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									City of Palo Alto Utilities (CPAU)
 Solar Water Heating Program

   Contractor & Self-Installer
CPAU SWH Eligibility
Eligibility Criteria & Requirements

•   Participants         •   Warranty
•   Equipment            •   Energy Efficiency
•   Shade Factor         •   Metering
•   Surface              •   Field Inspections
    Orientation Factor
Participants Eligibility
Host Customer: The CPAU customer of record
at the location where the SWH system will be

• Natural Gas Customers
• Electric Customers
• Propane Customers
    Participants Eligibility
Customer Class and Incentive Rate determined by
  Utility Rate Schedule

  – Residential Rate = Single-family residential
  – Commercial Rate = Commercial
  – Master Meter Rate = Multi-family Residential
Participants Eligibility
System Owner:

• Owner of SWH system at time incentive
  is paid
• Host Customer or Third Party
Participants Eligibility
• Entity that completes/submits CPAU SWHP
• Serves as main contact throughout process
• Eligible solar contractor or self installer will be
  the applicant for CPAU SWHP applications
• System sellers are NOT eligible to be the
  applicant (unless they are the contractor)
 Participants Eligibility
Solar Contractor:
• Contractors must have an active A, B, C-4, C-36, or
C-46 License
• Must attend CPAU SWHP Contractor & Self-Installer
Workshop or a CSI-Thermal workshop
• Maintain eligibility: 3 installations per year or attend
workshop annually
Participants Eligibility

Self-Installer: Homeowners or building owners who
choose to install a SWH system on their property. Must
meet definition of Host Customer. Self-Installer is also the

Equipment Sellers: Refers to retail sellers such as
manufacturers, distributors, retail businesses, and
contractors. An Equipment Seller is not an in-home sales
representative. These participants are NOT eligible to be
an applicant (unless they are the contractor).
    Technology Eligibility
                                     Solar Water
                                     Heater Types

           Open Loop                                           Closed Loop
            (Direct)                                             (Indirect)

  Active                   Passive                     Active                 Passive

       1                       2                           4                       5
           Direct Forced                                        Indirect Forced
                                    Thermosiphon                                       Thermosiphon
            Circulation                                           Circulation

                                    Integral Storage
Not eligible systems                 Collector (ICS)
   for incentives
   End-Use Eligibility
SHW applications must directly consume the solar heated potable
water, as opposed to using the solar heated water as a medium to
carry heat for some other end use.

Combination Systems: Applicants must provide documentation
proving domestic hot water (DHW) energy savings for combination
systems. Incentives will only apply to the DHW portion of the load.
    Eligible Equipment
All SWH Components must be new and unused, except
for the following components:

      • De-scaled copper piping
      • Collector racking (design stamped by an Engineer to
        ensure the existing racks are appropriate for expected
        wind loading)
     Eligible Equipment
• Single family residential projects must have
SRCC OG-300 System Certification
  – Installation must match OG-300 system
  configuration exactly: collector area, solar storage
  capacity, number of tanks, type of back up fuel
  source, type of back up water heater (tank vs tankless)

• Multi-Family &Commercial projects must have
SRCC OG-100 Collector Certification

       SRCC = Solar Rating & Certification Corp
   SRCC Ratings
    Ineligible Systems (not eligible for incentives)
•   Pools, spas, space heating, space cooling
•   Non OG-100 collectors (e.g. concentrating solar collectors)
• Direct Forced Circulation, Open Loop Thermosiphon systems, Closed
Loop Recirculation Systems that re-circulate water in the collector loop
• Combination systems will only receive an incentive for domestic hot
water (DHW) energy savings (must clearly isolate DHW energy savings)
• End uses that do not directly consume the solar heated water, but rather
use the water as a medium to carry heat for some other end use
• A SWH system that replaces a SWH system which previously received an
incentive through the CPAU SWHP.
•   Portable systems or systems that are not permanently installed.
Permit Requirements
• All SWH projects must receive a CPAU city inspection

• Eligibility is valid up to 24 months after date on final
permit sign-off

• Contractors should be familiar with local code
requirements as they relate to SWH installations
Shade Factor
  Shade Factor
• The minimum allowable average annual solar availability of the
collector(s) is 85% between 10am to 3pm (no more than 15%

• Collectors with less than 85% average annual availability between
10am to 3pm are ineligible

• For each percentage of average annual availability below 100% on
the collector(s) between 10am and 3pm, there will be an equal
percentage reduction in the system incentive payment down to 85%.

