Uncertainty of Calorimeter Measurements at NREL's High Flux Solar Furnace

    Research output: Contribution to conferencePaper


    The uncertainties of the calorimeter and concentration measurements at the High Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL) are discussed. Two calorimeter types have been used to date. One is an array of seven commercially available circular foil calorimeters (gardon or heat flux gages) for primary concentrator peak flux (up to 250 W/cm2). The second is acold-water calorimeter designed and built by the University of Chicago to measure the average exit power of the reflective compound parabolic secondary concentrator used at the HFSF (over 3.3 kW across a 1.6-cm2 exit aperture, corresponding to a flux of about 2 kW/cm2). This paper discusses the uncertainties of the calorimeter and pyrheliometer measurements and resulting concentrationcalculations. The measurement uncertainty analysis is performed according to the ASME/ANSI standard PTC 19.1 (1985). Random and bias errors for each portion of the measurement are analyzed. The results show that as either the power or the flux is reduced, the uncertainties increase. Another calorimeter is being designed for a new, refractive secondary which will use a refractive material toproduce a higher average flux (5 kW/cm2) than the reflective secondary. The new calorimeter will use a time derivative of the fluid temperature as a key measurement of the average power out of the secondary. A description of this calorimeter and test procedure is also presented, along with a pre-test estimate of major sources of uncertainty.
    Original languageAmerican English
    Number of pages10
    StatePublished - 1991
    EventASME International Solar Energy Conference - Maui, Hawaii
    Duration: 4 Apr 19928 Apr 1992


    ConferenceASME International Solar Energy Conference
    CityMaui, Hawaii

    NREL Publication Number

    • NREL/TP-254-4593


    • calorimeter measurements
    • concentrated solar power
    • high flux solar furnace


    Dive into the research topics of 'Uncertainty of Calorimeter Measurements at NREL's High Flux Solar Furnace'. Together they form a unique fingerprint.

    Cite this