Each thermal zone discussed above may be subdivided into spaces. This section presents the building descriptors that relate to the space uses. Space uses and the defaults associated with them are 'listed in Appendix 5.4A. Every thermal zone shall have at least one space, as defined in this section. Daylit spaces should generally be separately defined.
Space Type
Applicability
All projects
Definition
For identifying space type, either the complete building method or area category method may be used.
If lighting compliance is not performed, use either approach, but actual LPDs cannot be entered for the spaces – the LPDs of the building match the standard design.
The allowed building types in complete building category or space types in area category is available from Nonresidential Appendix 5.4A. The building or space type determines the following baseline inputs:
Number of occupants (occupant density)
Equipment Power Density
Lighting Power Density
Hot Water Load
Ventilation Rate
Schedules (from Appendix 5.4B)
Units
List
Input Restrictions
Only selections shown in the Appendix 5.4A may be used.
For unconditioned spaces, the user must enter “Unconditioned” as the occupancy and ventilation, internal loads and uses are set to zero. Compliance software shall require the user to identify if lighting compliance is performed (lighting plans are included or have already been submitted).
Standard Design
Same as proposed.
Standard Design, Existing Buildings
Same as proposed
Floor Area
Applicability:
All projects that use the space-by-space area category classification method (see above)
Definition:
The floor area of the space. The area of the spaces that make up a thermal zone shall sum to the floor area of the thermal zone.
Units
Square feet (ft²)
Input Restrictions:
Area shall be measured to the outside of exterior walls and to the center line of partitions.
Standard Design
Area shall be identical to the proposed design.
Standard Design, Existing Buildings
Same as proposed
Infiltration Method
Applicability
All projects
Definition
Energy simulation programs have a variety of methods for modeling uncontrolled air leakage or infiltration. Some procedures use the effective leakage area which is generally applicable for small residential scale buildings. The component leakage method requires the user to specify the average leakage through the building envelope per unit area (ft²). Other methods require the specification of a maximum rate, which is modified by a schedule.
Units
List: effective leakage area, component leakage, air changes per hour
Input Restrictions
For the purpose of California Compliance and Reach, the component leakage area is prescribed; a fixed infiltration rate shall be specified and calculated as a leakage per area of exterior envelope, including the gross area of exterior walls and fenestration, , but excluding roofs and exposed floors.
Standard Design
The infiltration method used for the standard design shall be the same as the proposed design.
Infiltration Data
Applicability
All projects
Definition
Information needed to characterize the infiltration rate in buildings. The required information will depend on the infiltration method selected above. For the effective leakage area method, typical inputs are leakage per exterior wall area in ft² or other suitable units and information to indicate the height of the building and how shielded the site is from wind pressures. Only zones with exterior wall area are assumed to be subject to infiltration.
Units
A data structure is required to define the effective leakage area model,
Input Restrictions
For the purpose of California Compliance and Reach, infiltration shall be calculated each hour using Equation 1:
(1)
where:
Infiltration
= zone infiltration airflow
(m³/s-m²)
Idesign
= design zone infiltration airflow
(m³/s-m²)
Fschedule
= fractional adjustment from a prescribed schedule, based on HVAC
availability schedules in Appendix
5.4B(unitless)
tzone
= zone air temperature
(°C)
todb
= outdoor dry bulb temperature (°C)
ws
= the windspeed
(m/s)
A
= overall coefficient
(unitless)
B
= temperature coefficient
(1/°C)
C
= windspeed coefficient
(s/m)
D
= windspeed squared coefficient (s²/m²)
For the proposed design, Idesign shall have a fixed value of 0.0448 cfm/ft2 (0.000228 m³/s-m²) times the gross wall area exposed to ambient outdoor air. A, B and D shall be fixed at zero. C shall be fixed at 0.10016 hr/mile (0.224 s/m).
Standard Design
The standard design shall use the equation 'listed above, with coefficients A,B,D set to 0. C shall be set to 0.10016 hr/mile (0.224 s/m). Idesign shall be 0.0448 cfm/ft2.
Infiltration Schedule
Applicability
When an infiltration method is used that requires the specification of a schedule
Definition
With the ACH method and other methods (see above), it may be necessary to specify a schedule that modifies the infiltration rate for each hour or time step of the simulation. Typically the schedule is either on or off, but can also be fractional.
Units
Data structure: schedule, fractional
Input Restrictions
The infiltration schedule shall be prescribed based on the HVAC System operating schedules from Appendix 5.4B. The infiltration schedule shall be set equal to 1 when the HVAC system is scheduled off, and 0.25 when the HVAC system is scheduled on. This is based on the assumption that when the HVAC system is on it brings the pressure of the interior space above the pressure of the exterior, decreasing the infiltration of outside air. When the HVAC system is off, interior pressure drops below exterior pressure and infiltration increases.
Standard Design
The infiltration schedule for the standard design shall be set equal to 1 when the HVAC system is scheduled off, and 0.25 when the HVAC system is scheduled on.
For space level information on occupancy, lighting and plug load schedules, as well as occupant density, allowed lighting power density, Appendix 5.4A provides a table of allowed space types.
Number of Occupants
Applicability
All projects
Definition
The number of persons in a space. The number of persons is modified by an hourly schedule (see below), which approaches but does not exceed 1.0. Therefore, the number of persons specified by the building descriptor is similar to design conditions as opposed to average occupancy.
Units
The number of persons may be specified in an absolute number, ft²/person, or persons/1000 ft².
Input Restrictions
The number of occupants is prescribed, and the values are given by Space Type in Appendix 5.4A.
Standard Design
The number of occupants must be identical for both the proposed and baseline design cases.
Standard Design, Existing Buildings
The number of occupants must be identical for both the proposed and baseline design cases.
Occupant Heat Rate
Applicability
All projects
Definition
The sensible and latent heat produced by each occupant in an hour. This depends on the activity level of the occupants and other factors. Heat produced by occupants must be removed by the air conditioning system as well as the outside air ventilation rate and can have a significant impact on energy consumption.
Units
Btu/h specified separately for sensible and latent gains
Input Restrictions
The occupant heat rate is prescribed for California Compliance and Reach.
Standard Design
The occupant heat rate for the baseline building shall be the same as the proposed design.
Standard Design, Existing Buildings
Same as proposed
Occupancy Schedule
Applicability
All projects
Definition
The occupancy schedule modifies the number of occupants to account for expected operational patterns in the building. The schedule adjusts the heat contribution from occupants to the space on an hourly basis to reflect time-dependent usage patterns. The occupancy schedule can also affect other factors such as outside air ventilation, depending on the control mechanisms specified.
Units
Data structure: schedule, fractional.
Input Restrictions
The occupant schedule is prescribed for California Compliance and Reach. For California Compliance and Reach, an appropriate schedule from Appendix 5.4B shall be used.
Standard Design
Occupancy schedules are identical for proposed and baseline building designs.
Standard Design, Existing Buildings
Same as proposed
The building descriptors in this section are provided for each lighting system. Typically a space will have only one lighting system, but in some cases, it could have two or more. Examples include a general and task lighting system in offices or hotel multi-purpose rooms that have lighting systems for different functions. It may also be desirable to define different lighting systems for areas that are daylit and those that are not.
Lighting Classification Method
Applicability
Each space in the building
Definition
Indoor lighting power can be specified using the complete building method, area category method or the tailored method.
Complete building method can be used for building types 'listed in Appendix 5.4A. Parking garage portion of the building shall be considered as a separate space. This method cannot be combined with other lighting classification methods described in this section.
Area category method can be used for all areas of the building with space types listed in Appendix 5.4A. This method can be used by itself or with the tailored lighting method.
