Lennox SunSource M215, SunSource M250 Application Manuallines
SunSource® Home Energy System
E2015 Lennox Industries Inc.
Dallas, Texas, USA
APPLICATION AND DESIGN GUIDELINES
Many Dave Lennox Signature® Collection air conditioners
and heat pumps manufactured after April of 2010 are
factory-equipped with components that make them
SunSource
solar modules and other optional equipment so that they can
become part of a SunSource® Home Energy System.
Units can be upgraded for use with solar equipment at the
time of installation or in the future.
Solar energy is first used to meet cooling/heating demands.
When the outdoor unit is not operating, the system powers
lighting, appliances and other electronic devices in the
home. Any surplus power is sent back to the utility company
for a possible credit (check with your local utility company for
availability).
See bulletin number 210680 for a complete list of all
available SunSource® Home Energy System and
SolarWorld® Pre-engineered Kits for ordering.
Wiring runs from the roof-mounted solar modules to the
outdoor unit. From there, power travels to the home
electrical service panel using the existing outdoor unit power
wiring.
®
solar-ready. These units can be matched with
Corp. 1312-L2
March 1, 2013
Revised April 21, 2015
TABLE OF CONTENTS
Introduction 2...................................
How SunSource® Home Energy System Works 2...
Utility-Interactive Microinverters 3.................
Electric Utilities and Solar PV Utility Interactive
Systems
SunSource®-Ready Heat Pumps and
Air Conditioners 3...............................
Over Current Protection 4........................
Codes and Permits 4.............................
U.S. and Canada Codes
Local Jurisdiction and Code Requirements
PV Module Roof Mounting & Structure Requirements
Wind Loading
Rebates and Incentives (Programs) 6..............
Site Evaluation 6.................................
General
Specifics
SunSource® Home Energy System — Components.. 11
Featured System Components
Basic System Requirements
Lennox® Solar Sub-Panel
Solar Modules
Roof Mounting Kits
Installation Kits and Tools
System Monitoring
SunSource® Home Energy System and SolarWorld® Pre-engineered
Kits - Components Package Accessories
Wiring 19........................................
Warning and Safety
System Start Up and Checkout 22.................
Commissioning
System Equipment Maintenance 23...............
Troubleshooting 23..............................
Warranty 29.....................................
Glossary 29.....................................
Solar Resources on the Web 29...................
Appendix A – Roof Pitch 31.......................
Page 1
Introduction
A solar module is made up of multiple photovoltaic cells
wired together in series and/or parallel to achieve a desired
power output.
Each cell produces
approximately 0.5 Volt. The
cells are encased in a frame
to protect them from the
environment. The modules
(silver or black) are flat plat
technology with mono
crystalline silicon cells
which produce 270 watts.
The rating on each module
indicates the nominal DC
power output in watts of a
module when it is in bright
sunlight in 25 degree C
conditions, and the sun’s
rays are perpendicular to
the surface of the module Because the microinverter operates
at about 96% efficiency, the AC output of the system will be
approximately 4% less than the peak DC output. So, at peak
conditions, a 265 watt module will produce up to about 259
watts of power.
Each module operates independently, so if one is shaded or
dirty the adjacent modules will still operate to maximize their
energy output. The microinverter is factory-installed on the
back of the module. Because the microinverter is pre-wired,
grounded and mounted, there are fewer parts that must be
assembled on the roof or side of a house.
In real-world conditions, as the sun rises, moves across the
sky and sets throughout the day, the output of the modules
will increase from about zero at dawn to a peak of about
195-235 watts (depending on season, sun angle, mounting
angle and roof orientation), and then decline again to zero.
How the SunSource® Home Energy System
Works
1. Photovoltaic modules are installed in an area that has
good solar exposure throughout the year, generally a
south-facing roof.
2. When sunlight shines on the solar module(s), their
built-in microinverter(s) produce 240 volt alternating
current power synchronized to the utility’s power grid.
Each module has a dedicated microinverter.
3. The 240-volt alternating current (AC) from the
microinverter(s) is wired through a circuit breaker into
the heating, ventilating and air conditioning (HVAC)
outdoor unit. This power can be used to operate the
HVAC unit and/or the power can be re-directed into the
home’s main distribution panel to handle other power
demands in the home. When the produced power is
more than the home needs, the excess power can flow
into the utility grid, running the electric meter in a
backward direction.
4. The electric bill is reduced because the homeowner only
pays for the net electricity used.
