P5 M3: Sustainable Construction Techniques
Sustainability in construction is a concept that embraces the preservation of the environment we live in today, as well as the continuing development, economic growth and efficient use of resources. Adopting a sustainable approach throughout the construction industry will increase the balance between the natural and built environment, in turn shaping a sustainable future. Over half of the world’s population live in urban environments, making it evident that social, economic and environmental viability must be secured. Transferable and innovative progress is essential in the development of disciplines involving architecture, design and engineering. The life cycle of construction projects should have minimal negative effect on the environment and should aim to emphasise use of the renewable energy and reduce the carbon footprint.
Sustainable construction techniques can be based on energy, materials or waste. Different techniques have varied performances and cost. Most sustainable techniques have the highest performance and lower costs. Sustainable construction techniques must be fit for purpose.
Sustainable construction techniques that are energy based involve using renewable energy resources, reducing energy consumption and improving energy efficiency. Renewable energy is generated by using natural sources such as geothermal energy from the ground or sunlight. It is important to use renewable energy because it provides benefits including the low impact on the environment, will no run out, and provides security on energy resources.
Solar panels are largely invested in as a domestic and commercial way of utilising the energy from the sun. Solar PV uses semi-conductor (usually silicon) technology that converts the energy from the sun into the usable electricity. In order to perform, solar PV doesn’t require direct sunlight meaning electricity is produced all year. In recent years more efficient systems are the result of improvements in technology making the payback time shorter and solar PV a more economically beneficial investment. Environmentally, photovoltaics are clean as they do not produce CO2: they do not cause any threats to biodiversity and are increasingly efficient.
Sustainable construction techniques that are materials based, develop from the specification of renewable materials and the cost of manufacture on the environment. Low energy manufacture decreases the embodied energy of a material making it more sustainable. The embodied energy of materials refers to the energy expenditure of the complete process from sourcing, manufacturing, transporting and installing.
Using renewable, low embodied energy materials for the building envelope can be a highly sustainable technique of effectively utilising natural light and ventilation. Ways in which the building envelope can increase sustainability:
Optimizing energy use throughout a building is done by designing the envelope to perform and adapt throughout climatic changes without compromising energy expenditure. Incorporating good thermal insulation and high performance glazing techniques will ensure benefits over the buildings lifecycle.
The use of “green” building materials is an important strategy in modern construction. For building materials to be classified as “green”, it should be efficiently sourced, locally available to reduce carbon emissions, durable design and material, refurbished material, recyclable or in some cases reusable and if packaging is required, that must also be recyclable.
Biomass heating systems uses waste biological material for fuel to generate heat more efficiently. Plants absorb carbon in the form of CO2 from the atmosphere as they grow. Burning biomass is a closed carbon cycle because the amount of CO2 returned when burning is equal to the amount that was absorbed. This doesn’t increase CO2 levels as it is over a short time period. O the other hand, burning fossil fuels does increase the levels of CO2 because the carbon was locked up millions of years ago and is just recently being released.
Biomass is a very efficient technique that provides a powerful heat source, which is cheaper to run than using electricity reducing energy cost as well as being environmentally friendly. The diagram opposite compares the typical cost of using fuel for heat by the pence per Kwh. Using biomass fuels such as logs and chips is significantly lower than the cost of electricity. Renewable Heat Incentives (RHI) from the UK government reward those who chose to use renewable biomass energy increasing the economic benefits further. The demand for biomass fuel has resulted in better management of woodlands. The thinning of woodlands increases the amount of sunlight that reaches the woodland floor, increasing the amount of life and biodiversity. Naturally, strong winds and activity leads to broken branches and material being left to rot however good management allows this material to be collected and used in the production of biomass fuel.
Although each technique has sustainable qualities, some outperform others where as some are better economically. Biomass uses carbon neutral fuel, influences management of woodlands and has economic incentives however the is still lifetime costs to the environment. The need for a suitable storage system for the biomass fuel and the transfer machinery for the system to work. This can be an expensive sum before the techniques pays back. Also, CO2 emissions from the transportation of biomass fuel on a regular basis throughout its lifecycle are still contributing to the atmosphere.
Solar PV requires the least amount of maintenance, does not generate any noise pollution and is renewable. The flexibility of size and moderate aesthetics is also appealing. However, the manufacture of the solar PV is very costly in comparison to biomass with the pound per unit being £4200-4800 and biomass just £200-600. Harmful toxins are also produced in the production of the PV panels.
The benefits of using “green” building materials as a sustainable construction technique include the lack of maintenance needed throughout the lifecycle and the upkeep costing compared to solar PV and biomass. A more sustainable material might come in at a fractionally larger cost however, little maintenance and replacement of materials throughout the lifecycle means the overall cost is reduced. The higher quality, more efficient and sustainable materials result in a more efficient building with reduced energy consumption and improved standard of occupant’s health and the functionality of the building. The benefits of designing a durable and efficient building envelope has the most potential CO2 savings and the biggest impact on reducing energy bills.
In my opinion, incorporating high performance and sustainable strategies that reflect the full life cycle of the building that reach above the general elements that we associate with the building envelope, will increase sustainable design and construction universally. With limited budgets for construction projects, it is important to ensure a building is designed with a balance between security, architecturally innovative design and energy efficiency.