A Thorough Approach to Measurement Uncertainty Analysis Applied to Immersed Heat Exchanger Testing

Measurements are frequently taken with little or no regard for the uncertainties or errors of those measurements, which may lead to incorrect conclusions and d ecisions. Professional societies today, including ASME, are becoming more and more concerned with measurement uncertainty. This paper is developed in full support of that concern. This paper discusses the value of an uncertainty analysis, discusses how to determine measurement uncer-· tainty, and then details the sources of error in instrument calibration, data acquisition, and data reduction for a particular experiment. Methods are discussed to determine both the systematic (or bias) error in an experiment as well as to determine the ran­ dom (or precision) error in the experiment. The detailed analysis is applied to two sets of conditions in measuring the effectiveness of an immersed coil heat exchanger. It shows the value of such analysis as well as an approach to reduce overall measurement uncer­ _tainty and to improve the experiment. This paper outlines how to perform an uncertainty analysis and then provides a detailed example of how to apply the methods discussed in the paper. The authors hope this paper will encourage researchers and others to become more concerned with their measurement pro­ cesses and to report measurement uncertainty with all of their test results.