Tailored lighting method can be used for spaces with primary function listed in Table 140.6-D POWER ALLOWANCES of the Standards. The tailored lighting method is intended to accommodate special lighting applications. The tailored lighting method can be used by itself for all areas of the building or with the area category method. For a given area only one classification type can be used.
Units
List
Input Restrictions
Only Complete Building, Area Category or Tailored Lighting are allowed.
Use of the Complete Building method triggers an Exceptional Condition requires that the compliance software include reporting of special documentation requirements. Also, a single lighting designation in the Complete Building may not be used for any nonresidential building with an attached parking garage.
Standard Design
Same as proposed.
Standard Design, Existing Buildings
Same as proposed.
|
Options: Lighting Classification Method |
Complete Building Method |
Area Category Method |
Tailored Lighting Method |
|
Allowed combinations with other lighting classification methods |
None |
May be combined with Tailored method |
May be combined with Area Category Method |
|
Allowed Regulated lighting power types |
General Lighting Power |
General Lighting Power Custom Lighting Power |
General Lighting Power Custom Lighting Power |
|
Allowed Trade-offs |
None |
General lighting between spaces using area category method General lighting between spaces using area category and tailored method. |
General lighting between spaces using tailored method General lighting between spaces using tailored and area category method |
|
Exception: With the Area Category method, custom lighting power can be used only if the tailored lighting method is not used in any area of the building. | |||
Regulated Interior Lighting Power
Applicability
All projects when lighting compliance is performed
Definition
Total connected lighting power for all regulated interior lighting power. This includes the loads for lamps and ballasts. The total regulated interior lighting power is the sum of general lighting power and applicable custom lighting power. Calculation of lighting power for conditioned spaces is done separately from unconditioned spaces.
Units
Watts
Input Restrictions
Derived – not a user input. The proposed value is:
a) For the area category method, the sum of the proposed General Lighting Power and the proposed General Lighting Exceptional Power
b) For the tailored lighting method: the sum of the proposed General Lighting Power and the proposed Custom Lighting Power.
When lighting compliance is not performed, the lighting power may not be entered and is set equal to the lighting level of the baseline building, which is set to the levels for the selected occupancy from Appendix 5.4A.
Standard Design
For spaces without special task lighting, wall display lighting or similar requirements, this input will be the same as the general lighting power. See the general lighting power building descriptor for details.
With the area category and tailored method regulated interior lighting power for each space will be the sum of general lighting power and allowed custom lighting power.
For alterations where less than 40 luminaires have been modified the standard design is the existing lighting condition before the alteration. If 40 or more luminaires have been modified, the prescriptive requirements for new construction apply.
General Lighting Power
Applicability
All spaces or projects
Definition
General lighting power is the power used by installed electric lighting that provides a uniform level of illumination throughout an area, exclusive of any provision for special visual tasks or decorative effect, and also known as ambient lighting.
Units
Watts
Input Restrictions
As designed. For spaces without special task lighting, wall display lighting or similar requirements, this input will be the same as the regulated lighting power.
Trade-offs in general lighting power is allowed between spaces all using the area category method, between spaces all using the tailored lighting method and between spaces that use area category and tailored methods. See Table Lighting Specification Options.
Standard Design
With the complete building classification method, general lighting power is the product of the lighting power density for the building classification from Appendix 5.4A and the floor area of the space.
With the space-by-space area category method, general lighting power is the product of the lighting power densities for the space type from Appendix 5.4A and the floor areas for the corresponding spaces.
With the tailored lighting method, general lighting power is the product of the lighting power density for the primary function type in Table 140.6-D of the Standards and floor area of the space. The lighting power density is given as a function of room cavity ratio (RCR) and interior illumination level in Table 140.6-G. No interpolation is allowed for this table.
The general lighting power in the tailored method is calculated by the following steps:
Step 1. Determine illumination level from Table 140.6-D by matching the Primary Function Area in Table 140.6-D with the space type in Appendix 5.4A.
Step 2. Calculate the room cavity ratio (RCR) by using the applicable equation in Table 140.6-F.
Rectangular Rooms: RCR = 5 x H x (L+W) / (L x W)
Irregular Rooms: RCR = 2.5 x H x P / AWhere: L =Length of room; W = Width of room; H =Vertical distance from the work plane to the centerline of the lighting fixture; P = Perimeter of room, and A = Area of room
Step 3. Determine the general lighting in the space(s) using the tailored method by a look-up in Table 140.6-G, where the general lighting LPD is a function of illuminance level and RCR. No interpolation is allowed for this table. A space between two illuminance levels (for example, 150 lux) uses the applicable LPD from the next lower illuminance level (100 lux).
Standard Design, Existing Buildings
For alterations where less than 40 luminaires have been modified, the baseline is the existing lighting condition before the alteration. If 40 or more luminaires have been modified, the general lighting power for the baseline is defined for each space type in Appendix 5.4B.
General Lighting Exceptional Power
Applicability
Spaces that use the area category method; note that some exceptional allowances are only applicable to certain space types – see Table 140.6-C of the Standards
Definition
The Standards provide an additional lighting power allowance for special cases. Each of these lighting system cases is treated separately as “use-it-or-lose-it” lighting: the user receives no credit (standard design matches proposed), but there is a maximum power allowance for each item). There are eight lighting power allowances, as defined in the Standards Table 140.6-C footnotes:
Units
Data structure: this input has 8 data elements:
1) Specialized task work, laboratory (W/ft2)
2) Specialized task work, other approved areas (W/ft2)
3) Ornamental lighting (W/ft2)
4) Precision commercial and industrial work (W/ft2)
5) White board or chalk board lighting (W/linear foot)
6) Accent, display and feature lighting (W/ft2)
7) Decorative Lighting (W/ft2)
8) Videoconferencing studio lighting (W/ft2)
Input Restrictions
As designed.
Standard Design
The standard design General Lighting Exceptional Power is given by the following equation:
Where
GLEPstd = the General Lighting Exceptional Power of the standard design,
GLEPprop,i = the proposed General Lighting Exception Power of the footnote allowance i in the data structure above, or in the footnotes to Table 140.6-C of the Standards,
GLEAi = the General Lighting Exceptional Allowance, which is the maximum allowed added lighting power in the rightmost column in Table 140.6-C of the Standards. These allowances are, for GLEA1 through GLEA8, 0.2 W/ft2, 0.5 W/ft2, 0.5 W/ft2, 1.0 W/ft2, 5.5 W/linear foot, 0.3 W/ft2, 0.2 W/ft2 and 1.5 W/ft2, respectively.
GLETAi = the General Lighting Exceptional Task Area for the ith exception, where the exception number corresponds to the area category exception number in the footnotes to Table 140.-C of the Standards.
General Lighting Exceptional Task Area
Applicability
Spaces that use area category method
Definition
The area associated each of the exceptional lighting allowances in the General Lighting Exceptional Power building descriptor.
Units
ft2
Input Restrictions
As designed, but cannot exceed the floor area of the space
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as proposed
White Board Length
Applicability
Spaces that use area category method and take General Lighting Exceptional Power allowance #5
Definition
The linear length of the white board or chalk board in feet
Units
Ft2
Input Restrictions
As designed.
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as proposed
Custom Lighting Power
Applicability
All spaces or projects that use the tailored lighting method
Definition
Custom lighting power covers lighting sources that are not included as general lighting. These include task lighting, display lighting and other specialized lighting designated in the footnotes to Table 140.6-C and lighting systems in Table 140.6-D of the Standards This lighting must be entered separately from the general lighting because it is not subject to tradeoffs.
Software shall allow the user to
input a custom lighting input for the allowed lighting system. Custom lighting
power cannot be used with the complete building method. If area category method
is used, custom lighting power cannot be used if the tailored method is used for
any area of the building. See Table Lighting Specification Options for
details.
