Troffer Reference Design

Cree® XLamp® XQ-B LED
2’ x 2’ Troffer Reference Design
Table of Contents
Introduction
Introduction....................................................................................1
This application note details the design of a 2’ x 2’ troffer using
Design approach/objectives.........................................................2
Cree’s XLamp® XQ-B LED. This troffer is intended to be used
The 6-step methodology................................................................2
in commercial and industrial applications. These applications,
1. Define lighting requirements.................................................2
that historically have used U-bend and T8 fluorescent luminaires
2. Define design goals................................................................5
typically providing 70‑80 lumens/watt, can benefit from
3. Estimate efficiencies of the optical, thermal & electrical
the energy savings and high efficiency provided by a XQ-B
systems...................................................................................5
4. Calculate the number of LEDs...............................................7
5. Consider all design possibilities............................................7
6. Complete the final steps: implementation and analysis......8
Conclusions..................................................................................12
Bill of materials............................................................................12
CLD-AP156 rev 0C
Application Note
LED‑based troffer.
The XLamp XQ-B LED is designed specifically for applications
that require a broad light distribution. The breakthrough lightemission pattern, where more light is directed toward the edge
rather than center of the LED, and the high flux output and
efficacy offered by the XLamp XQ-B LED make it a particularly
strong candidate for use in a troffer. The performance of the
XQ-B LED enables a troffer that provides energy savings while
www.cree.com/Xlamp
delivering superior light output.
Reliance on any of the information provided in this Application Note is at the user’s sole risk. Cree and its affiliates make no warranties or representations about, nor assume
any liability with respect to, the information in this document or any LED-based lamp or luminaire made in accordance with this reference design, including without limitation
that the lamps or luminaires will not infringe the intellectual property rights of Cree or a third party. Luminaire manufacturers who base product designs in whole or part on
any Cree Application Note or Reference Design are solely responsible for the compliance of their products with all applicable laws and industry requirements.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are
registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection
Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor
endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information,
please contact Cree Sales at [email protected].
Cree, Inc.
4600 Silicon Drive
Durham, NC 27703
USA Tel: +1.919.313.5300
1
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Design approach/objectives
In the “LED Luminaire Design Guide” Cree advocates a six-step framework for creating LED luminaires and lamps. All Cree reference
designs use this framework, and the design guide’s summary table is reproduced below in Table 1.
Table 1: Cree 6-step framework
Step
Explanation
1. Define lighting requirements
• The design goals can be based either on an existing fixture or on the application’s lighting requirements.
2. Define design goals
• Specify design goals, which will be based on the application’s lighting requirements.
• Specify any other goals that will influence the design, such as special optical or environmental requirements.
3. Estimate efficiencies of the optical, thermal &
electrical systems
• Design goals will place constraints on the optical, thermal and electrical systems.
• Good estimations of efficiencies of each system can be made based on these constraints.
• The combination of lighting goals and system efficiencies will drive the number of LEDs needed in the
luminaire.
4. Calculate the number of LEDs needed
• Based on the design goals and estimated losses, the designer can calculate the number of LEDs to meet the
design goals.
5. Consider all design possibilities and choose
the best
• With any design, there are many ways to achieve the goals.
• LED lighting is a new field; assumptions that work for conventional lighting sources may not apply.
6. Complete final steps
•
•
•
•
•
Complete circuit board layout.
Test design choices by building a prototype luminaire.
Make sure the design achieves all the design goals.
Use the prototype to further refine the luminaire design.
Record observations and ideas for improvement.
The 6-step methodology
The goal of the design is an XLamp XQ-B LED-based 2’ x 2’ troffer providing 100 lumens per watt for use in indoor commercial and
industrial ceiling applications.
1. Define lighting requirements
Table 2 shows a ranked list of desirable characteristics to address in a troffer.
Table 2: Ranked design criteria for a troffer
Importance
Critical
Important
Characteristics
Units
Luminous flux
lumens (lm)
Luminous efficacy
lm/W
Electrical power
watts (W)
Lifetime
hours
Operating temperatures
°C
Operating humidity
% relative humidity
Correlated color temperature (CCT)
K
Color rendering index (CRI)
100-point scale
Table 3 summarizes the ENERGY STAR® requirements for solid-state luminaires.1 There are no ENERGY STAR requirements for troffers.
