Table 401.2 specifies the tests that shall be conducted on each type of solar collector. An “X” in the table indicates the test shall be conducted. An “O” indicates the test shall be conducted but can be conducted on either collector if two collectors are used to complete testing requirements. The testing sequence is determined by identifying the type of collector, identifying the method of testing to be used, and then following the requirements in Table 401.2 and Sections 401.2.1 and 401.2.2.
SOLAR COLLECTOR TEST REQUIREMENTS
|TEST||SECTION||LIQUID HEATING COLLECTORS||AIR HEATING COLLECTORS|
|UNGLAZED||GLAZED (FLAT PLATE, TUBULAR)||PROTECTED BY CONTROLS (UNABLE TO WITHSTAND DRY STAGNATION)||NONSEPARABLE STORAGE (ICS)||CLOSED LOOP||TRANSPIRED|
|1||2 Q||2 P||1||2 Q||2 P||1||2 Q||2 P||1||2 Q||2 P||1||2 Q||2 P||1||2 Q||2 P|
|Test Specimen Selection||401.3||X||X||X||X||X||X||X||X||X||X||X||X||X||X||X||X||X||X|
|External Thermal Shock||401.8.1||X||X||X||X||X||X||X||X||X||X||X||X|
|Internal Thermal Shock||401.8.2||X||X||X||X||X||X||X||X||X||X|
|Rupture and Collapse||401.11||X||X||X||X|
|Freeze Resistance (only when freeze tolerance claimed)||401.12||X||X||X||X||X||X||X||X|
|Thermal Capacity/Time Constant||401.13||X||X||X||X||X||X||X||X||X||X||X||X|
|Incident Angle Modifier||401.15||X||X||X||X||X||X||X||X||X||X|
|Rain Penetration (glazed only)||401.17||X||X||X||X||X||X||X||X|
There are two methods for conducting the test. Table 401.2 demonstrates the appropriate requirements for each type of collector and each method as follows:
1.When all of the tests are conducted on a single collector, the testing requirements for each type of collector are designated with the column heading “1.”
2.When two collectors are tested, one shall be subjected to the qualification tests, designated in column heading of “2Q,” and the other shall be subjected to the performance tests, designated in column heading of “2P.”
The test sequence shall follow the order as listed in Table 401.2.
1.The following tests can be conducted in any sequence relative to each other: thermal capacity and time constant, thermal performance, incident angle modifier and pressure drop.
2.The following tests can be conducted in any sequence relative to each other: high-temperature resistance, exposure, external thermal shock, and internal thermal shock.
3.All solar collectors containing heat pipes shall be subjected to the exposure test in accordance with Section 401.7 before the thermal performance test is conducted. The same serial-numbered collector shall be subjected to the exposure test and then to the thermal performance test.
Random selection of test collectors shall be accomplished through a personal visit by the laboratory, certification body, or authority having jurisdiction or selection from photographs of the collectors in stock. The selected collectors, or collector components, shall be affixed with nonremovable serial-numbered labels.
Collectors shall be randomly selected from a group of at least five collectors. Where final assembly of the collector components occurs only at the installation site, each of the components shall be randomly selected from a group of at least five components. The collector’s final assembly geometry shall not change from its design specification.
1.Large collectors greater than 4.6 m2 (50 ft2) shall be randomly selected from a group of at least two collectors where either:
1.1.Transport in a fully constructed condition is impractical; or
1.2.Collectors are not inventoried in a fully constructed condition.
2.If the collector design to be tested is always built for a specific installation, the collector is to be tested in-situ without random selection.
3.For distributed assembly solar concentrating collectors where the subcomponents are not physically connected to each other, the manufacturer shall specify the geometric parameters and configuration of all subcomponents and the total collector.
3.1.Parameters shall include orientation, distance, height, and angle of all solar collector subcomponents in relation to each other and the installation site, including the quantity of each.
3.2.The manufacturer’s specifications shall include minimum and maximum values for each geometric parameter defining the configuration’s final assembly with minimum- and maximum-operating specifications.
3.3.The configuration(s) to be tested shall fall within these specified ranges, representing operating conditions closest to the minimum and maximum allowed. The most rigorous test conditions applicable shall be used.
The collectors shall be tested as received from the manufacturer when assembled per manufacturer’s documentation. Test specimens shall be inspected prior to testing and any visible damage or assembly flaws shall be recorded. Documentation shall include photographs of the collector or its constituent parts, as received, showing all visible surfaces. Any abnormalities shall be noted and photographed in detail.
It is permissible to conduct the internal pressure test according to Section 401.9 to confirm the flow passages are in a condition suitable for testing.
A high temperature resistance test shall be performed as specified in Section 9 of ISO 9806.
The collector stagnation temperature shall be determined as specified in Section 10 of ISO 9806.
Exposure testing shall be in accordance with Section 11 of ISO 9806, using a minimum of Class B climate conditions, for no less than 30 days of exposure to adverse conditions.
When testing is conducted outdoors, each shock shall be performed on a different day.
When testing is conducted indoors under a solar simulator, it is permissible to conduct multiple shock tests on the same day provided the collector is allowed to cool to ambient air temperature between shock tests.
When the solar collector design incorporates one or more factory-sealed containers charged with a refrigerant, other fluid, or phase-change material, these containers shall not be removed for these tests.
If the collector assembly has active mechanisms that are intended to be functional during operation, those mechanisms shall be operational during testing.
Any test specimen having integrity that is permanently compromised by this test, such that it obviously will not be able to perform, shall be considered to have failed the test.
Two external thermal shock tests shall be performed as specified in ISO 9806, Section 12, using a minimum of Class B conditions.
Two internal thermal shock tests shall be performed as specified in ISO 9806, Section 13, using a minimum of Class B conditions. All parts of the solar collector assembly that are not factory sealed shall be subjected to this test.
Exception: This test is not applicable to collectors in which heat transfer fluid is continuously flowing for protection purposes. In such cases, control(s) used to manage a no-flow condition shall be validated to be functional in such a way that any failure can be detected. Control functions that have been verified shall be described and reported with the test results.
An internal pressure test shall be performed as specified in ISO 9806, Section 6.
A leakage test shall be performed on closed loop air heating collectors as specified in ISO 9806, Section 7.
A rupture and collapse test shall be performed on air heating collectors as specified in ISO 9806, Section 8.
A freeze resistance test shall be performed on collectors claimed to be resistant to freezing as specified in ISO 9806, Section 15.
This test evaluates the impact of freeze-thaw cycles on heat pipes. The test shall be performed in a controllable climate chamber for the duration of a set number of freeze and thaw cycles (see Table 401.12.1.6). This test shall be performed on heat pipes that are part of the solar collector submitted for testing, regardless of the collector loop design heat transfer fluid.
During the disassembly phase (Section 401.19) of the testing protocol, a minimum of six heat pipes shall be selected to undergo a freeze resistance test. In addition, at least one heat pipe shall be retained as a control sample for comparison with the tested samples. It is permissible to destroy part of the collector (evacuated tubes, collector housing, etc.) to extract the heat pipes. However, when the heat pipes cannot be separated from the evacuated tube without damage to the heat pipe, it is permissible to conduct the test with the evacuated tube in place.
After the heat pipes are extracted from the collector, they shall be kept at a minimum tilt angle of 15 degrees with respect to horizontal, with the condenser at the upper end so that all components of the fluid (inhibitors, particles, etc.) remain in the bottom part of the heat pipe. If the solar collector was stored at less than a 15-degree tilt between the qualification tests and disassembly, the heat pipes must be tilted to at least 15 degrees then raised to and held for 1 hour at what their normal operating temperature would be when exposed to 800 W/m2.
A detailed initial inspection of all of the heat pipes shall document the following:
1.The shape (round, oval, cylindrical, conical, etc.) of all parts of the heat pipe;
2.The outside dimension of all parts of the heat pipe; and
3.A photographic record of all test samples.
Two heat pipes shall have a temperature sensor attached to ensure an accurate and average temperature is measured. Each temperature sensor shall have a maximum standard uncertainty of +/- 1 K and shall be mechanically and thermally attached to the outside of the lower end of a heat pipe near the fluid level when all of the fluid inside the heat pipe is condensed and the heat pipe is held at the tilt specified in Section 401.12.1.3. The temperature indicated by these sensors shall be assumed to represent the temperature of the fluid inside the heat pipe.
