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  • APPENDIXA
    TEST GUIDELINES FOR CONCENTRATING COLLECTORS

    The information contained in this portion of the document is not part of this American National Standard (ANS) and has not been processed in accordance with ANSI’s requirements for an ANS. As such, this Appendix A may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the standard.

    Concentrating collectors can be categorized based on the type of assembly and the control strategy. The test procedure must be configured to be compatible with both of these parameters.

    Assembly Type:

    1. 1.Complete Assembly – All components of the collector are defined and the geometry (spatial relationship between components) does not change. Since the reflector(s) and absorber(s) are contained in a single housing, the test unit can be randomly selected from a group of at least five collectors and shipped to the test laboratory (see Section 401.3.2). Examples include compound parabolic concentrating collectors and collectors where the entire reflector/absorber assembly is mounted inside a box.

    2. 2.Combined Assembly – All components of the collector are defined and the geometry (spatial relationship between components) does not change upon installation, but the components must be field assembled. When the collector is large, the reflector(s) and/or the absorber(s) may be shipped to the installation site separately and the collector is assembled in the field. Selection of the test unit is accomplished by randomly selecting each component of the collector from a group of at least two of each component (see Section 401.3.2, Exception 1). Examples include large linear concentrating collectors (parabolic or Fresnel) and large single point (2-axis tracking) concentrating collectors.

    3. 3.Distributed Assembly - Receiver(s) and reflector(s) are defined, but quantities and spacing can vary at the time of installation. The power tower is an example of a distributed assembly.

    Control Strategy:

    1. 1.No Control – The collector is fixed in place on installation and no action is taken to protect it from overheating, loss of heat transfer fluid flow, high winds, power failure, etc.

    2. 2.Passive Control – The collector is capable of protecting itself without electrical power. This is frequently done with thermally activated actuators to control admission of solar radiation into the collector.

    3. 3.Active Control – Electrical power is required to protect the collector. Electronic actuators (motors, solenoids, etc.) are used to control admission of solar radiation into the collector.

    TABLE A.1

    EXAMPLE IMPLEMENTATIONS OF TABLE 401.2

    Configuration:12345
    Assembly TypeCompleteCompleteCombinedCombinedDistributed
    Control StrategyNoneActivePassive or ActiveActiveActive
    TrackingNone1-Axis1-Axis2-Axis2-Axis
    Tracking TypeNoneTime of DayTime of Day or Time of YearTime of DayTime of Day
    Thermal Shock/Overheat ProtectionNoneHeat Transfer Fluid & DefocusHeat Transfer Fluid & DefocusHeat Transfer Fluid & DefocusHeat Transfer Fluid & Defocus
    Mechanical (wind, snow, etc.) Stress ProtectionNoneNoneStowStowStow
    Specific tests:
    Test Specimen SelectionYesYesYesYesYes
    Baseline InspectionYesYesYesYesYes
    High-Temperature ResistanceYesNoNoNoNo
    Stagnation TemperatureYesNoNoNoNo
    ExposureYesWet, with continuous fluid flowWet, with continuous fluid flowWet, with continuous fluid flowWet, with continuous fluid flow
    External Thermal ShockYesYesYesYesYes
    Internal Thermal ShockYesNoNoNoNo
    Internal PressureYesYesYesYesYes
    LeakageOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluid
    Rupture & CollapseOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluidOnly if gaseous heat transfer fluid
    Freeze Resistance (only when freeze tolerance claimed)YesYesYesYesYes
    Thermal Capacity/Time ConstantYesYesYesYesYes
    Thermal PerformanceYesYesYesYesYes
    Incident Angle ModifierYesYesYesNoNo
    Pressure DropYesYesYesYesYes
    Rain PenetrationYesYesYesYesYes
    Mechanical LoadYesYesYesYesYes
    Impact ResistanceYesYesYesYesYes
    Final InspectionYesYesYesYesYes
    Control systems tests (Section 401.8.7, exception): -Flow loss -Power loss -High wind -Over temperatureNoYesYesYesYes

    TABLE A.2

    EXAMPLE TIME SEQUENCING OF TESTS

    Configuration (From Table A.1)
    1Selection & Inspection (Sections 401.2, 401.4)Qualification Testing (Sections 302.1, 401.5, 401.6, 401.7, 401.8.1, 401.9, 401.16, 401.17, 401.18)Thermal Performance Testing (Sections 401.13, 401.14.2, 401.15)Final Inspection (Section 401.19)
    2, 3, 4Selection & InspectionQualification TestingThermal Performance TestingActive Control Testing (Section 401.8.7, Exception)Final Inspection
    2, 3, 4Selection & InspectionQualification TestingActive Control TestingFinal Inspection
    Thermal Performance Testing
    2, 3, 4Selection & InspectionQualification TestingFinal Inspection
    Thermal Performance Testing
    Active Control Testing
    5Selection & InspectionQualification TestingRange Thermal Performance Testing (Sections 401.3.2 Exception 3.3, 401.15.1)Range Thermal Performance Testing (Sections 401.3.2 Exception 3.3, 401.15.1)Active Control TestingFinal Inspection