1
ENERGY STAR Program Requirements, Product Specification for Luminaires (Light Fixtures), Eligibility Criteria, Version 1.2
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
2
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Table 3: ENERGY STAR luminaire requirements
Characteristic
Requirements
Light source life requirements: all
luminaires
The LED package(s) / LED module(s) / LED array(s), including those incorporated into LED light engines or GU24 based integrated
LED lamps, shall meet the following L70 lumen maintenance life values (refer to Lumen Maintenance Requirements in the next
section):
• 25,000 hours for residential grade indoor luminaires
• 35,000 hours for residential grade outdoor luminaires
• 35,000 hours for commercial grade luminaires
Lumen maintenance life projection claims in excess of the above requirements shall be substantiated with a TM-21 lumen
maintenance life projection report.
Lumen maintenance requirements:
directional and non-directional
luminaires
The LED package(s) / module(s) / array(s), including those incorporated into LED light engines or GU24 based integrated LED
lamps, shall meet the following
• L70(6k) rated lumen maintenance life values, in situ:
• L70(6k) ≥ 25,000 hours for residential indoor
• L70(6k) ≥ 35,000 hours for residential outdoor, or commercial
Compliance with the above shall be documented with a TM-21 lumen maintenance life projection report as detailed in TM-21,
section 7. The report shall be generated using data from the LM-80 test report for the employed LED package/module/array
model (“device”), the forward drive current applied to each device, and the in situ TMPLED temperature of the hottest LED in the
luminaire. In addition to LM-80 reporting requirements, the following information shall be reported:
•
•
•
•
•
•
sampling method and sample size (per LM-80 section 4.3)
test results for each TS and drive current combination
description of device including model number and whether device is an LED package, module or array (see Definitions)
ANSI target, and calculated CCT value(s) for each device in sample set
Δ u’v’ chromaticity shift value on the CIE 1976 diagram for each device in sample set
a detailed rationale, with supporting data, for application of results to other devices (e.g. LED packages with other CCTs)
Access to the TMPLED for the hottest LED may be accomplished via a minimally sized hole in the luminaire housing, tightly
resealed with a suitable sealant if created for purposes of testing.
All thermocouple attachments and intrusions to luminaire housing shall be photographed.
CCT requirements: all indoor
luminaires
The luminaire (directional luminaires), or replaceable LED light engine or GU24 based integrated LED lamp (non-directional
luminaires) shall have one of the following nominal CCTs:
•
•
•
•
•
2700 Kelvin
3000 Kelvin
3500 Kelvin
4000 Kelvin
5000 Kelvin (commercial only)
The luminaire, LED light engine or GU24 based integrated LED lamp shall also fall within the corresponding 7-step chromaticity
quadrangles as defined in ANSI/NEMA/ANSLG C78.377-2008.
Color rendering requirements: all
indoor luminaires
The luminaire (directional luminaires), or replaceable LED light engine or GU24 based integrated LED lamp (non-directional
luminaires) shall meet or exceed Ra ≥ 80.
Color angular uniformity requirements:
directional solid state indoor
luminaires
Throughout the zonal lumen density angles detailed above, and five degrees beyond, the variation of chromaticity shall be within
0.004 from the weighted average point on the CIE 1976 (u’,v’) diagram.
Color maintenance requirements: solid
state indoor luminaires only
The change of chromaticity over the first 6,000 hours of luminaire operation shall be within 0.007 on the CIE 1976 (u’,v’) diagram,
as demonstrated by either:
• the IES LM-80 test report for the employed LED package/array/module model, or
• as demonstrated by a comparison of luminaire chromaticity data in LM-79 reports at zero and 6,000 hours, or
• as demonstrated by a comparison of LED light engine or GU24 based integrated LED lamp chromaticity data in LM-82 reports
at zero and 6,000 hours.
Source start time requirement:
directional and non-directional
luminaires
Light source shall remain continuously illuminated within one second of application of electrical power.
