An overview of blackbox reduced-basis output bound methods for elliptic partial differential equations

We present a two-stage off-line/on-line blackbox reduced-basis output bound method for the prediction of outputs of interest of elliptic partial differential equations with affine parameter dependence. The computational complexity of the on-line stage of the procedure scales only with the dimension of the reduced-basis space and the parametric complexity of the partial differential operator. The method is both efficient and certain: thanks to rigorous a posteriori error bounds, we may retain only the minimal number of modes necessary to achieve the prescribed accuracy in the output of interest. The technique is particularly appropriate for applications such as design, optimization, and control, in which repeated and rapid evaluation of the output is required. In this paper three versions of this method are presented: (i) for coercive equilibrium problems, (ii) for symmetric eigenvalue problems, and (iii) for non-coercive equilibrium problems

Adaptive building envelope simulation in current design practice: findings from interviews with practitioners about their understanding of methods, tools and workarounds and implications for future tool developments

Adaptive building envelopes can dynamically adapt to environmental changes to improve thermal building performance. To predict the performance of design proposals with adaptive building envelopes, Building Performance Simulation (BPS) tools can be employed. However, one shortcoming of existing tools is their limited extensibility, which implies that accurately predicting adaptive building envelope performance remains a challenge and requires ad hoc approaches. This challenge has made practitioners reticent in considering adaptive building envelopes, which in turn has led to a slow uptake of them in the built environment. This study seeks to advance the understanding of the limitations of adaptive building envelope simulation in current design practice and to suggest implications for future tool developments. To this aim, the study adopts a user-centred perspective through interviews with experts in the field. Findings suggest that current BPS tools hinder the reliable prediction of adaptive building envelope performance, as accurately representing the level of detail of the building envelope is challenging. The subsequent workarounds applied are either time- and cost-intensive or do not consider the dynamic building envelope components. More flexible modelling approaches that allow for rapid prototyping and easy integration are required to enable designers to take full advantage of adaptive building envelopes

Modeling of Photovoltaic-Thermal District Heating with Dual Thermal Modes

Solar photovoltaic thermal (PVT) collectors could be a competitive addition to district heating systems, particularly in areas with high energy density since they simultaneously produce electricity and heat whilst increasing the PV efficiency through cooling. This study presents a new Modelica PVT model, which is used together with EnergyPlus in a co-simulation setup to assess the technical feasibility of solar PVT district heating in new builds. The model has been applied to a block of 12 2-bedroom terraced houses with a 184m2 PVT array on the south facing side of the roof. It was identified that well-designed seasonal PVT heating configurations and control schemes are required to maximise PVT outputs. PVT dual thermal modes occur when the PV is either connected to a load or producing at close to the maximum power point. Integrating the dual modes into a control system could be more economical if heat tariffs were higher than electrical ones when heat demand is greater than the PVT thermal output

A new approach to engineering design

In the following paper, we present two components which have been used together to solve engineering design problems. Firstly, we recall some results on Reduced-Basis Output Bound methods which provide real-time outputs and their associated error estimators for a parametrized mathematical model. Then, we propose an original architecture – called SimRes– for scientific computing which itself comprises several components. Put together, these two components provide a complete solution for certain classes of engineering design problems in terms of numerical methods and software

The relationship between vapour pressure excess and air change rates in bedrooms : a pilot study

Air change rates can be measured using tracer gas techniques which can be costly and intrusive. Moisture data is more accessible, and there is a relationship between moisture conditions and ventilation. This study aims to investigate the relationship between vapour pressure excess and air change rates in bedrooms. The CO2 decay method was used to estimate air change rates when bedrooms were unoccupied in the morning. The relationship between the average hourly change in vapour pressure excess and the air change rate was examined. Results showed a very weak to no correlation between the variables possibly due to moisture buffering and airflow from other rooms

Challenges in developing a moisture metric to assess air change rates

Air change rates are difficult to measure in naturally ventilated buildings. There is incentive to develop alternative techniques to measure air change rates. Using a moisture metric is a possibility, but this is challenging as it requires the ability to quantify processes that affect the moisture balance in a room. This paper consolidates literature about how the moisture balance can be understood in field studies in terms of moisture generation, moisture buffering, and ventilation. Moisture generation rates have been reported in literature with some disparity. Moisture buffering is difficult to account for due to the complexity of the process in real buildings. Ventilation can be measured using tracer gas techniques, but these often provide a ‘snapshot’ of the air change rate which varies both spatially and temporally in buildings. However, a promising approach has been identified whereby moisture and ventilation conditions are examined over a longer period of time i.e. weeks

Scalable pathways to net zero carbon in the UK higher education sector: A systematic review of smart energy systems in university campuses

The following literature review sets out the state-of-the-art research relating to smart building principles and smart energy systems in UK higher education university campuses. The paper begins by discussing the carbon impact of the sector and the concept of ‘smart campuses' applied to the sector in the context of decarbonisation. Opportunities and challenges associated with integrating smart energy systems at the university campus from a policy and technical perspective are then discussed. This is followed by a review of building and campus-scale frameworks supporting a transition to smart energy campuses using the BPIE’ Smart Buildings' framework. The paper finds that the complexity of achieving net-zero carbon emissions for new and existing higher education buildings and energy systems can be addressed with the adoption of ‘smart building principles' and integrating 'smartness' into their energy systems. Several universities in the UK and worldwide are integrating smart services and Information and Communication Technologies (ICT) in their operations following the smart campus premise. At the building level, existing frameworks often create conceptual roadmaps for the smart building premise or propose technical implementation and assessment methods. At university campus scale, implementation typically comes through single-vector interventions, and only few examples exist that propose a multi-vector approach. Comparisons of the drivers and the decision-making process are made, with carbon and cost reduction being the most prominent from leveraging distributed energy generation. Therefore, this study identified the need for a comprehensive technical or policy framework to drive the uptake of the smart energy campus, aiming to bring together the holistic value of smart energy campuses