Performance metrics for room air-conditioners: energy, comfort and environmental impacts

Abstract

India’s current standards and labels for room air-conditioners (RACs) account for energy efficiency, but omit other important criteria that could influence product development and consumer choice: thermal comfort and environmental impact. This study proposes comprehensive RAC evaluation criteria by accounting for the operational energy, thermal comfort and environmental impact through the metrics of the Indian seasonal energy efficiency ratio (ISEER), cooling seasonal energy consumption (CSEC) and total equivalent warming impact (TEWI), respectively. It uses five RAC product cases based on the Indian RAC market to demonstrate the enhanced evaluation criteria across the climatic conditions of 55 Indian cities subject to static and adaptive (air-conditioned, AC; and mixed-mode, MM) thermal setpoints. The analysis yields a significant difference in the number of RAC operational hours between the static and adaptive (AC and MM) methods, resulting in a difference in the overall performance of RACs across varied climatic contexts. <em><strong>Practice relevance</strong></em> RACs are increasingly being adopted as a standard method of active cooling with the modernisation of small and medium-sized commercial and residential spaces in India. However, current standards and labels only provide a partial evaluation of RAC performance. This study targets three aspects of RAC performance in energy, comfort and environmental impacts. It demonstrates that existing RAC performance standards in India can be improved to account for climatic variability and environmental impact in addition to the existing understanding of energy efficiency. The outcomes of this study can serve as inputs to standards and labelling programmes by improving the component-level energy efficiency of RACs, educating the end-users on optimising their thermal setpoints for improved performance, and supporting the development of RACs with low/zero global warming potential refrigerants.