• Example: 95% solar availability between 10am and 3pm=5%
incentive reduction
Shade Factor Tools: Solar Pathfinder
Shade Factor Tools: Solmetric SunEye
Calculate Shade Factor

• Add total hours of shading between 10am and
3pm, based on shade analysis results

• Divide by total hours in the year between 10am
and 3pm (1825)

• Example: 219 hours of shading/1825 hours= 12%

• Shade Factor = 88%
Surface Orientation Factor (SOF)
The SOF is one of the variables in the incentive
calculation formula.

• SOF value is determined by Azimuth and Tilt

• The ideal SOF = 1.0; Minimum SOF required = .75

• SOF less than 1.0 receives a lesser incentive

• SOF should be no less than .75
Surface Orientation Factor (SOF)

    NE = Not Eligible
    * Please reference the manufacturer instructions for collectors tilted at 0°
Collector Tilt
  – Tilt - Angle at which the collectors are mounted
    relative to 0º (flat horizontal surface)

                                 Ex. 30º   tilt angleº
Magnetic North is measured using a compass, which does not represent
  the true north point because of the Earth’s magnetic fields

True Azimuth is the angle between Magnetic North Point and the
   direction the direction panels are facing

                                                True North on a Compass
                        Magnetic Declination

                       Magnetic North on a
   Magnetic Declination Correction
• Look up magnetic declination for specific location at:
• Enter in zip code, and it will calculate the magnetic declination for
  that location.

                  For example:
     If you are in Palo Alto and your compass
      shows you a reading of 180°you would
    look up the zip code (e.g. 94301) and add
         the given correction for magnetic
      declination of 14° to get a true azimuth
                       of 194°
Tips for Determining Azimuth
– Try to stay 10-15 ft away from metal, motors,
  rooftop package units or magnets
– Store compasses away from cell phones and
– Do not place compass directly on collector or
  racking in case there are any magnetic fields
– Check reading against tools like Google Earth.
  There is no azimuth function, but it can be used
  to provide sanity check for azimuth.
Warranty Requirements
• Collector Manufacturer:
   • 10-year minimum

• Contractor:
   • 1- year minimum on installation labor and
   • 10-year minimum to protect the purchaser
     against more than a 15% degradation of
     system performance that may occur as a
     result of faulty installation
 Energy Efficiency Requirements

• Energy Efficiency Survey/Audit: required for all
existing residential and commercial buildings or proof
of Title 24 energy efficiency compliance

   – Must have been performed during the past three years

   – Acceptable surveys include online, telephone, or onsite
     audit provided by CPAU, or a qualified independent
     vendor or consultant
Energy Efficiency Requirements

• All accessible hot water piping must be
insulated with a minimum of R2.6

• If there is a recirculation loop, all accessible
piping must be insulated with a minimum of R2.6
Metering Requirements
Purposes of Metering
1) Measurement and Evaluation (M&E)
  – Program Selected, or
  – Opt-in

2) Customer Performance Metering (CPM)
  – System owner knowledge of system performance
  – Required for systems >30kWth
   Metering: M&E
Program Selected M&E Program
• Allows for evaluations of program performance and
  technology over time
• Small sample of all projects will be selected by CPAU
  SWHP for M&E
• Customer to be notified after payment of incentive
• 100% of cost paid for by the CPAU SWHP
• If selected, participants must agree to allow third party to
  install metering on their system
• Systems selected for M&E Program may also require CPM
  monitoring requirements (systems >30kWth)
Metering: M&E
Opt-in M&E Program

• Voluntary program which allows customers with any
  size system to participate in M&E program

• The CPAU SWHP will pay an additional $500 to
  contractor to offset costs

• One-time payment provided after proof that metering
  requirements are met
    Metering Equipment: M&E
Opt-In Program Measurement and Evaluation (M&E)
Required Equipment
   • Systems with Two or More Tanks:
      For systems that have separate solar storage tank(s) and a back-up water heater,
     required equipment consists of a BTU meter, i.e., a flow meter on the cold water
     supply line, an appropriately located temperature sensor pair, and a calculator.

