5.4 Space Uses
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 by space type
and/or orientation.
5.4.1 General Information
|
Space Type |
|
Applicability |
All projects |
|
Definition |
The space function type that defines occupancy,
internal load, and other characteristics, as indicated in Appendix
5.4A.
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 space function types in area category are
available from 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 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 |
|
Existing Buildings |
Same as proposed |
|
Floor Area |
|
Applicability |
All projects |
|
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 |
|
Existing Buildings |
Same as proposed |
5.4.2
Infiltration
|
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, or 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.
For the purpose of California compliance and reach,
infiltration shall be calculated each hour using the following
equation:
Where:
|
|
zone infiltration airflow (m³/s-m²) |
|
 =
|
design zone infiltration
airflow (m³/s-m²) |
|
 =
|
fractional adjustment
from a prescribed schedule, based on HVAC availability schedules in
Appendix
5.4B(unitless) |
|
 =
|
zone air temperature
(°C) |
|
 =
|
outdoor dry bulb
temperature (°C) |
|
 =
|
the windspeed (m/s) |
|
A = |
overall coefficient
(unitless) |
|
B = |
temperature coefficient
(1/°C) |
|
C = |
windspeed coefficient
(s/m) |
|
D = |
windspeed squared
coefficient (s²/m²) |
|
|
Input Restrictions |
For the proposed design,2 (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).
For nonresidential spaces with operable windows that do
not have interlocks, the CBECC software shall automatically increase
infiltration to the space by 0.15 cfm/ft2 whenever the outside
air temperature is between 50°F and 90°F and when the HVAC system is
operating.
For high-rise residential spaces with operable windows
that do not have interlocks, the CBECC software shall automatically
increase infiltration to the space by 0.02 cfm/ft2 whenever the
outside air temperature is between 50°F and 90°F and when the HVAC system
is operating. |
|
Standard Design |
The standard design shall use the equation listed
above, with coefficients A, B, and D set to 0. C shall be set to 0.10016
hr/mile (0.224 s/m).2. |
|
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.
A possible incorporation of the prescriptive
requirement for interlocks for operable windows will model mixed mode
ventilation as an increased infiltration rate when outside air conditions
allow. |
|
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. |
5.4.3
Occupants
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.
|
Fixed Seating in Space |
|
Applicability |
All projects that have a space with fixed seating (such
as a theater or auditorium) |
|
Definition |
This is a flag that indicates that the space has fixed
seating. If checked, this flag allows the user to override the default
occupancy with values that comply with the California Building
Code. |
|
Units |
Boolean |
|
Input Restrictions |
As designed
May not be used with high-rise residential,
hotel/motel, unoccupied, and unleased tenant area spaces. The default is
false. |
|
Standard Design |
Same as proposed |
|
Existing Buildings |
The number of occupants must be identical for both the
proposed and baseline design cases. |
|
Dwelling Units per Space |
|
Applicability |
High-rise residential projects |
|
Definition |
The number of residential living units within a single
compliance model space |
|
Units |
Boolean |
|
Input Restrictions |
As designed |
|
Standard Design |
1 |
|
Existing Buildings |
1 |
|
Number of Bedrooms |
|
Applicability |
High-rise residential projects |
|
Definition |
The number of bedrooms per dwelling unit |
|
Units |
Integer |
|
Input Restrictions |
As designed but constrained to a minimum of 0 (studio)
and a maximum of 5 |
|
Standard Design |
Same as proposed |
|
Existing Buildings |
Same as proposed |
|
Number of Occupants |
|
Applicability |
High-rise residential projects |
|
Definition |
The number of people in a space.
The number of people is modified by an hourly schedule
(see below), which approaches but does not exceed 1.0. Therefore, the
number of people specified by the building descriptor is similar to design
conditions as opposed to average occupancy. |
|
Units |
The number of people may be specified in an absolute
number, ft²/person, or people/1000 ft². |
|
Input Restrictions |
The number of occupants is prescribed, and the values
are given by Space Type in Appendix
5.4A, For high-rise residential spaces, the number of occupants is
defined as: Max (number of bedrooms +1, 2). |
|
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 |
|
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. For California compliance, 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 s 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 area
category method or the tailored method.
