Active-LIVing Envelopes (ALIVE)

The UK Government is committed to reduce greenhouse gas emissions by at least 80% (from the 1990 baseline) by 2050. There is therefore an urgent need for a radical reduction in the UK dependence on fossil fuel based heating in buildings. The vital role of the building envelope in building energy efficiency and thermal comfort has long been recognized, though until recently, all effort and attention has been focused on optimising the insulation and envelope components. It has become evident that new and more innovative ideas and technologies are needed to improve the energy efficiency of existing envelopes. The benefits from such innovative technologies are of extreme importance as the building envelope plays a major role in the energy flow in and out of buildings. The building envelope also offers significant opportunities to exploit solar energy through integrating solar thermal technologies into the buildings.

Many different approaches have been adopted to reduce energy consumption in the built environment, including insulation, on-site renewable energy generation and storage. The active generation of energy from building integrated structures has been largely confined to a few countries. Research has shown the potential for active generation of solar thermal energy and its integration into the built environment, but this approach is not widely accepted in industry due to complexity, design criteria and high initial cost.

This project develops previous theoretical work on responsive building envelopes by Dr. Shukla, PI of the proposed project. The proposed design incorporates many novel features, and its in-lab performance will be tested and evaluated. The basis of the proposed envelope system utilises a perforated metal profile attached to the exterior of a building, and an underlying layer of heat storage material separated by an air gap. Initial research and simulation suggests that total energy savings in the range of 30-50% can be achieved, depending upon the type of building and set point temperature used in UK buildings. The proposed design operates close to ambient temperature, thus using solar and ambient energy to warm and cool the building envelope more efficiently by minimising losses. The design of the perforated metal profile will provide enough buoyancy force through a temperature gradient across the metal profile to move air through correctly positioned gaps at a very low velocity and so maximise the benefits of the system. For the required heat transfer between air and heated boundary layer of ALIVE, it is vital that the approach air velocity is low. This will also provide enough time for the PCM to store surplus energy that can be released to heat or cool the building as required. The heated boundary layer across the building envelope will also help in minimising heat loss from the building envelope. The proposed building envelope has the potential to significantly reduce the thickness of insulation used in buildings.

This project has been developed by the PI after discussion with industry partners working in the area of sustainable building envelope design, active generation of energy from building integrated structures and potential users of the proposed technology that includes housing organisations. The proposed research project will consist of three main elements; numerical simulations and mathematical modelling, indoor testing and electrical simulations to determine optimum performance of the system and environmental and economic assessment of the technology. The use of PCM in the envelope design will also be investigated to determine how the introduction of this material affects heat transfer between the building envelope and the micro-climate created around the building. The project will include a detailed analysis of the proposed system through lab testing, numerical simulation and mathematical modelling to evaluate the performance of the system.

This research project has multiple impacts broken down into environmental, social and economic impacts and summarized below:

Environmental
The "Climate Change Act 2008" has set a target of 80% reduction in CO2 emissions in the UK (relative to 1990 emissions) to be achieved by 2050. Managing the transition to a low carbon economy is a major challenge, and the built environment has to make significant energy efficiency gains combined with a shift to non-fossil fuel based energy sources. The built environment is a significant contributor to CO2 emissions and energy consumption. The UK building stock contributes around 40% of all UK carbon emissions. The ALIVE project has the potential to reduce space heating and cooling energy demands by approximately 30-50% irrespective of building types. This project will determine the credibility of this proposition. If feasible, this reduction will directly impact on greenhouse gas emissions arising from buildings. The premise of the ALIVE project to utilise solar energy and passive ventilation to heat and cool buildings is a timely and very novel solution to reduce CO2 emissions in all types of domestic and non-domestic buildings.

Social
The proposed project exhibits social gains as well as environmental benefits. The ALIVE approach can provide high levels of thermal comfort and improved interior air quality, a problem often associated with other energy reduction strategies. These will contribute to improved quality of life for building occupants. The project will further benefit them by reducing their energy bills.

Economic
The future energy supply challenge is one of the biggest concerns faced by the UK today. In an uncertain world, it is prudent to ensure a resilient energy supply, given the exposure to uncertain imports, volatile markets and climate change. More immediately, consumers are facing ever increasing energy bills.
The proposed research project will lead to reduced energy consumption and provide practical solutions for improved building fabric lifespan as ALIVE will decrease the possibility of condensation and decay in building fabric. Sustainability is a major factor in all construction projects largely due to legislation. Contractors benefit from being seen to be 'green' in addition to being socially and environmentally aware businesses. Construction companies and builders, under tremendous pressure from government policies to deliver energy efficient and high performance buildings, will benefit from this research, and be able to develop and implement this novel technology, gaining competitive advantage. The research will provide to local housing agencies, community and social housing authorities a new low cost method for wider application in any type of building without any extra cost.


Project will also impact on project partners e.g. Sustainable Building Envelope Centre (SBEC), TATA Steel, to further understand use of steel on building envelopes and will impact their industrial and economic wellbeing. Phase Change Material Products Limited, will be impacted on findings to use PCM on building envelope design followed by positive impact on other project partners. Findings from the project will also be very important to academia and researcher and will impact on research work going on in the design of sustainable building envelopes.