SOLAR
MODULES
OUTDOOR UNIT
(SUNSOURCE
SOLAR
SUB-PANEL
INSTALLED)
ELECTRICAL
PANEL
FUTURE
SOLAR
MODULES
COMMUNICATION
MODULE
STANDARD
OUTLET
BROADBAND
INTERNET
CONNECTION
PERFORMANCE
MONITORING
WEBSITE
Figure 1. SunSource® Home Energy System
Page 2
Utility-Interactive Microinverter
The rapidly advancing technology making this new product
possible is the utility-interactive microinverter. These
devices are governed by IEEE1547 — Standard for
Interconnecting Distributed Resources with Electric Power
Systems. This is a standard of the Institute of Electrical and
Electronics Engineers meant to provide a set of criteria and
requirements for the interconnection of distributed
generation resources into the power grid in the United
States. UL1741 - Standard for Safety Inverters, Converters,
Controllers and Interconnection System Equipment for Use
with Distributed Energy Resources -- addresses
requirements for microinverters, converters, charge
controllers and interconnection system equipment (ISE)
intended for use in stand-alone (not grid-connected) or
utility-interactive (grid-connected) power systems.
Utility-interactive microinverters, converters and ISE are
intended to be operated in parallel with an electric power
system (EPS) to supply power to common loads.
IMPORTANT
The customer needs to understand that this is a
utility-interactive photovoltaic (PV) system which WILL
NOT generate power when the grid power is down (OFF).
Due to the differences in power quality between the grid
and generators, the PV module system will not produce
power concurrently with a back-up generator.
Is there a minimum kilowatt (KW) threshold?
Some utilities require a 1KW or 2KW threshold for this
rebate/incentive programs.
Does the electric utility have a net-metering program?
The larger and publicly owned utilities tend to have
net-metering programs. Net-metering rules specify how
credit for net generation of energy is returned to the
homeowner. The total is the amount of electricity
consumed, less the amount of electricity produced.
NOTE — Additional liability insurance may be required when
a utility-interactive system is installed in a home.
SunSource®-Ready Heat Pumps and Air
Conditioners
The outdoor portion of the SunSource® HVAC system has a
standard power connection to the dedicated HVAC branch
circuit. It also has a second 240-volt AC power source
connection for the utility-interactive solar power input. Solar
photovoltaic (PV) alternating current modules (incorporating
grid tie microinverters) are the source of the solar power.
ELECTRIC UTILITIES AND SOLAR PV UTILITY
INTERACTIVE SYSTEMS
Does the electric utility have any special
requirements?
The local utility will want to be aware of the presence of
such a system on the grid. Usually, there will be an
interconnection application that needs to be submitted to
the local utility. Some utilities will have a particular type of
electrical disconnect (indicating, lockable disconnect
switch) which they want to be used in an interactive
system.
Is there an incentive program?
If there is a rebate involved, the utility may require that a
separate meter, which is usually referred to as a
Renewable Energy Credit {REC} meter, be installed in a
location where it measures the power generated by the
solar PV system.
Figure 2. SunSource® Solar Sub-Panel
The heat pumps and air conditioners have been Electrical
Testing Laboratories (ETL) listed to accept the Lennox
Solar Sub-Panel (an ETL-listed accessory). Units not
designated as solar-ready are NOT safety agency approved
for solar applications.
®
Page 3
Over-Current Protection
Each solar PV AC module will supply a small increment of
240 VAC electrical current (up to 0.9 amps). The number of
modules is limited to 17, so that no more than 15 amps is
supplied to the HVAC outdoor unit. Each microinverter
automatically limits its output current to its 0.9 amp
nameplate value. This upper limit on the number of modules
that can be used is compatible with the branch circuit
ampacity of the smallest (1.5-ton) Dave Lennox Signature
Collection (DLSC) outdoor units. The Lennox® Sub-Panel
for the SunSource® outdoor unit has a 20 amp circuit breaker
for dedicated over-current protection of the solar power
system and branch conductors from the modules to the
outdoor HVAC unit.
In Canada, the Canadian Electrical Code (CE Code). Article
690 of the NEC covers requirements for solar photovoltaic
systems. There are a number of important requirements
regarding solar PV systems. A licensed electrician who is
knowledgeable about NEC Article 690 should supervise the
electrical installation. Because the system does not involve
high-voltage DC wiring, most of the wiring details will be
familiar: wire sizing, working space (110.26) around
electrical equipment, etc.
®
A few details will be new because the
system is utility-interactive:
D The current flow on the HVAC
branch circuit is bi-directional.
Check to ensure that the HVAC
breaker in the distribution panel is
suitable for back feed. If it is not
marked with LINE and LOAD, then
it is okay.
