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ASTM E861-94(2001)

(Practice)

Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors

Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors

SCOPE
1.1 This practice sets forth a testing methodology for evaluating the properties of thermal insulation materials to be used in solar collectors with concentration ratios of less than 10. Tests are given herein to evaluate the pH, surface burning characteristics, moisture adsorption, water absorption, thermal resistance, linear shrinkage (or expansion), hot surface performance, and accelerated aging. This practice provides a test for surface burning characteristics but does not provide a methodology for determining combustibility performance of thermal insulation materials.  
1.2 The tests shall apply to blanket, rigid board, loose-fill, and foam thermal insulation materials used in solar collectors. Other thermal insulation materials shall be tested in accordance with the provisions set forth herein and should not be excluded from consideration.  
1.3 The assumption is made that elevated temperature, moisture, and applied stresses are the primary factors contributing to the degradation of thermal insulation materials used in solar collectors.  
1.4 Solar radiation is not considered a contributing factor since insulating materials are not normally exposed to it.
1.5  This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
14-Jul-1994
ICS
27.160 - Solar energy engineering
Technical Committee
E44 - Solar, Geothermal and Other Alternative Energy Sources
Current Stage
Ref Project

Relations

Replaces
ASTM E861-94 - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
Effective Date
15-Jul-1994
Replaced By
ASTM E861-94(2007) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
Effective Date
01-Mar-2007

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ASTM E861-94(2001) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar CollectorsASTM E861-94(2001) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
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ASTM E861-94(2001) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
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Standards Content (Sample)


NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E861–94 (Reapproved 2001)
Standard Practice for
Evaluating Thermal Insulation Materials for Use in Solar
Collectors
This standard is issued under the fixed designation E 861; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope ments and Thermal Transmission Properties by Means of
the Guarded-Hot-Plate Apparatus
1.1 This practice sets forth a testing methodology for
C 209 Test Methods for Cellulosic Fiber Insulating Board
evaluating the properties of thermal insulation materials to be
C 356 Test Method for Linear Shrinkage of Preformed
used in solar collectors with concentration ratios of less than
High-Temperature Thermal Insulation Subjected to Soak-
10. Tests are given herein to evaluate the pH, surface burning
ing Heat
characteristics, moisture adsorption, water absorption, thermal
C 411 Test Method for Hot-Surface Performance of High-
resistance, linear shrinkage (or expansion), hot surface perfor-
Temperature Thermal Insulation
mance, and accelerated aging. This practice provides a test for
C 518 Test Method for Steady-State Thermal Transmission
surface burning characteristics but does not provide a method-
Properties by Means of the Heat Flow Meter Apparatus
ology for determining combustibility performance of thermal
C 553 Specification for Mineral Fiber Blanket Thermal
insulation materials.
Insulation for Commercial and Industrial Applications
1.2 The tests shall apply to blanket, rigid board, loose-fill,
C 687 Practice for Determination of theThermal Resistance
and foam thermal insulation materials used in solar collectors.
of Loose-Fill Building Insulation
Otherthermalinsulationmaterialsshallbetestedinaccordance
D 2842 Test Method forWaterAbsorption of Rigid Cellular
with the provisions set forth herein and should not be excluded
Plastics
from consideration.
E 84 Test Method for Surface Burning Characteristics of
1.3 The assumption is made that elevated temperature,
Building Materials
moisture, and applied stresses are the primary factors contrib-
uting to the degradation of thermal insulation materials used in
3. Summary of Practice
solar collectors.
3.1 The following factors, in most cases, should be consid-
1.4 Solar radiation is not considered a contributing factor
ered when evaluating insulation materials for use in solar
since insulating materials are not normally exposed to it.
collectors. Design considerations should dictate priorities in
1.5 This standard does not purport to address all of the
material test evaluations:
safety concerns, if any, associated with its use. It is the
Factor Reference
responsibility of the user of this standard to establish appro-
Section
priate safety and health practices and determine the applica-
pH 7.2
bility of regulatory limitations prior to use. Surface Burning Characteristics 7.3
Moisture Adsorption 7.4
Water Absorption 7.5
2. Referenced Documents
Thermal Resistance 7.6
2.1 ASTM Standards:
Linear Shrinkage (or Expansion) 7.7
Hot Surface Performance 7.8
C 177 Test Method for Steady-State Heat Flux Measure-
Chemical Compatibility 7.9
Outgassing 7.10
Durability 7.11
These test methods are under the jurisdiction of ASTM Committee E44 on
Solar, Geothermal, and Other Alternative Energy Sources and is the direct
responsibility of Subcommittee E44.05 on Solar Heating and Cooling Subsystems
and Systems. Annual Book of ASTM Standards, Vol 04.06.
Current edition approved July 15, 1994. Published September 1994. Originally Annual Book of ASTM Standards, Vol 08.02.
published as E 861 – 82. Last previous edition E 861 – 82 (1988). Annual Book of ASTM Standards, Vol 04.07.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E861
4. Significance and Use 7.4 Moisture Adsorption—Determine the moisture adsorp-
tion of the insulation material in accordance with Specification
4.1 The exposure conditions in solar collectors, especially
C 553. Express the quantity of moisture (water) adsorbed by
under stagnation conditions, may degrade the performance of
the insulation material as a percentage by mass and by volume.
thermal insulation materials. This practice sets forth a meth-
7.5 Water Absorption— Determine the water absorption of
odology for evaluating the degree of degradation, if any, of the
the insulation material in accordance with Methods C 209 or
thermal insulation materials after exposure to simulated in-
Test Method D 2842 as applicable. Express the quantity of
service conditions.
water absorbed by the insulation material as a percentage by
4.2 This practice is also intended to aid in the assessment of
mass and by volume.
long-term performance by comparative testing of insulation
7.6 Thermal Resistance—Determine the thermal resistance
materials. However, correlations between performance under
of the insulation material in accordance with Test Methods
laboratory and actual in-service conditions have not been
C 518, C 177, or Practice C 687, as applicable.
established.
7.7 Linear Shrinkage— Determine the linear shrinkage (or
4.3 This practice also sets forth criteria that shall be con-
expansion) of the insulation material in accordance with Test
sidered in the selection and specification of thermal insulation
Method C 356, at the expected maximum in-service tempera-
materials. One such criterion is surface burning characteristics
ture, including stagnation conditions.
(Test Method E 84), which is used by many code officials as a
reference. This practice does not represent that the numerical
NOTE 1—Maximum in-service temperatures, including stagnation con-
values obtained in any way reflect the anticipated performance
ditions must be determined by testing the solar collector design under
of the thermal insulation under actual fire conditions. consideration.
7.8 Hot Surface Performance—Determine the hot surface
5. Sampling and Test Specimens
performance in accordance with Test Method C 411. Test
5.1 Representative specimens shall be selected at random
materials at the expected maximum in-service temperature,
from the original sample lot for each test condition.
including stagnation conditions. See Note 1.
5.2 At least three representative specimens shall be mea-
7.9 Chemical Compatibility with Adjoining Material:
sured for each property tested unless otherwise stipulated in a
7.9.1 Cut samples of adjoining materials to be evaluated to
particular test.
100 by 40 mm (3.7 by 1.5 in.) from stock materials and wash
5.3 The size and shape of the representative specimens shall
thoroughly with cr grade isopropyl alcohol. After drying
be as specified in the property measurement test.
overnight in a desiccator, weigh the samples to at least f
...