Source run-up time requirements:
directional and non-directional
luminaires
Light source shall reach 90% of stabilized lumen output within one minute of application of electrical power.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
3
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Characteristic
Requirements
Power factor requirements: directional
and non-directional luminaires
Total luminaire input power less than or equal to 5 watts: PF ≥ 0.5
Transient protection requirements: all
luminaires
Ballast or driver shall comply with ANSI/IEEE C62.41.1-2002 and ANSI/IEEE C62.41.2-2002, Class A operation. The line transient
shall consist of seven strikes of a 100 kHz ring wave, 2.5 kV level, for both common mode and differential mode.
Operating frequency requirements:
directional and non-directional
luminaires
Frequency ≥ 120 Hz
Noise requirements: directional and
non-directional luminaires
All ballasts & drivers used within the luminaire shall have a Class A sound rating.
Total luminaire input power greater than 5 watts:
Residential: PF ≥ 0.7
Commercial: PF ≥ 0.9
Note: This performance characteristic addresses problems with visible flicker due to low frequency operation and applies to
steady-state as well as dimmed operation. Dimming operation shall meet the requirement at all light output levels.
Ballasts and drivers are recommended to be installed in the luminaire in such a way that in operation, the luminaire will not emit
sound exceeding a measured level of 24 BA.
The DesignLights Consortium® (DLC) and the Department of Energy (DOE) Better Buildings Alliance (BBA) provide requirements for 2’ x 2’
troffers, summarized in Table 4.2,3
Table 4: DLC and BBA 2’ x 2’ troffer requirements
Characteristic
Minimum light output
Unit
lm
DLC Value
BBA Value
2,000
2,000
0°-180°: 1.0-1.20
90°-270°: 1.0-2.0
≥ 75% 0-60°
0°-180°: 1.0-2.0
90°-270°: 1.0-2.0
lm/W
85
85
K
< 5000
2700, 3000, 3500,
4000/4100, 4500, 5000
80
Ra > 80 and R9 > 0
L70 lumen maintenance
hours
50,000
> 50,000
Minimum luminaire warranty
years
5
5
Spacing criteria
Minimum luminaire efficacy
Allowable CCTs (ANSI C78.377-2008)
Minimum CRI
The spacing criteria value provides information about the uniformity of light distribution of one luminaire. It is a horizontal-spacing-tomounting-height ratio without units. The 0°-180° value applies along a luminaire’s length; the 90°-270° value applies along a luminaire’s
width.
When two overhead luminaires are at their maximum horizontal spacing, the illuminance directly beneath one is due mainly to the luminaire
overhead. A low point of illumination is apt to be at the midpoint between two luminaires. The horizontal spacing between two luminaires
is typically chosen so the illumination at the midpoint is equal to the illumination directly beneath one luminaire that is due only to that
luminaire. For luminaires arranged in a square, a low illumination point is apt to be at the center of the square and the luminaire spacing
is chosen so that the illumination at the center of the square is equal to the illumination directly beneath one luminaire that is due only to
that luminaire. A larger spacing criteria value therefore suggests luminaires that can be spaced farther apart, and require fewer luminaires
to achieve a given illumination, than those having a smaller spacing criteria value.
Installing luminaires at their spacing criteria value does not guarantee a good lighting system. The spacing criteria value does not account
for reflected illumination or for illumination from other luminaires and is an estimate and only a guideline.
2
3
Technical Requirements Table v2.0, DesignLights Consortium Qualified Products List - Non-Residential Applications
BBA Model Technical Specification: High-Efficiency Troffers, A Better Building Alliances (BBA) Project, Version 4.0, Released 4/15/2013
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
4
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
2. Define design goals
Table 5 shows the design goals for this project.
Table 5: Design goals
Characteristic
Light output
Luminaire efficacy
Unit
Minimum Goal
Target Goal
lm
4000
> 4000
lm/W
100
> 100
Power
W
40
< 40
CCT
K
5000
< 5000
CRI
100-point scale
80
>80
0.9
> 0.9
Power factor
3. Estimate efficiencies of the optical, thermal & electrical systems
We used Cree’s Product Characterization Tool (PCT) tool to determine the drive current for the design. For the 4000‑lm target, we estimated
85% optical efficiency and 90% driver efficiency. We also estimated a 40 °C solder‑point temperature.
The PCT output highlighted in Figure 1 shows that, at 56 mA, 225 XQ-B LEDs provide sufficient light output to meet the design goals.
