Experimental investigation and CFD analysis of heat transfer in single phase subcooler of a small scale waste heat recovery ORC
Tryfon Roumpedakis, Spyros Chapaloglou, Platon Pallis, Aris-Dimitrios Leontaritis, Konstantinos Braimakis, Sotirios Karellas, Panagiotis Vourliotis
Session: Poster session & Welcome drinks
Session starts: Wednesday 13 September, 17:30
Tryfon Roumpedakis (National Technical University of Athens)
Spyros Chapaloglou (National Technical University of Athens)
Platon Pallis (National Technical University of Athens)
Aris-Dimitrios Leontaritis (National Technical University of Athens)
Konstantinos Braimakis (National Technical University of Athens)
Sotirios Karellas (National Technical University of Athens)
Panagiotis Vourliotis (National Technical University of Athens)
In the present work, a detailed investigation of the single phase heat transfer mechanism in a novel subcooler of an experimental small scale waste heat recovery Organic Rankine Cycle (ORC) unit is presented. The ORC unit is operating with R134a as the working fluid and it is designed to utilize the waste heat from the jacket water of marine diesel auxiliary internal combustion engines (ICEs). The ORC unit produces 3.7 kWel net electrical power at a cycle pressure of 25 bar and a high temperature of 82oC. The application of subcooling in such systems is common practice, so as to ensure the cavitation free operation of the pump.
The subcooler is designed to achieve a certain level of subcooling and minimizing at the same time the pressure losses on both the refrigerant side and the cooling water side. A theoretical CFD model is developed to predict the behavior of the respective heat exchanger. A novel heat transfer correlation is proposed for the single phase heat transfer inside a corrugated tube for the R134a, to enhance the accuracy of the model predictions and is compared with proposed from literature correlations. The results of the heat transfer model are validated by the experimental data collected from the respective ORC unit.