Opportunities for financing sustainable development using complementary local currencies
Financing building retrofit projects that contribute to climate change mitigation has always represented a significant barrier. With 28% of global emissions coming from existing buildings, it is of paramount importance to carry out retrofit measures that lead to significant reduction of these emissions. Whilst this is perfectly possible to achieve with current methods and current technology, there is no sufficient conventional finance to carry out zero carbon retrofit at scale required for climate change mitigation. The article introduces an alternative and sustainable business model that creates new opportunities for financing zero carbon retrofit of buildings. It demonstrates that the value of solar energy falling on roofs of buildings can become a driver for new local economic systems, and discusses the requirements for practical application.
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Improving Building Energy Efficiency through Measurement of Building Physics Properties Using Dynamic Heating Tests
Buildings contribute to nearly 30% of global carbon dioxide emissions, making a significant impact on climate change. Despite advanced design methods, such as those based on dynamic simulation tools, a significant discrepancy exists between designed and actual performance. This so-called performance gap occurs as a result of many factors, including the discrepancies between theoretical properties of building materials and properties of the same materials in buildings in use, reflected in the physics properties of the entire building. There are several different ways in which building physics properties and the underlying properties of materials can be established: a co-heating test, which measures the overall heat loss coefficient of the building; a dynamic heating test, which, in addition to the overall heat loss coefficient, also measures the effective thermal capacitance and the time constant of the building; and a simulation of the dynamic heating test with a calibrated simulation model, which establishes the same three properties in a non-disruptive way in comparison with the actual physical tests. This article introduces a method of measuring building physics properties through actual and simulated dynamic heating tests. It gives insights into the properties of building materials in use and it documents significant discrepancies between theoretical and measured properties. It introduces a quality assurance method for building construction and retrofit projects, and it explains the application of results on energy efficiency improvements in building design and control. It calls for re-examination of material properties data and for increased safety margins in order to make significant improvements in building energy efficiency.
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Lessons learnt from design, off-site construction and performance analysis of deep energy retrofit of residential buildings
The article introduces the process of deep energy retrofit carried out on a residential building in the UK, using a ‘TCosy’ approach in which the existing building is completely surrounded by a new thermal envelope. It reports on the entire process, from establishing the characteristics of the existing building, carrying out design simulations, documenting the off- site manufacture and on-site installation, and carrying out instrumental monitoring, occupant studies and performance evaluation. Multi-objective optimisation is used throughout the process, for establishing the characteristics of the building before the retrofit, conducting the design simulations, and evaluating the success of the completed retrofit. Building physics parameters before and after retrofit are evaluated in an innovative way through simulation of dynamic heating tests with calibrated models, and the method can be used as quality control measure in future retrofit programmes. New insights are provided into retrofit economics in the context of occupants’ health and wellbeing improvements. The wide scope of the lessons learnt can be instrumental in the creation of continuing professional development programmes, university courses, and public education that raises awareness and demand. These lessons can also be valuable for development of new funding schemes that address the outstanding challenges and the need for updating technical reference material, informing policy and building regulations.
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Modelling Computational Fluid Dynamics with Swarm Behaviour
The paper looks at replacing the current top-down approach to modelling, predominantly used in dynamic simulation tools, with a nature inspired bottom-up approach based on principles of swarming. Computational fluid dynamics (CFD) is chosen for this research, as one of the most time-consuming processes under the traditional simulation approach. Generally based on Navier-Stokes simultaneous differential equations, CFD requires considerable user preparation time and considerable CPU execution time. The main reason is that the top-down equations represent the system as a whole and generate a large solution space, requiring a solver to find a solution. However, air and building materials do not have cognitive capabilities to solve systems of equations in order to ‘know’ how to transfer heat. Instead, heat transfer occurs through proximity interaction between molecules, leading to self-organised behaviour that is much faster than the behaviour modelled by the top-down systems of equations. The paper investigates how the bottom-up approach using the principles of swarming could improve the speed and interactivity of CFD simulation.
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Designing Resilience of the Built Environment to Extreme Weather Events
Built environment comprises of a multitude of complex networks of buildings and processes in and between buildings. The paper looks at resilience design on three different levels: the building, the site, and the region. The building resilience design is studied using multi-objective optimization of a recently completed Passivhaus retrofit, under four different climate years: current, 2030, 2050, and 2080. The site resilience design is studied on the basis of a balance between incoming solar radiation and evaporative cooling from transpiration of plants to mitigate heat island effect. The regional resilience design is studied using a network model, taking into account connectivity, information capacity, and the ability to reconfigure. A common denominator found between these three aspects is a degree of system redundancy. Thus, a provision for adaptable building thermal insulation, a provision for adaptable green areas, and a provision for adaptable connectivity are the ingredients for resilient designs on these three respective levels. The findings increase our understanding of practical issues and implications for the resilience design of the built environment under extreme weather events. A combination of qualitative and quantitative approaches discussed in the paper provides practical guidance for designers and policy makers.
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Reducing simulation performance gap in hemp-lime buildings using fourier filtering
Abstract: Mainstream dynamic simulation tools used by designers do not have a built-in capability to accurately simulate the effect of hemp-lime on building temperature and relative humidity. Due to the specific structure of hemp-lime, heat travels via a maze of solid branches whilst the capillary tubes absorb and release moisture. The resultant heat and moisture transfer cannot be fully represented in mainstream simulation tools, causing a significant performance gap between the simulation and the actual performance. The author has developed an analysis method, based on a numerical procedure for digital signal filtering using Fourier series. The paper develops and experimentally validates transfer functions that enhance simulation results and enable accurate representation of behaviour of buildings built from hemp-lime material using the results of a post-occupancy research project. As a performance gap between design simulation and actual buildings occurs in relation to all buildings, this method has a wider scope of application in reducing the performance gap.
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