14-ncbc-2012-cx-the-sun-Salmon by gstec

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									Commissioning the Sun: Popular
Renewable Systems
Pete Salmon                      Optional: Insert
Project Manager                  Company Logo
Eaton Corporation
             AIA Quality Assurance



The Building Commissioning Association is a Registered Provider with
The American Institute of Architects Continuing Education
Systems (AIA/CES). Credit(s) earned on completion of this program
will be reported to AIA/CES for AIA members. Certificates of
Completion for both AIA members and non-AIA members are available
upon request.

This program is registered with AIA/CES for continuing professional
education. As such, it does not include content that may be deemed
or construed to be an approval or endorsement by the AIA of any
material of construction or any method or manner of handling, using,
distributing, or dealing in any material or product.

Questions related to specific materials, methods, and services will be
addressed at the conclusion of this presentation.
                Course Description

This presentation will review best practices for commissioning solar
thermal systems, emphasizing lessons learned through design,
construction and functional testing.

The method of system protection, whether drain-back or
mechanical heat rejection, can create challenges for a solar thermal
project. Designers must carefully weigh pros and cons for selecting
the best type of protection and how it should operate. The
construction team must carefully plan installation and startup
activities to prevent expensive and time-consuming accidents, such
as damaging components due to freezing or overheating. Either can
occur when flow is stopped, or if piping in a drain-back system is
not adequately sloped. If possible, sequences of operation should
be functionally tested and tuned prior to adding the heat source, to
flush out programming bugs that may result in damaging the
system.
              Learning Objectives


At the end of this session, participants will be able to:

1. Advise design teams and owners about the benefits and risks
   of solar thermal systems.
2. Understand methods of solar thermal system protection.
3. Understand design considerations for solar thermal systems.
4. Develop and execute a solar thermal system startup
   schedule.
               Agenda


Basics of Solar Thermal Systems
Design Considerations
Construction Considerations
Summary
   Basic Solar Thermal System

                                          Heat
                                        Exchanger

                        Hot Fluid Out
                                                     Hot Fluid Out



             Solar
            Collector




Cold Fluid In
                                                    Cold Fluid In
                            Pump
        Benefits and Risks

• BENEFIT - Free energy, no fuel
  costs.
• RISK - Requires engineered
  systems to protect from freezing
  and over-heating.
            Design Considerations


                   Design
                Considerations



Collector                 Storage   Protection
            Array Size
 Type                      Size       Type
Design Considerations – Collector Type
              Flat Plate
Design Considerations – Collector Type
            Evacuated Tube
Design Considerations – Collector Type
             Thermal + PV
             Design Considerations – Array Size
50
45                             ○ Systems may serve
                                 baseloads or baseloads
40
                                 + varying loads.
35                             ○ Varying loads will
30                               increase size of system
                                 protection.
BTUs




25
20             Space Heating

15
10
               Domestic Hot Water
 5
 0
       Jan   Feb   Mar   Apr   May   Jun    Jul   Aug   Sep   Oct   Nov   Dec
                           Baseloads       Seasonal Loads
 Design Considerations – Storage Size

• Adding storage…
  ○ Increases cost.
                              2 Days
  ○ Requires larger
    mechanical footprint.
  ○ Increases capability to   1 Days
    provide steady heat in
    absence of sun.
                              ½ Day



                              ¼ Day
Design Considerations – System Protection
 Effective protection is the most important
 benchmark that will define a solar project’s
          success post construction.

• Protect from…              • Protection Methods
   ○ Freezing                   ○ Drainback
      - Fluid Expansion         ○ Glycol/Mechanical Heat
          » Pipe/Collector        Rejection
             Damage             ○ Glycol/Shade Device
   ○ Overheating                ○ Glycol/Rotate away from sun
      - Fluid Expansion
          » Loss of Fluid
             through PRV
     Design Considerations – Drainback
Protection

• Protects from both overheating and freezing.

Sequences

• Fill collectors with fluid when array temperature >110F and <200F.
• Drain when…
  • Storage reaches setpoint (load is met).
  • Array temperature drops below freezing setpoint or rises above
    overheating setpoint.

Considerations

• Redundant pump not necessary.
• Sloped piping required.

Take-away

• Once system is drained, it is typically done for the day.
Example Drainback Piping Arrangement
          To/From Load    To/From Solar
                            Collectors
Design Considerations – Mech Heat Rejection

  Protection

  • Protection from over-heating only.
  • Requires glycol for freeze protection.

  Sequences

  • Pump ON when array temperature > setpoint (i.e. 110F) and OFF <105F for 10m.
  • Heat rejection equipment ON when fluid temperature > setpoint (i.e. 190F) and off
    when <175F for 10m.

  Considerations

  • Redundant pumps in case of failure.
  • Redundant heat rejection in case of failure.
  • Backup power.

  Take-away

  • More design and risk than drainback, but ensures heat is available entire day.
Example Heat Rejection Piping Arrangement
Design Considerations – Lessons Learned
 Drainback Systems

 • Confirm pipe slope requirement clearly stated.
 • If system fluid is H2O, request tank/HX be rated
   and sized for small % of glycol.

 Mechanical Heat Rejection

 • Consider 3-way valves only. Valves fail to heat
   rejection equipment.
 • Consider operating pump on astronomical
   clock instead of fluid temperature.
 • Confirm rejection equipment sized for max
   collector load.
 • Confirm PRV at every array.
 Construction Considerations - Observations

Inspect Piping

• Drainback – confirm
  properly sloped pipe. ¼”
  per foot minimum.
• Accessible balance
  valves, PRV and
  isolation valves at every
  array.
• Confirm locations of
  array and pipe
  temperature sensors.
    Construction Considerations - Startup

Startup Sequence
is Critical


• Carefully plan and
  execute to minimize
  chance of damaging
  event.
• Different startup order
  depending on flatplate vs
  evacuated tube and
  drainback vs heat
  rejection.
  Construction Considerations - Startup
 Flatplate with Drainback Startup Sequence

             Piping and controls complete.



                 Functional test controls.


                      Flush and fill piping.
                                  During day, but monitor fluid temperature
        At night or
                                   to ensure no overheating or freezing.



Monitor first day of operation. Debug and retest.
   Construction Considerations - Startup
Evacuated Tube with Drainback Startup Sequence
             Piping and controls complete.


                  Flush and fill piping.


                Functional test controls.


                Install evacuated tubes.


    Monitor first day of operation. Debug and retest.
 Construction Considerations - Startup
Mechanical Heat Rejection Startup Sequence
            Piping and controls complete.


          EM Generator startup complete.

               Functional test controls.
     EM Generator                        Solar Controls


                    Flush/fill system.

  Monitor first day of operation. Debug and retest.
        Confirm heat rejection capacity on sunny day.
                               Summary
Advise design teams of benefits and risks.

• Zero fuel cost. Very low maintenance cost. Contributes to sustainability goals.
• Failures lead to downtime and potentially damaged components.

Methods of solar thermal system protection.

• Effective protection is the most important benchmark for project success.
• (1) Drainback, (2) mechanical heat rejection or (3) shade.
• Consider hybrid using 2 out of 3 methods of protection.

Understand design considerations.

• Baseloads and/or seasonal loads.
• System storage
• Protection from freezing and overheating

Generate a construction startup schedule.

• Test sequences prior to adding fluid or heat source.
• Mechanical Heat Rejection, test emergency equipment prior to solar startup.
     Pete Salmon
   Eaton Corporation
petergsalmon@eaton.com

								
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