Performance of the domestic micro ORC equipped with the shell-and-tube condenser with minichannels

In this paper, the original compact shell-and-tube heat exchanger with circular minichannels of in-house design and manufacturing is presented as the condenser for the domestic micro heat and power plant investigations as well as other future technical applications. The heat exchanger is equipped with turbulizing baffles inside the shell. The shell itself is made of a tubular sleeve having an inner diameter of 0.067 m and the length of 0.38 m. The tube bundle constitutes of 103 pipes arranged hexagonally with the active length equal to 0.31 m. The tubes inner diameter equals to 0.002 m and the wall thickness is 0.001 m. The calculations of the heat transfer coefficient for the condensation in the flow of the ethanol as a working fluid was done by means of several methods, among others the one developed in-house. That model accounts for the non-adiabatic effects in the convective heat transfer coefficient. The experimental validation of the prototype construction was accomplished. During the tests the condenser was cooled by water with ethanol as a working fluid. The obtained results are in a good consistency with the in-house model predictions.