Units
Watts
Input Restrictions
As designed.
Standard Design
Same as proposed, but subject to the maximum limits specified in the footnotes to Table 140.6-C and Table 140.6-D of the Standards. For spaces using the tailored method, the maximum allowed custom power is defined by the following procedure:
The Standard Design Custom Lighting Power is calculated by the sum of the following four terms:
1) The product of the standard design Wall Display Power and the standard design Wall Display Length,
2) The product of the standard design Floor and Task Lighting Power and the standard design Floor and Task Lighting Area,
3) The product of the standard design Ornamental and Special Effect Lighting Power and the standard design Ornamental and Special Effect Lighting Area,
4) The product of the standard design Very Valuable Display Case Power and the standard design Very Valuable Display Case Area,
Standard Design, Existing Buildings
For alterations where less than 40 luminaires have been modified, the baseline is the existing lighting condition before the alteration. If 40 or more luminaires have been modified, the custom lighting power for the baseline is the same as proposed, but subject to the limits specified in the footnotes to Table 140.6-C of the Standards.
Wall Display Power
Applicability
All spaces that use the tailored lighting method
Definition
The lighting power allowed for wall display, as specified in Standards Table 140.6-D, column 3
Units
W/ft
Input Restrictions
As designed.
Standard Design
The standard design lighting power is the lesser of the proposed design wall display power or the limit specified in Table 140.6-D for the applicable space type.
Standard Design, Existing Buildings
Same as proposed
Wall Display Length
Applicability
All spaces that use the tailored lighting method
Definition
The horizontal length of the wall display lighting area using the tailored method for the space.
Units
ft
Input Restrictions
As designed, but this value of this input cannot exceed the floor area of the space.
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as proposed
Floor and Task Lighting Power
Applicability
All spaces that use the tailored lighting method
Definition
The lighting power allowed for wall display, as specified in Standards Table 140.6-D, column 4
Units
W/ft2
Input Restrictions
As designed.
Standard Design
The standard design floor and task lighting power is the lesser of the proposed design floor and task lighting power or the limit specified in Table 140.6-D, column 4, for the applicable space type.
Standard Design, Existing Buildings
Same as proposed
Floor and Task Lighting Area
Applicability
All spaces that use the tailored lighting method
Definition
The lighting area that is served by the floor and task lighting defined using the tailored method for the space.
Units
ft2
Input Restrictions
As designed, but this value of this input cannot exceed the floor area of the space.
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as proposed
Ornamental and Special Effect Lighting Power
Applicability
All spaces that use the tailored lighting method
Definition
The lighting power allowed for ornamental and special effect lighting, as specified in Standards Table 140.6-D, column 5
Units
W/ft2
Input Restrictions
As designed.
Standard Design
The standard design floor and task lighting power is the lesser of the proposed design floor and task lighting power or the limit specified in Table 140.6-D, column 5, for the applicable space type.
Standard Design, Existing Buildings
Same as proposed
Ornamental and Special Effect Lighting Area
Applicability
All spaces that use the tailored lighting method
Definition
The lighting area that is served by the ornamental and special effect lighting defined using the tailored method for the space.
Units
ft2
Input Restrictions
As designed, but this value of this input cannot exceed the floor area of the space.
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as proposed
Very Valuable Display Case Lighting Power
Applicability
All spaces that use the tailored lighting method and that have very valuable display cases holding Very Valuable Merchandise as defined in the Standards.
Definition
The lighting power allowed for very valuable display case lighting, as specified in Standards section 140.6(c)3L.
Units
W/ft2
Input Restrictions
As designed.
Standard Design
The standard design Very Valuable Display Case Lighting Power is the lesser of the proposed design very valuable display case lighting power or the following limit:
The lesser of:
a) The product of the area of the primary function and 0.8 W/ft2, and
b) The product of the area of the display case and 12 W/ft2.
Standard Design, Existing Buildings
Same as proposed
Very Valuable Display Case Lighting Area
Applicability
All spaces that use the tailored lighting method
Definition
The area of the very valuable display case(s) in plan view.
Units
ft2
Input Restrictions
As designed, but this value of this input cannot exceed the floor area of the space.
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as proposed
Non-Regulated Interior Lighting Power
Applicability
All projects
Definition
For California, §140.6(a)3. of the energy efficiency standards identifies non-regulated (exempted) lighting.
Units
W/ft² or Watts
Input Restrictions
As designed. The non-regulated lighting power should be cross-referenced to the type of exception and to the construction documents. The default for non-regulated lighting power is zero.
Standard Design
The non-regulated interior lighting in the baseline building shall be the same as the proposed design.
Standard Design, Existing Buildings
Same as proposed
Lighting Schedules
Applicability
All projects
Definition
Schedule of operation for interior lighting power used to adjust the energy use of lighting systems on an hourly basis to reflect time-dependent patterns of lighting usage.
Units
Data structure: schedule, fractional
Input Restrictions
The lighting schedule is prescribed for California Compliance and California Reach. An appropriate schedule from Appendix 5.4B shall be used.
Standard Design
The baseline building shall use the same lighting schedules as the proposed design.
Standard Design, Existing Buildings
Same as proposed
Tailored Lighting Illumination Height
Applicability
Spaces that have special tailored lighting power allowances
Definition
The illumination height is the vertical distance from the work plane to the luminaire. This is used in the calculation of the Room Cavity Ratio.
Units
ft
Input Restrictions
As designed
Standard Design
Same as proposed. The baseline general lighting power for the space that uses the tailored lighting method is calculated by one of the following equations:
for rectangular rooms
for irregular-shaped rooms
Where the illumination height defined for this input is H, the room length is L, width is W, perimeter is P and room area is A.
The allowed general lighting power for the tailored method is a function of the room cavity ratio and the space illumination level (in lux), and specified in Table 140.6-G of the Standards.
Standard Design, Existing Buildings
Same as for new construction
Mounting Height Above Floor
Applicability
Spaces that have wall display or floor display lighting and tailored lighting power allowances
Definition
The mounting height of wall display lighting above the floor. To qualify for an additional lighting allowance, all luminaires must be located at or above the specified height.
Units
List: one of three choices: <12 ft, 12 ft to 16 ft, > 16 ft
Input Restrictions
As designed. The entered value maps to Table 140.6-E of the Standards, that provides an adjustment multiplier for the tailored lighting wall power allowance in Table 140.6-D. The multiplier is 1.15 if the mounting height is 12’ to 16’, and 1.30 if greater than 16’. The compliance software must perform input processing to perform the necessary requirements.
Standard Design
Same as proposed.
Standard Design, Existing Buildings
Same as for new construction
Fixture Type
Applicability
All interior light fixtures
Definition
The type of lighting fixture, which is used to determine the Light Heat Gain Distribution
Units
List: one of three choices: Recessed with Lens, Recessed/Downlight, Not in Ceiling
Input Restrictions
As designed.
Standard Design
Recessed/Downlight
Standard Design, Existing Buildings
Recessed/Downlight
Luminaire Type
Applicability
All interior light fixtures
Definition
The type of lighting luminaire, which is used to determine the Light Heat Gain Distribution.
The Dominant Luminaire type determines the daylight dimming characteristics, when there are more than one type of luminaire in the space.
Units
List: Linear Fluorescent, CFL, Incandescent, LED, Metal Halide, Mercury Vapor, High Pressure Sodium
Input Restrictions
As designed.
