By Michael Lauring and Rob Marsh
INTENT AND PURPOSE.
The paper aims to further integrated design of low energy buildings with high architectural quality.
A precondition for qualified integrated design is a holistic approach that on the technical side covers all sorts of energy used to construct, run and use modern buildings, and on the humane side includes functional, social and aesthetic aspects of modern living.
The paper shows how qualified integrated design up till now has not been achieved. It shows how a narrow focus on the solution of sub-problems may result in big problems elsewhere in the complex system of designing buildings. The paper concludes that future ambitious low energy building strategies cannot focus only on heat consumption but must include a stronger focus on the use of electricity for non-heating purposes and on the related architectural aspects: Building depths, spatial organization, daylight, natural ventilation and solar cells.
In order to get a truer, well-focused perception of how to design sustainable buildings, one needs to know basically what is more and what is less important among all the energy-related environmental issues. One of the main purposes of the paper is therefore to provide some sense of essentiality.
The paper deals with Danish conditions which may differ from those of other countries when it comes to climate, natural resources, patterns of settlement, building traditions, education of builders, energy supplies and ways of living and working, just to mention some of the most important determinants. However, it can be assumed that many of these factors will be similar in countries in northern Europe with a maritime climate and an effective regulation of heat consumption in new buildings, and where the transition from an industrial to an information- or knowledge-based society is well-developed.
The last three decades of the 20th century show many conscientious - both governmental and architectural - Danish attempts at creating buildings with lower heat consumption. The lower U-values of the building envelope have had markedly good effects, but the regulation of window-area, sun and light has in general failed both regarding indoor climate and energy consumption. And the positive effects of big glass facades have been largely overrated.
In the Building Regulations of 2008, the rules concerning energy have been changed profoundly according to the EU-directive on the energy performance of buildings. The rules take their starting point in two premises: To assess the whole and the primary energy consumption. Included is the needed energy for heating, cooling, hot water, lighting (not in dwellings), building services (like pumps and ventilation) and the system losses (heat loss from internal plant, pipe work etc). On the other hand building integrated energy production from solar heat and solar cells is included in the assessment. For calculated overheating going over 26 degrees, the electricity for running a standard cooling system to eliminate the overheating must be included in the assessment.
As the above shows, much attention has to be paid to non-heating purposes. The question is whether the focus is now broad enough? Another question is what will happen in the light (and heat) of global climate changes: In what way will they change the focus and the needed strategies?
If we take a look at the current primary energy consumption in typical new terraced houses, heating stands for 23% while hot water is 12%, cooling 11%, building services 8%, lighting 7% and appliances are 39%. All in all heat purposes are 35% while electricity covers 65%. Out of the consumptions the current Building Regulations cover 54%, but not the last 46% (lighting and appliances). These tendencies are more radical when it comes to offices. The figures for typical new offices are that heating stands for 16%, hot water is 5%, cooling is 10%, building services are 6%, lighting is 9% and appliances are 53%. All in all heat purposes are 21%, while electricity covers 79%. Out of the consumptions the Building Regulations cover 47%, but not the last 53% (appliances). All together this calls for a much broader focus with stronger emphasis on electricity.
A recent publication combines the above mentioned current consumptions with future climate changes. In the calculations the temperatures are set to rise (compared to 2010) with 0,5 degrees in 2020, 1,4 in 2050 and 2,7 degrees in 2085, which is in the lower end of IPCC's estimation of average global temperatures expected to rise between 1 and 6 degrees in the 21st century. The calculations show that the primary energy for cooling may rise approximately 40%, while heating may drop 30%. Inside the next 25 years consumption related to cooling may exceed consumption related to heating in dwellings built according the current regulations. In a typical new office cooling may rise 40% while heating may drop 15%. All ready now, the cooling consumption is often bigger than the heat consumption.
These calculations indicate that climate scenarios should be integrated as part of the regulative and designing process to quantify the effect of cooling-reducing strategies. They also indicates that passive design strategies should be combined with active strategies to control overheating, strategies such as daylight regulation, sun shielding, controlled natural ventilation and thermal mass.
The figures strengthen the viewpoint that light buildings are preferable to deep and darker buildings both from an architectural and a low energy perspective, an viewpoint that is further substantiated in the paper.
|Title of host publication||Joint Actions on Climate Change : Conference Proceedings|
|Editors||R. D. Andersen, M. Lehmann|
|Publisher||Institut for Samfundsudvikling og Planlægning, Aalborg Universitet|
|Publication status||Published - 2009|
|Event||Joint Actions on Climate Change - Aalborg, Denmark|
Duration: 8 Jun 2009 → 10 Jun 2009
|Conference||Joint Actions on Climate Change|
|Period||08/06/2009 → 10/06/2009|