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4.4 Fig. 1 illustrates the hot spot effect in a module of a series string of cells, one of which, cell Y, is partially shadowed. The amount of electrical power dissipated in Y is equal to the product of the module current and the reverse voltage developed across Y. For any irradiance level, when the reverse voltage across Y is equal to the voltage generated by the remaining (s-1) cells in the module, power dissipation is at a maximum when the module is short-circuited. This is shown in Fig. 1 by the shaded rectangle constructed at the intersection of the reverse I-V characteristic of Y with the image of the forward I-V characteristic of the (s-1) cells.
FIG. 1 Hot Spot Effect  
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FIG. 2 Bypass Diode Effect  
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1.1 This test method provides a procedure to determine the ability of a photovoltaic (PV) module to endure the long-term effects of periodic “hot spot” heating associated with common fault conditions such as severely cracked or mismatched cells, single-point open circuit failures (for example, interconnect failures), partial (or nonuniform) shadowing, or soiling. Such effects typically include solder melting or deterioration of the encapsulation, but in severe cases could progress to combustion of the PV module and surrounding materials.  
1.2 There are two ways that cells can cause a hot spot problem: either by having a high resistance so that there is a large resistance in the circuit, or by having a low resistance area (shunt) such that there is a high current flow in a localized region. This test method selects cells of both types to be stressed.  
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SIGNIFICANCE AND USE
4.1 Although this practice is intended for evaluating solar absorber materials and coatings used in flat-plate collectors, no single procedure can duplicate the wide range of temperatures and environmental conditions to which these materials may be exposed during in-service conditions.  
4.2 This practice is intended as a screening test for absorber materials and coatings. All conditions are chosen to be representative of those encountered in solar collectors with single cover plates and with no added means of limiting the temperature during stagnation conditions.  
4.3 This practice uses exposure in a simulated collector with a single cover plate. Although collectors with additional cover plates will produce higher temperatures at stagnation, this procedure is considered to provide adequate thermal testing for most applications.
Note 1: Mathematical modeling has shown that a selective absorber, single glazed flat-plate solar collector can attain absorber plate stagnation temperatures as high as 226 °C (437 °F) with an ambient temperature of 37.8 °C (100 °F) and zero wind velocity, and a double glazed one as high as 245 °C (482 °F) under these conditions. The same configuration solar collector with a nonselective absorber can attain absorber stagnation temperatures as high as 146 °C (284 °F) if single glazed, and 185 °C (360 °F) if double glazed, with the same environmental conditions (see “Performance Criteria for Solar Heating and Cooling Systems in Commercial Buildings,” NBS Technical Note 1187).4  
4.4 This practice evaluates the thermal stability of absorber materials. It does not evaluate the moisture stability of absorber materials used in actual solar collectors exposed outdoors. Moisture intrusion into solar collectors is a frequent occurrence in addition to condensation caused by diurnal breathing.  
4.5 This practice differentiates between the testing of spectrally selective absorbers and nonselective absorbers.  
4.5.1 Testing Spectrally Selective...
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1.1 This practice covers a test procedure for evaluating absorptive solar receiver materials and coatings when exposed to sunlight under cover plate(s) for long durations. This practice is intended to evaluate the exposure resistance of absorber materials and coatings used in flat-plate collectors where maximum non-operational stagnation temperatures will be approximately 200 °C (392 °F).  
1.2 This practice shall not apply to receiver materials used in solar collectors without covers (unglazed) or in evacuated collectors, that is, those that use a vacuum to suppress convective and conductive thermal losses.  
1.3 The values stated in SI units are to be regarded as the standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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SIGNIFICANCE AND USE
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2.2 This practice describes a standard procedure for mounting the test specimen, conducting the impact test, and reporting the effects.  
2.2.1 The procedures for mounting cover plate materials and collectors are provided to ensure that they are tested in a configuration that relates to their use in a solar collector.  
2.2.2 The corner locations of the four impacts are chosen to represent vulnerable sites on the cover plate. Impacts near corner supports are more critical than impacts elsewhere. Only a single impact is specified at each of the impact locations. For test control purposes, multiple impacts in a single location are not permitted because a subcritical impact may still cause damage that would alter the response to subsequent impacts.  
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2.2.4 Ice balls are used in this practice to simulate hailstones because natural hailstones are not readily available to use, and ice balls closely approximate hailstones. However, no direct relationship has been established between the effect of impact of ice balls and hailstones. Hailstones are highly variable in properties such as shape, density, and frangibility.2 These properties affect factors such as the kinetic energy delivered to the cover plate, the period during ...
SCOPE
1.1 This practice covers a procedure for determining the ability of cover plates for flat-plate solar collectors to withstand impact forces of falling hail. Propelled ice balls are used to simulate falling hailstones. This practice is not intended to apply to photovoltaic cells or arrays.  
1.2 This practice defines two types of test specimens, describes methods for mounting specimens, specifies impact locations on each test specimen, provides an equation for determining the velocity of any size ice ball, provides a method for impacting the test specimens with ice balls, and specifies parameters that must be recorded and reported.  
1.3 This practice does not establish pass or fail levels. The determination of acceptable or unacceptable levels of ice-ball impact resistance is beyond the scope of this practice.  
1.4 The size of ice ball to be used in conducting this test is not specified in this practice. This practice can be used with various sizes of ice balls.  
1.5 The categories of solar collector cover plate materials to which this practice may be applied cover the range of:  
1.5.1 Brittle sheet, such as glass,  
1.5.2 Semirigid sheet, such as plastic, and  
1.5.3 Flexible membrane, such as plastic film.  
1.6 Solar collector cover materials should be tested as:  
1.6.1 Part of an assembled collector (Type 1 specimen), or  
1.6.2 Mounted on a separate test frame cover plate holder (Type 2 specimen).  
1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 This international standard was developed in accordance with internatio...

