This section is a summary of the analysis procedures used in demonstrating compliance with approved compliance software programs. Program 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 program. Although there are numerous requirements for each compliance software input, the data entered into each software version may be organized differently from one program 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 program. The aim is simply to identify the procedures used to calculate the standard design energy budget and the TDV energy use of the proposed building.
11.2
Any approved compliance software version may be used to comply with the Standards. The following steps are a general outline of the process:
•All detailed data for the building component or components must be collected including fenestration areas and energy properties, wall, door, roof/ceiling, and floor areas, construction assemblies, solar heat gain coefficients, mass characteristics, equipment specifications, lighting, and service water heating information from the drawings and specifications.
•Although most computer programs require the same basic data, some information, and the manner in which it is organized, may vary according to the particular program used. Refer to the compliance supplement that comes with each program for additional details.
•Be sure that the correct climate information has been selected for the building site location (see Reference Joint Appendix JA2). Compliance software also adjusts outside heating and cooling design temperatures for local conditions using ASHRAE design data, which is also located in Joint Appendix 2.
•Prepare an input file that describes the other thermal aspects of the proposed design according to the rules described in the program’s compliance supplement.
•Input values and assumptions must correctly correspond to the proposed design and conform to the required mandatory measures.
•Run the computer program to automatically generate the energy budget of the standard design and calculate the energy use of the proposed design.
11.3
11.3.1
11.3.1.1 Computer Input Files
When creating any computer input file, use the space provided for the project title information to concisely and uniquely describe the building 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.
11.3.2
11.3.2.1 The following elements
The following elements are used by approved computer programs. These elements must be consistent with plans and specifications submitted in the building permit application:
•Opaque Exterior Walls: Each opaque exterior wall construction assembly, as well as 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.
•Doors: All doors must be included.
•Opaque Roofs/Ceilings: Each opaque exterior roof/ceiling construction assembly, as well as roof/ceiling area, solar reflectance and 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, as well as floor area.
•Fenestrations in Walls and Shading: Each vertical glass area, orientation, tilt, U-factor and solar heat gain coefficient.
•Horizontal (Skylight) Glass and Shading: Each horizontal or skylight glass area, orientation, tilt, U-factor and solar heat gain coefficient.
•Ventilation (Outside) Air: Ventilation (or outside air) values in cfm/ft².
•Fan Power: Fan power must be included. Fan power should be based on either brake horsepower (HP) at ARI conditions, nominal HP at ARI conditions, or brake horsepower at actual operating conditions (modeled horsepower must be substantiated by information contained in the construction documents).
•Cooling and Heating Efficiency: The actual efficiency of the equipment included in the proposed design.
•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.
•No Heating or Cooling Installed: If total heating or cooling capacity is not specified, the TDV energy use will be based on a standard design heating or cooling system (§140.1(b)).
•Sensible and Total Cooling System Capacity: Sensible and total output capacity of the cooling system at ARI conditions.
•Heating System Capacity: The output capacity of the heating system.
•Indoor Lighting: Lighting loads and modeling non-required controls for credit
•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
11.3.2.2 Compliance Software
Refer to the compliance software user’s 'manual for more detailed information on how each of the above values is used by the program.
The compliance software calculates TDV energy for three main components: the space conditioning energy use, the indoor lighting energy use, and the service water heating energy use. It does not allow energy credits or penalties for plug loads (even though a default value for the internal gains from plug loads are modeled in the hourly computer simulation), vertical transportation (elevators), garage ventilation, outdoor lighting or other miscellaneous energy uses.
The proposed building energy budget is defined by §140.1(b) 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 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 energy budget defined in §140.1(a). That means that if a permit is submitted for a shell building (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 a combination of the envelope features 'listed in the prescriptive package requirements in Tables 140.3 B or C and the lighting and mechanical values associated with the building occupancy and. design defined in the Alternative Calculation Reference 'Manual.
11.3.3
11.3.3.1 Space Conditioning Energy Budget
The space conditioning energy budget is automatically determined from the program user’s inputs and the corresponding elements of the proposed design. This budget is automatically re-calculated with each compliance run.
11.3.3.2 Lighting Energy Budget
The indoor lighting 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 building is not known, the standard lighting power density is 0.6W/ft².
•When no lighting plans or specifications are submitted for permit and the occupancy of the building is known, the standard lighting power density is equal to the corresponding Watt per ft² value derived in the Complete Building Method of §140.6(c)1.
•When lighting plans and specifications are submitted for permit, the standard lighting power density 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 Complete Building Method, the Area Category Method, or the Tailored Method [§140.6(c)1, 2 or 3]. . For "merchandise sales" areas, where the proposed lighting power is lower than the Prescriptive allowed lighting power, the ACM program calculates the proposed lighting power at the Prescriptive allowed lighting power. A complete set of lighting plans and prescriptive forms are required for use of the Tailored Lighting Method in the performance approach.
For all occupancies except hotel guest rooms and high-rise residential living quarters, the proposed lighting power density is expressed in W/ft². For residential occupancies (hotel guest rooms or high-rise residential buildings), the approved computer program will set the proposed lighting power density and the standard design LPD at the same the value as specified in the Nonresidential ACM Reference Manual.
11.3.3.3 Service Water Heating Energy Budget
The service water heating budget consists of the service water heating energy used by a building, assuming the service water heating system meets both the mandatory and prescriptive requirements for water heating.
The service water heating TDV energy use is calculated using one of two methods. For nonresidential occupancies a method described in the Nonresidential ACM Reference Manual uses the proposed design with minimal efficiency equipment as the standard design. For hotel, motels and high-rise residential buildings the method is described in the Residential ACM Reference Manual. This method sets the standard design based on gas fired equipment using either individual water heaters in each unit or a central system to define the standard design. The installed system must be consistent with plans and specifications submitted in the building permit application. When complete building method performance approach is used for nonresidential occupancies the service water heating systems must be included in the performance analysis. If mechanical compliance is met using prescriptive approach water heating can also use the prescriptive approach.
For high-rise residential buildings, hotel and motels the water heating TDV energy budget is calculated using the methods and assumptions documented in the Residential ACM Reference Manual. The approval procedure is the same as that used for nonresidential occupancies: – service water heating may use the prescriptive approach only if mechanical is also approved using prescriptive approach.