Exception: When the heat pipe cannot be separated from the evacuated tube without damage to the heat pipe, it is permissible to conduct the test with the evacuated tube in place if a temperature sensor is placed inside one of the heat pipes. On one sample, the condenser shall be opened by drilling a hole so that a temperature sensor can be inserted and run to the location where the heat pipe heat transfer fluid rests. The temperature sensor shall have a maximum standard uncertainty of +/-1 K. Every effort shall be made to minimize disruption to the basic structure of the heat pipe, while maximizing the accuracy of temperature measurement at this location.
All conditions in Table 401.12.1.6 shall be met.
REQUIRED TEST CONDITIONS
|TEST PARAMETER||REQUIRED VALUE|
|Tilt angle||The highest of 60 degrees or the manufacturer’s highest recommended tilt angle|
|Freezing temperature||Negative 20 +/- 2°C|
|Freezing time||The temperature sensor shall indicate the freezing temperature for at least 30 minutes per cycle|
|Thawing temperature||Positive 10 +/- 2°C|
|Thawing time||The temperature sensor shall indicate the thawing temperature for at least 30 minutes per cycle|
|Number of cycles||20|
A visual inspection of all heat pipes shall be conducted after the initial five freeze-thaw cycles. If there is a failure, (e.g., fluid leaking or burst pipe) as a result of the freeze-thaw cycling in any of the test samples, the test shall be terminated.
A detailed final inspection of all samples shall document the following for each sample tested:
1.Any permanent change in shape or dimension of all parts of the heat pipe;
2.Any evidence of fluid leaking from the heat pipe; and
3.A photographic record of all test samples.
The following shall be reported:
1.The tilt angle of the heat pipes during the test;
2.All changes to the physical condition of the heat pipes and that of any collector components adjacent to the heat pipe;
3.The number of temperature cycles that were performed;
4.The temperature indicated by the temperature sensor(s) during the required dwell periods;
5.The time the heat pipes were exposed to each dwell period;
6.Before and after photographs of the tested heat pipes; and
The thermal performance test on collectors that do not contain internal storage shall be performed as specified in ISO 9806, Section 20.
Additional testing shall be required for collectors containing storage because the mass of the storage precludes measurement of instantaneous efficiency. Such collectors include both integral collector storage designs and thermosiphon designs where the collection function cannot be separated from the storage function for testing. Such collectors shall be subjected to the applicable tests described in Sections 401.14.2.1 through 401.14.2.2.
Test objects shall be mounted in a manner that is similar to the intended usage. This requirement includes the use of such devices as reflectors and roof support structures. The hydraulic, thermal and optical characteristics shall be reproduced during the test.
Where testing with a fluid other than water, fluid composition tests shall be performed to ensure that the specified fluid composition exists. At a minimum, a hygrometer test or its equivalent shall be performed and checked with the fluid specification before proceeding with the test.
In any collector with a heat exchanger containing more than 2.5 percent by volume of the storage vessel volume, the heat exchanger shall be preheated to the same temperature as the rest of the collector for all tests. This heat exchanger shall not be directly purged at the end of the test. The energy within it shall be purged in the normal operating fashion.
Performance testing shall not be performed in excess of manufacturer’s recommended operating conditions. Adjustment of test-operating conditions is permissible to conform to the intent of the test
Table 401.14.2.1.4 indicates the required assurances for the instrumentation used in the tests required in Section 401.14.2. The radiation measurements shall be performed with devices that meet the standards of the World Meteorological Organization for a first-class pyranometer or pyrheliometer. The data resolution shall be not lower than the stated accuracy. The test lab shall ensure that data is checked for any offsets immediately prior to and at the conclusion of the test. Offsets shall be applied to the processed data and noted in the test report.
