Thermal Mass – Cool Solution for Schools
With mounting legislation, an increased need to build more energy efficient schools and rising energy prices, heating and ventilation engineers are adopting new and innovative technologies. Many schools now have a requirement for heating and ventilation systems that not only deliver optimum performance but also offer significantly reduced environmental impact. Geoff Russell-Smith of Tarmac TermoDeck discusses why thermal mass should be firmly on the radar when it comes to installing an environmentally friendly solution.
PFI and PPP initiatives coupled with the Government’s Building Schools for the Future programme have seen an increase in school construction schemes. But building a new school today presents a number of challenges that simply weren’t issues 20 years ago. For example, selecting a cooling and ventilation system that is able to cope with the climate change predicted over the next 80 years is by far the biggest factor facing engineers. It is likely that climate change will lead to the UK seeing higher average temperatures, and yet legislation to combat global warming requires that less energy should be used to keep buildings comfortable. And with multi-million pound investments being poured into schools up and down the country, a new school must also offer the local authority the benefits of a long-term low energy and low-maintenance solution.
While there are a vast number of options available to schools including natural and mechanical ventilation, each solution has its own unique benefits and problems. But perhaps the greatest challenge is being able to provide adequate ventilation, without losing energy within the building or incurring high running and maintenance costs.
The TermoDeck system utilises the high thermal mass of concrete to increase the efficiency of heating and cooling a building, and combines this with a fresh air ventilation system to offer an exceptionally effective way of maintaining stable temperatures. The concrete is able to absorb heat from the occupied space in a building and act as a thermal store. Fresh air is passed through standard concrete hollowcore slabs, which form the floors and ceilings of the building. The fresh air within these slabs is either heated or cooled by the concrete and then delivered to the internal space, offering a comfortable environment for occupants. This approach is being increasingly adopted as the sustainable, low energy solution and an environmentally sound alternative to air conditioning and other mechanical ventilation systems.
Recent research from the consultants Arup conducted for the Concrete Centre highlighted the useful role of concrete's thermal mass in reducing internal temperatures in housing. The research compared lightweight, and heavyweight structures and the cooling effect of thermal mass. It showed that the heavyweight structure would be better able to cope with expected rises in summertime temperatures.
"The findings of the research apply equally to other building types," said Andrew Minson from the Concrete Centre. "Schools that are being built or improved as part of the Government's £40 billion Building Schools for the Future programme need to take full account of the impact of higher summer temperatures upon school life. Utilisation of the thermal mass potential of concrete should provide a more comfortable teaching and learning environment without the need for excessive air conditioning".
For schools, the TermoDeck system not only offers extensive energy saving benefits but also a host of advantages for building managers and end-users, primarily focused around its ability to provide superior indoor air quality.
The good old days of opening a few windows to increase air circulation in a classroom is now known to be ineffective. Whilst this was perceived as a low cost natural ventilation option, the variability of factors such as outdoor temperature and wind pressures can lead to some areas being draughty whilst other areas of the building do not receive adequate ventilation. In many cases opening the window may lead to additional problems such as noise or pollutants entering the classroom.
Insufficient supplies of fresh air can lead not only to health problems, as we have seen with sick office syndrome in the workplace, but reduces the ability of students and teachers to concentrate. According to a recent BRE report, figures indicate that in many schools across the UK, air quality remains consistently below acceptable standards. Ironically, the changes in the Building Regulations have exacerbated this problem in newer buildings. A reduction in air leakage, coupled with higher levels of insulation, has reduced the ability of fresh air to be naturally circulated within a building.
If the expenditure of each of these systems is taken into account, then natural ventilation is often regarded as offering the most cost-effective building solution. However, this can be misleading – especially when the lifetime costs of a building are taken into account.
Jersey’s Hautlieu School is a fantastic example of a school that has had thermal mass “designed in” as an active component using TermoDeck. . Hautlieu benefits from using TermoDeck for heating, cooling and ventilation system which is helping to reduce carbon dioxide emissions and overall energy consumption by exploiting the thermal mass of the building’s core.
Hautlieu is not alone in terms of the innovations that it has achieved. There are a number of educational establishments across the UK adopting similar ways of combining an effective learning environment alongside an energy efficient solution. As far back as 1994, De Montfort University in Leicester was enjoying the benefits of TermoDeck and more recently the system has been installed at the Manchester Interdisciplinary Biocentre and the University of East Anglia in Norwich.
There are many more educational establishments that can benefit from green innovations, but it is vital that heating and ventilation engineers working on new build projects understand how thermal mass technology can become the very fabric of a sustainable building.
4 December 2007
