Responding to climate change
There are two aspects to be considered in responding to climate change — and here we are considering the how, not the why. One is reducing the consumption of fossil fuels that generate the carbon dioxide which increases the greenhouse effect of the Earth’s atmosphere, leading to global warming. The other is achieving comfortable buildings in the warmer climate that we are assured is inevitable. In principle, at least, as much renewable energy is available as we need. As is pointed out in our feature on responding to climate change in this issue of Modern Building Services, 1600 km2 of photo-voltaic panels in the Sahara Desert could generate the world’s electricity requirements. The reality is that the Sahara Desert is not close enough to home for most of the world and the intensity of solar radiation is much smaller over most of the planet, so a balance of the two aspects is required. One of the key drivers for developing the wider use of renewable energy in the UK is the planning process. The London Borough Of Merton pioneered this approach by requiring 10% of carbon savings for a building project to be achieved using renewable energy. There ought to come a stage where a building’s energy consumption is so small that the cost of providing 10% of a building’s energy requirements from on-site renewable energy on site is disproportionately high. That observation could be behind the Government’s intention to increase the requirement for sustainable and renewable energy to the 30% mark for residential buildings by 2010 and for commercial buildings to 20%. Capital-cost considerations will decide the balance between providing large quantities of sustainable and renewable energy and reducing a building’s energy requirements. As Gerry Stapley, president of the HEVAC Association, says, users will take up energy-efficient products if they are competitively priced, and prices will come down as demand increases. The task of delivering comfortable conditions in buildings is also giving rise to a new approaches. Underfloor heating, for example, enables a building to be comfortable at a lower air temperature than other forms of heating — by virtue of the large area of radiant surface. It is also well suited to the low flow temperatures that are efficiently provided by heat-pumps and condensing boilers. We are also hearing of projects where air-conditioning equipment is being selected for its ability to deliver space heating with a COP of 3 to 4. Likewise, chilled ceilings and beams are enjoying a new prominence for their ability to provide comfort in a more subtle way than conventional air conditioning. As with underfloor heating, the temperature of cold water required opens up the prospect of reducing the energy needed to cool buildings. Responding to climate change is much more of an opportunity than a problem.