   • One Tank Systems:
     For one-tank systems in which the storage tank is heated by both thermal solar and
     an auxiliary heat source, required equipment consists of a BTU meter, i.e., a flow
     meter on the cold water supply line, an appropriately placed temperature sensor pair,
     and a meter that measures the gas or electric contribution from the back-up water
     heater or boiler.

Equipment Location: Metering equipment must be installed on the
  potable water side of the SWH system.
      Metering Equipment: CPM
Customer Performance Monitoring (30 kWth<system ≤ 250 kWth)

• Required Equipment: Required equipment consists of a BTU meter, i.e., a flow
  meter, a temperature sensor pair, and a calculator.

• Equipment Location: Metering equipment may be installed either on the
  collector loop or potable water side of the SWH system.

• Communication Requirements: For a period of five years from start of
  operation, System Owner must have the means to determine if the system is
  operating. At a minimum, the CPM equipment must provide the quantity of
  solar energy delivered to the System Owner.
Metering, Monitoring, and Communication

System Size    Metering     Incentive     Metering         CPM      PPD Required   Who Bears
               Process      Structure    Equipment       Required                    Cost

≤ 30 kWth        None       Lump-sum         N/A           N/A          N/A           N/A

                                        Collector loop
               Customer       Single                                               Paid for by
                                         or potable
 >30 kWth     Performance   Lump-sum                       Yes          No          System
                                         water side
               Monitoring     Rebate                                                 Owner
CPAU SWHP Incentives &
  Application Process
Incentive Structure

      Natural Gas/ Propane
   Displacing System Incentives
    Electric Displacing System

       • Single-Family
   • Multi-Family/Commercial
Incentive Cap: Single Family
• Customers are eligible for one OG-300 incentive per single-
  family residential dwelling unit, not to exceed the stated
  cap per step.

• A single-family residential dwelling unit is defined as a
  group of rooms, such as a house, a flat, an apartment, or a
  mobile home which provides complete single-family living
  facilities in which the occupant normally cooks meals, eats,
  sleeps, and carries on the household operations incident to
  domestic life.
Single Family Residential Incentives
 • Lump sum/one-time payment

 • Paid after project is completed, approved, and
   inspected (if applicable)

 • Based on the SRCC OG-300 rating (the
 estimated annual therm or kWh savings)

 • Additional variables include Palo Alto climate zone
   (CZ 03), SOF, and Shade Factor
SRCC OG-300 Incentive Calculator:
Single Family Residential
4 Factors:
1) SRCC estimated annual energy savings, based on the CEC climate zone of the project site
2) Incentive Step Level at the time the Incentive Claim Form is approved
3) Surface Orientation Factor (SOF), which includes the azimuth and tilt of the collectors
4) Shade Factor

                          Incentive Calculation Formula:
                (SRCC OG-300 estimated annual energy savings) X
             (Current Incentive Step Level) X (SOF) X (Shade Factor)=
                               $ Incentive Amount

               Calculator at
Example: OG-300 Incentive Formula

Single Family Residential            NATURAL GAS/ PROPANE
       Annual Energy Savings            120 Therms

        x Price/Therm (Step 1)           x $12.82

      x Surface Orientation Factor        x   1.0

            x Shade factor                x   .98

             = $ Savings                 = $1508
Example: OG-300 Incentive Formula

Single Family Residential                        ELECTRIC
       Annual Energy Savings          2800 kWh
          x Price/kWh (Step 1)        x $0.37

       x Surface Orientation Factor    x 1.0
             x Shade factor            x .98
              = $ Savings             = $1015
OG-300 Incentive Calculator

                                   Enter in the SRCC
                                 OG-300 system number

                                      Select any utility (this
                                     calculator is for estimate
                                          purposed only)
OG-300 Incentive Calculator Results
Incentive Cap: Multi-Family/Commercial

  • A maximum of one multi-family or commercial incentive
    will be allowed per SWH system, not to exceed $100,000
    for natural gas or electric displacing systems.