|VALUE TO BE MEASURED||ACCURACY SI UNITS (±)||ACCURACY IP UNITS (±)|
|Temperature||0.1°C (precision 0.1°C)||0.2°F (precision 0.2°F)|
|Temperature Difference||0.1 K (precision 0.1 K)||0.2 R (precision 0.2 R)|
|Fossil Fuel Usage||1%||1%|
|Liquid Flow||1% measured mass value||1% measured mass value|
Data shall be sampled at a maximum interval of 15 seconds. This data shall be averaged and reported at a maximum rate of 5 minutes for long-term tests having a duration longer than 1 day, or 0.5 minute for short-term tests. Because of the interaction with the transient system simulation software, which uses a fixed time step, data for all collected channels shall be reported in fixed time steps. Note that any test using an energy purge shall be measured with the highest data resolution available at the laboratory.
Calibration of instrumentation used in the testing setup shall be traceable to a national standard and be performed at least annually.
The minimum real time data to be collected for the tests shall consist of the following in metric units. Data channels shall be reported on a regular time interval. Channels not used in a particular test shall be populated with a value not found elsewhere in the data for that channel. The test lab shall review for and address any missing or erroneous data. This data reduction shall occur prior to submission for modeling.
Gaps or corrections for critical data shall not last longer than 10 minutes during non-purge periods. During purge periods, critical data shall not be missing or erroneous. The missing or adjusted data shall be filled in using proxy measurements or interpolation to existing data and highlighted in the data set and noted in the test report.
A log indicating the timing of the draw, purge, and irradiation start and stop times shall be included. Other data including site elevation, longitude, latitude, and test sample orientation shall be supplied. Any data sets that do not meet these minimum requirements shall be excluded from the analysis. Required data includes:
1.Data collection time, both local and solar, and date and day of year (dd-mm-yyyy)
2.Inlet temperature(s) (°C)
3.Outlet temperature(s) (°C)
4.Ambient temperature (i.e., “Outside,” if applicable) (°C)
5.Environmental temperature (i.e., “Inside,” if applicable) (°C)
6.Flow rate(s) (kg/hr)
7.Fluid heat capacities(s) (kJ/kg-°C)
8.Wind velocity (m/s)
9.Auxiliary energy usage, if applicable (kJ)
10.Radiation measurements (kJ/m2)
d.Horizontal infrared, integral collector storage and unglazed collectors only
Easily accessible significant characteristics of the component or collector shall be measured and reported in consistent sets of units, including:
1.Diameters, lengths and widths, internal and external.
2.Lengths, internal and external, and spacing of tubes and fins.
3.Heights, internal and external, minimum and maximum water levels shall be denoted.
4.Thickness, such as insulation, tank shell, tank vessel, and fins.
5.Volumes at ambient air temperature of the tank and any integral heat exchangers.
6.A diagram indicating geometry including vessel, shell, and any protrusions such as heat exchangers and plumbing connections.
7.Materials used for vessel, including insulation, shell, tank liner, and heat exchangers.
8.Piping lengths and orientations.
9.Slope of components.
The following documentation shall be provided:
1.Equipment model number(s);
2.Description of the test method(s) and any deviations from the standard method; and
3.Photographs of any applicable equipment.
The testing and analytical work shall consist of these steps:
1.The test lab shall determine physical parameters from the tests.
2.The test lab shall collect extended test data from warm up tests.
3.The test lab shall prepare the data in the format requested by the certification body.
4.The certification body shall create a model using transient system simulation software.
These tests shall provide data for computer modeling of collectors or collector components, or both. The method of modeling shall depend upon the test and available transient system simulation software models. The certification body will provide direction for new and innovative collector tests that are not explicitly covered in this test method.
The calculation of temperature-dependent densities and heat capacities shall be performed using real-time data by the test lab. Data reduction shall include the filtering out of any erroneous data. The delivered energy value shall be used where matching net delivered energy with the transient system simulation software. It is permissible to not adjust this value if the simulation software accounts for energy changes caused by different starting and ending temperatures and losses from the collector during the purge period.
All data shall be consistent with the test conditions. When the pyranometer and pyrheliometer are not covered by the collector cover, the visual radiation shall be set to zero and the sky infrared radiation shall be adjusted to an equivalent sky radiation to account for the covering of the collector during the purge period. Any adjustments shall be noted in the test report.