1
LED 1
Cree XLamp XQ-B {WT} x75
Current (A)
Model
$
Price
SYS lm tot SYS lm/W
0.052
0.054
0.056
0.058
0.060
5090.1
5269.6
4086.1
4219.2
4351.6
Flux
K2 [30.6]
102.5
101.9
101.3
100.8
100.2
Tsp (ºC)
SYS W
49.674
51.719
40.329
41.874
43.426
40
SYS # LED
300
300
225
225
225
Figure 1: PCT view of the number of LEDs used and drive current
Troffer Housing
We used a market-available 2’ x 2’ troffer housing, shown in Figure 2. Because of the troffer’s relatively large size and the low LED current,
we believe that a heat sink is not needed. We mounted the LED printed‑circuit boards (PCB) directly to the housing and are confident the
housing provides sufficient thermal dissipation.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
5
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Figure 2: Troffer housing
Optical Requirements
This LED troffer reference design uses a shallow housing, creating an optical cavity that requires efficient light recycling to achieve the
100 lm/W goal. We used an optical system consisting of reflective paper to maximize the amount of light emitted from the troffer and a
polycarbonate diffuser sheet provided with the housing to cover the opening of the troffer and provide smooth light output without hot
spots. The reflector sheet was made to fit the housing and accommodate the LED arrangement.
Electrical Requirements
Driver
Because this is not an integrated lamp design, the driver form factor is not constrained and the driver can be remotely located above the
ceiling. We used a constant-current driver, shown in Figure 3, located separate from the troffer.
Figure 3: Driver
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
6
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
4. Calculate the number of LEDs
Using Cree’s PCT, we determined that 225 XLamp XQ-B LEDs produce sufficient light to meet the
4000-lm design goal. The LEDs are arranged in a 15 x 15 array that spans the length and width
of the housing with even spacing between the individual LEDs. As shown in Figure 4, the LEDs in
adjacent rows are symmetrically offset to aid in diffusing the light output of the luminaire. Fifteen
LEDs are connected in series on each of fifteen metal‑core printed‑circuit boards (MCPCB) that
are connected in parallel.
Figure 4: XQ-B LED arrangement
The XLamp XQ-B LED offers a wide range of color temperatures. We selected a neutral white LED for this troffer design, shown highlighted
in Table 6. To show the performance available from the XQ-B LED, we selected an LED from a high‑level bin.
Table 6: XQ-B order codes
XLamp XQ-B LED Standard Kit Codes - White
Chromaticity
Kit
CCT
Minimum Luminous
Flux (lm) @ 80 mA
Code
Flux (lm)
Order Codes
70 CRI Minimum
75 CRI Typical
80 CRI Minimum
ANSI Neutral White (3700 K – 5000 K)
E3
5000 K
F4
4750 K
E4
4500 K
F5
4250 K
E5
4000 K
K2
30.6
XQBAWT-00-0000-00000B0E3
XQBAWT-00-0000-00000L0E3
XQBAWT-00-0000-00000B0F4
XQBAWT-00-0000-00000L0F4
J3
26.5
K2
30.6
J3
26.5
K2
30.6
J3
26.5
K2
30.6
XQBAWT-00-0000-00000B0F5
XQBAWT-00-0000-00000H0E3
XQBAWT-00-0000-00000HXE3
XQBAWT-00-0000-00000H0F4
XQBAWT-00-0000-00000HXF4
XQBAWT-00-0000-00000B0E4
XQBAWT-00-0000-00000L0E4
XQBAWT-00-0000-00000H0E4
XQBAWT-00-0000-00000HXE4
J3
26.5
XQBAWT-00-0000-00000BXF5
K2
30.6
XQBAWT-00-0000-00000B0E5
J3
26.5
XQBAWT-00-0000-00000BXE5
J2
23.5
XQBAWT-00-0000-00000L0F5
XQBAWT-00-0000-00000H0F5
XQBAWT-00-0000-00000HXF5
XQBAWT-00-0000-00000L0E5
XQBAWT-00-0000-00000H0E5
XQBAWT-00-0000-00000HXE5
XQBAWT-00-0000-00000HWE5
5. Consider all design possibilities
There are many ways to design an LED-based 2’ x 2’ troffer. This reference design aims to show that the XLamp XQ-B LED enables a
2’ x 2’ troffer offering superior performance. Table 7 contains data from the PCT for various numbers of XQ-B LEDs that indicate that
troffers using different numbers of XQ-B LEDs are possibilities. Like the data in Figure 1, for the 4000-lm target, we estimated 85% optical
efficiency and 90% driver efficiency. The solder point temperature estimates are given in the table. Increasing the drive current and
