22 May 2002
A new type of plate heat exchanger for water-refrigerant systems such as chillers has been developed. Plates embossed with pyramid-like structures are stacked up to form the heat exchanger. Three pyramid sizes, namely, similarly shaped patterns with heights of 1.0, 1.2 and 1.5 mm, were evaluated. Measured heat-transfer coefficients corresponding to the three plate sizes (convective vaporization) show a weak correlation with channel height, and they are about one and a half to two times higher than those of commercial herringbone-type plate heat exchangers. Moreover, measured heat-transfer coefficient for water convection was found to be lower for the smaller channel height; however, it was still higher than that of conventional plate heat exchangers. It was also found that the plate surface with the pyramid height of 1.0 mm makes the plate heat exchanger more compact and reduces the pressure drop on the water side by nearly half.