  • In addition, the total incentives for multiple systems on
    one site cannot exceed the incentive maximums
Multi-Family/Commercial Site Definition

  For multi-family/commercial projects, site is defined as:
  • The Host Customer’s premises, consisting of all the real property and apparatus
      employed in a single enterprise on an integral parcel of land undivided (See Example
      #1), excepting in the case of industrial, agricultural, oil field, resort enterprises, and
      public or quasi-public institutions divided by a dedicated street, highway or other
      public thoroughfare or railway (See Example #2).

  •   Automobile parking lots constituting a part of and adjacent to a single enterprise may
      be separated by an alley from the remainder of the premises served.

  •   Separate business enterprises or homes on a single parcel of land undivided by a
      highway, public road, and thoroughfare or railroad would be considered for purposes
      of CPAU SWHP as separate sites (See Example #3).
  Site Definition Example #1
                                 For Illustration Purposes Only

Site #1                                                                                                                               Site #2

                                            186 Temple
                                                                                                         2125 Walnut Ave.

                                                                                           2123 Walnut Ave.
                                                                                                                                2131 Walnut Ave.

                       2121 Walnut Ave.
                                                                                              2127 Walnut Ave. 2129 Walnut Ave.

 Walnut Avenue                                                                                                Walnut Avenue

                                                         Temple Street
     (public street)                                                                                                (public street)

Site #3
                                                                         (public street)
                                            178 Temple

                                                                                                         = Walnut Gardens Apartment Complex

The Host Customer’s premises, consisting of all the real property
and apparatus employed in a single enterprise on an integral parcel
of land undivided.
    Site Definition Example #2
                                      For Illustration Purposes Only

  Site #1

                                                              Building F
                                                                                                                              Building D

                                                                                                             Building E
                                                                                                                                                  Building A

                         Building G
                                                                                                                 Building C         Building B

                                                                           Temple Street
  Walnut Avenue                                                                                                       Walnut Avenue

                                                                                           (public street)
       (public street)                                                                                                          (public street)

                                                                                                                              = University of Hastings
                                                 Building H

In the case of industrial, agricultural, oil field, resort enterprises,
and public or quasi-public institutions divided by a dedicated
street, highway or other public thoroughfare or railway, these are
considered to be one site.
Site Definition Example #3
              For Illustration Purposes Only
                                                    Site #1

Separate business enterprises or homes on a single
parcel of land undivided by a highway, public road, and
thoroughfare or railroad would be considered as
separate sites
OG-100 Multi-Family/Commercial
Incentive Calculator

     •   Not a design tool
     •   It is strictly a tool to estimate the incentive
     •   Run by TRNSYS software
     •   May take 15 plus minutes to obtain results
     •   Available at
OG-100 Multi-Family/Commercial
Incentive Calculator
OG-100 Multi-Family/Commercial
Incentive Calculator Results

Incentive Details

 Project Details
Payment Process

• Upon final approval of the Incentive Claim Form and
  passed onsite field inspection (if applicable), CPAU
  SWHP will disburse the incentive payment.

• Payment will be made to the Host Customer or a third
  party as indicated on the Incentive Claim Form, and
  will be mailed to the address provided.
Field Inspection Process
Onsite Field Inspection Process
  • Required:
    – First 3 ICFs for projects that displace 30kWth or less (462 sq
      ft of collector area or less)
    – First 3 ICF for projects that displace more than 30kWth
      (more than 462 sq ft of collector area)
  • CPAU SWHP will inspect a random sample of projects
  • Contractors are encouraged to attend inspections
  Onsite Field Inspection Results
• Infractions: Items that do not require corrections, but are
  identified as educational items for improvements on future

• Failure items: Items that do require corrections and will
  delay the incentive payment. Failure Sanctions will be

    (These items will be discussed in detail in the technical
                Section of this presentation)
Onsite Field Inspection Results
   • PAs notify System Owner and Contractor of
     Inspection Results
   • Inspection may uncover incorrect SOF or shading,
     resulting in a change in the estimated incentive
   • Results:
      – Pass = Process Payment
      – Fail = Failure Sanctions
Failure Sanction Process: Notification
Applicant will either accept or dispute the results:

      Accepted results:
       – 30 days to correct the failure item(s)
       – Re-inspection may be onsite or via photos of
       – Failure to correct items may be grounds for removal
         from the program
      Disputed results:
       – Appeal in writing to the CPAU SWHP within 30
         calendar days of notification
       – Panel will review and notify of the decision within
         60 days
    Failure Sanction Process
Three failures* in a rolling 12-month period=
• Probation for 6 months
• Re-attend Contractor/Self Installer training workshop
• Additional program applications will not be processed until
completion of the workshop

Five failures* in a rolling 12-month period=
• Disqualification from the program for a minimum of 6
CPAU SWHP Technical
   Requirements &
 Inspection Checklist
Inspection Checklist
 • Condensed from SRCC OG-300
 • Shows OG-300 Section reference
 • MF/Commercial system designers must follow
   SRCC OG-300 Standards
 • Extracts exact language relevant to installers
   and commercial designers
 • Explains CPAU SWHP interpretations
 • Identifies 18 Failure Items & 18 Infractions
Technical Requirements
• System Sizing
• Inspection Checklist
  – Failure Items
  – Infraction Items
System Sizing: Single Family Residential
 • Single Family Projects – size according to
   Gallons of hot water used per day (GPD)
   – Number of occupants
      • 1st person= 20 GPD; 2nd person= 15 GPD; Each
        person thereafter=10 GPD
   – Number of bedrooms (if occupants unknown)
      • 1st bedroom= 20 GPD; 2nd bedroom= 15 GPD; Each
        bedroom thereafter=10 GPD
   – Rules of thumb:
      • 1 ft2 of collector area per GPD
      • 1.5 gallons of storage per ft2 of collector area
System Sizing: Single Family Residential
    Single Family project example:
    – 3 occupants
    – 45 gallons of hot water per day
    – Collector Area: approximately 45 ft2 of
      collector space is needed
    – Storage Capacity: at least 68 gallons of storage
      capacity is needed
    – Appropriate OG-300 system would likely
      include one 4X10 collector (40 square feet)
      and 80 gallons of storage capacity
System Sizing: MF/Commercial
 •   Multi-family (MF)/Commercial Projects – Annual average GPD is estimated based on
     the Maximum GPD Guideline Table (Appendix D).
 •   SWH systems for the building types listed in Maximum GPD Guideline Table must be
     sized using the GPD value in this table for the appropriate building type. The GPD
     values in the table are maximum values. Systems may be sized using a lesser GPD
 •   Building types not listed in the Maximum GPD Guideline Table must immediately let
     the CPAU SWHP know.
 •   Fluid collector square footage cannot exceed 1.25 times the GPD, or 1.85 times for
     air collectors.
 •   Systems with two or more tanks must have a minimum of one gallon of storage per
     square foot of collector. One-tank systems must have a minimum of 1.25 gallons of
     storage per square foot of collector.
System Sizing: MF/Commercial      Appendix D
                 Maximum Gallon per Day (GPD) Guideline Table
                     for Multi-Family/Commercial Projects*

                 Type of Building                                                               GPD

   Apartments/Condos: Number of Units

       2 to 20                                                                                   42
       21 to 50                                                                                  40
       51 to 100                                                                                 38
       101 to 200                                                                                37
       201 plus                                                                                  35

   Student Housing                                                                     15 GPD per unit

   Hotels/Motels                                                                       15 GPD per unit

   Retirement/Nursing Homes                                                           18 GPD per room

   Office Building without showers                                                  1.0 GPD per person


       Meal Service Restaurants                                              2.4 GPD per full meal served
       Quick Service Restaurants                                              0.7 gallons per meal served

   Elementary schools                                                      0.6 gal/student/day of operation

   Junior and senior high schools                                          1.8 gal/student/day of operation

   Laundries                                                         20 GPD per 10 lbs per washing machine

                    *Small multi-family/commercial systems are those that displace 30 kWth or less.
Multi-Family/Commercial Incentive Calculator