reducing the number of LEDs to reduce cost can enable a troffer that meets the DLC and BBA requirements.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
7
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Table 7: Possible troffer implementations
Number of XQ-B LEDs
Current
(mA)
System Flux
(lm)
System Power
(W)
System Efficacy (lm/W)
TSP
(°C)
225
56
4070
40.5
101
40
185
70
4071
42.0
97
45
150
90
4080
44.6
92
50
130
110
4113
47.8
86
60
Because this prototype troffer uses XLamp XQ-B LEDs from the same bin, in fact, from the same reel of LEDs, color mixing is not a
consideration and unit-to-unit consistency is ensured. Such a situation is less likely in a production environment. Our choice of housing
determined the fixture depth and the distance from the LEDs to the diffuser. The goal of this reference design is not to design the optimum
troffer, but to show the performance possible from a troffer based on the XLamp XQ-B LED. Refer to Cree’s Color Mixing and Distributed
Illumination application notes for other approaches to designing LED-based luminaires that produce uniform, consistent white light.
6. Complete the final steps: implementation and analysis
Using the methodology described above, we determined a suitable combination of LEDs, components and drive conditions. This section
describes how Cree assembled the troffer and shows the results of the design.
Prototyping Details
1. We verified the component dimensions to ensure a correct fit.
2. Following the recommendations in Cree’s Soldering and Handling Application Note for the XQ-B LED, with an appropriate solder paste
and reflow profile, we reflow soldered the LEDs to the MCPCBs. We cleaned the flux residue with isopropyl alcohol (IPA).
3. We applied a small amount of thermally conductive compound to the back of the MCPCBs and mounted the MCPCBs on the base of
the housing, securing them with screws.4
4. We soldered the MCPCB interconnect wires to the MCPCBs and fed the wires through an opening in the back of the housing.
5. We soldered the MCPCB interconnect wires to the driver and tested the troffer to make sure the LEDs illuminated.
6. We installed reflective paper (with cutouts for the LEDs) over the LEDs and on the inside walls of the housing.
7. We installed the diffuser sheet, aligning it on the top of the housing.
8. We finished the construction by securing the diffuser using the top decorative housing frame.
9. We performed final testing.
Results
Thermal Results
Cree used a thermocouple to measure the troffer’s thermal performance. The measured TSP of 32.5 °C confirms that the thermal dissipation
of the troffer’s aluminum housing is sufficient for this design.
4
Refer to Cree’s Chemical Compatibility application note for compounds that are safe to use with Cree LEDs.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
8
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Based on the measured solder point temperature, the junction temperature (TJ) can be calculated as follows.
TJ = TSP + (LED power * LED thermal resistance)
TJ = 32.5 °C + (.2 W * 17 °C/W)
TJ = 35.9 °C
Estimated LED lifetime
Based on thousands of hours of long-term testing of the XLamp XQ-B LED at operating conditions similar to those of this troffer, Cree
expects an L70 lifetime significantly longer than the DLC and BBA 50,000-hour L70 lumen maintenance requirements for this design.
Optical and Electrical Results
We obtained the results in Table 8 by testing the troffer in a 1.5-meter sphere at steady state after a 60-minute stabilizing time.5 The results
meet the ENERGY STAR performance levels for a solid-state luminaire and the DLC and BBA light output requirements for a 2’ x 2’ troffer.
Table 8: XQ-B 2’ x 2’ troffer steady-state results
Characteristic
Light output
Unit
Result
lm
4070
0°-180°: 1.28
90°-270°: 1.28
Spacing criteria
Luminaire efficacy
lm/W
101
Power
W
40.5
CCT
K
5087
CRI
100-point scale
Power factor
CBCP
Beam angle
83
0.9
cd
1400
degrees
114
We also tested the intensity distribution of the XQ-B troffer. Figure 5 shows that the troffer has an even intensity distribution.
