Thermal Mass – a cool solution for sustainable buildings
By 2040, the number of days on which temperatures will exceed 25 degrees Celsius, will have doubled according to The Chartered Institute of Building Service Engineers*. By 2080, it will have tripled. * CIBSE’s TM36 Guide
Understanding how this will impact on humans and our lifestyles is a crucial first step in creating environmentally sustainable buildings and as a result of this thought process, traditional heating and cooling methods are now being challenged by less energy intensive methods.
Geoff Russell-Smith, general manager, Tarmac Termodeck, explains how the unique thermal mass properties of concrete are helping to provide a viable alternative, which many innovative companies are already using in building projects.
“There are two major factors to consider when looking at ways to heat and cool a building. Firstly, how effective is the product at providing good quality indoor air? This is especially important in premises that require its user to sustain high levels of concentration such as schools, universities and offices. The good old days of opening a few windows to increase air circulation in a classroom or office is now known to be ineffective. While this was once perceived as a low-cost ventilation option, the variability in factors such as outdoor temperature and wind pressure make this an inadequate solution. And in many cases, opening the window can lead to problems of noise or pollutants entering the workplace or classroom.
“Insufficient fresh air can also result in concentration difficulties and other health problems, as seen with sick office syndrome. Ironically, recent changes in Building Regulations have exacerbated the problem in newer buildings. A reduction in draughts due to double and triple glazing, coupled with greater insulation, has reduced the ability of buildings to efficiently circulate naturally ventilated air.
“Secondly, buildings now have to demonstrate energy saving credentials in order to obtain planning permission, not to mention assuring investors that the projects have viable life-spans. As a result, architects and building designers are examining the feasibility of incorporating low energy technologies from the very outset of the design process.”
Russell-Smith explains how using the thermal mass of a concrete building, combined with a fresh air ventilation system can produce an effective sustainable, low-energy method of maintaining comfortable and stable temperatures.
“The TermoDeck principle is relatively simple, but its impact is extensive. Fresh air is passed through hollowcore flooring at low velocities, allowing prolonged contact between the air and the concrete slabs. This enables the slabs to behave as passive heat exchange elements that release heat to, or absorb heat from, the air in the slabs (depending if heating or cooling is required). The temperature difference between the slab and the air that exists within the slab is not more than one or two degrees Celsius, thereby creating a stable and fresh indoor environment. The heating or cooling of the rooms is not only achieved from the convective element of the air entering the space, but also the radiant effect of the exposed soffit of the TermoDeck hollowcore concrete slabs.”
TermoDeck buildings offer significant energy saving benefits, delivering a host of advantages for building managers and users. However, it is the system’s low energy factor that will become increasingly significant in the future.
“TermoDeck can play a significant part in alleviating some of these environmental pressures by enabling the building to have low energy consumption levels, as well as reduced operating and maintenance costs. In some cases, TermoDeck can reduce running costs by up to 46% compared with buildings utilising traditional methods,” says Russell-Smith.
Since the first UK installation in 1993, many other buildings across the country have adopted this methodTermoDeck. This includes the facility for bioscience (MIB) at the University of Manchester – one of the country’s most technologically and environmentally advanced constructions. Tarmac’s TermoDeck system was used in the office support accommodation to exploit the thermal mass of the floor and assist in the regulation of temperature in these areas.
“These buildings are well equipped to deal effectively with the predicted gradual rise in ambient temperatures,” concludes Russell-Smith. “Thanks to TermoDeck’s use of the thermal mass properties of concrete, they will continue to deliver a comfortable internal environment while consuming relatively low levels of energy. The design choices of new buildings today are going to have far reaching implications tomorrow. The construction industry must continue to demonstrate its ability to innovate and help develop a bright and sustainable future.”
4 December 2007