Standard Design
Linear Fluorescent
Standard Design, Existing Buildings
Linear Fluorescent
Light Heat Gain Distribution
Applicability
All projects
Definition
The distribution of the heat generated by the lighting system that is directed to the space, the plenum, the HVAC return air, or to other locations. This input is a function of the luminaire type and location. Luminaires recessed into a return air plenum contribute more of their heat to the plenum or the return air stream if the plenum is used for return air; while pendant mounted fixtures hanging in the space contribute more of their heat to the space. Common luminaire type/space configurations are 'listed in Table 3, Chapter 18, 2009 ASHRAE Handbook of Fundamentals, summarized in Table 9 below. Typically the data will be linked to list of common luminaire configurations similar to Table 9 so that the user chooses a luminaire type category and heat gain is automatically distributed to the appropriate locations.
Units
List (of luminaire types) or data structure consisting of a series of decimal fractions that assign heat gain to various locations.
Input Restrictions
Default values listed in Table 9 shall be used as a default when the luminaire categories apply...
Where lighting fixtures having different heat venting characteristics are used within a single space, the wattage weighted average heat-to-return-air fraction shall be used.
Standard Design
The baseline building shall use the values in the Table below for Recessed fluorescent luminaires without lens.
Standard Design, Existing Buildings
Same as for new construction
Based on Table 3, Chapter 18, 2009 ASHRAE Handbook – Fundamentals
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Fixture Type |
Luminaire Type |
Return Type |
Space Fraction |
Radiative Fraction |
|
Recessed with Lens |
Linear Fluorescent |
Ducted/Direct |
1.00 |
0.67 |
|
Plenum |
0.45 |
0.67 | ||
|
Recessed/Downlight |
Linear Fluorescent |
Ducted/Direct |
1.00 |
|
|
Plenum |
0.69 |
0.58 | ||
|
CFL |
Ducted/Direct |
1.00 |
0.97 | |
|
Plenum |
0.20 |
0.97 | ||
|
Incandescent |
Ducted/Direct |
1.00 |
0.97 | |
|
Plenum |
0.75 |
0.97 | ||
|
LED |
Ducted/Direct |
1.00 |
| |
|
Plenum |
|
| ||
|
Metal Halide |
Ducted/Direct |
1.00 |
| |
|
Plenum |
|
| ||
|
Non In Ceiling |
Linear Fluorescent |
Ducted/Direct |
1.00 |
0.54 |
|
Plenum |
1.00 |
0.54 | ||
|
CFL |
Ducted/Direct |
1.00 |
0.54 | |
|
Plenum |
|
0.54 | ||
|
Incandescent |
Ducted/Direct |
1.00 |
0.54 | |
|
Plenum |
|
0.54 | ||
|
LED |
Ducted/Direct |
1.00 |
0.54 | |
|
Plenum |
1.00 |
0.54 | ||
|
Metal Halide |
Ducted/Direct |
1.00 |
0.54 | |
|
Plenum |
1.00 |
0.54 | ||
|
Mercury Vapor |
Ducted/Direct |
1.00 |
0.54 | |
|
|
Plenum |
1.00 |
0.54 | |
|
High Pressure Sodium |
Ducted/Direct |
1.00 |
0.54 | |
|
|
Plenum |
1.00 |
0.54 |
In this table, the Space Fraction is the fraction of the lighting heat gain that goes to the space; the radiative fraction is the fraction of the heat gain to the space that is due to radiation, with the remaining heat gain to the space due to convection.
Power Adjustment Factors (PAF)
Applicability
All projects
Definition
Automatic controls that are not already required by the baseline standard and which reduce lighting power more or less uniformly over the day can be modeled as power adjustment factors. Power adjustment factors represent the percent reduction in lighting power that will approximate the effect of the control. Models account for such controls by multiplying the controlled watts by (1 – PAF).
Eligible California power adjustment factors are defined in Table 140.6-A. Reduction in lighting power using the PAF method can be used only for non-residential controlled general lights. Only one PAF can be used for a qualifying lighting system unless additions are allowed in Table 140.6.A of the standards. Controls for which PAFs are eligible are 'listed in Table 140.6-A of the California energy efficiency standards and include:
•Occupancy Sensing Controls for qualifying enclosed spaces and open offices
•Demand Control – Demand responsive lighting control that reduces lighting power consumption in response to a demand response signal for qualifying building types.
•Manual and multiscene programmable dimming for qualifying area types.
•Manual Dimming plus multi-level occupancy sensor for qualifying area types.
Units
List: eligible control types (see above) linked to PAFs
Input Restrictions
PAF shall be fixed for a given control and area type
Standard Design
PAF is zero
Standard Design, Existing Buildings
PAF is zero
This group of building descriptors is applicable for spaces that have daylighting controls or daylighting control requirements.
California prescribes a modified version of the split flux daylighting methods to be used for compliance. This is an internal daylighting method because the calculations are automatically performed by the simulation engine. For top-lighted or sidelit daylighted areas, California Compliance prescribes an internal daylighting model consistent with the split flux algorithms used in many simulation programs. With this method the simulation model has the capability to model the daylighting contribution for each hour of the simulation and make an adjustment to the lighting power for each hour, taking into account factors such as daylighting availability, geometry of the space, daylighting aperture, control type and the lighting system. The assumption is that the geometry of the space, the reflectance of surfaces, the size and configuration of the daylight apertures, and the light transmission of the glazing are taken from other building descriptors.
Applicability
All spaces with exterior fenestration
Definition
The extent of daylighting controls in skylit and sidelit areas of the space
Units
List; when the installed general lighting power in the primary daylit zone exceeds 120W, daylighting controls are required, per the Title 24 mandatory requirements.
Input Restrictions
None, Primary Only, Secondary Only, Primary and Secondary
As designed
The value of “None” is only allowed when there are less than 120 Watts of lighting installed in the primary daylit zone.
Standard Design
The Daylight Control Requirements are defined according to the table below.
|
Installed General Lighting Power in the Primary and Skylit Daylit Zone |
Installed General Lighting Power in the Secondary Daylit Zone |
Daylight Control Requirements |
|
<120 W |
<120 W |
None |
|
>=120 W |
<120 W |
Primary Only |
|
<120 W |
>= 120 W |
Secondary Only |
|
>=120 W |
>=120 W |
Primary and Secondary |
As designed
Standard Design, Existing Buildings
When alterations include skylight replacement or addition and recirculation of existing general lighting system, the standard design will be same as new construction.
Skylit, Primary and Secondary Daylighted Area
Applicability
All daylighted spaces
Definition
The floor area that is daylighted. The skylit area is the portion of the floor area that gets daylighting from a skylight. Two types of sidellit daylighted areas are recognized. The primary daylighted area is the portion that is closest to the daylighting source and receives the most illumination. The secondary daylighted area is an area farther from the daylighting source, but still receives useful daylight.
The primary daylight area for sidelighting is a band near the window with a depth equal to the distance from the floor to the top of the window and width equal to window width plus 0.5 times window head height wide on each side of the window opening. The secondary daylight area for sidelighting is a band beyond the primary daylighted area that extends a distance double the distance from the floor to the top of the window and width equal to window width plus 0.5 times window head height wide on each side of the window opening. Area beyond a permanent obstruction taller than 6 feet should not be included in the primary and secondary daylight area calculation.
The skylit area is a band around the skylight well that has a depth equal to the 70% of the ceiling height from the edge of the skylight well. The geometry of the skylit daylit area will be the same as the geometry of the skylight. Area beyond a permanent obstruction taller than 50% of the height of the skylight from the floor should not be included in the skylit area calculation.
Double counting due to overlaps is not permitted. If there is an overlap between Secondary and Primary or Skylit areas, the effective daylit area used for determining Reference position shall be the area minus the overlap.
Units
ft²
Input Restrictions
The daylit areas in a space is derived using other modeling inputs like dimensions of the fenestration and ceiling height of the space.