5
Testing was performed at Cree’s Shanghai Technology Center. An IES file for the troffer is available.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
9
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Figure 5: Polar plot of XQ-B 2’ x 2’ troffer
Table 9 shows the illuminance of the XQ-B troffer at various distances from the light source.
Table 9: XQ-B 2’ x 2’ troffer illuminance
Height
Illuminance
Eavg
Emax
Eavg
Emax
Diameter
1m
3.3 ft
37.5 fc
130.7 fc
403.7 lx
1407.0 lx
3.1 m
10.1 ft
2m
6.6 ft
9.4 fc
32.7 fc
100.9 lx
351.8 lx
6.1 m
20.1 ft
3m
9.8 ft
4.2 fc
14.5 fc
44.9 lx
156.3 lx
9.2 m
30.2 ft
4m
13.1 ft
2.3 fc
8.2 fc
25.2 lx
88.0 lx
12.3 m
40.2 ft
5m
16.4 ft
1.5 fc
5.3 fc
16.2 lx
56.3 lx
15.3 m
50.3 ft
We used DIALux software to simulate the illumination of a room 30’ wide and 30’ long, with a 15’ ceiling.6 Figure 6 shows simulated
false‑color illumination of the room with four troffers. The legend shows the minimum values in footcandles (fc) for the various colors
in the simulation. The diagrams in the bottom show the minimum illumination values on the floor. The troffers were specified as surface
mounted, evenly spaced at 7.5’ from the nearest walls and 15’ from the adjacent troffers. Simulations were done for two comparison
fluorescent 2’ x 2’ troffers and the XQ-B 2’ x 2’ troffer. The fluorescent troffers simulated were included as comparison troffers in the
US Department of Energy (DOE) Commercially Available Light-Emitting Diode Product Evaluation and Reporting (CALiPER) study of LED
troffers.7
The simulation shows that the XQ-B troffer provides more light throughout the room than fluorescent troffer A. The XQ-B troffer illumination
pattern is similar to that of fluorescent troffer B, but provides more light on the walls and ceilings.
6
7
DIALux software version 4.11, DIALux GmbH
US DOE Caliper Exploratory Study: LED Troffer Lighting
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
10
Project 1
07 / 15 / 2013
DIALux 4.11 Output
Operator
Telephone
Fax
e-Mail
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XQB
07 / 15 / 2013
Project 1
Operator
Telephone
Fax
e-Mail
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
07 / 15 / 2013
Room 1 / False Color Rendering
Operator
Telephone
Fax
e-Mail
Room 1 / False Color Rendering
Room 1 / False Color Rendering
DIALux 4.11 Output
Project 1
Page 3 of 8
XQB
Project 1
07 / 15 / 2013
07 / 15 / 2013
Operator
Telephone
Fax
e-Mail
Legend (fc)
4.64
5.57
5.57
5.57
6.50
0
0.93
6.50
0
0.93
1.86
7.43
7.43 7.43
4.64
7.43
7.43
7.43
7.43
5.57
7.43
5.57
5.57
DIALux 4.11 by DIAL GmbH
11.15
6.50
5.57
7.43
7.43
7.43
Room 1 / Summary
fc
30.00 ft
11.15
11.15
9.29
13.012.79
1.86
3.72
4.64
5.57
13.01
6.50
7.43
fc
0
9.29
Page 8
1.86
0.93
4.64
3.72
2.79
fc
9.29
13.01
13.01
11.15
DIALux 4.11 Output
11.15
5.57
9.29
9.29
Page 8
9.29
fc
7.43
11.15
Page 8 of 8
11.15
9.29
9.29
9.29
Page 8
9.29
11.15
DIALux 4.11 by DIAL GmbH
11.15
9.29
7.50
Page 8
11.15
9.29
