Energy performance objectives

The objectives

Akerra buildings meet the regulatory criteria (e.g. PEB, RT 2020) but are designed to achieve enhanced energy performance objectives.

 

The project characteristics obviously depends on the environmental context. For example, in a dense urban area, the renewable energy potential of the site is often insufficient to reach the global zero energy objective and only the zero thermal energy objective will be retained.

 

The target energy performance level in the technical study will be evaluated using specific performance indicators. Evaluated on a full annual cycle, these metrics serve as a basis for equiment sizing. It should be noted that the real level of performance achieved depends on the climatic conditions as well as the consumption practices of the residents. The performance evaluation will therefore only be valid if carried out at the end of at least twelve months of occupation.

Detailled objectives

The objectives

1 : le Zéro énergie thermique

Zero thermal energy

Projects designed in the long term view
and budget optimized

 

  • The needs of the residence in heat (heating and domestic hot water) and in summer cooling are covered on an annual basis by renewable energy produced locally (solar or air exchanger).
  • Although residents are still responsible for grid connection fees and a significant portion of their electricity consumption, this is the most economically relevant energy performance target. It makes it possible, by taking advantage of the thermal inertia of the building, to maximize the level of self-consumption and thus make the solar panels investments more profitable.

Zero-energy housing does not affect residents’ lifestyles.

The objectives

2 : Zero energy

Zero energy

Projects defined in an ecological approach impacting the habits of consumption.

 

  • The residential needs in heat (heating and domestic hot water) and in summer cooling as well as the electricity consumption for domestic use (lighting, washing machines, entertainment …) are covered, on an annual basis, by the renewable energy produced locally (solar, geothermal, air exchanger …).
  • Although the building is in global energy balance, we will take into account the grid connection costs as well as the electricity consumption from the network. Grid connection remains necessary when the photovoltaic input is not sufficient (typically at night and in winter). This type of project therefore calls for careful management of the different consumptions.

The local electricity production returned to the grid (typically the summer days) is generally poorly redistributed, a project of this type, attractive in terms of ecology and comfort, is not the most financially profitable.

The objectives

3 : Full autonomy

Full energy autonomy

Radical environmentalism

 

  • The needs of the residence in heat (heating and domestic hot water) and in summer cooling as well as the electrical consumption for domestic use (lighting, washing machines, entertainments …) are fully covered for each period of the year by the renewable energy produced locally (solar, geothermal, …).
  • Full energy autonomy projects are very dependent on the site (e.g. old mills having a right of water usage, important collective projects). They are often associated with practices of food autonomy (permaculture) and mobility.

This type of project usually has no economic logic at the individual scale because it leads to over-sized renewable electricity generation systems associated with expensive storage units.