Joseph Andrew Clarke

Simulation-assisted control in building energy management systems

Technological advances in real-time data collection, data transfer and ever-increasing computational power are bringing simulation-assisted control and on-line fault detection and diagnosis (FDD) closer to reality than was imagined when building energy management systems (BEMSs) were introduced in the 1970s. This paper describes the development and testing of a prototype simulation-assisted controller, in which a detailed simulation program is embedded in real-time control decision making. Results from an experiment in a full-scale environmental test facility demonstrate the feasibility of predictive control using a physically-based thermal simulation program.

Integrating CFD and building simulation

Abstract To provide practitioners with the means to tackle problems related to poor indoor environments, building simulation and computational fluid dynamics can usefully be integrated within a single computational framework. This paper describes the outcomes from a research project sponsored by the European Commission, which furthered the CFD modelling aspects of the ESP-r system. The paper summarises the form of the CFD model, describes the method used to integrate the thermal and flow domains and reports the outcome from an empirical validation exercise.

A technique for the prediction of the conditions leading to mould growth in buildings

Epidemiological evidence suggests that the presence of mould growth in buildings can have a detrimental effect on the well-being of occupants. Based on an extensive literature review, growth limits for six generic mould categories have been formulated in terms of the minimum combination of temperature and relative humidity for which growth will occur on building materials. These limits were incorporated within the ESP-r system for building energy and environmental simulation in order to provide a design tool which can predict the likelihood and extent of mould infestation. The systems new predictive capability has been tested against monitored data and mycological samples taken from a mould infested house.

Development of an adaptive window-opening algorithm to predict the thermal comfort, energy use and overheating in buildings

This investigation of the window-opening data from extensive field surveys in UK office buildings demonstrates: (1) how people control the indoor environment by opening windows; (2) the cooling potential of opening windows; and (3) the use of an ‘adaptive algorithm’ for predicting window-opening behaviour for thermal simulation in ESP-r. It was found that when the window was open the mean indoor and outdoor temperatures were higher than when closed, but it was shown that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window-opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys. The adaptive algorithm is shown to provide insights not available using non adaptive simulation methods and can assist in achieving more comfortable, lower energy buildings while avoiding overheating.

Developing a Student-Centred Approach to Reflective Learning

One of the goals of higher education is to enable students to become autonomous independent learners. To achieve this goal it is necessary to shift our emphasis from teaching to facilitating effective learning and to promote the concepts of ownership and ‘reflection on learning’. Reflection is a nebulous concept not necessarily amenable to simple translations articulated in the abstract. Rather, it is necessary to provide a framework for reflection over which students themselves have a level of control. In the context of a postgraduate Environmental Studies Diploma/MSc programme professional development workshops were contextualized within the disciplinary based programme to promote a sense of ownership with respect to the learning outcomes and criteria for excellence associated with a group based special studies project. This was achieved through the development of project management logbooks which are presented on a website alongside the special studies project report.

Design and testing of a contra-rotating tidal current turbine

Abstract A contra-rotating marine current turbine has a number of attractive features: nearzero reactive torque on the support structure, near-zero swirl in the wake, and high relative inter-rotor rotational speeds. Modified blade element modelling theory has been used to design and predict the characteristics of such a turbine, and a model turbine and test rig have been constructed. Tests in a towing tank demonstrated the feasibility of the concept. Power coefficients were high for such a small model and in excellent agreement with predictions, confirming the accuracy of the computational modelling procedures. High-frequency blade loading data were obtained in the course of the experiments. These show the anticipated dynamic components for a contra-rotating machine. Flow visualization of the wake verified the lack of swirl behind the turbine. A larger machine is presently under construction for sea trials.

Integration in building physics simulation

For more than a quarter of a century, building simulation programs have been developed to undertake non-trivial performance appraisals. In general these programs deal only with a small sub-set of the overall problem. However, advanced architectural developments require an integrated approach to design. The domains of heating, lighting, ventilation and acoustics, for example, are often closely related and it is only by taking into account their interactions that a complete understanding of building behaviour can be obtained. This paper describes some recent work to further the development of a multiple-domain approach.

Comparison of the simplified methods of the ISO 13790 standard and detailed modelling programs in a regulatory context

The CEN standards that support the European Energy Performance of Buildings Directive requirement for calculation of the energy consumption of buildings allow various methods to be used for the same calculation. The impact of using the different methods within the updated ISO 13790 standard for space heating and cooling energy calculations was examined with a parametric analysis of a common building specification. The impact was assessed by considering the energy band, which would be assigned for the building based on the calculation results. The standard describes three different methods that can be used for the calculations: a monthly quasi-steady state method, a simplified hourly method and detailed simulation. For most cases studied, differences in the building rating given by the various methods were a maximum of one band. More significant differences were noticed in some cases. Parameter values in the monthly method were determined, which would lead to improved matching.

Occupancy monitoring using environmental & context sensors and a hierarchical analysis framework

Saving energy in residential and commercial buildings is of great interest due to diminishing resources. Heating ventilation and air conditioning systems, and electric lighting are responsible for a significant share of energy usage, which makes it desirable to optimise their operations while maintaining user comfort. Such optimisation requires accurate occupancy estimations. In contrast to current, often invasive or unreliable methods we present an approach for accurate occupancy estimation using a wireless sensor network (WSN) that only collects non-sensitive data and a novel, hierarchical analysis method. We integrate potentially uncertain contextual information to produce occupancy estimates at different levels of granularity and provide confidence measures for effective building management. We evaluate our framework in real-world deployments and demonstrate its effectiveness and accuracy for occupancy monitoring in both low- and high-traffic area scenarios. Furthermore, we show how the system is used for analysing historical data and identify effective room misuse and thus a potential for energy saving.

Assessing building performance by simulation

Abstract This paper characterizes the state-of-the-art in the assessment of a buildings performance by computer simulation. Theoretical and application aspects are outlined and current developments are described which will help to ensure that simulation can be effectively applied in practice by designers with limited knowledge of the technology. Remaining problems are identified.