Terms on emissions

Short descriptions of selected terms with relevance for environment in refrigeration.

ODP – Ozone Depletion Potential

Potential of 1 kg of the refrigerant to destroy ozone in the atmospheric ozone layer, relative to 1 kg R11 (Fluorotrichloromethane). High ODP values are typically found for chlorine and bromine containing hydrocarbon derivates. There are, however, also substances without chlorine and bromine, like nitrous oxide (N₂O) with – mostly lower – ODP.

GWP – Global Warming Potential

Potential of 1 kg of the refrigerant to heat up the atmosphere, relative to 1 kg carbon dioxide (CO₂, R744). The value is usually determined based on a 100 year time horizon. The calculation and publication of the values is usually done by the International Panel on Climate Change (IPCC).

TEWI – Total Equivalent Warming Impact

Calculated value for the global warming effect of a refrigerant in an individually defined application. It is a part of a greenhouse gas balance, where the two so far largest parts are evaluated: refrigerant emissions and energy consumption. Numbers have to be determined for the carbon dioxide equivalent of the refrigerant emitted during operation and disposal and added to the carbon dioxide emissions from the energy consumption. In this way, GWP and energy consumption can be balanced. The evaluation is to some extent depending on the assumed size of certain values and changes with the amount of renewable energy available, as e.g. the conversion factor in kg CO₂ per kWh electrical energy consumption can decrease. Details: Refrigerant-Report.

Greenhouse gas balance

This makes a balance for the whole or a part of the life time of a product in a defined application. It contains also the emissions necessary for production, disposal and material production. Emissions of other greenhouse gases and values for energy consumption resp. fuels are converted to carbon dioxide equivalents and finally balanced as a total. It was formerly also called primary energy balance.

CFP – Carbon Footprint of a Product

Standardised greenhouse gas balance, covering the life cycle of a product. Can a.o. be performed according to ISO14067.

Ecobalance

An ecobalance balances the impact of a product, an application or a measure on the environment. It can be of different extent, be like a greenhouse gas balance, but can also include resource use, toxic substances and irreversible pollution. For the extent and for balancing of non comparable values there are different concepts with different methods and impact evaluations. Total balances are quite intricate and usually serve as base for determination of the most important impacts at present. As the balances are mostly used for comparisons of processes or products, the majority of them are partial balances. But also here it is essential to use reliable and acknowledged sources for the emission data.

Eco-Efficiency

A balancing including environmental impacts and life cycle costs meaning a combination of ecologic and economic evaluations. By this, the target is to find the most economic way to reduce the environmental impacts by comparing different processes or changes of processes with same gain or use. Details: Refrigerant-Report.

Alternative refrigerants

This term was appearing early in the discussions around avoiding emissions of substances with ODP. The refrigerants with no ODP, developed to replace the previously used ones, were called alternative refrigerants. The denomination also appears similarly in e.g. the Montreal Protocol as "alternative substances" or in the EU-F-Gas Regulation as "alternatives" or "alternative refrigerants". In the USA large projects with the title "Significant New Alternatives Program" (SNAP) were initiated to investigate the use of alternatives for ozone depleting substances.