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 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 area category or tailored lighting are
allowed |
|
Standard Design |
Same as proposed |
|
Standard Design:
Existing
Buildings |
Same as proposed |
Table 6: Lighting
Specification
|
Options:
Lighting Classification Method |
Area
category method |
Tailored
lighting Method |
|
Allowed combinations with
other lighting classification methods |
May be combined with
tailored method |
May be combined with area
category method |
|
Allowed Regulated lighting
power types |
General lighting
power
Custom lighting
power |
General lighting
power
Custom lighting
power |
|
Allowed
Trade-offs |
General lighting between
conditioned spaces using area category method
General lighting between
conditioned spaces using area category and tailored method |
General lighting between
conditioned spaces using tailored method
General lighting between
conditioned 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
Density |
|
Applicability |
All projects when lighting compliance is
performed |
|
Definition |
Total connected lighting power density for all
regulated interior lighting power
This includes the loads for lamps and ballasts. The
total regulated interior lighting power density is the sum of general
lighting power and applicable custom lighting power per floor area in a
space. Calculation of lighting power for conditioned spaces is done
separately from unconditioned spaces.
Lighting in unconditioned spaces can be modeled, but
total lighting power in unconditioned spaces is not enforced in the
compliance software. Lighting in unconditioned spaces must follow
prescriptive compliance, and must be documented on appropriate compliance
forms. No tradeoffs are allowed between lighting in conditioned spaces and
lighting in unconditioned spaces. |
|
Units |
W/ft2 |
|
Input Restrictions |
Proposed value is:
a) For the area category
method: the sum of the proposed general lighting power and the proposed
general lighting exceptional power within a conditioned space or a user
input value if no interior lighting systems are modeled.
b) For the tailored lighting method: the sum of
the proposed general lighting power and the proposed custom lighting power
within a conditioned space or a user input value if no interior lighting
systems are modeled.
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 density. 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 are 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 6: Lighting
Specification for details. |
|
Standard Design |
With the 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 conditioned 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 the 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 / A
Where: 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).
The standard design uses the irregular room RCR
equation for both simplified and detailed geometry models.
The standard design lighting power is modified by a
factor of 1/1.20 (0.833) if the simplified geometry approach is used and
if the visible transmittance of any fenestration in the space does not
meet the prescriptive requirements established in Section
140.3 of the standards. |
|
Standard Design:
Existing Buildings |
When the lighting status is “existing” (and unaltered)
for the space, the standard design is the same as the existing, proposed
design.
When the lighting status is “altered” for the space,
and at least 10 percent of existing luminaires have been altered:
a)
If the lighting status is “existing”, then the standard design LPD is the
same as the proposed design.
b)
If the lighting status is “new”, then the standard design LPD is same as
new construction.
c)
If the lighting status is “altered”, then the standard design LPD is the
same as new construction. |
|
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 eight 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 (GLEP) is given by the following
equation:
Where:
|
|
The GLEP of the
standard design |
|
|
The proposed GLEP
of the footnote allowance i in the data structure above, or in the
footnotes to Table
140.6-C of the standards |
|
|
The general
lighting exceptional allowance (GLEA) , 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 |
|
|
The general
lighting exceptional task area (GLETA) 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 |
|
|
Standard
Design:
Existing
Buildings |
|
|
General Lighting Exceptional Task Area |
|
Applicability |
Spaces that use area category method |
|
Definition |
The area associated with each of the exceptional
lighting allowances in the GLEP 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 GLEP
allowance #5 |
|
Definition |
The linear length of the white board or chalk board in
feet |
|
Units |
Ft |
|
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, including 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. 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 6: Lighting
Specification 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; and
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 10 percent of existing
luminaires have been modified, the baseline is the existing lighting
condition before the alteration. If 10 percent or more luminaires have
