§ 140.1
This section is a summary of the analysis procedures used to demonstrate building compliance when using approved compliance software programs. Software users and those checking for enforcement should consult the most current version of the compliance software user’s manual and/or on-line help and associated compliance supplements for specific instructions on the operation of the compliance software. Although there are numerous requirements for each software input, the data entered into each software version may be organized differently from one vendor to the next. As a result, it is not possible in this summary to present all variables in their correct order or hierarchy for any one software version. The aim is to identify the procedures used to calculate the standard and proposed design TDV energy and HSE budgets.
Any compliance software version approved by the Energy Commission may be used to comply with the Energy Standards. The following steps are a general outline of the process:
1. All detailed data for the building components must be collected including areas and performance properties (i.e., U-factor, SHGC, R-Value, and other thermal properties) for fenestration, walls, doors, roofs, ceilings, floors, and other construction assemblies; and specifications for HVAC and other mechanical equipment, lighting systems, and water heating systems based on the building design plans, drawings, and/or specifications.
2. Although most compliance software requires the same basic data, some information requirements, and the way it is organized in the software may vary according to the software used. Refer to the compliance supplement that comes with each version of compliance software for details.
3. Be sure that the correct climate information has been selected for the building site location (see Reference Appendix JA2). Compliance software also adjusts outside heating and cooling design temperatures for local conditions using ASHRAE design data that is also located in Reference Appendix JA2.
4. Prepare an input file that describes the other thermal aspects of the proposed design according to the rules described in the software’s compliance supplement.
5. Input values and assumptions must correctly correspond to the proposed design and conform to the required mandatory measures.
6. Run the compliance software to automatically generate the energy budgets of the proposed and standard design buildings.
When creating any computer input file, use the space provided for the project title information to describe concisely and uniquely the building that is being modeled. User-designated names should be clear and internally consistent with other buildings being analyzed in the same project. Title names and explanatory comments should assist individuals involved in both the compliance and enforcement process.
The following elements are examples of the information used by compliance software programs to calculate the standard design energy budget and proposed design building energy use. All information entered into the proposed building model, like those shown below, must be consistent with the plans and specifications submitted in the building permit application:
•Opaque Walls: Each opaque exterior wall construction assembly, wall area, orientation, and tilt. Heat capacities, or characteristics necessary to determine the heat capacity (conductivity, mass, volume) of opaque exterior walls, must be included. Interior demising wall area and characteristics must also be input.
•Doors: All doors must be included.
•Opaque Roofs/Ceilings: Each opaque exterior roof/ceiling construction assembly, roof/ceiling area, solar reflectance, thermal emittance, orientation, and tilt. Heat capacity, or characteristics necessary to determine the heat capacity (conductivity, mass, volume) of opaque exterior roof/ceilings, must be included.
•Raised Floors and Slab Floors: Each floor construction assembly, including floor area.
•Fenestrations in Walls and Shading: Each vertical glass area, orientation, tilt, U-factor, Solar Heat Gain Coefficient (SHGC), and Visible Transmittance (VT). Shading from permanently affixed shading devices, such as window overhangs and fins should be included in the model. Shading inputs consist of device depth, distance, and extension relative to the glass.
•Horizontal (Skylight) Fenestration: Each horizontal or skylight glass area, orientation, tilt, U-factor, SHGC, and VT.
•Ventilation Air: Ventilation (introduction of outside air) values in cubic feet per minute (cfm).
•Fan Power: Fan power must be included. Fan power should be based on shaft brake horsepower at the equipment’s rated condition (modeled horsepower must be substantiated by information contained in the construction documents).
•Cooling and Heating Efficiency: The efficiency of the equipment included in the proposed design at AHRI conditions.
•HVAC System Type: The basic type of the cooling and heating system (multiple zones or single zone) and the heating system fuel type (fossil fuel or electric). Note that some projects may have different system types serving separate zones.
•Sensible and Total Cooling System Capacity: Sensible and total output capacity of the cooling system at AHRI conditions.
•Heating System Capacity: The output capacity of the heating system.