Standard Design
The daylit areas in the baseline building is derived from other modeling inputs like dimensions of the fenestration and ceiling height of the space. Daylit area calculation in the standard design is done after Window to wall ratio and Skylight to roof ratio rules in Section 5.5.7 of this 'manual are applied.
Standard Design, Existing Buildings
Same as new construction, when skylights are added or replaced and general lighting altered.
Installed General Lighting Power in the Primary and Skylit Daylit Zone
Applicability
All spaces
Definition
The installed lighting power of general lighting in the primary and skylit daylit zone. The primary and skylit daylit zone shall be defined on the plans and be consistent with the definition of the primary and skylit daylit zone in the Standards. Note that a separate building descriptor, Fraction of Controlled Lighting, defines the fraction of the lighting power in the space that is controlled by daylighting.
Units
Watts
Input Restrictions
As designed.
Standard Design
The Installed lighting power for the standard design is the product of the primary daylit area and the lighting power density (LPD) for general lighting in the space.
Standard Design, Existing Buildings
Same as new construction when skylights are added, replaced and general lights are altered.
Installed General Lighting Power in the Secondary Daylit Zone
Applicability
All spaces
Definition
The installed lighting power of general lighting in the secondary daylit zone. The secondary daylit zone shall be defined on the plans and be consistent with the definition of the secondary daylit zone in the Standards. Note that a separate building descriptor, Fraction of Controlled Lighting, defines the fraction of the lighting power in the space that is controlled by daylighting.
Units
Watts
Input Restrictions
As designed.
Standard Design
The Installed lighting power for the standard design is the product of the secondary daylit area and the lighting power density (LPD) for general lighting in the space.
Standard Design, Existing Buildings
Same as new construction when skylights are added, replaced and general lights are altered.
Reference Position for Illuminance Calculations
Applicability
All spaces or thermal zones – depending on which object is the primary container for daylighting controls.
Definition
The position of the two daylight reference points within the daylit space. Lighting controls are simulated so that the illuminance at the reference position is always maintained at or above the illuminance setpoint. Thus, for step switching controls, the combined daylight illuminance plus uncontrolled electric light illuminance at the reference position must be greater than the setpoint illuminance before the controlled lighting can be dimmed or tuned off for stepped controls. Similarly, dimming controls will be dimmed so that the combination of the daylight illuminance plus the controlled lighting illuminance is equal to the setpoint illuminance.
Preliminary reference points for primary and secondary daylit areas are located at the farthest end of the daylit area aligned with the center of the each window. For skylit area, the preliminary reference point is located at the center of the edge of the skylit area closest to the centroid of the space. In each case, the Z – coordinate of the reference position (elevation) shall be located 2.5 feet above the floor.
Up to two final reference positions can be selected from among the preliminary reference positions identified in for each space.
Units
Data structure
Input Restrictions
The user does not specify the reference position locations; reference positions are automatically calculated by the compliance software based on the procedure outlined below. Preliminary reference positions are each assigned a Relative Daylight Potential (RDP) which estimates the available illuminance at each position, and the final reference position selection is made based on the RDP.
Relative Daylight Potential (RDP): an estimate of daylight potential at a specific reference position. This is NOT used directly in the energy simulation, but it used to determine precedence for selecting the final reference points. The relative daylight potential is calculated as a function of Effective Aperture, Azimuth, Illuminance Setpoint and the type (skylit, primary sidelit, or secondary sidelit) of the associated daylit zone. RDP is defined as:
RDP = C1*EAdz + C2*SO +C3
Where:
C1, C2 and C2 are selected from the following table.
|
Skylit Daylit Zones |
Primary Sidelit Daylit Zones |
Secondary Sidelit Daylit Zones | |||||||
|
Illuminance Setpoint |
C1 |
C2 |
C3 |
C1 |
C2 |
C3 |
C1 |
C2 |
C3 |
|
≤ 200 lux |
3,927 |
0 |
3,051 |
1,805 |
-0.40 |
3,506 |
7,044 |
-3.32 |
1,167 |
|
≤ 1000 lux |
12,046 |
0 |
-421 |
6,897 |
-7.22 |
475 |
1,512 |
-2.88 |
-22 |
|
> 1000 lux |
5,900 |
0 |
-516 |
884 |
-5.85 |
823 |
212 |
-0.93 |
57 |
Illuminance Setpoint: this is defined by the user, and is entered by the user, subject to the limits specified in Appendix 5.4A, determined from the space type.
Source Orientation (SO): the angle of the outward facing normal of the daylight source’s parent surface projected onto a horizontal plane, expressed as degrees from South. This is not a user input but is calculated from the geometry of the parent surface. For Skylights, the Source Orientation is not applicable. For vertical fenestration SO is defined:
SO = AbsoluteValue(180 – Azimuth)
Where:
Azimuth is defined as the azimuth of the parent object containing the fenestration associated with the preliminary reference point.
Effective Aperture (EA): for the purpose of this calculation, effective aperture represents the effectiveness of all sources which illuminate a specific reference position in contributing to the daylight available to the associated daylit zone. In cases where daylit zones from multiple fenestration objects intersect, the effective aperture of an individual daylit zone is adjusted to account for those intersections according to the following rules:
•For skylit and primary sidelit daylit zones, intersections with other skylit or primary sidelit daylit zones are considered
•For secondary sidelit daylit zones, intersections with any toplit or sidelit (primary or secondary) daylit zones are considered.
Effective aperture is defined as follows:
EAdz = ( VTfdz*Afdz + ∑(Fi*VTi*Ai) ) / Adz
Where: primary
EAdz is the combined effective aperture of all daylight sources illuminating a specific daylit zone.
VTfdz is the user specified visible transmittance of the fenestration object directly associated with the daylit zone
Afdz is the area of the fenestration object directly associated with the daylit zone
VTi is the user specified visible transmittance of the fenestration object associated with each intersecting daylit zone
Ai is the area of the fenestration object directly associated with each intersecting daylit zone
Fi is the fraction of intersecting area between the daylit zone in question and each intersecting daylit zone:
Fi = Aintersection/Adzi
Adzi is the area of each intersecting daylit zone (including area that might fall outside a space or exterior boundary)
Adz is the area of the daylit zone (including area that might fall outside a space or exterior boundary).
1. First Reference Position:
Select the preliminary reference point with the highest relative daylight potential (RDP) from amongst all preliminary reference points located within either top or primary sidelit daylit zones. If multiple reference points have identical RDPs, select the reference point geometrically closest to the centroid of the space.
2. Second Reference Position:
Select the preliminary reference point with the highest RDP from amongst all remaining preliminary reference points located within either top or primary sidelit daylit zones.If multiple reference points have identical RDPs, select the reference point geometrically closest to the centroid of the space.
Standard Design
Reference positions for the standard design shall be selected using the same procedure as those selected for the proposed design.
Standard Design, Existing Buildings
The additions of lighting or alteration of lighting in spaces trigger the daylighting control requirements whenever the total installed lighting in the daylit zone is 120 W or greater, and the reference positions shall be determined in the same manner as with new construction. This is only applicable when alterations or additions to the lighting in an existing building trigger daylighting control requirements.
Illumination Adjustment Factor
Applicability
All daylighted spaces
Definition
Recent studies have shown that the split flux interreflection component model used in many simulation programs overestimates the energy savings due to daylighting, particularly deep in the space. A set of two adjustment factors is provided, one for the primary daylit zone and one for the secondary daylit zone.
For simulation purposes, the input daylight illuminance setpoint will be modified by the Illuminance Adjustment factor as follows:
LIGHT-SET-PTadj = LIGHT-SET-PT x Adjustment Factor
Units
unitless
Input Restrictions
As per prescribed values for space type in Appendix 5.4A
Standard Design
The baseline building illumination adjustment factors shall match the proposed.
