Experimental and Numerical Study of Recuperative Heat Recirculation

In many power-generating systems heat recirculation is needed in order to increase their thermal efficiency and ensure sufficiently high temperatures required in fuel processing. The current article investigates experimentally and numerically a heat recirculation phenomenon by using gas-gas recuperation. The systematized description of practicalities of heat recirculation is reported. The experimental characteristics of a heat recirculator are presented in terms of the effect of power of the heater at constant mass flow rate, effect of mass flow rate at constant power of the heater, and effect of mass flow rate at constant ratio power of the heater/mass flow rate on heat transferred, heat lost to the surroundings, and processing temperatures. The results show that heat recirculation is maximized at moderate mass flow rate, at large power, and in miniaturized channels. Further, a numerical model is used in order to interpret and extend the experimental data set. The simulations are focused on heat recirculation under conductive, dispersive, and convective regimes of heat transfer. Finally, the principles of thermal integration of power-generating systems by using heat recirculation are expounded.