Airconditioning and the Environment

Global Warming and Airconditioning

Air conditioning and refrigerant systems are significant contributors to global warming in three ways:

1. Their widespread use creates an immense scale of potential environmental impact – they account for 15% of worldwide energy use (Coulomb, 2006).
2. The refrigerants used within the systems can be potent greenhouse or ozone depleting gases. If the system is not totally sealed or the refrigerants are not correctly recovered at the point of disposal, they can escape into the environment (ibid).
3. Each unit /system consumes a large amount of energy – "contributing to the emission of large amounts of [carbon dioxide]" (ibid).

Given the environmental impact of air conditioning and refrigerant systems is twofold, the International Institute of Refrigeration – the intergovernmental organization representing refrigeration practitioners and scientific communities at international level – suggests that the benchmark for considering the impact of a system should be in terms of the "…overall equipment emissions… throughout the life cycle of the equipment", measured in carbon dioxide equivalent units (Billard, 2000).

The International Institute of Refrigeration has established two main objectives in order to reduce the impact of air conditioning and refrigerant system life cycles and operating cycles:

1. Reduce direct emissions of greenhouse gases: The IIR objective is to reduce the impact of emissions to 50% by 2020, using the year 2000 as the base measurement. Measures taken include improving refrigerant and using refrigerants with the lowest overall impact in terms of global warming potential (International Institute of Refrigeration, 2000)
2. Reduction of energy consumption: The IIR objective is to reduce the unitary energy consumption of refrigerating plants by 30-50% — according to applications — by 2020, using the year 2000 as the base measurement. Measures taken include optimizing systems, using high performance technologies and improving the efficiency of systems and their components (ibid).

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What is Global Warming Potential (GWP)?

Global Warming Potential (GWP) is an index which allows a standardised measurement of the potential effect of greenhouse gases in terms of trapping infrared radiation.

The Global Warming Potential of a greenhouse gas is defined as "the total impact over time of adding a [kilogram] of a given greenhouse gas (GHG) to the atmosphere" (CO-OP, 2006) relative to an equal amount of carbon dioxide (ICBE, 2006).

In the Global Warming Potential scale, carbon dioxide has the value of 1 with the effect of other greenhouse gases calculated in multiples of this value - the potential of a greenhouse gas to trap infrared radiation described in terms of Carbon Dioxide Equivalent (ibid). This allows for a standardized measurement of the potential harming effect of greenhouse gases. Comparatively, carbon dioxide is the least powerful greenhouse gas in terms of trapping infrared radiation, while also being the most common (ibid).

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Global Warming Potential (GWP) and Refrigerants

The Australian Institute of Refrigeration Air Conditioning and Heating states that "a refrigerant should have zero or a low ozone depletion potential, a low global warming potential and a short estimated atmospheric life" (2003).

The Australian Good Environmental Choice Label, a consumer goods environmental labelling program indicating the environmental performance of a product from product life cycle perspective, states that any refrigerant emitting greenhouse gases into the atmosphere must have a GWP no greater than 50 for the final product as part of its criteria for labeling (2005).

The International Institute of Refrigeration (2005) suggests the way to reduce direct greenhouse gas emissions from air conditioning and refrigerant systems by the 2020 deadline (see Global Warming and Air Conditioning note), is to:

• Improve refrigerant containment
• Use refrigerants with the lowest overall impact on global warming:
  • Develop alternative refrigerants with zero or low Global Warming - which also meet stringent user safety measures.
  • Continue to use Hydrofluorocarbons*, these being safe, but selecting hydrofluorocarbons with the lowest GWP, which also enhance the energy-efficiency of refrigeration plants.

The Australian Institute of Refrigeration Air Conditioning and Heating has produced a guide to refrigerant selection for the air conditioning and refrigeration industry which includes a table of selection based on the refrigerant's environmental properties, including the products GWP. See Point 7.6 of the document: http://www.airah.org.au/downloads/AIRAH_RSG2003.pdf

*IIR Note: Hydrofluorocarbons were developed as a replacement for Chlorofluorocarbons and Hydrochlorofluorocarbons. They are not ozone depleters, but they do have GWP - at a lesser extent than Chlorofluorocarbons and Hydrochlorofluorocarbons - and are therefore also targeted by the Kyoto Protocol (2005).

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What is Global Warming?

Global warming is the term given to the rise in the average temperature of the Earth's atmosphere and oceans which has been observed and measured over the last couple of decades.

The average surface temperature on Earth temperature has significantly increased over the last 140 years. This increase is outside the normal pattern of temperature variation and is "likely to be without precedent during at least the last 10,000 years, based on palaeoclimate data" (IPCC, 2001).

From 1900 onwards the increase in temperature attributed as global warming has been measured at roughly 0.6°C (IPCC, 2001).

