Heating and Ventilating appeals to the masses
Rising energy costs and growing environmental concerns demand ever more sustainable and commercially viable construction methods. Modern structures now have a firm requirement to reduce overall environmental impact and find innovative ways to cap energy costs. Air conditioning has traditionally been the first choice when it comes to keeping building temperatures stable but this is increasingly being challenged by less energy intensive methods such as thermal mass.
Geoff Russell–Smith, general manager, Tarmac TermoDeck discusses the sustainable future of conventional heating and cooling solutions and looks at the latest building projects that have harnessed the modern benefits of thermal mass.
“The construction industry is at the vanguard of reducing CO2 emissions in comparison with industries such as aviation, automobiles and power generation. Through the new building regulations, building projects have to demonstrate energy-saving credentials in order to obtain planning permission, not to mention assure investors the projects have viable lifespans. As a result, architects and building designers are examining the feasibility of incorporating low energy technologies from the very outset of the design process.
Utilising a method that harnesses the thermal mass of a building, and combining it with a fresh air ventilation system, is a very effective way of maintaining comfortable and stable temperatures. This practice is increasingly being adopted as a sustainable, low energy solution.
The new facility for bioscience (MIB) at the University of Manchester, is one of the country’s most technologically and environmentally advanced buildings. It has incorporated a thermal mass system into the fabric of its interdisciplinary open plan building. 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. This is being used in conjunction with a high performance façade and automated solar shading.
One of the most significant factors in the commercial new-build environment is not only ensuring that the proposed building can meet the increases in temperature predicted as a result of global warming, but use less energy in the process. The CIBSE (Chartered Institute of Building Service Engineers) TM36 guide shows that the number of days that outside temperatures will exceed 25 degrees Celsius will double by 2040, and triple by 2080. Understanding how this will impact on humans and our lifestyles is a crucial first step in creating environmentally sustainable buildings. Efficient use of thermal mass is a design choice that gives an effective basis for cooling the building.
The TermoDeck principle is relatively simple, but its impact is far-reaching. 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 exits 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 extensive 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. With climate change in mind, the energy demand for cooling is set to increase during a time when we will see major changes and volatility within oil and gas markets.
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 significantly reducing running costs by up to 46% compared with buildings utilising traditional methods.
But, arguably, the biggest benefit for occupants of the buildings is the provision of good-quality indoor air, particularly in premises that require its users to sustain high levels of concentration such as in 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 not to be effective. Whilst this was perceived as a low cost ventilation option, the variability in factors such as outdoor temperature and wind pressures make this an inadequate solution. And in many cases, opening the window may 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 the Building Regulations have exacerbated the problem in newer buildings. A reduction in draughts, coupled with greater insulation, has reduced the ability of buildings to circulate naturally ventilated air.
Since the UK’s first TermoDeck installation in 1993, over 400 buildings worldwide have benefited from this unique thermal mass system, many of which have since been cited amongst the UK’s finest examples of sustainable development. One example is the award-winning Elizabeth Fry Building at the University of East Anglia, which, since the first installation of TermoDeck back in 1994, is about to see the sixth installation of TermoDeck at the campus.
These buildings are well equipped to deal effectively with the predicted gradual rise in ambient temperatures. Thanks to TermoDeck’s use of thermal mass, 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
