Comparison of thermal performance in solution heat exchangers with different chevron angles in absorption system

Abstract

In this study, a solution heat exchanger (SHEX), one of the components of LiBr–H2O absorption refrigeration, is selected as a 60° and 30° chevron angle brazing-type plate heat exchanger, and its performance is experimentally investigated. The result shows that as the mass flow rate of the strong solution side increased, the heat transfer rate increased significantly. When the chevron angle is 60° in the SHEX, the overall heat transfer coefficient, j-factor, differential pressure, f-factor, and JF-factor of the solution heat exchanger increased by 86%–149 %, 72%–180 %, 221%–376 %, 220%–378 %, and 16.6%–66.2 %, respectively, compared with the SHEX with a 30°-chevron angle. The SHEX with a 30°-chevron angle shows a 138%–221 % higher performance index than that with a 60°-chevron angle. In addition, the Nusselt number prediction correlation of the SHEX, including various chevron angles and Reynolds numbers, was proposed, which can provide essential information for designing SHEXs in actual absorption systems.

Keywords

• Absorption heat pump system (AHPS)
• Plate heat exchanger
• Heat transfer
• LiBr/H2O solution
• Solution heat exchanger
• Nu correlation