7.43
0.00
7.43
9.29
0.00
30.00 ft
Figure 6: Illumination simulation
- left:
XQ-B troffer
0.00 fluorescent troffer A, center: fluorescent
30.00 ft troffer
0.00B, right:7.50
0.00
6.50
5.57
9.29
DIALux 4.11 by DIAL GmbH
5.57
22.50
11.15
11.15
6.50
30.00 ft
9.29
9.29
9.29
9.29
9.29
6.50
6.50
0.93
DIALux 4.11 by DIAL GmbH
7.43
7.43 7.43
7.43
2.79 7.433.72
7.43
5.57
0
6.50
7.43
9.29
11.15
9.29
11.15
5.57
5.57
2.79
9.29
6.50
6.50
Room
1 / Summary
3.72
4.64
5.57
1.86
30.00 ft
4.64
Operator
Telephone
Fax
e-Mail
Operator
Telephone
Fax
e-Mail
0.00
22.50
30.00 ft
Height of Room: 15.000 ft, Mounting Height: 15.000 ft, Light loss factor:
Values
in Footcandles,
Scale
1:118
Height of Room:
15.000
ft, Mounting
Height:
15.000 ft, Light lossHeight of Room:
Values 15.000
in Footcandles,
Scale
ft, Mounting
Height: 15.000 ft, Light loss factor:
factor:
1:118 to be 2.493’
0.80workplane was specified
Table0.80
10 shows the illumination values throughout
the0.80
room for the simulations in Figure 6. The
Surface
E
[fc]
E
[fc]
E
[fc]
u0
 [%]
Eav [fc] the room
EminSurface
[fc]
Emax [fc] troffer
Eav [fc]
av
min
max [%]
 [%]A u0
above the floor. Table 10 also
shows that
the XQ-BSurface
troffer
puts more
light throughout
than
fluorescent
and more
light
on
Workplane
the
walls and
Floor
ceiling
Ceiling
the fluorescent
troffers.
Walls (4)
/
6.21
than
troffer
20 fluorescent
5.61
80
50
1.39
3.43
3.66
Workplane
B.Floor
The3.58
ratios
1.01
Ceiling
Walls1.35
(4)
show
7.54 /
that
6.94
20the
1.64
80
5.39
50
0.58911
XQ-B
troffer
0.639
9.65
0.728
2.19
/
5.14
5.40
13
Workplane
produces
of
5.79
Floora uniformity12
1.63
2.61
Ceiling
2.17
7.88
Walls (4)
0.510
/
light 20
nearly
0.600
0.745
80
/
50
11
identical
9.52
to
2.51
6.22
Emin
5
5
1
2
Workplane:
UGR
LengthwaysAcross data
to luminaire
Table
10: Illumination
from axis
simulation
Workplane:Across to luminaire axis
Workplane:
UGR
LengthwaysHeight:
2.493 ft
Left Wall
16
17
Height:
2.493 ft
Left Wall
17Height:
18
2.493 ft
Grid:
32 x 32 Points
Lower Wall
16
17
64 x 64 Points
Grid:
64 x 64 Points
Lower Wall
17Grid:
18
Emax
Emin
Boundary Zone:
0.000
ft
(CIE,
SHR
=
0.25.)
Troffer
Surface
(fc)
Emax/Emin
Emax/Eavg 0.000 ft
BoundaryEav
Zone:
0.000 ft
(CIE, SHR =Eavg/Emin
0.25.) Boundary Zone:
(fc)
(fc)
Illuminance Quotient (according to LG7): Walls / Working Plane: 0.559,
Ceiling / Working Plane:
0.224.
Quotient
(according
LG7): Walls / Working Plane: 0.604,
Illuminance Quotient (according to LG7): Walls / Working Plane:Illuminance
0.487, Ceiling
/ Working
Plane: to
0.207.
Luminaire Parts List
Workplane
7.54
6.21 List 3.66
2.1
1.7
Luminaire Parts 1.2
List
Luminaire Parts
No.
1
Pieces
4
Designation (Correction Factor)Floor
A
FINELITE,Troffer
INC. FINELITE
HPR-x-2X2-2T8Ceiling
DCO 2' X 2' FLUORESCENT RECESSED
LUMINAIRE WHITE REFLECTOR,
Walls&
FROSTED PLASTIC SIDE LENSES
FROSTED .080 CENTER LENS (1.000)
[W]
 (Luminaire)
 3.58
(Lamps) [lm] P1.9
6.94
5.61[lm]
No.
Pieces
Designation
(Correction Factor)
1.6No.
