Experimental investigation of a helical coil heat exchanger operating at sub- and supercritical state in a small-scale solar orc installations

Abstract

In this study, an experimental investigation of the performance a helical coil heat exchanger operating at sub- and supercritical conditions was carried out. The heat exchanger was coupled and tested in a small-scale Organic Rankine Cycle installation with a net cycle capacity of 3 kW and with a heat source inlet temperature of 100 °C. The first measurements were conducted under controlled conditions in a laboratory. Towards determining the effects of different parameters on the heat transfer rate in the heat exchanger several set of measurements were conducted. Particularly, the performance analysis are elaborated considering the changes of various parameters such as the mass flow rate, inlet temperature and operating pressure of the organic (working) fluid (R-404A) at the cold side. While all the parameters at the inlet of the hot side were kept stable for all set of measurements. From the experimental results and the performance evaluation of the heat exchanger it was found that a better performance is achieved when operating at supercritical state.