Upon receipt of the processed data, the certification body shall create a series of computer models using transient system simulation software. One model shall be created for each test. This model is called the “audit” model. Each of the audit models is then fit to the test data as indicated in Items 1 through 4:
1.Collector heat loss shall be determined as follows:
1.1.When both capacitance and heat loss tests are performed, the results from the heat loss test and capacitance tests shall be iterated upon until a final value of collector loss rate is determined. The loss value shall be used directly in the model. No other explicit fit is required at this point.
1.2.When only the heat loss test is performed, the results are used to calibrate a transient system simulation software computer model. The loss value shall be used directly in the model. No other explicit fit is required at this point.
2.Parameters for heat exchangers integral to a collector shall be used directly in the model. No other explicit calibration is required at this point. The calibration is done by minimizing the chi-squared value for all data sets.
3.The data from each of the individual data points in the warm-up tests shall be used to calibrate a transient system simulation software computer model using the FRτα and FRUL isothermal initial conditions. A calibration routine shall be used to compare the observed net, solar or auxiliary energy deliveries to the observed data points (one per test). The calibration is done by minimizing the chi-squared (x2) value for all data sets.
For integral collector storage collectors, the FRUL adjustment is actually a UAloss adjustment since there is no measured value for FRUL. (Note that the ICS nighttime loss test shall be calibrated as part of the data set.) The net result of this process is two points (FRτα and FRUL) that are used in the transient system simulation software model.
4.When the collector is initially stratified due to the presence of an auxiliary heater, a separate set of tests and calibrations shall be completed. This is required when a heater is located within the storage vessel of a thermosiphon collector.
Collectors containing internal storage shall be tested using the procedures described in ISO 9459-4, Annex C, with the following clarifications:
1.During the collector purge described in ISO 9459-4, Section B.2, a bypass loop shall be used to precondition the inlet water to the specified temperature before introducing water to the test article. Unless otherwise specified, the purge temperature shall be the same temperature as the charge temperature in order to minimize internal energy change in the collector.
2.During the heat loss test described in ISO 9459-4, Section B.4.1, any source of heating, including resistance heaters and/or solar radiation, shall be shut off or blocked. All pumps shall be shut off for the duration of the test.
3.During the heat loss test described in ISO 9459-4, Section B.4.1, when internal temperature probes are used, the test shall continue until both of the following are satisfied:
3.1.The collector temperature drops at least 3°C.
3.2.The differential between the average collector temperature and the average environmental temperature changes by at least 3°C.
4.During the warm-up tests described in ISO 9459-4, Section C.3, the temperature in the collector at the beginning of a low-temperature test shall be close to ambient temperature.
5.During the warm-up tests described in ISO 9459-4, Section C.3, wind at a speed between 1 and 3 m/s shall be required when testing collectors with integral storage tanks or unglazed collectors, or both.
The incident angle modifiers of the collector shall be determined for each test specimen in accordance with ISO 9806, Section 27. Biaxial incident angle modifiers are required on collectors that are nonsymmetrical in their response to irradiance as solar altitude and azimuth change. Data shall be taken in each of the two perpendicular planes that characterize the collector geometry.
Concentrating solar collector testing shall include all operational conditions in which the collector is designed to operate. Incident angle modifiers shall be found for the maximum acceptance angle and all intermediate angles as needed to properly characterize the optical behavior of the collector. Unless the manufacturer stipulates otherwise, the maximum acceptance angle to be tested shall be at least 60 degrees.
Biaxial incident angle modifiers testing and reporting shall be conducted on all nontracking concentrating collectors as covered by this standard and any single axis tracking collector where reflectors and/or receivers move independently of each other.
The manufacturer shall submit a drawing showing the optical normal, transverse plane and longitudinal plane.
The pressure drop across the collector shall be measured as specified in ISO 9806, Section 28.
A rain penetration test shall be performed on glazed collectors as specified in ISO 9806, Section 14.
The ability of the collector to withstand loading by wind or snow shall be determined as specified in ISO 9806, Section 16.
After the completion of testing, test specimens shall be disassembled and inspected in accordance with Section 306. Any visible damage, deformation, discoloration or flaw shall be recorded.