ASTM_C_1784_-_14.pdf

Designation:C178414Standard Test Method forUsing a Heat Flow Meter Apparatus for Measuring ThermalStorage Properties of Phase Change Materials andProducts1This standard is issued under the fixed designation C1784;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement of non-steady-state heat flow into or out of a flat slab specimen to determinethe stored energy(that is,enthalpy)change as a function oftemperature using a heat flow meter apparatus(HFMA).1.2 In particular,this test method is intended to measure thesensible and latent heat storage capacity for products incorpo-rating phase-change materials(PCM).1.2.1 The storage capacity of a PCM is well defined via fourparameters:specific heats of both solid and liquid phases,phase change temperature(s)and phase change enthalpy(1).21.3 To more accurately predict thermal performance,infor-mation about the PCM products performance under dynamicconditions is needed to supplement the properties(thermalconductivity)measured under steady-state conditions.NOTE1This test method defines a dynamic test protocol for productsor composites containing PCMs.Due to the macroscopic structure of theseproducts or composites,small specimen sizes used in conventionalDifferential Scanning Calorimeter(DSC)measurements,as specified inE793 and E967,are not necessarily representative of the relationshipbetween temperature and enthalpy of full-scale PCM products.1.4 This test method is based upon the HFMA technologyused for Test Method C518 but includes modifications forspecific heat and enthalpy change measurements for PCMproducts as outlined in this test method.1.5 Heat flow measurements are required at both the top andbottom HFMA plates for this test method.Therefore,this testmethod applies only to HFMAs that are equipped with at leastone heat flux transducer on each of the two plates and that havethe capability for computerized data acquisition and tempera-ture control systems.Further,the amount of energy flowingthrough the transducers must be measureable at all points intime.Therefore,the transducer output shall never be saturatedduring a test.1.6 This test method makes a series of measurements todetermine the thermal energy storage of a test specimen over atemperature range.First,both HFMA plates are held at thesame constant temperature until steady state is achieved.Steady state is defined by the reduction in the amount of energyentering the specimen from both plates to a very small andnearly constant value.Next,both plate temperatures arechanged by identical amounts and held at the new temperatureuntil steady state is again achieved.The energy absorbed orreleased by the specimen from the time of the temperaturechange until steady state is again achieved will be recorded.Using a series of temperature step changes,the cumulativeenthalpy stored or released over a certain temperature range isdetermined.1.6.1 The specific heats of the solid and liquid phases aredetermined from the slope of the temperature-dependant en-thalpy function during sensible heating/cooling,before andafter the phase change process.1.7 Calibration of the HFMA to determine the correctionfactors for the energy stored within the plate heat fluxtransducers and any material placed between the test specimenand the HFMA plates must be performed following Annex A1.These correction factors are functions of the beginning andending temperatures for each step,as described in Annex A1.1.8 This test method applies to PCMs and composites,products and systems incorporating PCMs,including thosewith PCM dispersed in or combined with a thermal insulationmaterial,boards or membranes containing concentrated ordispersed PCM,etc.Specific examples include solid PCMcomposites and products,loose blended materials incorporat-ing PCMs,and discretely contained PCM.1.9 This test method may be used to characterize materialproperties,which may or may not be representative of actualconditions of use.1.10 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition approved Oct.1,2014.Published December 2014.Originallyapproved in 2013.Last previous edition approved in 2013 as C1784-13.DOI:10.1520/C1784-14.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1.11 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsi