Development of an experimental method to generate a non-uniform air flow distribution at the inlet of a heat exchanger

Abstract

As already demonstrated by many authors, the non-uniformity of the air distribution at the inlet of both condensers and evaporators entails not negligible performance degradation. Its experimental quantification is mainly complicated by the difficulties connected to the air velocity measurement in a traditional air-conditioning installation. For this reason, many works are supported by the application of CFD models or others simulation tools. In order to analyze experimentally the effect of the nonuniform air distribution on the performance of a condenser, in this work a simple method for generating a specific air velocity profile at the inlet of a heat exchanger will be presented. It consist in allocating several filters along the heat exchanger height. Once characterized the filter, identifying the relation between the length of the filters, the pressure drop and the air velocity, any type of air velocity profile can be generated. The method presents high flexibility and allows being used with any typology of heat exchanger. In this work, the method will be used for generating a non-uniform air velocity profile at the inlet of two condenser: a round tube plate fins heat exchanger and a microchannel heat exchanger. The results show that, with a specific distribution of the filters, the nonuniform air velocity profile characterizing the A-shape condensation units has been reproduced with a very good agreement.