Heat transfer model in recuperative compact heat exchanger type honeycomb: Experimental and numerical analysis

This paper presents a model to calculate the thermal performance of a heat recovery unit fabricated from an alumina honeycomb matrix and a methodology for the discretization of the energy equations necessary to develop a calculation algorithm for designing and sizing compact heat recovery units. Based on the results from the algorithm, a prototype heat recovery unit built from alumina honeycomb was tested. The device reached an efficiency of 84% and an air preheating temperature of 621 °C for an 8.19 kW power level. There was a 7% difference between the model calculations and experimental results. The yield was higher than is typically reported in the literature for this type of heat exchanger. The prototype device was compact, with an areal density of 1860 m2/m3, a hydraulic diameter of 0.75 mm and an overall length of less than 15 cm.