     Multi-family Building
        • 10 units
        • Max 42 GPD/Unit

     42 x 10 = 420 GPD (maximum)
Multi-Family/Commercial Incentive Calculator
Inspection Checklists
• 2 Inspection Checklists:
  o Single Family Projects
  o Multifamily & Commercial Projects

• Both Inspection Checklists:
  o Are based on SRCC OG-300 principles and
Inspection Checklists
• Single Family:
   o Identifies 18 Failure Items

• Multifamily & Commercial:
  o Identifies 18 Failure Items

• The 18 failure items are the same; however,
  some of the pass/failure criteria differs
  between the two checklists
Summary of Failure Categories
   – Operational
   – Operating Limits (stagnation protection) and freeze
   – Control lines and sensors
   – UV radiation protection
   – Back thermosiphon protection
   – Leak and water damage protection
   – OG-100 or consistent with OG-300 certification
   – SOF and Shade Factor
   – Flow balance
Summary of Failure Categories
    – Consistent with OG-300 configuration (single family)
    – Consistent within sizing guidelines (multifamily/commercial)
    – Waterproofed
 Plumbing and Piping:
    – Insulation
    – Mixing Valve
 • Owner’s Manual
 • Meters (Multifamily/Commercial only):
    – Approved for metering purpose & installed correctly
Failure Item: System Operation

• Is the system operational?
• Are there any significant health and safety
Failure Item: Operating Limits
(Stagnation/Overheat Protection)

• High collector fluid temperatures (over 200˚F)
  can be generated during long (especially
  summer) vacations where the fluid is left in
  the collector un-cooled.

• This heat may damage glycol and/or critical
  system components, and may pose a serious
  risk of scald injury to humans
Failure Item: Operating Limits
• Means shall be provided to protect the SWH system within the design
  limits of temperature and pressure. Limit tank temperatures to a value
  not to exceed the tank supplier's specified high temperature limit (unless
  using emergency stagnation prevention cycling.)
• The pressure/temperature relief valve shall not be used for this purpose
  under normal operating circumstances.
• “Emergency stagnation prevention cycling is when the controller cycles the
  solar loop pump on and off during the day to allow the tank temperature
  to rise above the high temperature limit in order to prevent stagnation in
  the collector.”
• The system shall be able to withstand prolonged periods of stagnation(high
  solar flux, no hot water demand) without significant system deterioration
  and with no maintenance. This includes conditions during loss of electrical
  power to the system.
Failure Item: Operating Limits

Acceptable Stagnation Protection Mechanisms:
  – Controller with vacation mode
  – Controller with stagnation prevention cycling
  – Steam Back
  – Heat dump radiator or convector
  – Pressure Stagnation Protection
  – Integral Stagnation Temperature Control
  – Hartstat Thermosiphon Protection
Failure Item: Operating Limits
High Limit Setting
    Failure Item: Freeze Protection
• Collectors may freeze at ambient temperatures of 42˚F or
• Since every California climate zone has experienced recorded
  temperatures below 41°F, freeze protection is required.
• For solar systems where the collector fluid is water, a
  minimum of two freeze protection mechanisms shall be
  provided on each system. Manual intervention (draining,
  changing valve positions, etc.) is suitable as one mechanism.

  (Note. Direct Forced Circulation and Open Loop
  Thermosiphon Systems are not eligible for a rebate, whether
  freeze protection valves or recirculation is utilized.)
     Failure Item: Freeze Protection
• A system in which components and/or piping are subject to damage by
  freezing shall have the proper fitting to allow for pipe slope and collector
  design to allow for manual gravity draining and air filling of the affected
  components and piping.
• Pipe slope for gravity draining shall have a minimum 1/4 inch per foot
  vertical drop. This also applies to any header pipes or absorber plate riser
  tubes internal to the collector.
• At the time of installation, a conspicuously placed label how the system
  is protected from freezing and what actions the homeowner should take
  shall be attached to the system.
• For systems which rely on manual intervention for freeze protection, this
  label shall indicate the minimum ambient temperature conditions
  (Freeze Tolerance Limit) below which owner action is recommended and
  the procedure to be followed.
Failure Item: Freeze Protection:
ICS Systems
• ICS systems may not be installed in climate
  zones where historical temperatures drop
  below the rated FTL: Freeze Tolerance Level
  of the ICS System

