Performance Comparison between Selected Evaporative Air Coolers

The aim of this study is to determine which of the heat exchangers is characterized by the highest efficiency in different applications. Various types of evaporative air coolers were compared: a typical counter-flow unit, the same unit operating as a heat recovery exchanger, a regenerative unit and a novel, modified regenerative exchanger. The analysis includes comparing the work of evaporative heat exchangers during summer and winter season. The analysis is based on the original mathematical models. The numerical models are based on the modified ε-NTU (number of heat transfer units) method. It was established that selected arrangements of the presented exchangers are characterized by the different efficiency in different air-conditioning applications. The analysis faces the main construction aspects of those evaporative coolers and also compares two above-mentioned devices with modified regenerative air cooler, which can partly operate on cooled outdoor airflow and on the exhaust air from conditioned spaces. This solution can be applied in any climate and it is less dependent on the outdoor conditions. The second part of the study focuses on winter season and the potential of recovering heat with the same exchangers, but with dry working air channels. This allows establishing their total potential of generating energy savings during the annual operation