Experimental study of plant fiber-polymer composite for indirect evaporative cooler application

Abstract

• Plant fiber-polymer composite was used as a novel evaporative material. • Moisture transfer ability of five evaporative materials were comparatively tested. • Cooling performance of an IEC with plant fiber-polymer composite was tested. • The optimal working air/product air flow ratio was obtained. The cooling performance of indirect evaporative cooler (IEC) largely depends on the wettability of wet channels. Therefore, plant fiber-polymer composite was used as a novel evaporative material to enhance the wettability in IECs in this study. The plant fiber layer facing to the wet channel is hydrophilic, which can disperse water effectively by capillary action, while the opposite non-permeable polymer layer is facing to the dry channel. Firstly, comparative study was conducted to evaluate the moisture transfer properties of five evaporative materials (non-woven fabric, non-woven plant fiber, plant fiber-polymer composite, polyester fiber and Kraft paper) by wicking height, diffusivity and moisture absorption and release tests. Then, the cooling performance of a plant fiber-polymer composite based IEC prototype was tested under different working to product air ratio and climatic conditions. Results show that the plant fiber-polymer composite is promising for IEC application owing to its superior moisture transfer properties over the other selected ones. The performance test also show that the plant fiber-polymer based IEC is comparable to that of fabric coated polyurethane IEC but with cheap price and light weight. The successful application of the new material could contribute to further research and development of next generation IEC with better wettability.