•Indoor Lighting: Lighting loads and modeling non-mandatory controls for credit.
•Water Heating: The water heating capacity, volume, and efficiency (including any solar thermal contribution).
•Photovoltaic (PV) and Battery Storage: Required inputs include PV system direct current (DC) size in kW, description of PV system (i.e., standard or premium modules, fixed or tracking array, microinverters or DC power optimizers, solar access percentage), battery system capacity in kWh, and battery system description (i.e., basic or advanced control, and charge/discharge efficiencies and rate)
•Other System Values: All other space conditioning system components, process loads, or any other mechanical system that impacts the building energy performance must be included in the input file.
Refer to the compliance software user’s manual for information on all required modeling inputs and more detailed information on how each input is used by the software.
The TDV and HSE proposed design energy use and standard design energy budgets are separated into compliance totals, which are the basis for building compliance with the performance method, and total building energy use, which adds receptacle, process and other nonregulated energy usage.
The compliance total energy can be summarized into three main components:
1. The space conditioning energy use.
2. The indoor lighting energy use.
3. The service water heating energy use.
Non-regulated energy; process, receptacle, other lighting, and process motors; is treated as compliance neutral. The standard design will always match the proposed energy usage for these categories.
The proposed building energy use is defined by §140.1(b) (nonresidential) and §170.1(b) (multifamily) and includes the envelope, space conditioning and ventilation, indoor lighting, and water heating systems assigned to the building. The key component of calculating the TDV energy and HSE use of the proposed building is that if a feature of the building is not included in the building permit application, the energy use of that feature is equal to that of the standard design energy budget defined in §140.1(a) (nonresidential) or §170.1(a) (multifamily). That means that if a permit is submitted for a building shell (envelope only), and the performance approach is used to demonstrate compliance, trade-offs cannot be made between the envelope and the mechanical or lighting system.
The standard design budget is defined by replacing all of the energy features of the proposed building with the prescriptive requirements in §140.3|topic=SECTION 140.3 – PRESCRIPTIVE REQUIREMENTS FOR BUILDING ENVELOPES (nonresidential) or §170.2 (multifamily) of the Energy Code. Details of the standard design features are documented in the NRMFACM Reference Manual.
The space conditioning energy budget is automatically determined from the software’s user inputs and the corresponding elements of the proposed design. This budget is automatically re-calculated with each compliance run.
The indoor lighting energy budget consists of the lighting power used by a building based on one of the following criteria:
•When no lighting plans or specifications are submitted for permit and the occupancy of the space is not known, the standard lighting power density is 0.40 W/ft².
•When no lighting plans or specifications are submitted for permit and the occupancy of the space is known, the standard lighting power is equal to the corresponding watt per ft² value derived in the Area Category Method of §140.6(c)22 (nonresidential) or §170.2(e)3C (multifamily).
•When lighting plans and specifications are submitted for permit, the standard lighting power is equal to the corresponding total allowed lighting power (in watts) that was used in calculating the proposed lighting level which can be based on either the Area Category Method or the Tailored Method in §140.6(c)2 or 3 (nonresidential) or §170.2(e)3C or D (multifamily). A complete set of lighting plans and prescriptive documents are required to use the Tailored Lighting Method in the performance approach. When this method is used to justify an increase in the allowed lighting watts, a lower lighting load in the proposed design cannot be modeled for credit. The standard design building uses the lesser of allowed watts or actual lighting power to be installed in the building. The proposed design building uses the actual lighting power to be installed as detailed on the lighting plans. This value must be equal to or less than the allowed watts.
For all occupancies except hotel guest rooms and multifamily dwelling units, the proposed lighting power is input into the software. For hotel guest rooms or multifamily dwelling units, the compliance software will automatically set the proposed lighting power and the standard design lighting power at the same value as specified in the NRMFACM Reference Manual.
The service and domestic water heating energy budgets consist of the water heating energy used by a building assuming the water heating systems meet both the mandatory and prescriptive requirements for water heating.
The service and domestic water heating standard designs are documented in the NRMFACM Reference Manual.