D HVAC breaker cannot be GCFI or
arc-fault-type breaker.
D Route from the roof mounted solar power junction box
to vicinity of outdoor HVAC unit.
D Install service disconnect labels (provided).
D Connect HVAC branch circuit and solar circuit conduits
to solar sub-panel.
Photovoltaic Module
Microinverter
Lennox[ Solar Sub−Panel Kit
Figure 3. Components
Codes and Permits
U.S. AND CANADA CODES
In almost all United States jurisdictions, the NFPA 70
National Electrical Code (NEC) will be cited as the authority
for electrical inspections.
Main breaker plus feedback breaker less than or equal to 1.2
times bus rating.
D Feedback breaker = 20 amp
D Assume main breaker = bus rating (most conservative
case)
D Solving equation for minimum main breaker rating
yields: 100 amp
Page 4
Therefore, this system can be installed on a distribution
panel rated for 100 amp or more as long as the HVAC
breaker is positioned at the opposite end from the main
breaker.
For a residence with multiple outdoor units, multiply the
minimum main breaker size by the number of units. For
example: two outdoor units using solar power would need a
200 amp distribution panel.
IMPORTANT
Before finalizing your roof drawing, check with your local
building department to identify any unique wind and snow
load requirements that pertain to your jurisdiction. A
combination of shortening the maximum span between
roof attachments and increasing the length of your lag
bolts will enhance the wind load rating.
LOCAL JURISDICTION AND CODE REQUIREMENTS
IMPORTANT
It is advisable to meet with the local inspection department
to find out what requirements exist for solar PV
installations. Local jurisdictions may require electrical,
mechanical and structural inspections to be done.
Grounding of the PV array is important because it is subject
to being struck by lightning. The grounding requirements for
PV AC solar arrays are more flexible than DC solar arrays;
however, check with the authority having jurisdiction over
local area requirements.
D The AC output of the microinverters is grounded along
with the utility power to HVAC unit.
D Solar PV array must be grounded according to NEC
Article 690 Section V and all applicable local codes.
WARNING
The AC Solar Module System must be installed on a
fire-resistant roof covering rated for the application. The
minimum mechanical means (attachment points) are
offered in the diagrams provided in this guide. Note that the
specific number of attachment points should be
appropriate to the roof type, local building code, and wind,
snow and seismic loading conditions as defined by the
permitting jurisdiction.
Figure 5. Roof Illustration
Figure 4. Grounding
PV MODULE ROOF MOUNTING AND STRUCTURE
REQUIREMENTS
The authority having jurisdiction may want some information
about how the solar modules will be attached to the roof. To
satisfy minimal structural requirements there are two design
rules that usually dictate the minimum requirements:
1. The maximum span of the modules between roof
attachments should be no greater than 48”. These roof
attachments are located on both the top and bottom of
the single row array.
2. The second rule requires that modules which overhang
the last roof attachment in a row may overhang NO
MORE than a maximum of 16” from that roof
attachment.
WIND LOADING
The system designer must determine the appropriate
number of roof attachment points to ensure the solar
modules remain attached to the roof under (locally specified)
severe wind conditions. There is an excellent article about
PV roof mounting considerations, including wind loading and
structural mounting details in the February / March 2010
issue of SolarPro magazine. Regarding calculating wind
load, the article states:
“This calculation is unnecessary for a typical residential
PV system mounted on a sloped roof with standard
racking materials. In these situations, the racking
system and building structure can easily handle the wind
loads imposed. For particularly windy regions, tall
buildings, or non-standard roof framing, however, the
system designer should perform these calculations to
ensure the structural integrity of the system.”
The article goes on to say that there is a wind load calculation
procedure in development by the Solar America Board for
Codes and Standards (Solar ABCs). Until this procedure has
been finalized, the article recommends using the procedure
outlined in Chapter 6 of ASCE/SEI 7-05. It is a wind load
calculation procedure for components and cladding. The
article provides an explanation of the steps involved. Once
the wind loads are estimated, standard civil engineering
procedures are used to design construction. A useful
Page 5
reference is the American Wood Council's National Design
Specification for Wood Construction (NDS). This reference
provides a method for determining the “pull-out” capacity of
lag bolts in different species and grades of wood.
Near the end of the SolarPro magazine article, it says:
“Modern structures are built with factors of safety large
enough to account for the relatively small loads imposed
by a PV array. For older buildings or those built with
nonstandard construction practices, however the
structural members should be evaluated to ensure
structural integrity.
0If a roof structure on an existing residential building is
deficient, most authorities having jurisdiction require
that the roof structure below the array be brought up to
current building code.”
