11 April 2018

Real world “E+C–”

An appraisal conducted by Qualitel provides concrete feedback from two test housing operations on the leads than can be followed to optimize energy and carbon performance levels. An interesting enlightenment one year after the E+C– (positive energy, reduced carbon) label was launched.

The E+C– label, a government initiative launched at the end of 2016, anticipates the planned 2020 environmental regulations. It sets out to promote the construction of buildings with high energy performance (positive energy buildings) AND a minimal environmental footprint (low greenhouse gas emissions throughout the whole of the building’s lifecycle). This requirement stems from the nature of buildings as huge energy sinks and a significant source of GHG emissions (over 20%).

Tests and calculations

QUALITEL has assessed the impact of this E+C–* label on building design and identified energy solutions that would enable its various levels to be met. Three design offices have trialled the implementation of the label’s requirements in two housing operations. Overall, results common to all three drawing offices show that in the current state of design, levels of E2 C1* can be achieved.

The interest lay in identifying energy solutions that help optimize these levels: gas, electricity, collective heating, wood, etc.  Work was also carried out on the initial building envelope, with improvements in wall and floor insulation, solar protection, and draughtproofing. The combinations used enabled the higher energy and carbon ratings to be achieved and several interesting lessons to be learnt.

For the energy indicator :

  • with a gas system, level E3 can be attained by improving the envelope and adding photovoltaic (PV) panels
  • With an electrical system coupled with thermodynamic water heating, level E1 can be attained but only by improving the envelope and adding PV capacity
  • with collective heating (town mains using 72% renewable energy) and wood energy, level E3 can be attained without work on the envelope or adding PV capacity
  • There were no solutions enabling level E4 to be reached

For the carbon indicator

  • The Wood Energy solution is advantageous and enables level C2 to be attained for buildings designed with mixed wood-concrete structures
  • Gas solutions are disadvantageous in the operating phase of the lifecycle as they burn more carbon than electrical solutions
  • Electrical solutions depend on the installation of PV panels, which have a high carbon footprint

Today, the first E+C– buildings are rising from the ground. A year after initiating trials, the E+C– experiment watchdog keeps track of over 80 buildings, accounting for over 500 homes. This will become a database used to cast light on construction methods and energy choices. But, as the Qualitel Association’s chairman Bertrand Delcambre is quick to point out, this label dictates a radical change in the way of going about things, especially on the carbon side:

Exploring  eco-design and project optimization avenues is a must: the choice of architectural forms and construction systems to reduce the quantity of materials used or lengthen their lifespan, the choice of less carbon-rich products and energy sources, more accurate sizing of technical installations, a greater range of recycling/reuse possibilities, or even simply getting more use out of buildings.

The pathways to innovation are open.

* The label “E+C–” defines ratings of 1 to 4 in Energy and 1 or 2 in Carbon, making 8 possible combinations.

Source : Qualité logement, Cohésion territoires, Rt bâtiment

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