Climate Change: CO2 is Not the Only Gas Attack

Last Updated Nov 24, 2009 2:15 PM EST

How is your company air-conditioning its buildings? It may be the equipment it's using is unsustainable, even though it complies with today's environmental regulations.

Although CO2 is by far the most common greenhouse gas (gases that are trapped in the earth's atmosphere which retain more heat from the sun), there are other, more potent greenhouse gases with a defined Global Warming Potential (GWP).

Methane, for example, has a GWP of 40, meaning that one tonne of methane in the atmosphere has the same greenhouse effect as 40 tonnes of CO2.

The chemical Hydroflurocarbon (HFC) has a GWP of 2,000 and is in common use in air conditioning and refrigeration systems.

Ironically these gases were introduced to replace the ozone depleting chlrofluorcarbons (CFC), little did we know at the time that we were solving one problem and causing another. This gas is in the process of being banned from domestic refrigerators and car air conditioning systems but it remains present (and legal) in the vast majority of building air conditioning systems and commercial refrigerators.

According to Greenpeace, the massive rise in HFC related cooling in the world, driven by global warming, will result in as much greenhouse gas in the atmosphere by 2050 as we have today assuming, we are successful in reducing carbon emissions by 80 percent.

Once again, we are in danger of solving one problem and causing another.

I am pleased to see some companies taking a lead and the recent news about Sainsbury's tackling the issue is very welcome. Through my role on the London Olympics I have been able to influence the Olympic Delivery Authority (ODA) to adopt a presumption against HFC in the building design.

Businesses should be aware of this issue. It is only a matter of time before HFCs are banned, potentially leaving masses of equipment obsolete. The manufacturers of HFCs are working on a low GWP alternative but how long will this take, how much will it cost and what do you do with the HFCs that you have replaced?

A sensible "whole life cost" approach is required when selecting any cooling equipment. If HFCs are to be used, it is important to make some well advised financial assumptions about the anticipated life of the equipment and the cost of disposal.

The alternatives (ammonia, butane and CO2) are not without their problems so careful consideration on a case-by-case basis is necessary. Alternatively, you can do without cooling. Many buildings can be designed in an energy efficient manner that use free cooling, this can save money and reduce the need for messy financial calculations and difficult decisions.

(Pic: boliston cc2.0)