Application of global temperature potential to refrigerating systems: Total Lifetime Temperature Impact (TLTI) and Global Damage Impact (GDI).

Currently, the contribution of refrigerating systems towards climate change is evaluated through methods such as Total Equivalent Warming Impact (TEWI) and Life Cycle Climate Performance (LCCP). These employ the measure of Global Warming Potential (GWP), so the effect of different greenhouse gases such as refrigerant and carbon dioxide (from energy production) may be added together. GWP is defined as the radiative forcing due to a single emission of a gas, integrated over a given time horizon, relative to an emission of carbon dioxide. There has been dispute over the applicability and suitability of GWP (and thus TEWI and LCCP) in terms of its ability to represent the actual impact of a refrigerating system on global warming. In response to this, a recently developed concept known as Global Temperature Potential (GTP) has been employed to evaluate the impact of refrigerating systems. Adopting the GTP, the paper presents a new approach, TLTI as an alternative to those that employ GWP. Absolute GTP is used in two further measures of GDI. The paper describes the rationale behind the new approach, and gives example results to allow the comparison of the use of a natural and a synthetic refrigerant.