1.2
Pieces
Designation
P [W] Factor)
 (Luminaire)
[lm]  (Lamps)
[lm] (Correction
1.64
Lighting 2SP G B
2U316
1.39Lithonia 1.01
1.6
1.4 1
1
5.39
4 Troffer Air
Handling, 2'x2',
2 Lamp,
3.43
1.35
4.0
2.5
A12 GEB Specification
2329
2700 Premium
30.0
T8 U6, Pattern #12 Acrylic Lens,
Ballast (1.000)2.4
11 Electronic
5.4
Total: 9316
Total: 10800 120.0
4
*Modified Technical Specifications
3776
1.6
5300
53.0
13
Floor
12
9.65
5.79
2.1
Ceiling
2.61
2.19
1.63
1.6
1.3
1.2
Walls
7.88
5.14
2.17
3.6
2.4
1.5
Workplane
13
11
5.9
2.2
1.9
1.2
11
9.52
5.86
1.9
DIALux 4.11 by DIAL GmbH
1.6
1.2
4.11 Output2.51
Ceiling DIALux2.88
1.76
1.6
1.4
1.1
2.45
3.9
2.5
1.5
Total:
1.7
15104
Total:
1.2
21200
212.0
Specific connected load: 0.13
W/sq B
ft = 0.21 W/sq ft/10 fc (Ground area: 900.02 sq ft)
Troffer
Specific connected load: 0.24 W/sq ft = 0.22 W/sq ft/10 fc (Ground area: 900.02 sq ft)
DIALux 4.11 by DIAL GmbH
XQ-B Troffer
Floor
Walls
9.52
6.22
Page 3
To
Specific connected
2.0
1.2load: 0.16 W/sq ft = 0.16 W/sq ft/10 fc (Ground area
Workplane
DIALux 4.11 by DIAL GmbH
 (Lu
EVERFINE K2 5000K (Type 1)* (1.000)
1.2
Page 3
Page 3 of 8
Table 11shows luminous flux and power values from the simulation. The XQ-B troffer is not only brighter than the fluorescent troffers but
is also 41% more efficient than troffer A and 55% more efficient than troffer B.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
11
XLamp ® XQ-B LED 2’ x 2’ Troffer Reference Design
Table 11: Luminance and power data from simulation
Lumens (lm)
Troffer
1 Troffer
Power (W)
4 Troffers
1 Troffer
4 Troffers
Efficacy (lm/W)
Troffer A
2329
9316
30
120
78
Troffer B
3776
15,104
53
212
71
XQ-B Troffer
4071
16,283
37
148
110
Conclusions
This reference design illustrates the excellent results produced by a high-performance troffer based on the Cree XLamp XQ-B LED. The
design uses commercially available components to produce a 2’ x 2’ troffer that meets the DLC and BBA light output requirements for
the form factor. The troffer provides significantly more than 4000 lm of light output with excellent efficacy of better than 100 lm/W. The
lighting-class performance of the Cree XLamp XQ-B LED makes it an attractive design option for an LED-based troffer.
Bill of materials
Table 12: Bill of materials for XQ-B 2’ x 2’ troffer
Component
Order Code/Model Number
Company
Web Link
Driver
LP40W-48-C0830
XHG Tech
www.xhg-tech.cn
LED
XQBAWT-00-0000-00000H0E3
Cree, Inc.
XQ-B product page
Reflective paper
Micro Cell PET
Furukawa Electric
www.furukawa.co.jp/foam/english/mcpet/index.htm
Thermally conductive compound
Black Ice 712
Timtronics
www.timtronics.com/electricallyconductive.htm
Reliance on any of the information provided in this Application Note is at the user’s sole risk. Cree and its affiliates make no warranties or representations about, nor assume any
liability with respect to, the information in this document or any LED-based lamp or luminaire made in accordance with this reference design, including without limitation that
the lamps or luminaires will not infringe the intellectual property rights of Cree or a third party. Luminaire manufacturers who base product designs in whole or part on any Cree
Application Note or Reference Design are solely responsible for the compliance of their products with all applicable laws and industry requirements.
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree® and XLamp® are registered trademarks and the Cree logo is a trademark
of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not
imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact
Cree Sales at [email protected].
12