Direct contact heat exchanger development

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The purpose of this work was to develop tools that guide the design of a direct contact heat exchanger for small-scale commercial and/or residential HVAC applications. Experimental data was gathered with a temperature and humidity controlled wind tunnel having a 15 cm square test section that utilized flat-fan water sprays as the working fluid/surface. The data was used to develop an overall sensible heat transfer correlation. A numeric model simulating heat and mass transfer from a water spray was also developed. The correlation was found to accurately capture the fundamental behavior of the system; however, the uncertainty of predicted amount of heat transfer averaged 82%. The numeric model also trended well with the experimental data; however, the model under predicted the heat transfer by an average of 50%. Investigation into the discrepancies revealed information about droplet entrainment in the experimental system and the limiting factors of the correlation and model.