been altered, 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 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 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 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 method |
|
Definition |
The lighting power allowed for floor display and task
lighting, as specified in Table
140.6-D, column 4, of the standards |
|
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 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 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 method |
|
Definition |
The lighting power allowed for ornamental and special
effect lighting, as specified in Table
140.6-D, column 5, of the standards |
|
Units |
W/ft2 |
|
Input Restrictions |
As designed |
|
Standard Design |
The standard design ornamental and special effect
lighting power is the lesser of the proposed design ornamental and special
effect 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 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 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 method |
|
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:
a) The product
of the area of the primary function and 0.8 W/ft2;
b) The product
of the area of the display case and 12 W/ft2; or
c) The
proposed very valuable display lighting power. |
|
Standard Design:
Existing Buildings |
Same as proposed |
|
Very Valuable Display Case Lighting
Area |
|
Applicability |
All spaces that use the tailored method |
|
Definition |
The area of the very valuable display case(s) in plan
view |
|
Units |
ft2 |
|
Input Restrictions |
As designed but this value 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. An appropriate schedule from Appendix
5.4B shall be used. |
|
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 |
|
Tailored Lighting General 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 centerline of the luminaire. This distance is used
in the room cavity ratio (RCR) calculation which determines the allowed
general lighting power density for a tailored lighting space. |
|
Units |
Ft |
|
Input Restrictions |
As designed |
|
Standard Design |
Same as proposed
The illumination height, H, is used to calculate the
RCR and therefore the baseline general lighting power. See general
lighting power for details. |
|
Standard Design:
Existing Buildings |
Same as proposed |
|
Floor/Wall Display 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 or floor display
lighting above the floor |
|
Units |
List one of three choices:
a)
<12 ft
b)
12-16 ft
c)
> 16 ft |
|
Input Restrictions |
As designed |
|
Standard Design |
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:
Existing Buildings |
Same as proposed |
|
Fixture Type |
|
Applicability |
All interior light fixtures |
|
Definition |
The type of lighting fixture, which is used to
determine light heat gain distribution |
|
Units |
List: one of three choices:
a)
Recessed with lens
b)
Recessed/downlight
c)
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 used to determine the
light heat gain distribution
The dominant luminaire type determines the daylight
dimming characteristics, when there is more than one type of luminaire in
the space. |
|
Units |
List one of three choices:
a)
Linear fluorescent
b)
Compact fluorescent lamp
c)
Incandescent
d)
Light emitting diode
e)
Metal halide
f)
Mercury vapor
g)
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
7. Typically the data
will be linked to list of common luminaire configurations similar to Table 7 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 |
Heat gain distribution is fixed to Table 7 values based on the
luminaire, fixture, and distribution type.
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 Table
7 for recessed
fluorescent luminaires without lens. |
|
Standard Design:
Existing Buildings |
Same as new construction |
Table 7: Light Heat Gain Parameters for
Typical Operating Conditions
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 |
0.58 |
|
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 |
0.97 |
|
Plenum |
0.20 |
0.97 |
|
Metal Halide |
Ducted/Direct |
1.00 |
0.97 |
|
Plenum |
0.75 |
0.97 |
|
Non In
Ceiling |
Linear
Fluorescent |
Ducted/Direct |
1.00 |
0.54 |
|
Plenum |
1.00 |
0.54 |
|
CFL |
Ducted/Direct |
1.00 |
0.54 |
|
Plenum |
1.00 |
0.54 |
|
Incandescent |
Ducted/Direct |
1.00 |
0.54 |
|
Plenum |
1.00 |
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 nonresidential controlled general lights. Only one
PAF can be used for a qualifying lighting system unless multiple
adjustment factors 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 standards
and include:
a)
Occupancy Sensing Controls for qualifying enclosed spaces and open
offices.
b)
Demand Response Controls – Demand responsive lighting control that reduces
lighting power consumption in response to a demand response signal for
qualifying building types.
c)
Institutional tuning – lighting tuned to not use more than 85 percent of
rated power, per Section
140.6 of the standards.
d)
Daylight dimming plus off controls – daylight dimming controls that
automatically shut off luminaires when natural lighting provides an
illuminance level of at least 150 percent of the space requirement, as
specified by the standards. |
|
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.
