Satyanarayanan S

The study analyses correlations used to determine the condensation heat transfer coefficient of refrigerant mixtures, R410A and R407C, in a tube in tube condenser. Shah [1], Jaster and Kosky [2], Thome et al. [3], and Dobson and Chato [4] correlations have been considered. The study identifies the flow parameters which influence the accuracy of correlations. The accuracy of the considered correlations is studied against the identified flow parameters. The flow parameters are used as a deciding criterion to select the most accurate correlation for a given case. This leads to a hybrid approach involving multiple correlations. The hybrid approaches are more accurate in comparison to the individual correlations.

Wankel expander are among the emerging technologies for use in cogeneration in process industries, ORCs, and other energy storage systems. Heat transfer and thermodynamic analysis is key to understand the expander and improve its performance. Previous investigations on heat loss models for Wankel expander were based on empirical models from canonical experiments such as flat-plate geometry. In this work, we have built a numerical model with the actual geometry to predict the temperature distribution along the periphery of the expander. Python was used to code and predict the temperature distribution of the expander which was compared with COMSOL solutions with close agreement (<1% variation). Hence, our numerical approach can be extrapolated to sale the Wankel prototype and also create a physics based digital twin.

A desiccant-based heat pump system along with a direct evaporative cooling system has been proposed as an alternative to the baseline cooling and dehumidifying system. Dynamic hourly simulation is performed for three consecutive summer days of Chennai to evaluate the performance of the proposed system. The proposed system achieves the comfort condition and is energy efficient. The results showed that the average COP of the proposed system is 2.62. The average COP improvement ratio compared to the baseline system is 1.52. A carbon emissions reduction of 48.2% is estimated by adopting the proposed system.