     Source: SunEarth           CPAU
Failure Item: Freeze Protection:
Thermosiphon Systems
     Must be Indirect with Glycol (closed loop)

         Direct (open loop) thermosiphon systems are not
         eligible for an incentive
   Source: SunEarth                CleanTech
Failure Item: Freeze Protection:
Indirect Forced Circulation Systems
  Indirect Forced Circulation (closed loop) Systems
    must be protected by one of the following:
  • Anti-freeze/heat transfer fluid (Propylene
    Glycol, Mineral Oil, etc): must have a pressure
    gauge showing minimum acceptable collector
    loop pressure
  • Drain back: must have 1/4 inch per foot
    vertical drop in the pipe slope to ensure fluid
    drains from collectors; must have a water level
    gauge or transparent in-line flow meter
Failure Item: Freeze Protection:
Direct Forced Circulation (Open-Loop)
Direct Forced Circulation, open loop systems are not
  eligible for an incentive. These systems have what
  is known as recirculation freeze protection. This
  type of freeze protection is not considered
  adequate for any of the Palo Alto Climate Zone.
Failure Items:
Control Line and Sensors

 • Shall be sufficiently protected from degradation or
   from introducing false signals

 • Weather-exposed wiring must be rated sunlight and
 moisture resistant and comply with NEC Articles 340
 and 690. Sensor wiring shall be separated from hot
 collector piping and shall be protected from UV
Failure Items: Control Line and Sensors

                        Wire nuts not
                        weather protected
Strap on Sensor
Do not do this!
Poor Sensor Placement
Poor Sensor Placement

Sensor is not
attached to the
absorber or
return pipe.
Must use stainless steel hose
clamp or immersion well.
Sensor Wire
Flashing and Hood
                   insulation is not
                   adequate to hold
Note the spring    the tank sensor to
clip holding the   the tank wall
sensor to the
tank wall
Believe it or not, this
sensor was attached
to the outer wall of
the solar tank!
Failure Item:
Protection from UV Radiation
Components or materials shall not be affected by
  exposure to sunlight to an extent that will signifi-
  cantly deteriorate their function during their design
  life. Insulation must be protected from UV by
  jacketing or at least two coats of the insulation
  manufacturer's recommended UV coating, or at least
  two coats of exterior grade latex paint.
Example of good jacketing to protect

     Source: Sunlight and Power
Insulation Protection

 Unprotected            Protected
Insulation gap
Was plastic and not protected
Should miter & cover
Rain gutter

   Clever use of
reversed rain gutter
   for jacketing
Failure Item:
Back Thermosiphon Prevention

Means shall be provided to prevent undesired
escape from storage through thermosiphoning
action. Acceptable means are check valves,
solenoid valves, and/or 18" heat traps.
Wrong check valve

CV mounted wrong
Failure Item:
Back Thermosyphon Prevention
 • Acceptable Back Thermosyphon
   Prevention Mechanisms:
   – Check Valve
   – Solenoid Valve
   – Heat Trap (at least 18”)
Failure Item:
Protection from Leaks
  All potable water sections of a solar water
  heating system shall not leak when tested in
  accordance with the codes in force at the
  installation site. All non-potable sections of a solar
  water heating system shall be tested for leaks in
  accordance with the supplier's instructions.
Failure Item:
Water Damage
  Collectors and support shall be installed in such a
  manner that water flowing off the collector
  surface or pressure relief valve shall not damage
  the building or cause premature erosion of the
  roof. Water tanks located in or above the living
  space shall be installed on a drip pan with a drain
  line to a waste or outside or have other means to
  safely remove any excess liquid.
Water Damage
Failure Item: Collector
• Collectors:
   – Must be consistent with Incentive Claim Form
      • Manufacturer, Make and Model
      • # of collectors and square footage
      • In accordance with program sizing requirements
   – Must be SRCC certified and labeled
      • Single Family: Must be the collector identified in the
        OG-300 certification
      • Multi-family/Commercial: Must be OG-100 certified
Non-certified collectors