For daylight control using a
simplified geometry approach, daylight control for both the primary daylit zone
(mandatory) and secondary daylit zone (prescriptive) must be indicated on the
compliance forms. If the simplified geometry approach is used and the visible
transmittance of fenestration does not meet prescriptive requirements, the
standard design lighting power is reduced by 20 percent as a penalty. See
Interior Lighting.
|
Daylight
Control Requirements |
|
Applicability |
All spaces with exterior fenestration |
|
Definition |
The extent of daylighting controls in skylit and
sidelit areas of the space |
|
Units |
List |
|
Input Restrictions |
When the installed general lighting power in the
primary daylit zone exceeds 120W, daylighting controls are required, per
the Title 24 mandatory requirements. |
|
Standard Design |
For nonresidential spaces, when the installed general
lighting power in the skylit or primary sidelit daylit zone exceeds 120W,
daylighting controls are required in the primary daylit zone, per the
Title 24 mandatory requirements.
For parking garages, when the installed general
lighting power in the primary sidelit or secondary sidelit daylit zone
exceeds 120W, daylighting controls are required, per the Title 24
mandatory requirements. Luminaires located in daylit transition zones or
dedicated ramps are exempt from this requirement.
For nonresidential spaces, daylighting controls are
specified when the installed general lighting power in the skylit, primary
sidelit, or secondary sidelit daylit zone(s) exceeds 120W.
For parking garages, when the installed general
lighting power in the primary sidelit or secondary sidelit daylit zone
exceeds 120W, daylighting controls are required. Luminaires located in
daylit transition zones or dedicated ramps are exempt from this
requirement. |
|
Standard Design:
Existing Buildings |
When lighting systems in an existing altered building
are not modified as part of the alteration, daylighting controls are the
same as the proposed design.
When an alteration increases the area of a lighted
space, increases lighting power in a space, or when luminaires are
modified in a space where proposed design lighting power density is
greater than 85 percent of the standard design LPD, daylighting control
requirements are the same as for 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 sidelit 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,
which 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 percent 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 percent 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 are 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 are derived
from other modeling inputs, including the 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/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 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 |
W |
|
Input Restrictions |
As designed |
|
Standard Design |
The installed lighting power for the standard design is
the product of the secondary daylit area and the 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. 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.
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:
Where: , , and  are selected from the following
table.
|
|
Skylit Daylit
Zones |
Primary Sidelit
Daylit Zones |
Secondary Sidelit
Daylit Zones |
|
Illuminance
Setpoint |
|
|
|
|
|
|
|
|
|
|
≤ 200 lux |
3927 |
0 |
3051 |
1805 |
-0.40 |
3506 |
7044 |
-3.32 |
1167 |
|
≤ 1000
lux |
12046 |
0 |
-421 |
6897 |
-7.22 |
475 |
1512 |
-2.88 |
-22 |
|
> 1000
lux |
5900 |
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, it is defined:
Where: Azimuth is defined
as the azimuth of the parent object containing the fenestration associated
with the preliminary reference point.
Effective Aperture
(EA): For 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:
Where:
|
|
is the combined
effective aperture of all daylight sources illuminating a specific
daylit zone |
|
|
is the user
specified visible transmittance of the fenestration object directly
associated with the daylit zone |
|
|
is the area of the
fenestration object directly associated with the daylit
zone |
|
|
is the user
specified visible transmittance of the fenestration object
associated with each intersecting daylit zone |
|
|
is the area of the
fenestration object directly associated with each intersecting
daylit zone |
|
|
is the fraction of
intersecting area between the daylit zone in question and each
intersecting daylit zone:
|
|
|
is the area of each
intersecting daylit zone (including area that might fall outside a
space or exterior boundary) |
|
|
is the area of the
daylit zone (including area that might fall outside a space or
exterior boundary). |
First Reference
Position: Select the preliminary
reference point with the highest relative daylight potential (RDP) from
among 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.
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 |
Additions or alternations
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 only applies 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:
|
|
Units |
Unitless |
|
Input
Restrictions |
Prescribed values for
space type in Appendix 5.4A |
|
Standard
Design |
The baseline building
illumination adjustment factors shall match the proposed |
|
Standard
Design:
Existing
Buildings |
Same as new construction
when skylights are added/replaced and general light is
altered. |
|
Fraction of Controlled
Lighting |
|
Applicability |
Daylighted
Spaces |
|
Definition |
The fraction of the
general lighting power in the (daylighted) primary and skylit daylit zone,
or secondary sidelit daylit 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 for new
construction when skylights are added/replaced, and general light is
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.
