Yes I must confess that I am obsessed this "Net-Zero Energy Buildings". And I know that I have written articles on this subject before but I am worry, very worry, because I just have no idea on how on earth we architects are suppose to design building with zero renewable energy consumption buildings by the year 2020. Yes you read correctly, buildings that should not use any none renewable energy in six years time. Just round the corner.
We all know that our cities consume enormous quantities of energy, with the heating and cooling of buildings accounting for more than 41% of total demand in Europe alone. This means buildings have a dramatic negative global environmental impact, which is unsustainable, given the world’s predominant reliance on fossil fuels and their rapidly increasing costs. We accept that, but legislating in the limbo and not providing sufficient knowledge to us architects on how we are suppose to carry out is a bit risky to say the least.
It is clear that making buildings more energy efficient is essential, especially given the ever more stringent energy efficiency codes and building regulations, but it is also a sound business investment that benefits both owners and occupiers. Although there are new advances in building technology, in theory, it is very different to put it into practise.
We do know that energy efficient buildings are cheaper to run as well as they offer an attractive return on investment (ROI) for property owners, investors and tenants. Additional economic benefits for the property sector include higher rental income, maximisation of tenancy occupancy levels and future proofing property asset values.
This makes a compelling case for energy efficient buildings, especially when it does not impinge on their aesthetics, their functionality or the comfort level of those inside. Creating striking looking buildings that are Net-Zero Energy at the same time seems to be the ideal solution for everyone concerned with modern cities.
Is it possible?
Well all the above it is very well but a Net-Zero Energy Building is a building where, as a result of its very high level of energy efficiency, provision of on-site renewable energy systems and additional off-site measures, its overall annual primary energy consumption is equalled or exceeded by energy production related to renewable energy sources. Meaning that the energy that the building devour must be produced by the building itself...No more no less!!
Beyond the obvious environmental benefits of Net-Zero Energy (NZEBs), they also offer reduced energy bills, increased building value, controlled costs and even energy security, with less reliance on variable, insecure sources.
The superior energy efficient and sustainable buildings that we are suppose to design must be buildings with cost optimal solutions, low energy and operating costs (towards Net-Zero Energy).
To achieve affordable NZEBs, a whole building life cycle cost assessment needs to be carried out. This will take into account the construction’s capital cost, the costs of energy, maintenance and plant replacement throughout the building’s life, and the income from energy generated by on-site low or zero carbon technologies.
We should use a clearly defined method, divided into three steps.
The first step should take care of the shell of the building optimising the insulation and air tightness performance of the building envelope for its intended life, to at least comply with building codes, while also ensuring the building’s services are geared to energy efficient operation. It is of the utmost importance that the building envelope is appropriate before embarking on other energy efficient measures. The envelope must offer thermal performance suitable to the local climate.
But it is not just the building envelope that must be considered at this stage, it is important to take a comprehensive approach to energy efficiency. Important elements such as a building’s day-lighting design must always be carefully considered, taking location and climate into account. Sun light can be incorporated into building designs to further reduce energy consumption, by reducing the need for electric lighting. Energy efficient internal building services with intelligent controls must also be included at this stage.
Special building insulated panels and solutions provide enhanced thermal conductivity with low air permeability to ensure thermal performance robustness throughout the building’s life cycle must be thought of. That will include the roof, wall and façade. All products and solutions used must ensure low energy consumption as well as initial capital outlays for heating and cooling plant systems.
With the building envelope correctly specified and optimal building services incorporated into the design, the second step must be the generation of energy. At this stage, additional enhancements to the building fabric must be introduced and renewable energy systems must be added to further reduce its overall energy footprint. Low or zero carbon technologies are perfectly suited to help reduce energy bills.
Likewise, a thermal air heating system that channels passive solar heat gain into the heating system is perfectly suited for buildings with fresh air requirements. Other buildings may require different solutions, including solar thermal, wind and even heat pump technologies, all of which are available now.