Collectors must be labeled with SRCC
certification- this would constitute a failure
Failure Item: Shade Factor

  – Collectors may not have less than 85% solar
    availability (or more than 15% annual average
    shading) between the hours of 10am and 3pm.
  – Shade Factor must be within ± 5% of shade factor
    reported on ICF.
  – Shade Factor is within allowable parameters, but
    differs from ICF, incentive amount will be adjusted
Failure Item: Collector Flow Balance

  Ensure proper flow balancing in and among collector
  banks by using reverse return plumbing, flow
  balancing valves and adhering to manufacturer's
  maximum collectors allowed in banks.
Collector Flow Balance
Parallel Flow
Failure Item:
Collector Circulation Control

  The collector subsystem control shall be
  designed to be compatible with control
  requirements of the system.
Wrong check
valve for hard
Failure Item:
Solar Tank and Auxiliary Water Heater
     Single Family:
     – Must be consistent with ICF and OG-300 Certification:
       • Number of tanks
       • Solar Storage Capacity
       • Auxiliary water heater fuel source
       • Auxiliary water heater type: Tank or Tankless

     – Auxiliary water heater capacity does not have to be the
       exact capacity as the OG-300 certification; however, a
       tankless water heater may not be substituted for a tank
       type water heater unless it is OG-300 certified as such
Failure Item: Solar Tank
    – Must be in compliance with sizing requirements:
       • Two tank systems: minimum of 1 gallon/ ft2
       • One tank systems: minimum of 1.25 gallons/ft2

    – If capacity or number of tanks (both solar and
      auxiliary) differs from ICF but is in compliance with
      sizing requirements, this is an infraction and the
      incentive will be adjusted accordingly
Failure Item: Waterproofing

 Underground and above ground unsheltered
 storage tanks shall be waterproofed to
 prevent water seepage. Storage tanks used
 outdoors shall be rated for outdoor use.
Failure Item: Insulation

  All accessible hot water piping and the final 5 feet of
     metallic cold water supply pipe leading to the system shall
     be insulated with R-2.6 °F-ft2-hr/Btu or greater

  This includes recirculation loop piping.
Insulate over fittings
Poor Insulation Technique
Use Escutcheons
Failure Item:
Temperature Control/Mixing Valve
• The system must be equipped with a means to limit the
  temperature of the hot water at the fixtures
• Approved valves (must be installed according to
  manufacturer’s specification):
   •Mixing valve
   •ASSE rated anti-scald valves with a setpoint option
    appropriate for the use
   •Other ASSE rated valves such as point-of-use anti-
    scald valves
Watts Mixing Valve Warning
                    No mixing valve
                    No solar bypass

Sloppy insulation
No Mixing valve
ASSE 1017 Anti-Scald Valve
Failure Item: Owner's Manual
  An owner's manual or manuals shall be provided with
    each SWH system and should contain the following:
  • The name, phone number and address of the system
  • The system model name or number
  • A description the operation of the system and its
  • The procedures for operation and maintenance
Meters: Multifamily/Commercial
Projects Only
• Installed meters must be approved for the
  identified metering purpose
  – Opt-in Measurement & Evaluation
  – Customer Performance Monitoring
• Meters must be installed properly and in the
  correct locations
Summary of Infraction Categories
    •   Missing details in owner’s manual
    •   SOF below 0.75
    •   Bypass valves, air traps, and pressure relief valves
    •   Operating indicators
    •   Fluid / safety labeling
    •   Rain / snow build-up
    •   Expansion tank sizing
    •   Appropriate pumps and controllers
    •   Main shut-off valve
    •   Maintenance accessories
    •   Protection of buried components
    •   Pipe hangers and supports, pipe sloping
    •   Thermal expansion protection
    •   Appropriate building penetrations
    Solar Water Heating Program Contact
•   Jordan DiGiorgio – Program Manager
     – 858.634.4730

•   Skip Fralick- Energy Engineer
     – 858.244.4868

•   Jeff Wheeland– Associate Program Manager
     – 858.244.1179

                        (866) 611-CPAU / (866) 611-2728

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