Regulations and robust low-carbon buildings

Building regulations and associated calculation methods have been rapidly evolving, driven in Europe by the European Union Energy Performance of Buildings Directive. As an example, the current UK regulations are explored in relation to buildings that are naturally ventilated, mechanically ventilated, or mechanically ventilated and cooled. The UK regulatory energy and carbon calculation methods are investigated using a standard office design with typical, best practice, and advanced building fabric and systems applied. The criteria and calculations for demonstrating avoidance of excessive temperatures in buildings that have no mechanical cooling are also explored. Observations are made on how the regulations may influence future adoption of mechanical cooling. Current regulatory methods can be subjective and limited in scope. For example, they do not include adaptive comfort criteria or uncertainties in parameters such as occupant behaviour, climate, internal gains from equipment, etc. A design methodology is proposed that addresses these issues and provides a capability parameter to quantify robustness. This capability parameter allows comparison of design options and provides an indication to building users of the limitations to a building's use beyond which mitigating action would have to be taken for performance to be maintained

Simulation and BIM in building design, commissioning and operation: a comparison with the microelectronics industry

Analogy between the Microelectronics and Building industries is explored with the focus on design, commissioning and operation processes. Some issues found in the realisation of low energy buildings are highlighted and techniques gleaned from microelectronics proposed as possible solutions. Opportunities identified include: adoption of a more integrated process, use of standard cells, inclusion of controls and operational code in the design, generation of building commissioning tests from simulation, generation of building operational control code (including self-test) from simulation, inclusion of variation and uncertainties in the design process, use of quality processes such as indices to represent design robustness and formal continuous improvement methods. The possible integration of these techniques within a building information model (BIM) flow is discussed and some examples of enabling technologies given

Thermal mass, insulation and ventilation in sustainable housing - An investigation across climate and occupancy

Sustainable housing standards are reviewed including the UK 2005 building regulations, the UK Advanced Standard and EU Passive-house Standard. Conflicts between the standards are highlighted. The significance of insulation, orientation, ventilation, thermal mass, occupancy, gains, shading and climate on predicted energy performance is illustrated. An ESP-r model is then used to investigate these factors across a range of climates and occupancy / gains scenarios. The investigation covers both heating and cooling energy requirements. The relative importance of key factors is quantified and a matrix of results presented with conclusions. The role of simulation in informing design decisions is demonstrated as well as the importance of considering climate and occupancy/ gains patterns

Embracing variations in patterns of use, pre and post design phase, to improve tenant energy performance

This paper elaborates a new energy performance benchmarking method to support green tenancy agreements and other energy performance contracts. The existing national energy reporting method does not categorise systemic variations in patterns of use. Results of a case study monitoring operational data of a multi-tenanted office building are presented. The data reveals the actual designed spectrum of occupant density accounts for a 44% increase in tenant energy demand per square meter and a 112% increase in tenant energy demand per full time employees [FTE], dramatically affecting the buildings internal gains, heating and cooling requirements. The study highlights how low levels of occupancy and extended operational hours can give a false representation of energy efficiency

Air-conditioning : the impact of UK regulations, the risks of unnecessary air-conditioning and a capability index for non-air-conditioned naturally ventilated buildings

The UK building regulations have been rapidly evolving. New methodologies have been developed in part driven by the EU EPBD. In this paper the UK building regulations and energy performance calculations as they relate to naturally ventilated (NV), mechanically ventilated (MV) and air conditioned (AC) buildings are reviewed. Calculations are carried out for typical, best practice and advanced fabric and systems and observations made on how the results may influence future adoption of air conditioning. Calculations of overheating potential and risks of unnecessary air-conditioning are discussed. A design methodology is proposed that could help to address some of the risks and provide a capability parameter to quantify design quality and allow design comparison

Why advanced buildings don't work?

The intent of policy is to achieve robust comfortable low energy buildings. However there are obvious policy disconnects and, where there is evidence, it appears that in general advanced buildings do not achieve their intended performance. There are many industry and policy initiatives aimed at improving industry processes such as: Soft Landings, BREEAM, LEED, Green Star, AGBR and BIM. In this paper the performance of buildings likely to be promoted by current policy is investigated and a number of significant and recurring problems identified. The possibility that these problems will be resolved by current initiatives is discussed and it is concluded that important gaps remain to be addressed

Local Energy Perspectives on Scotland and Brazil

Policy support for climate change and sustainable energy deployment in the EU and Scotland has enabled Communities to implement and benefit from local energy schemes, there would appear to be potential for similar schemes in Brazil. There have however been miss-steps due to narrow criteria being applied in assessment of carbon emissions and sustainability, there is a need for more detailed environmental assessment. The ability of a Community to adopt a local energy scheme depends on its Governance, financial and technical capacity. A new multi-disciplinary assessment process is being developed and piloted in Scotland and Brazil which includes technical, environmental and socio-economic factors. The output will be an identification of appropriate energy systems and technical and socio-economic gaps to be addressed. The focus here is on local energy due to global funding availability however the Community capabilities developed for energy schemes can be applied to other projects and have wide benefits

IEQ Performance gaps : Failure modes, litigation risks, and the need for quality

There is much evidence that current building industry process does not deliver the intended outcomes1. Performance gaps exist including IEQ failures which have resulted in litigation. These performance gaps and litigation are likely to increase due to the move towards more advanced buildings and systems, changes in local weather, and the increasing availability and use of post occupancy performance monitoring. While there are many initiatives aimed at improving industry process, none of these directly address the quality issues2. It is proposed that a quality systems approach similar to that of other more performance sensitive industries could provide a solution

Strategies for low carbon buildings, assessment of design options and the translation of design intent into performance in practice

