Free cooling - an inconvenient truth

It is a little over two years ago that a lorry driver from Kent forced the UK Government to rewrite guidance for schools that wanted to show Al Gore’s Oscar-winning climate change film, An Inconvenient Truth. The high court action was brought against the screening of the documentary in schools, claiming that it was “politically partisan” and “sentimental”.

The High Court judge – Mr Justice Burton - said that the film contained nine statements that were not supported by mainstream scientific consensus and that distributing the film without guidance to counter its “one-sided” views would breach education laws.

The nine errors stated by the judge included: that a sea -level rise of up to 20 feet would be caused by melting of ice “in the near future”, and that the disappearance of snow on Mount Kilimanjaro in East Africa was expressly attributable to global warming. Neither of these or any of the other seven errors had scientific consensus according to the judge.

Were we really surprised by the information that a former US Vice-President had not strictly been telling the truth? However, when one considers the energy guzzling US audience that the film was primarily aimed at it, the sensationalist ‘shockumentory’ approach may be forgiven if it achieves the films goals. For while the ruling may have been mildly embarrassing for the Nobel prize winner Mr Gore, the judge did not dismiss the film’s main argument which is supported by the vast weight of scientific opinion, that climate change is mainly caused by man-made emissions of greenhouse gases and will have very serious consequences. Climate change costs lives, real human lives, and it is often the world’s poor that will suffer the most. To play politics with the lives of so many; to get tied up in games with semantics doesn’t help anyone in the long run.

Energy Consumption in Buildings

Whether as a consequence of Al Gore’s film or not, it does appear that public opinion in the US may be on the turn. On both sides of the pond (and every where else in the developed world for that matter), high energy consumption in buildings is a problem. Buildings world-wide consume enormous amounts of energy and the demand for new buildings continues relentlessly. Fortunately, global concerns regarding climate change, has created a sense of urgency for positive action. The path to global sustainability is forcing us to seek dramatic building energy performance improvements. By reducing building energy consumption we can help reverse the forecasted trends.

As engineers we are fortunate in that we find ourselves at a pivotal point in the history of the build environment - that is exciting, daunting and challenging. A period of change; when the old and new are forced to stand side by side to be compared; and when our accomplishments of the past will soon be replaced by the rich possibilities of the future.

The role of air conditioning in buildings will continue to be scrutinised with a leading UK Conservative politician warning the ACR industry that it is “on notice” regarding climate change and said it should not be surprised by Conservative proposals to ban new electric air-conditioning and cooling units in commercial buildings.

Free Cooling

There is not only considerable interest in challenging the concept of comfort that air conditioning delivers but also in examining ways and means that we can produce comfortable environments with minimal energy cost. One solution, passive cooling, could play a significant factor in building design in the future. By employing passive cooling techniques into modern buildings, it may be possible to eliminate mechanical cooling or at least reduce the size and cost of the equipment.

Passive cooling is based on the interaction of the building and its surroundings and can be achieved in several ways such as natural ventilation, high thermal mass with night ventilation, and evaporative cooling. This last one is well known to the ACR industry where it is better known as ‘free’ cooling.

There are a number of other free cooling systems that range from thermosyphonic cooling, to a dry cooler, which in simple terms is a free standing cooler over which outside air is drawn or blown.

The concept of free cooling is straight forward and has been used successfully for many years. It can produce attractive energy savings whenever the outside air conditions are suitable. The fact the free cooling is neither free to install nor completely free to operate is an inconvenient truth that may be overlooked as the end result of energy reduction is achieved. The fact that low energy consuming buildings are possible that incorporate ACR systems with free cooling is an inconvenient truth to those that question our ability to deliver energy efficient solutions.