Thermal radiation effect measurement in enclosure calibration

Abstract The effect of thermal radiation could be the biggest issue in enclosure calibration. Reducing it by taking accurate measurements can improve calibration uncertainty or measurement capability (CMC). However, there is still less information related to procedure that taken from references such as DKD-R 5-7: Calibration Climatic Chambers, 5-8: Hygrometers for Direct Measurement Relative Humidity, and KAN Pd-02.04: Pedoman Kalibrasi Enklosur Suhu. Moreover, one those reference documents suggests a value 0.35 °C standard contributed temperatures up about 30 above ambient. This large understood an attempt produce secure since not measured directly. Therefore, this study describes detailed radiation. Two enclosures, which are oven climatic chamber, used samples. represents with natural convection while chamber flowing air at certain relative humidity. two small PRTs class A diameter 3 mm length 15 mm. Those wrapped aluminum foil have low emissivity (ɛ=0.4) them then painted Nextel 811-21 high (ɛ=0.97). resistance outputs 34401A 6½ Digital Multimeter manufactured Keysight. Before being used, were calibrated stirred bath having U=0.06 confidence level 95 % coverage factor k=2. temperature range 60 140 40 %rh 90 20 25 °C. mathematical model proposed results presented graphically where higher effect, ranging ±0.1 ±0.4 Variation humidity inside does change difference 0.05 within