Use of Semi-Indirect Evaporative Cooling in HVAC systems: experimental study

Abstract

This study investigates the application of a Semi-Indirect Evaporative Cooler (SIEC) to develop a Decarbonised Evaporative-Based Air Conditioning System (DEBACS). The research aims to show the benefit of using the SIEC in combination with a traditional Air Conditioning Unit to enhance the energy efficiency of an HVAC system. The SIEC, constructed from ceramic material, operates in both dry and wet modes. By spraying water on the inner side, it functions as an efficient air-to-air recuperator, with the ceramic material improving water distribution and device performance. The SIEC device has been experimentally tested. Tests were conducted in both dry and wet modes across three airflow rates and three temperature levels. Moreover, a simple model that describes the SIEC behaviour in general operative conditions has been derived. Results indicated that under optimal conditions (lowest supply airflow), the SIEC achieved an efficiency ratio between 50 % and 70 % in dry mode, and nearly 100 % in wet mode, with the wet mode improving efficiency ratio by 30-50 %. These findings underscore the potential of the ceramic SIEC device as an effective technology for air conditioning systems, promoting energy efficiency, compliance with EPBD standards, and significant decarbonisation in the HVAC sector.