Research On Measurement Uncertainty In Air Conditioner Test

In the field of measurement, it is important and necessary to assess the uncertainty, and the determination method tends to be perfect. Meanwhile, many national and international standards have prescribed that the measurement uncertainty should be attached when presenting and using the results of measurement .So, the uncertainty assessment on the testing of air conditioner performance has begun to catch the eyes of the relative sections and some scientific and production units.The steps of rationally applying the uncertainty theory to the evaluation on the uncertainty in the testing of air conditioner performance are as following: Firstly, rightly analyze the factors of uncertainty, not to leave out or repeat; Secondly, rationally assess the uncertainty of every input quantity; Thirdly, correctly deduce the uncertainty transfer relations from the input quantities to the measurand; Fourthly, rightly analyze the relations between each input quantities (whether it is independent or correlative.), calculate the associated standard uncertainty and derive the expanded uncertainty as required.But during the assessment there are still some problems, such as the incompleteness of factors concerned; the irrationality in the partition of uncertainty contributions—partitioning the uncertainty contributions in terms of the middle variables but ignoring the correlativity between the middle variables; the ignorance of the correlativity that actually exists between the input quantities which are often treated as independent.To solve these problems, the concerns of this article are as follows: Divide the measurement uncertainty in the testing of air conditioner into 2 parts: the uncertainty transferring from the parameter measured by the measurement model; the uncertainty caused by the inaccuracy of the working condition measurement and the warp caused by the deviation of control on the working condition. And each part can be divided into uncertainty contributions caused by temperature and pressure respectively.Assess the uncertainty of every input quantity: establish the assessment model of temperature, pressure and flux rationally. For systems that apply nozzles to air flux measurement, analysis the using range of nozzle according to the limits prescribed by the standard[21], in terms of the air state in air-enthalpy method.Assess the uncertainty transferred from the parameters measured by the measurement model to the test result: establish the right transfer relation, analysis the appropriate range of parameters' uncertainty according to the existing accuracy levels of instruments. Discuss the impact of correlativity between parameters on the associated uncertainty.Analysis the uncertainty and warp of test result caused by working condition: establish the simulation model of air conditioner, and analysis the effect of working condition to the test result in terms of the limits prescribed by the standard[4].Program the software to assess the uncertainty of air-enthalpy method.