Experimental study of the effect of brazed compact metal-foam evaporator in an organic Rankine cycle performance: Toward a compact ORC

Abstract

Compact-sized organic Rankine cycle (ORC) power generators require small-scale heat exchangers to achieve high power density. The objective of this study is to investigate the effect of a Brazed Metal-foam Plate Heat Exchanger (BMPHE) in an Organic Rankine Cycle (ORC) performance parameters. This evaporator is one of the first industrial full BMPHE which is composed by Nickle-foam with 25 PPI (pore per inch). In addition, a series of the experiments have been done using conventional Brazed Plate Heat Exchanger (BPHE) to make a comprehensive comparison for both cycles. Two parameters of power density and pressure gradient are introduced to make a clear comparison in addition to ORC performance parameters. Experimental data are presented for a 1-kW scroll expander and heat source temperatures between 80 and 120 °C. The results show that although the compact evaporator (BMPHE) increases the pressure drop by factors of 1.4–2.6, the overall performance of the ORC is not adversely affected, and the power density is increased by a factor of 2.5 in maximum.