Environmental impact indicators for refrigerants : ODP, GWP, TEWI
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The environmental impact indicators for refrigerants, GWP, ODP and TEWI, describe their harmfulness to our environment. A higher value indicates a higher level of harmfulness to the atmosphere and the environment. When a substance is deemed to be environmentally friendly or ecological, this means that it presents little to no harm to the ozone layer and expedites global warming as little as possible. To be determined to have zero ozone depletion potential, a refrigerant may not contain chlorine (Cl) or bromine (Br).
GWP, Global Warming Potential?
GWP is an index/factor that indicates the harmfulness of a substance in terms of global warming. The values of other substances are compared to carbon dioxide (CO2), which has a GWP value of 1.0. GWP is calculated over a specific time span, generally for a period of 100 years. The scale starts at 0. The quantity of F-gases is described as carbon dioxide equivalent tonnes (F-gas weight + GWP).
ODP, Ozone Depletion Potential
CFC and HCFC refrigerants react negatively with the ozone layer: the chlorine molecule reacts with ozone, catalysing the conversion of ozone molecules into oxygen. A single chlorine atom may destroy more than 100,000 ozone molecules. This process has already caused demonstrable damage to the ozone layer.
The ODP value refers to the relative harmfulness of a substance to the ozone layer. The value of refrigerant R11, i.e. 1.0, is used as the reference value. The scale is 0–1.0.
The EU regulation on substances that deplete the ozone layer (EC) No 1005/2009 entered into force on 1 January 2010. The purpose of the Ozone Regulation is to prevent the thinning of the ozone layer. Read more about legislation concerning the refrigeration field.
TEWI, Total Equivalent Warming Impact
TEWI indicates the amount of greenhouse gases generated by a refrigeration plant in kilograms (kg) of carbon dioxide (CO2). TEWI encompasses direct refrigerant emissions and CO2 emissions due to the energy consumption of the device. The scale starts at 0.
Developments in the refrigeration field
Refrigerants have changed a great deal in recent decades as a result of experience, safety concerns, legislation and legislative changes. General awareness of environmental impacts has increased, and new environmentally friendly refrigerants are gaining ground. At the outset, ozone-depleting substances were eliminated, and now the sights have been set on refrigerants with global warming potential.
The transition periods are long since the legislation takes economy and the service life of heavy equipment into account. The core intention is not to implement a sudden about-turn. Moreover, knowledge is required on the suitability of new refrigerants for various systems and plants, along with staff training and an increase of safety awareness. Various warning symbols and any relevant changes, reporting arrangements, control and permits must also be considered.
The greenhouse emissions generated by a refrigeration plant over the course of its life span as kilograms of carbon dioxide.
The EU regulation on substances that deplete the ozone layer (EC) No 1005/2009 entered into force on 1 January 2010. The purpose of the Ozone Regulation is to prevent the thinning of the ozone layer.