Rebates and Incentives (Programs)
It is important to research the requirements for qualifying and
applying for rebates and incentives. Many utilities have
programs but certain requirements must be met to qualify.
The website at www.dsireusa.org is a useful resource for
researching federal and state incentives and getting
information on programs offered by electric utilities.
Examples of types of rebates and incentives are listed
below:
1. System output (either in DC or AC watts).
2. Performance-based -- Rebate levels are awarded based
on the predicted output of the system, given the
characteristics of the actual installation.
3. Tax credits for a percentage of the installed cost of the
system are widely available through both the federal and
state governments. The federal tax credit for solar
renewable energy applies to the solar components of the
SunSource® Home Energy System. This includes the
AC solar modules, solar sub-panel kit, roof mounting kits
and all other labor and components needed to install the
solar portion. The credit is in effect through 2016 and
allows for a credit of 30% of the installed cost of the solar
system. The credit is uncapped. For more information go
to the Department of Energy tax credit website at:
http://www.energy.gov/taxbreaks.htm
or the Energy Star website at:
www.energystar.gov/index.cfm?c=tax_credits.tx_index
4. Some states and local governments have enacted laws
that will NOT allow the tax assessment of a property to
be increased because of the addition of a renewable
energy system. Property Assessed Clean Energy
(PACE) programs are available from some governments
to provide financing for the installation of a renewable
energy system that is paid back, with interest, in the
homeowner’s property tax.
Site Evaluation
GENERAL
On earth, the energy available from the sun is about 1000
watts per square meter. A solar module converts about 14%
of that energy to electricity. For a fixed-orientation module,
the peak available energy occurs in a clear sky with the
module directly facing the sun. Throughout the day, the
angle that sunlight hits the module changes as the sun
moves across the sky. Because of this, the available energy
rises to a peak daily value and then declines. There is also a
seasonal variation: The sun is lower in the sky in winter and
higher in the sky in summer. The more closely that the tilt
angle of a solar module matches the local latitude; the more
optimized the annual energy output will be.
Compromises are frequently involved in locating and
installing solar PV modules. Homeowners may wish to have
the module located in a sub-optimal location/orientation for
esthetic reasons. This system is designed to be installed
parallel with the roof pitch (see Appendix A). The pitch of the
roof will determine the tilt of the solar modules The
orientation of the home itself may dictate the direction the
solarmodules face.
Figure 6. Orientation
Page 6
Figure 7. U.S. and Canada Longitudes
Figure 8. Annual Direct Normal Solar Radiation - U.S.
Page 7
Figure 9. Photovoltaic Potential - Canada
SPECIFICS
Good Southern Exposure
Does the site have good southern exposure? Perform a solar
survey using either Solar Pathfindert or Solmetric
SunEyet. Any other survey tool may be used to assess the
solar resource available (see web link page).
Figure 10. Solar Pathfinder Kit
Shading
There are several things to
consider in evaluating
candidate solar array locations.
D Consider direction and tilt.
D It is also important to
consider whether there is
any significant shading of
the location during the year.
Shading reduces the
amount of energy that will be gathered over the year.
The University of Oregon has a web-based software
program that can be used to plot sun path charts for any
given location. This is useful if there is a question about
shading.
Example: For instance, a neighbor's roof might cast a
shadow during the middle of the day if the sun is below 30
elevation. You can plot a sun path chart and get an idea how
many months of the year the sun is below this elevation
during the middle of the day. In Portland, Oregon, this would
occur in December, January and part of February.
The program can be accessed at:
solardat.uoregon.edu/SunChartProgram.html
Figure 11. Solmetric SunEye
PV Watts — Web Base Program
The web based program, PV Watts Version 1, from the
National Renewable Energy Laboratory (NREL), can be
used to estimate the monthly and annual solar energy
generation potential. (See web links) This handy tool uses
the following input data to predict output performance:
D Location
D Orientation
D Tilt Angle
D DC Nameplate Rating
D De-rating factors for the particular equipment and
installation
Page 8
The location will be set by selecting the state and nearest city
to the installation site. To determine the orientation stand on
the side of the house (facing away from the house) where the
solar modules will be installed and find out the direction (N, S,
E, W etc.) that you are facing. It is expressed in degrees with
180 equal to south. The tilt angle will be determined by the
pitch of the roof (see table 1). The DC nameplate rating is the
total DC output power of the solar modules (0.270 kW
multiplied by the number of modules to be installed.) The
de-rating factors are based on several different installation
specific factors including shading, microinverter efficiency,
voltage drop, etc. The value that should be used here for the
SunSource Home Energy System is 0.832. For more
information on how this number was derived see the
Enphase application note entitled PV Watts Calculation
Values for an Enphase Microinverter System available on
their website (see web links). If there is significant shading
use the option in PVWATTS to construct a different de-rate
factor by adjusting the component de-rate factor for shading.
