A novel indirect evaporative cooler with porous media under dual spraying modes : a comparative analysis from energy, exergy, and environmental perspectives

Abstract

Indirect evaporative cooling (IEC), which cools the air through the physical process, is regarded as one of the high-efficient air conditioning (AC) technology. The reliable performance of traditional IEC is maintained by consistent water spraying, consuming much energy and hindering further performance improvement. In this regard, we proposed a novel indirect evaporative cooler with porous media on the secondary air channel (PIEC) to mitigate the dependence on water spraying. For the PIEC, the water storage capacity of porous media enables periodic spraying. However, the performance comparison between periodic spraying and traditional consistent spraying is rarely carried out although the two modes have been achieved, which promotes this research. In this study, the PIEC model with consistent spraying and periodic spraying was briefly described based on our previous results. According to the results from the established model, the PIEC performance was analyzed and compared under dual spraying modes from the energy, exergy, and environmental (3E) perspectives. It is demonstrated that periodic spraying can significantly improve the system COP by 58.7% at the cost of tiny temperature fluctuations. Additionally, the periodic mode can increase the exergy efficiency and lessen the exergy loss ratio in the studied cases. Eventually, the PIEC system using periodic spraying can annually reduce up to 24.2% of CO2 emissions compared with the traditional consistent mode, indicating better environmental benefits.