To deliver low carbon buildings requires: a) Performance assessment and option appraisal; b) Industry process to translate selected options into low carbon performance in practice. This thesis aims to make some contribution in each of these two areas. Legislation such as the European Performance of Buildings Directive (EPBD) is stimulating the market to put forward many technical options for design or retrofit of low carbon buildings. The need is identified here for a low cost, EPBD compatible, simulation based, real time method for performance assessment and upgrade option appraisal to inform decisions for a range of users with various levels of technical knowledge. The hypothesis is advanced that such a method can be developed. An EPBD compatible, dynamic simulation based, real time, performance assessment and option appraisal method is then proposed and evaluated. A range of test applications and user groups are considered. Test applications include the generation of energy performance ratings based on a simple questionnaire. Other applications cover a range of individual building, policy or strategy contexts. A critical analysis is carried out of the applicability, scope and limitations of the method. The proposed method proved useful in a range of applications. For other applications some limitations were identified. How these can be addressed is discussed. The development and deployment examples are for a specific building stock but provide insights to enable replication for other situations. The research provides a foundation for further research and development. There is much evidence that selection of appropriate options is not sufficient to achieve low carbon performance. Many issues can lead to gaps between intended and actual performance. Problems are identified in the design and implementation of low carbon systems and controls. Problems include poor understanding, errors in implementation, and poor visibility of actual performance. The need for a method to address these problems is identified. The hypothesis is advanced that such a method can be developed.;A Modular Control Mapping and Failure Mode Effect Analysis (FMEA) method is then proposed and evaluated for a range of test applications to buildings intended to be low carbon. The insights from the test applications are reviewed and the scope and limitations of the proposed method discussed. Overall the applications were successful and the useful application demonstrated. The method was deployed post-occupancy, then applicability at various stages of the design process was demonstrated by using concept and detailed design information. The modular control mapping and FMEA process proposed leverages in part the approach taken in industrial sectors identified as benchmarks by proponents of the Building Information Modelling (BIM) initiative. The potential application of further processes from BIM benchmark industry is discussed in the context of current buildings industry initiatives. The performance assessment and option appraisal method, the modular control mapping and FMEA method, and the outcomes from their evaluations are intended to contribute to the realisation of low carbon buildings in practice. The future integration of both methods within a BIM framework is proposed.To deliver low carbon buildings requires: a) Performance assessment and option appraisal; b) Industry process to translate selected options into low carbon performance in practice. This thesis aims to make some contribution in each of these two areas. Legislation such as the European Performance of Buildings Directive (EPBD) is stimulating the market to put forward many technical options for design or retrofit of low carbon buildings. The need is identified here for a low cost, EPBD compatible, simulation based, real time method for performance assessment and upgrade option appraisal to inform decisions for a range of users with various levels of technical knowledge. The hypothesis is advanced that such a method can be developed. An EPBD compatible, dynamic simulation based, real time, performance assessment and option appraisal method is then proposed and evaluated. A range of test applications and user groups are considered. Test applications include the generation of energy performance ratings based on a simple questionnaire. Other applications cover a range of individual building, policy or strategy contexts. A critical analysis is carried out of the applicability, scope and limitations of the method. The proposed method proved useful in a range of applications. For other applications some limitations were identified. How these can be addressed is discussed. The development and deployment examples are for a specific building stock but provide insights to enable replication for other situations. The research provides a foundation for further research and development. There is much evidence that selection of appropriate options is not sufficient to achieve low carbon performance. Many issues can lead to gaps between intended and actual performance. Problems are identified in the design and implementation of low carbon systems and controls. Problems include poor understanding, errors in implementation, and poor visibility of actual performance. The need for a method to address these problems is identified. The hypothesis is advanced that such a method can be developed.;A Modular Control Mapping and Failure Mode Effect Analysis (FMEA) method is then proposed and evaluated for a range of test applications to buildings intended to be low carbon. The insights from the test applications are reviewed and the scope and limitations of the proposed method discussed. Overall the applications were successful and the useful application demonstrated. The method was deployed post-occupancy, then applicability at various stages of the design process was demonstrated by using concept and detailed design information. The modular control mapping and FMEA process proposed leverages in part the approach taken in industrial sectors identified as benchmarks by proponents of the Building Information Modelling (BIM) initiative. The potential application of further processes from BIM benchmark industry is discussed in the context of current buildings industry initiatives. The performance assessment and option appraisal method, the modular control mapping and FMEA method, and the outcomes from their evaluations are intended to contribute to the realisation of low carbon buildings in practice. The future integration of both methods within a BIM framework is proposed

Performance assessment of tariff-based air source heat pump load shifting in a UK detached dwelling featuring phase change-enhanced buffering

Using a detailed building simulation model, the amount of thermal buffering, with and without phase change material (PCM), needed to time-shift an air source heat pump's operation to off-peak periods, as defined by the UK 'Economy 10' tariff, was investigated for a typical UK detached dwelling. The performance of the buffered system was compared to the case with no load shifting and with no thermal buffering. Additionally, the load shifting of a population of buffered heat pumps to off-peak periods was simulated and the resulting change in the peak demand on the electricity network was assessed. The results from this study indicate that 1000 L of hot water buffering or 500 L of PCM-enhanced hot water buffering was required to move the operation of the heat pump fully to off-peak periods, without adversely affecting the provision of space heating and hot water for the end user. The work also highlights that buffering and load shifting increased the heat pump's electrical demand by over 60% leading to increased cost to the end user and increased CO2 emissions (depending on the electricity tariff applied and time varying CO2 intensity of the electricity generation mix, respectively). The study also highlights that the load-shifting of populations of buffered heat pumps wholly to off-peak periods using crude instruments such as tariffs increased the peak loading on the electrical network by over 50% rather than reducing it and that careful consideration is needed as to how the load shifting of a group of heat pumps is orchestrated