Figure 12 is a sample output from the PV Watts program. It is
a 3.24 kW DC nameplate system 12 solar modules in Fort
Worth, TX. The insolation (sunshine) used is from historical
data collected at the local weather station. Note that you can
also input a local electrical cost and the program calculates
the dollar value of the generated solar energy. (If you do not
input a local electrical rate, the program uses a default value
for the average rate for the state.)
Table 1. PV Array Tilt Angle by Roof Pitch
Roof Pitch Tilt Angle (º)
4 IN 12 18.4
5 IN 12 22.6
6 IN 12 26.6
7 IN 12 30.3
8 IN 12 33.7
9 IN 12 36.9
10 IN 12 39.8
11 IN 12 42.5
12 IN 12 45.0
Homeowners Associations (HOA)
HOAs may have rules regarding the
placement of solar PV modules. It is
important to find out what limitations may
be imposed by HOA by-laws. Typically, it is
the responsibility of the homeowner to
identify any HOA restrictions, if any.
System Component Locations
The locations of the electric service entrance, the solar
modules and the HVAC outdoor unit should be mapped out.
In most cases, the electrical distribution panel will be near
the service entrance. Determine what the local utility
company's requirements are for routing wires from the solar
modules.
Figure 12. Sample Output
The program can be used to judge the impact of the
variations from optimal roof orientation and pitch by first
running the case for south and tilt angle equal to latitude.
Note the annual output. Next, rerun for the actual orientation
and roof pitch to see how the output changes.
Example: Some utilities require a solar PV disconnect within
sight of the service entrance. There must also be a solar
disconnect within sight of the HVAC outdoor unit. Typically,
two disconnects will need to be installed if the two
requirements cannot be met with a single disconnect. The
Enphase DC and AC connectors have been listed as suitable
for load disconnecting means. Remember, it is acceptable to
wire the output of the solar system back to the distribution
panel, if it makes more sense. An example of this would be
the case in which the HVAC outdoor unit is on the north side
of the home, but the solar modules, service entrance and
distribution panel are on the south side.
SOLAR PV
DISCONNECT
SWITCH
HVAC DISCONNECT
SWITCH
Figure 13. Solar PV Disconnect
Page 9
Internet Access
An internet connection, with broadband router is required for
the Envoy Communication Gateway to connect to the
monitoring service.
Distribution Panel
The utility-interactive SunSource® Home Energy System is
for split-phase power (typical residential service) and will
only interconnect and supply power if the grid power meets
the following specification:
D L1–L2 voltage measures between 211 volts and\ 264
volts.
D Line to neutral/ground voltage measures between 106
and 132 volts.
D Frequency measures between 59.3 Hz and 60.5 Hz
Roof Site Survey (Module Mounting, Penetration and
Fire Safety
Figure 14. Broadband Router
The Envoy Communication Gateway is an integral
component of the SunSource® Home Energy System. It
operates between the microinverters on the solar modules
and the Enphase Enlighten™ performance monitoring
website and analysis system. The Envoy functions as a
gateway and monitors the microinverters that are connected
to the modules. NOTE — For more detailed information refer
to Enphase manual.
Figure 15. Envoy Communication Gateway
The roof itself should be evaluated.
D Fall protection for workers is addressed in OSHA
Directive STD 03-00-0-0.
D All necessary re-roofing should be performed before
installing solar modules.
D There must be enough area for the solar modules (one
module requires about 20 square feet).
D Note the style of the roof — Composition (asphalt)
shingles, flat (cement) tile, S or barrel tile and
standing-seam.
D Mark the location of skylights and plumbing vents. Solar
modules cannot block these openings in the roof.
D Fire departments request that solar modules not be
placed within three feet of the roof's apex. Modules
should be set back from the eaves by a few feet and a
pathway, three feet wide, should always be left from the
eaves to ridge.
PLACE LABEL NEXT TO HVAC OUTDOOR UNIT
CIRCUIT BREAKER
Figure 16. Breaker Installation Location
Page 10
Main Dist
Panel
MAIN
NOTE — HVAC OUTDOOR UNIT
CIRCUIT BREAKER MUST BE MOVED
TO THE OPPOSITE END OF PANEL /
LOAD CENTER FROM THE MAIN
BREAKER.
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