Standard Design, Existing and Altered
Same as for new construction, when skylights are added, replaced and general light altered.
Fraction of Controlled Lighting
Applicability
Daylighted spaces
Definition
The fraction of the general lighting power in the (daylighted) primary and skylit daylitzone, or secondary sidelit dayli zone, that is controlled by daylighting controls.
Units
Numeric: fraction for primary and skylit daylit zone, and fraction for secondary zone
Input Restrictions
As designed for secondary daylit areas. If the proposed design has no daylight controls in the secondary daylit area the value is set to 0 for the general lights in the secondary daylit area. Primary and skylit daylit area fraction of controlled general lighting shall be as designed when the Daylight Control Requirements building descriptor indicates that they are not required, and shall be 1 when controls are required.
Standard Design
When daylight controls are required according to the Daylight Control Requirements building descriptor in either the primary daylit and skylit zone, or the secondary daylit zone, or both, the Fraction of Controlled Lighting shall be 1.
Standard Design, Existing Buildings
Same as new construction when skylights are added, replaced and general lights are altered.
Daylighting Control Type
Applicability
Daylighted spaces.
Definition
The type of control that is used to control the electric lighting in response to daylight available at the reference point. The options are:
•Stepped Switching Controls vary the electric input power and lighting output power in discrete equally spaced steps. See At each step, the fraction of light output is equal to the fraction of rated power.
•Continuous Dimming controls have a fraction to rated power to fraction of rated output that is a linear interpolation of the minimum power fraction at the minimum diming light fraction to rated power (power fraction = 1.0) at full light output. See Figure 8|topic=Figure 8 – Example Dimming Daylight Control.
•Continuous Dimming + Off controls are the same as continuous dimming controls except that these controls can turn all the way off when none of the controlled light output is needed. See Figure 8.
Units
List (see above)
Input Restrictions
As designed.
Standard Design
Baseline does not have a daylighting control. Continuous
Standard Design, Existing Buildings
Same as for new construction, when skylights are added, replaced and general lighting altered.
Minimum Dimming Power Fraction
Applicability
Daylit spaces
Definition
The minimum power fraction when controlled lighting is fully dimmed. Minimum power fraction = (Minimum power) / (Full rated power). See Figure 8.
Units
Numeric: fraction
Input Restrictions
As designed, specified from Luminaire Type (not a user input)
Standard Design
Baseline building uses continuous dimming control with a minimum dimming power fraction of:
|
Light Source |
Power Fraction |
Light Output Fraction |
|
LED |
0.1 |
0.1 |
|
Linear Fluorescent |
0.2 |
0.2 |
|
Mercury Vapor |
0.3 |
0.2 |
|
Metal Halide |
0.45 |
0.2 |
|
High Pressure Sodium |
0.4 |
0.2 |
|
CFL |
0.4 |
0.2 |
|
Incandescent |
0.5 |
0.2 |
Where the Controlled Luminaire Type, input by the user, determines the Minimum Dimming Power Fraction
LED.
Standard Design, Existing Buildings
Same as for new construction, when skylights are added, replaced and general lighting altered
Minimum Dimming Light Fraction
Applicability
Daylighted and dimming controls
Definition
Minimum light output of controlled lighting when fully dimmed. Minimum light fraction = (Minimum light output) / (Rated light output). See Figure 8.
Units
Numeric: fraction
Input Restrictions
As designed
Standard Design
Baseline building uses continuous dimming control with a minimum dimming light fraction of :
|
Light Source |
Power Fraction |
Light Output Fraction |
|
LED |
0.1 |
0.1 |
|
Linear Fluorescent |
0.2 |
0.2 |
|
Mercury Vapor |
0.3 |
0.2 |
|
Metal Halide |
0.45 |
0.2 |
|
High Pressure Sodium |
0.4 |
0.2 |
|
CFL |
0.4 |
0.2 |
|
Incandescent |
0.5 |
0.2 |
Where the Controlled Luminaire Type, input by the user, determines the Minimum Dimming Power Fraction
Standard Design, Existing Buildings
Same as for new construction, when skylights are added, replaced and general lighting altered
Number of Control Steps
Applicability
Daylighted spaces that use stepped controls
Definition
Number of control steps. For step dimming, identifies number of steps that require fraction of rated light output and rated power fraction.
Units
Numeric: integer
Input Restrictions
Integer 1 or 4 for primary and skylit daylit areas, as designed for secondary daylit areas.
Standard Design
Not applicable.
Standard Design, Existing Buildings
Same as for new construction, when skylights are added, replaced and general lighting altered
Controlled Luminaire Type
Applicability
Daylit spaces
Definition
The predominant luminaire type in the daylit control zone. This is defined as the type of luminaire that has the most installed wattage in the daylit control zone. This input defines which dimming curve to use (from a lookup table)
Units
List
Metal halide
Compact fluorescent
Linear fluorescent
LED
Input Restrictions
As designed
Standard Design
Same as proposed
Receptacle loads contribute to heat gains in spaces and directly use energy.
Receptacle Power
Applicability
All building projects
Definition
Receptacle power is power for typical general service loads in the building. Receptacle power includes equipment loads normally served through electrical receptacles, such as office equipment and printers, but does not include either task lighting or equipment used for HVAC purposes. Receptacle power values are slightly higher than the largest hourly receptacle load that is actually modeled because the receptacle power values are modified by the receptacle schedule, which approaches but does not exceed 1.0.
Units
Total power (W) or the space or power density (W/ft²)
Compliance software shall also use the following prescribed values to specify the latent heat gain fraction and the radiative/convective heat gain split.
For software that specifies the fraction of the heat gain that is lost from the space, this fraction shall be prescribed at 0.
Receptacle Power heat gain fractions:
Radiative = 0.20, Latent = 0.00, Convective = 0.80
Gas Equipment Power Heat Gain Fractions:
Radiative = 0.15, Latent = 0.20, Convective = 0.65
Input Restrictions
Prescribed to values from Appendix 5.4A
Standard Design
Same as Proposed
Standard Design, Existing Buildings
Same as for new construction
Receptacle Schedule
Applicability
All projects
Definition
Schedule for receptacle power loads used to adjust the intensity on an hourly basis to reflect time-dependent patterns of usage.
Units
Data structure: schedule, fraction
Input Restrictions
The schedule is prescribed in appendix 5.4A.
Standard Design
Schedules for the baseline building shall be identical to the proposed design.
Standard Design, Existing Buildings
Same as for new construction
Commercial refrigeration equipment includes the following:
•Walk-in refrigerators
•Walk-in freezers
•Refrigerated casework
Walk-in refrigerators and freezers typically have remote condensers. Some refrigerated casework has remote condensers, while some have a self-contained condenser built into the unit. Refrigerated casework with built-in condensers rejects heat directly to the space while remote condensers reject heat in the remote location, typically on the roof or behind the building.
Refrigerated casework can be further classified by the purpose, the type of doors and, when there are no doors, the configuration: horizontal, vertical or semi-vertical. USDOE has developed standards for refrigerated casework. Table 10 shows these classifications along with the standard level of performance, expressed in kWh/d, which depends on the class of equipment, the total display area, and the volume of the casework.
Walk-in refrigerators and freezers are not covered by the USDOE standards and test procedures. Title-24 default values for these are given in Table 11. These values are expressed in W/ft² of refrigerator or freezer area. This power is assumed to occur continuously. Some walk-ins have glass display doors on one side so that products can be loaded from the back. Glass display doors increase the power requirements of walk-ins. Additional power is added when glass display doors are present. The total power for walk-in refrigerators and freezers is given in Equation (1).
