The international Energy Agency has cited energy efficiency criteria in construction codes as the most effective way of curbing carbon emissions1. Many feel that new and better ways to build structures which will be less taxing on the environment must be developed in response to the new environmental and societal challenges we are facing. The major factors reducing a Binishells’ environmental impact both in terms of life-cycle footprint and embodied energy are listed below. The video below summarizes the information following.
a) Thermal Bridging:
The primary reason for Binishells’ life-cycle energy efficiency relative to traditional construction is their thermal bridge-free building envelope. Heating and cooling drains known as thermal bridges result whenever materials with different resistance to heat flow are assembled in traditional building envelopes. Thermal bridges equate to significant losses in heating and cooling loads. This in turn places greater demands on the mechanical systems, expending greater amounts of resources to maintain constant temperatures. Heating and cooling represents the single biggest expenditure in energy for residences (amounting to a total of 48% of total energy used by households in the U.S.2). As is shown in the image below, testing by the International Energy Agency show that energy use may be reduced by 87% when thermal bridges are eliminated3.
Binishells are monolithic concrete domes. Their building envelopes are made up of a single material with consistent depth (no connections and consistent resistance to heat flow throughout). When such an envelope is insulated appropriately, energy efficiency is optimized, even in extreme climates. Thermal bridges occur only wherever openings such as doors and windows are required. Such openings are of course necessary in any building, but their impact can be effectively mitigated by using appropriate specifications, details and materials which are readily available in the market. Binishells can therefore be easily designed to provide high performance building envelopes at affordable costs.
Fig 6. difference in energy consumption when thermal bridging is eliminated
b) Resources used:
Binishells require far fewer material resources. This is primarily due to their shape. The inherent strength of their structural system means wall thickness may be reduced. Overall, Binishells require about 50% of the materials employed by conventional structures of similar volume for their exterior envelope. The comparatively little material that is used can also be more environmental. Substituting Portland Cement with fly-ash not only creates further efficiencies in the performance of the building envelope
but also re-purposes an undesirable industrial waste product, resulting in carbon credits. Furthermore, low calcium fly-ash based geopolymer concrete is comprised 78-80% of aggregates which can themselves be recycled concrete or other waste products. Substituting steel for other reinforcing fibers can reduce embodied footprints in reinforced concrete. All in all by comparison Binishells may contain 50% or less in terms of embodied energy or CO2 of a traditional home of similar size.
c) On-site waste:
Binishells can minimize on-site waste. This is because their building envelope are made entirely of reinforced concrete, which unlike sheet or linear materials such as metals, gypsum board or wood is not cut on site. On site cutting and package bundling, which inevitably produce waste, are almost entirely avoided with Binishells. Binishells therefore use less material, use it far more efficiently and produce little or no waste. Even the pneumoform, if cared for properly, may be re-used 50 to 100 times.[/one_half]
d) Life-Cycle Flexibility:
Binishells interiors are free of structural columns and bearing walls. Their open plan enables them to be used and re-purposed for a variety of different uses during their life-cycle. Due to their high-performance building envelope, Binishells also lend themselves to applications in a wide variety of climactic zones including, arid, semi-temperate, temperate, tropical, and polar climates.
1 European Union, Green Paper of 29 November 2000, “Towards a European strategy for the security of energy supply”
2 US Energy Information Administration, AEO2014 Early Release Overview
3 Global Strategy for Energy Efficient Buildings for G8. IEA & RESNET Roundtable on G8 Policy on Energy Efficiency. ASE Washington, 3/13/08. International Energy Agency IEA Jens Lausten Senior Policy Analyst (Buildings)