to be represented in one block in accordance with Section L2.2.3.1. c. Each block shall have a single definition of floor-to-floor or floor-to-ceiling heights. Where story heights
differ by more than 2 ft, unique blocks shall be created for the stories with varying heights. d. Each block can include either above- grade or below- grade exterior stories . For buildings with both
above- grade and below- grade stories, separate blocks shall be created for each. For buildings with sto- ries partially above grade and partially below grade, if the total wall area of the story in consideration is greater than or equal to 50% above grade, it shall be simulated as a completely above- grade block; otherwise, it shall be simulated as a below- grade block. e. In order to combine multiple stories into a single block, each wall on a facade of a block shall have sim ilar vertical fenestration area . The product of the proposed design U-factor times the area of vertical fen- estration (UA VerFen ) on each facade of a given story cannot differ by more than 15% of the average UA VerFen for that facade in each block. The product of the proposed design solar heat gain coefficient ( SHGC ) times the area of vertical fenestration ( SHGCAVerFen ) on each facade of a given story cannot differ by more than 15% of the average SHGCAVerFen for that facade in each block. If these conditions are not met, additional blocks shall be created consisting of stories with similar fenestration .
376 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)