(1)
Where
PWalk-in is the estimated power density for the walk-in refrigerator or freezer in (W)
Axxx the area of the walk-in refrigerator or freezer (ft²)
Nxxx the number of glass display doors (unitless)
PDxxx the power density of the walk-in refrigerator or freezer taken from Table 11 (W/ft²)
Dxxx the power associated with a glass display door for a walk-in refrigerator or freezer (W/door)
xxx subscript indicating a walk-in freezer or refrigerator (Ref or Frz)
Source: These values are determined using the procedures of the Heatcraft Engineering 'Manual, Commercial Refrigeration Cooling and Freezing Load Calculations and Reference Guide, August 2006. The EER is assumed to be 12.39 for refrigerators and 6.33 for Freezers. The specific efficiency is assumed to be 70 for refrigerators and 50 for freezers. Operating temperature is assumed to be 35 F for refrigerators and -10 F for freezers.
|
Floor Area |
Refrigerator |
Freezer |
|
100 ft² or less |
8.0 |
16.0 |
|
101 ft² to 250 ft² |
6.0 |
12.0 |
|
251 ft² to 450 ft² |
5.0 |
9.5 |
|
451 ft² to 650 ft² |
4.5 |
8.0 |
|
651 ft² to 800 ft² |
4.0 |
7.0 |
|
801 ft² to 1,000 ft² |
3.5 |
6.5 |
|
More than 1,000 ft² |
3.0 |
6.0 |
|
Additional Power for each Glass Display Door |
105 |
325 |
|
Note: | ||
Refrigeration Modeling Method
Applicability
All buildings that have commercial refrigeration for cold storage or display
Definition
The method used to estimate refrigeration energy and to model the thermal interaction with the space where casework is located. Two methods are included in this 'manual:
•Title 24 defaults. With this method, the power density values provided in Appendix 5.4A are used; schedules are assumed to be continuous operation.
•USDOE performance ratings. With this method, the energy modeler takes inventory of the refrigerated casework in the rated building and sums the rated energy use (typically in kWh/day). Walk-in refrigerators and freezers shall use the defaults from Equation (1) and the values from Table 11. All refrigeration equipment is then assumed to operate continuously.
The remaining building descriptors in this section apply to buildings that use either the Title-24 defaults or the USDOE performance ratings.
Units
List (see above)
Input Restrictions
NoneFor California Compliance, the Title 24 defaults shall be used. Otherwise, there are no input restrictions.
Standard Design
Same as proposed
Standard Design, Existing Buildings
Same as for new construction
Refrigeration Power
Applicability
All buildings or spaces that have commercial refrigeration for cold storage or display.
Definition
Commercial refrigeration power is the average power for all commercial refrigeration equipment, assuming constant year-round operation. Equipment includes walk-in refrigerators and freezers, open refrigerated casework, and closed refrigerated casework. It does not include residential type refrigerators used in kitchenettes or refrigerated vending machines. These are covered under receptacle power.
Units
W/ft2
Input Restrictions
With the Title 24 defaults method, the values in Appendix 5.4A are prescribed. These values are multiplied times the floor area of the rated building to estimate the refrigeration power. With the USDOE performance ratings method, refrigeration power is estimated by summing the kWh/day for all the refrigeration equipment in the space and dividing by 24 hours. The refrigeration power for walk-in refrigerators and freezers is added to this value.
Standard Design
Refrigeration power is the same as the proposed design when the Title 24 defaults are used. When the USDOE performance ratings method is used, refrigeration power for casework shall be determined from Table 10; the power for walk-in refrigerators and freezers shall be the same as the proposed design.
Standard Design, Existing Buildings
Same as for new construction
Remote Condenser Fraction
Applicability
All buildings that have commercial refrigeration for cold storage or display and use the Title 24 defaults or USDOE performance ratings methods
Definition
The fraction of condenser heat that is rejected to the outdoors. For self-contained refrigeration casework, this value will be zero. For remote condenser systems, this value is 1.0. For combination systems, the value should be weighted according refrigeration capacity.
For refrigeration with self-contained condensers and compressors, the heat that is removed from the space is equal to the heat that is rejected to the space, since the evaporator and condenser are both located in the same space. There may be some latent cooling associated with operation of the equipment, but this may be ignored with the Title 24 defaults or USDOE performance ratings methods. The operation of self-contained refrigeration units may be approximated by adding a continuously operating electric load to the space that is equal to the energy consumption of the refrigeration units. Self-contained refrigeration units add heat to the space that must be removed by the HVAC system.
When the condenser is remotely located, heat is removed from the space but rejected outdoors. In this case, the refrigeration equipment functions in a manner similar to a continuously running split system air conditioner. Some heat is added to the space for the evaporator fan, the anti-fog heaters and other auxiliary energy uses, but refrigeration systems with remote condensers remove more heat from the space where they are located than they add. The HVAC system must compensate for this imbalance.
For remotely located condensers using the Title 24 defaults or USDOE performance ratings methods, the heat that is removed from the space is determined as follows:
(2)
Where
Q The rate of heat removal from the space due to the continuous operation of the refrigeration system (kBtu/h). A negative number means that heat is being removed from the space; a positive number means that heat is being added.
kW The power of the refrigeration system determined by using the Title 24 defaults or the USDOE performance ratings method (kW)
F The remote condenser fraction (see building descriptor below) (unitless)
COP The coefficient of performance of the refrigeration system (unitless)
The simple approach outlined above assumes that there is no latent cooling associated with the refrigeration system. The heat addition or removal resulting from the above equation can be modeled in a number of ways, to accommodate the variety of calculation engines available. It can be scheduled if the engine can accommodate a heat removal schedule. It can be modeled as a separate, constantly running air conditioner, if the engine can accommodate two cooling systems serving the same thermal zone. Other modeling techniques are acceptable as long as they are thermodynamically equivalent.
Units
Fraction
Input Restrictions
None
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Same as for new construction
Refrigeration COP
Applicability
All buildings that have commercial refrigeration for cold storage or display and use the Title 24 defaults or USDOE performance ratings methods
Definition
The coefficient of performance of the refrigeration system. This is used only to determine the heat removed or added to the space, not to determine the refrigeration power or energy.
Units
Fraction
Input Restrictions
This value is prescribed to be 3.6 for refrigerators and 1.8 for freezers.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Same as for new construction
Refrigeration Schedule
Applicability
All buildings that have commercial refrigeration for cold storage or display
Definition
The schedule of operation for commercial refrigeration equipment. This is used to convert refrigeration power to energy use.
Units
Data structure: schedule, fractional
Input Restrictions
Continuous operation is prescribed.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Same as for new construction
Elevators, escalators and moving walkways account for 3% to 5% of electric energy use in buildings. Buildings up to about five to seven stories typically use hydraulic elevators because of their lower initial cost. Mid-rise buildings commonly use traction elevators with geared motors, while high-rise buildings typically use gearless systems where the motor directly drives the sheave. The energy using components include the motors and controls as well as the lighting and ventilation systems for the cabs.
Elevators are custom designed for each building. In this respect they are less like products than they are engineered systems, e.g. they are more akin to chilled water plants where the engineer chooses a chiller, a tower, pumping and other components which are field engineered into a system. The main design criteria are safety and service. Some manufacturers have focused on energy efficiency of late and introduced technologies such as advanced controls that optimize the position of cars for minimum travel and regeneration motors that become generators when a loaded car descends or an empty car rises. These technologies can result in 35% to 40% savings.
The motors and energy using equipment is typically located within the building envelope so it produces heat that must be removed by ventilation or by air conditioning systems. In energy models, a dedicated thermal zone (elevator shaft) will typically be created and this space can be indirectly cooled (from adjacent spaces) or positively cooled.
