It is a shy but promising initiative undertaken by the France in the EcoBatiment. After the first Foundation recently launched on the subject, the Government part of its climate plan a "prebat" plan for next year (read box). It is a very modest response on the issue: 20 of greenhouse gas emissions are attributed to consumption of buildings. If heat requirements tend to naturally reduce, power consumption is rather in full progress because of the multiplication of household appliances and air conditioning. "Rising to the challenge of climate change, we can't answer that breaks", launches Alain Maugard, the President of the scientific and technical building Centre (CSTB) and the instigator of this research.
Specialists offer to prepare two generations of building these next few decades. The first begins to lower their consumption to 40 kWh/m2 around six times greater heat insulation combined with a reduction by 2.5 power. Its generalization would not happen until twenty-five years, but many technologies are already available. They could be applied to existing infrastructure, via retrofits, but especially to new homes because one third of them in 2050 will be built in the 21st century.
Houses "3 l"
New insulation techniques are emerging. The participation of Arcelor, but producer of steel, the Foundation is precisely explained by technology of insulation that is currently developing the French steelmaker. On the same principle as the double-glazed Windows, two steel blades separated by the vacuum are a curtain wall that can be mounted to dry on the frames of the building.
Other avenues of isolation are possible in wet mounting (concrete) as these mosses of the BASF German who has used a polystyrene sophisticated in its houses "3 l" in Ludwigshafen demonstrators. It is an ironic return in time that propose these buildings based on tens of centimeters thick walls, with for modern stone polymer. Similarly, engineers are reinventing the cob with phase change material to store and render the heat or the cold of the day and night. Except that the technology today to cover ranges of larger temperatures for longer periods of time.
In parallel with the insulation, heat production offers another source of renewable energy, heating economy representing two thirds of consumption of a building. In addition to solar water heaters, a new generation of window glazing triple thicknesses to retrieve more heat from the Sun the day, while bringing a thermal insulation near opaque material.
All "green" building projects rely also on heat pumps. The new generation of these recovery of energy is the interest to achieve a positive return while traditional heating solutions do not exceed 50 efficiency.
Large gains are also feasible in air conditioning. In addition to common sense to correctly orient the buildings, researchers have already developed with little gourmet systems electricity as ventilation hygrothermal circuits. A new generation of air conditioners to gas-fired absorption works already, but at prohibitive cost.
Reduction of power consumption of dwellings and offices through to their various equipments, what remains realistic given the short response time of these industries. Large gains are for example expected to lighting with the advent of light-emitting diodes or the integration of sensors that cut channels in empty rooms. There are however some technology gaps to fill. This is the case of seasonal heat storage for which daily solutions are unsuitable. Longer term, by 2050, the visionaries offer a second generation of buildings that would revolutionize the market attractive concept of positive energy buildings. This system which produces more than it consumes could flourish in the wake of the possible "hydrogen economy" because this energy vector, combined with the fuel cell, would provide an effective solution for storage of electricity.
Alain Maugard defends a liberal approach to motivate the public in this direction. "The opportunity to produce and sell a surplus of electricity would allow each of us to convert a virtuous behavior in positive EDF invoice." One can also imagine financial products that promote these behaviours, such as advantageous mortgages to those who acquire and Ã©cologements. "Remains to motivate all industrialists involved in these issues. For example, Saint-Gobain and Total have shunned the Foundation while they have skills all shown with respectively their glass and their work on renewable energy.