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ASTM
ASTM E881-92(2022)(Practice)
Standard Practice for Exposure of Solar Collector Cover Materials to Natural Weathering Under Conditions Simulating Stagnation Mode

SIGNIFICANCE AND USE
4.1 This practice describes a weathering box test fixture and establishes limits for the heat loss coefficients. Uniform exposure guidelines are provided to minimize the variables encountered during outdoor exposure testing.  
4.2 Since the combination of elevated temperature and solar radiation may cause some solar collector cover materials to degrade more rapidly than either exposure alone, a weathering box that elevates the temperature of the cover materials is used.  
4.3 This practice may be used to assist in the evaluation of solar collector cover materials in the stagnation mode. No single temperature or procedure can duplicate the range of temperatures and environmental conditions to which cover materials may be exposed during stagnation conditions. To assist in evaluation of solar collector cover materials in the operational mode, Practice E782 should be used. Insufficient data exist to obtain exact correlation between the behavior of materials exposed in accordance with this practice and actual in-service performance.  
4.4 This practice may also be useful in comparing the performance of different materials at one site or the performance of the same material at different sites, or both.  
4.5 Means of evaluating the effects of weathering are provided in Practice E765, and in other ASTM test methods that evaluate material properties.  
4.6 Exposures of the type described in this practice may be used to evaluate the stability of solar collector cover materials when exposed outdoors to the varied influences that comprise weather. Exposure conditions are complex and changeable. Important factors are material temperature, climate, time of year, presence of industrial pollution, etc. Generally, because it is difficult to define or measure precisely the factors influencing degradation due to weathering, results of outdoor exposure tests must be taken as indicative only. Repeated exposure testing at different seasons over a period of more than one year is req...
SCOPE
1.1 This practice covers a procedure for the exposure of solar collector cover materials to the natural weather environment at elevated temperatures that approximate stagnation conditions in solar collectors having a combined back and edge loss coefficient of less than 1.5 W/(m2·°C).  
1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials.  
1.3 This practice does not apply to cover materials for evacuated collectors, photovoltaic cells, flat-plate collectors having a combined back and edge loss coefficient greater than 1.5 W/(m2·°C), or flat-plate collectors whose design incorporates means for limiting temperatures during stagnation.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM E782-95(2022)(Practice)
Standard Practice for Exposure of Cover Materials for Solar Collectors to Natural Weathering Under Conditions Simulating Operational Mode

SIGNIFICANCE AND USE
3.1 This practice describes a weathering box test fixture and provides uniform exposure guidelines to minimize the variables encountered during outdoor exposure testing.  
3.2 This practice may be useful in comparing the performance of different materials at one site or the performance of the same material at different sites, or both.  
3.3 Since the combination of elevated temperature and solar radiation may cause some solar collector cover materials to degrade more rapidly than either alone, a weathering box that elevates the temperature of the cover materials is used.  
3.4 This practice is intended to assist in the evaluation of solar collector cover materials in the operational, not stagnation mode. Insufficient data exist to obtain exact correlation between the behavior of materials exposed according to this practice and actual in-service performance.  
3.5 Means of evaluation of effects of weathering are provided in Practice E781, and in other ASTM test methods that evaluate material properties.  
3.6 Tests of the type described in this practice may be used to evaluate the stability of solar collector cover materials when exposed outdoors to the varied influences which comprise weather. Exposure conditions are complex and changeable. Important factors are solar radiation, temperature, moisture, time of year, presence of pollutants, etc. These factors vary from site to site and should be considered in selecting locations for exposure. Control samples must always be used in weathering tests for comparative analysis. Outdoor exposure for at least two years is required to make evident changes, such as surface degradation without the use of sophisticated analytical equipment.  
3.7 Temperature conditions attained with this box may not exactly duplicate those that occur under operational conditions with fluid flow. Dependent on environmental exposure conditions, the cover plate temperatures obtained with this box may be higher or lower than those obtained und...
SCOPE
1.1 This practice provides a procedure for the exposure of cover materials for flat-plate solar collectors to the natural weather environment at temperatures that are elevated to approximate operating conditions.  
1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials.  
1.3 This practice does not apply to cover materials for evacuated collectors or photovoltaics.  
1.4 The values stated in SI units are to be regarded as the standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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