Little information is known on how to model elevators. As engineered systems, the model would need information on the number of starts per day, the number of floors, motor and drive characteristics, and other factors. Some work has been done to develop and categorize energy models for elevators; however a simple procedure is recommended based on a count of the number of elevators, escalators and moving walkways in the building. This data is shown in Table 12.
|
Mode
|
Elevators |
Escalators and Moving Walkways | ||
|
Power (W) |
Annual Hours |
Power (W) |
Annual Hours | |
|
Active |
10,000 |
300 |
4,671 |
4,380 |
|
Ready |
500 |
7,365 |
n.a. |
0 |
|
Standby |
250 |
1,095 |
n.a. |
0 |
|
Off |
0 |
0 |
0 |
4,380 |
|
Typical Annual Energy Use |
7,000 kWh/y |
20,500 kWh/y | ||
Elevator/Escalator Power
Applicability
All buildings that have commercial elevators, escalator, or moving walkways
Definition
The power for elevators, escalators and moving walkways for different modes of operation. Elevators typically operate in three modes: active (when the car is moving passengers), ready (when the lighting and ventilation systems are active but the car is not moving), and standby (when the lights and ventilation systems are off). Escalators and moving walkways are either active or turned off.
Units
W/unit
Input Restrictions
The power values from Table 12 for different modes of operation are prescribed for the proposed design.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Elevator/Escalator Schedule
Applicability
All buildings that have commercial elevators, escalator, or moving walkways
Definition
The schedule of operation for elevators, escalators, and moving walkways. This is used to convert elevator/escalator power to energy use.
Units
Data structure: schedule, state
Input Restrictions
The operating schedule is prescribed California Compliance and Reach. For California Compliance, an appropriate schedule from Appendix 5.4B shall be used. If values other than those shown in Appendix 5.4B are used, this will be reported as a condition requiring an Exceptional Condition Review by a third party reviewer
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Commercial gas equipment includes the following:
•Ovens
•Fryers
•Grills
•Other equipment
The majority of gas equipment is located in the space and may contribute both sensible and latent heat. Gas equipment is typically modeled by specifying the rate of peak gas consumption and modifying this with a fractional schedule. Energy consumption data for gas equipment is only beginning to emerge.
Because of these limits, the procedure for commercial gas is limited. The procedure consists of prescribed power and energy values for use with both the proposed design and the baseline building. No credit for commercial gas energy efficiency features is offered.
The prescribed values are provided in Appendix 5.4A. Schedules are defaulted to be continuous operation.
Gas Equipment Power
Applicability
All buildings that have commercial gas equipment
Definition
Commercial gas power is the average power for all commercial gas equipment, assuming constant year-round operation.
Units
Btu/h-ft²
Compliance software shall also use the following prescribed values to specify the latent heat gain fraction and the radiative/convective heat gain split.
For software that specifies the fraction of the heat gain that is lost from the space, this fraction shall be prescribed at 0.
Gas Equipment Power Heat Gain Fractions:
Radiative = 0.15, Latent = 0.20, Convective = 0.65
Input Restrictions
The values in Appendix 5.4A are prescribed.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Gas Equipment Schedule
Applicability
All buildings that have commercial gas equipment
Definition
The schedule of operation for commercial gas equipment. This is used to convert gas power to energy use.
Units
Data structure: schedule, fractional
Input Restrictions
Continuous operation is prescribed.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Gas Equipment Location
Applicability
All buildings that have commercial gas equipment
Definition
The assumed location of the gas equipment for modeling purposes. Choices are in the space or external.
Units
List (see above)
Input Restrictions
As designed.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Radiation Factor
Applicability
Gas appliances located in the space
Definition
The fraction of heat gain to appliance energy use
Units
Fraction
Input Restrictions
Default value is 0.15. Other values can be used when a detailed inventory of equipment is known. The override value shall be based on data in Table 5C, Chapter 18, ASHRAE HOF, 2009, or similar tested information from the manufacturer.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Usage Factor
Applicability
Gas appliances located in the space
Definition
A duty cycle or usage factor to appliance energy use
The radiation factor and usage factor are used together to determine the sensible heat gain to the space:
Qsens = Qinput x FU x FR
Where Qinput is the heat input of the equipment in Btu/h or Btu/h-ft2,
FU is the usage factor and
FR is the radiation factor
Units
Fraction
Input Restrictions
Default value is 0.70. Other values can be used when a detailed inventory of equipment is known. The override value shall be based on data in Table 5C, Chapter 18, ASHRAE HOF, 2009, or similar tested information from the manufacturer.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Gas Process Loads
Applicability
Spaces with process loads
Definition
Process load is the gas energy consumption in the conditioned space of a building resulting from an activity or treatment not related to the space conditioning, lighting, service water heating, or ventilating of a building as it relates to human occupancy. Process load may include sensible and/or latent components
Compliance software shall model and simulate process loads only if the amount of the process energy and the location and type of process equipment are specified in the construction documents. This information shall correspond to specific special equipment shown on the building plans and detailed in the specifications. The compliance software Compliance Documentation shall inform the user that the compliance software will output process loads including the types of process equipment and locations on the compliance forms.
Units
Data structure: sensible (Btu/h), latent (Btu/h)
Input Restrictions
Compliance software shall receive input for Sensible and/or Latent Process Load for each zone in the proposed design. The process load input shall include the amount of the process load (Btu/h-ft2) and the thermal zone where the process equipment is located. The modeled information shall be consistent with the plans and specifications of the building.
Standard Design
The standard design shall use the same gas process loads and sensible and latent contribution and radiative/convective split for each zone as the proposed design.
Standard Design, Existing Buildings
Same as for new construction
Electric Process Loads
Applicability
Spaces with electric process loads
Definition
Process load is the electrical energy consumption in the conditioned space of a building resulting from an activity or treatment not related to the space conditioning, lighting, service water heating, or ventilating of a building as it relates to human occupancy.
Data centers loads including transformers, UPS, PDU, server fans and power supplies are considered receptacle loads, not process loads, and the equipment schedules are given in Appendix 5.4B.
Compliance software shall model and simulate process loads only if the amount of the process energy and the location and type of process equipment are specified in the construction documents. This information shall correspond to specific special equipment shown on the building plans and detailed in the specifications. The compliance software Compliance Documentation shall inform the user that the compliance software will output process loads including the types of process equipment and locations on the compliance forms.
Units
Data structure: load (kW)
For electric process loads, the radiative fraction shall be defaulted to 0.2 and the convective fraction shall be defaulted to 0.8 by the compliance software. The user may enter other values for the radiative/convective split, but the compliance software shall verify that the values add to 1.
Input Restrictions
Compliance software shall receive input for Sensible and/or Latent Process Load for each zone in the proposed design. The process load input shall include the amount of the process load (Btu/h-ft2) and the thermal zone where the process equipment is located. The modeled information shall be consistent with the plans and specifications of the building.
Standard Design
The standard design shall use the same process loads and radiative/convective split for each zone as the proposed design.
Standard Design, Existing Buildings
Same as for new construction
Gas Process Load Schedule
Applicability
All buildings that have commercial gas equipment
Definition
The schedule of operation process load. This is used to convert gas power to energy use.
Units
Data structure: schedule, fractional
Input Restrictions
As designed.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable
Electric Process Load Schedule
Applicability
All buildings that have commercial gas equipment
Definition
The schedule of operation process load. This is used to convert gas power to energy use.
Units
Data structure: schedule, fractional
Input Restrictions
As designed.
Standard Design
Same as the proposed design
Standard Design, Existing Buildings
Not applicable