Options:
•
Stepped switching controls
vary the electric input power and lighting output power in discrete
equally spaced steps. 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: Example Continuous Dimming
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 the example control chart below.
|
|
Units |
List (see
above) |
|
Input
Restrictions |
As
designed |
|
Standard
Design |
Baseline does not have
daylighting control (continuous). |
|
Standard
Design:
Existing
Buildings |
Same as for new
construction when skylights are added/replaced, and general light is
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. |
|
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 from
Table 8: Baseline Power/Light Output
Fraction. 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 light is
altered. |
|
Minimum Dimming Light
Fraction |
|
Applicability |
Daylighting and dimming
controls |
|
Definition |
The minimum light output
when controlled lighting is fully dimmed. Minimum light fraction = minimum
light output / rated light output. |
|
Units |
Numeric:
fraction |
|
Input
Restrictions |
As
designed |
|
Standard
Design |
Baseline building uses
continuous dimming control with a minimum dimming light fraction from
Table 8: Baseline Power/Light Output
Fraction. 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 light is
altered. |
Table 8: Baseline Power/Light Output Fraction
|
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 |
5.4.6
Receptacle Loads
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 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.
Heat Gain
Fractions:
|
|
Radiative |
Latent |
Convective |
|
Receptacle
Power |
0.20 |
0.00 |
0.80 |
|
Gas Equipment
Power |
0.15 |
0.00 |
0.00 |
|
|
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 |
Prescribed to schedule in
Appendix 5.4A |
|
Standard
Design |
Same as
proposed |
|
Standard
Design:
Existing
Buildings |
Same as for new
construction |
5.4.7
Commercial Refrigeration Equipment
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.
DOE has developed standards for refrigerated casework.
Table 9 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 DOE standards and test procedures. Title 24
default values for these are given in Table
10: Default Power for Walk-In Refrigerators and Freezers
(W/ft²). 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.
Equation 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 10:
Default Power for Walk-In Refrigerators and Freezers (W/ft²) (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)
Table 10: Default Power for
Walk-In Refrigerators and Freezers (W/ft²)
|
Floor Area |
Refrigerator |
Freezer |
|
100 ft² or
less |
8.0 |
16.0 |
|
101 ft² to 250
ft² |
6.0 |
12.0 |
|
0251 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 |
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.
|
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.
•
DOE 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
9. 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 DOE performance ratings. |
|
Units |
List (see
above) |
|
Input
Restrictions |
None. For 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 |
See Table C-43, p. 146 of NREL/TP-550-41956, Methodology for Modeling Building
Energy Performance across the Commercial Sector, Technical Report, Appendix C,
March 2008. The values in this report were taken from Table 8-3 of the
California Commercial End-Use Survey, Consultants Report, March 2006,
CEC-400-2006-005
|
Refrigeration
Power |
|
Applicability |
All buildings 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 DOE 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 DOE performance ratings method is used, refrigeration power for
casework shall be determined from Table
9 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 DOE 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 DOE 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 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 DOE performance ratings methods,
the heat that is removed from the space is determined as
follows:
Where:
|
|
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. |
|
|
The power of the
refrigeration system determined by using the Title 24 defaults or
the DOE performance ratings method (kW) |
|
|
The remote
condenser fraction (see building descriptor below)
(unitless) |
|
|
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 DOE 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 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 |
5.4.8
Elevators, Escalators and Moving Walkways
Elevators,
escalators and moving walkways account for 3 percent to 5 percent 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 percent to 40 percent 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
11.
Table 11: Unit Energy Consumption Data for
Elevators, Escalators,
and Moving Walkways
|
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, escalators, 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 11 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, escalators, 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. 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 |
5.4.9
Process, Gas
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, Convective = 0 |
|
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 shall inform the user that the
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 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 center loads
including transformers, uninteruptible power supplies, power delivery
units, 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 shall inform the user that the
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 new
construction |
|
Gas Process Load
Schedule |
|
Applicability |
All buildings that have
commercial gas equipment |
|
Definition |
The schedule of process
load operation. 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 electric
process load operation. |
|
Units |
Data structure: schedule,
fractional |
|
Input
Restrictions |
As
designed. |
|
Standard
Design |
Same as the proposed
design |
|
Standard
Design:
Existing
Buildings |
Not
applicable |