Wide scale climate change has been brought about by this increase in temperature - including radical changes in rainfall patterns, snow coverage, glacier and ice coverage, ocean temperature, currents and the sea level.

Research conducted by the Intergovernmental Panel on Climate Change (IPCC) found that the major contributing factor to global warming observed over the last 50 years was human activity (2001), particularly the production of greenhouse gases through human activity.

The IPCC research further concluded that if current trend of greenhouse gas emissions continues, we will face additional increases in temperature - projected as a global increase of 1.4°C to 5.8°C by 2100 (IPCC, 2001).

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What are Greenhouse Gases?

Greenhouse gases are chemical compounds which absorb infrared radiation. Some occur naturally (i.e. water vapour, carbon dioxide and methane), others are human made (i.e. gases used in aerosols).

When sunlight strikes the Earth's surface, some of it is reflected back towards space. Greenhouse gases absorb this radiant energy (i.e. heat) - trapping it in the atmosphere.

Human activity over the past two millennia has significantly increased the level of greenhouse gases in Earth's atmosphere. Factors that continue to contribute to this increase include:

• Processing and burning fossil fuels (coal, oil)
• Large scale deforestation and interference with wetlands
• Land use changes
• Industrial Emissions
• Use of greenhouse gases in refrigeration and air conditioning systems.
• Agricultural activities and practices, including the farming of livestock, paddy systems and the use of fertilizers

With this exponential increase in the production of greenhouse gases, the natural equilibrium between the amount of radiant energy sent from the sun to the Earth's surface and the amount of radiant energy radiated back into space has been disrupted - ideally these two amounts should be of equal value - so the temperature of the Earth's surface remains consistent (USA Energy Information Administration, 2006).

The significant increase in the level of greenhouse gases present in the Earth's atmosphere has meant an increase in the amount of radiant energy that is trapped within the atmosphere rather than being reflected into space.

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What is Global Dimming?

Global Dimming is another by-product of our production of fossil fuels, aerosols and even vapour trails left in Earth"s atmosphere by aircraft. These activities create pollutants which permeate the atmosphere, as well as producing greenhouse gases which significantly contribute to global warming.

The pollutant particles act as reflective surfaces which absorb and reflect radiant energy.

One effect of the production of these particles is the alteration of cloud structures - particularly cloud reflectivity and cloud lifetime (Real Climate 2005). Water droplets in clouds coalesce around the pollutant particles creating clouds consisting of smaller water droplets, making the clouds themselves more reflective (Wikipedia 2006).

Additionally, the unpredictable cooling effects of global dimming have also radically disrupted traditional seasonal climate patterns - creating areas of drought and famine as a result. Unpredictable weather patterns caused by global dimming are now believed to have caused the catastrophic 1984 Ethiopian Famine (Horizon, 2005).

Another significant side effect of global dimming is that it masks - to some extent - the extent of climate and temperature changes caused by global warming, the by-product of our production of greenhouse gases. Dr David Travis conducted research into whether vapour trails left by aircraft were having a significant effect on the climate, he noted while all aircraft in the USA were grounded - in the three days after September 11th 2001 - the temperate in the USA increased by 1°C (ibid).

The twin effects of global dimming and global warming have created a paradox. Addressing one of these effects without addressing the other exacerbates the negative impact of the other. Steps taken in Europe to address the production of pollutants creating smog - the same pollutants which cause global dimming - have also lessened the severity of droughts and rainfall patterns disrupted by global dimming in the areas of Africa which were affected by the 1984 Ethiopian Famine (Shah, 2005), however it is believed that those same measures also brought about a major European Heatwave in 2003 (ibid).

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What is the Kyoto Protocol?

The Kyoto Protocol is the informal title of the Kyoto Protocol to the United Nations Framework Convention on Climate Change - an amendment to a definitive United Nations treaty on climate change.

The Kyoto Protocol is designed to limit global greenhouse gas emissions - setting targets for the reduction of greenhouse gas emissions which participating nations must meet. The Kyoto Protocol aims to reduce greenhouse gas emissions in developed countries by at least 5% with respect to the 1990 levels, during the period 2008-2012.

Countries which ratify the Kyoto Protocol are required to reduce their emissions of carbon dioxide and greenhouse gases, or - if they are unable to maintain or reduce current levels of emission production - engage in emissions trading (Wikipedia, 2006).

The Kyoto Protocol promotes sustainable development and encourages participating countries to implement or expand existing environmental impact countermeasures to achieve these reductions. Measures participating countries are encouraged to pursue include: enhancement of energy efficiency; reforestation; development of new and renewable forms of energy; development of environmental sound technologies; the phasing out of market imperfections in all greenhouse gas emitting sectors; and many more (Kyoto Protocol, 1997).

The Australian Government elected not to ratify the Kyoto Protocol with the view that ".while it has some positive elements, it does not provide a comprehensive or environmentally effective long-term response to climate change" (Australian Government, 2006).

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