An innovative environmental parameter: Expanded Total Equivalent Warming Impact

Abstract

The greenhouse gas emissions caused by human activities determined an increase of global mean temperature during last decade. The growing heating, cooling, ventilation and refrigeration demands for residential, commercial and industrial sectors represent the major contributor to environmental emissions. The environmental analysis represents a good strategy for evaluation, comparison and selection of energy supply system on the basis of users’ demands. The global warming potential of energy conversion devices is usually analysed by considering energy consumption, indirect and direct greenhouse gas emissions caused by refrigerants leakages through the well-known Total Equivalent Warming Impact index, TEWI. In this paper a detailed and extended version of TEWI index, Expanded Total Equivalent Warming Impact (ETEWI) parameter is proposed to calculate CO2 equivalent emissions from direct and indirect contributions in the HVAC&R sectors. The standard TEWI index contributes are revisited to determine the emissions by an accurate evaluation of direct refrigerant leakages and by detailing the indirect emissions caused by electric energy consumption . In addition, new emissions’ contributions are investigated. The novelty of this approach can be summarised in two key-points: the possibility of analysing the environmental impact of both electric and gas driven devices and the definition of an innovative environmental parameter to take into account the direct/indirect contributions of the Urban Heat Island effect and the indirect CO2 emissions due to losses in distribution and transportation pipelines that supply natural-gas to energy conversion systems.