Control of Naturally Ventilated Buildings: a Model Predictive Control Approach

During operation, buildings consume a large amount of energy, around 40\% of global final energy use. A major challenge is to reduce the amount of energy used while still providing a comfortable environment for building occupants. The use of passive techniques, such as natural ventilation, is promoted in certain climates to provide low energy cooling and ventilation. However, controlling natural ventilation in an effective manner to maintain occupant comfort can be a difficult task, particularly during warm periods. One area which has been identified as having the potential for reducing energy consumption while maintaining occupant comfort is the use of more advanced control techniques. A technique which has been much explored in recent years for application in mechanically ventilated buildings is Model Predictive Control (MPC). MPC is a control technique which uses a model of the system dynamics and by solving an optimisation problem is able to determine the optimal control inputs. In this thesis the application of MPC to naturally-ventilated buildings is investigated. The essential component of an MPC strategy is the predictive model of the building's thermal dynamics. An empirical approach to modelling was taken using multilayer perceptron (MLP) neural network models. To use empirical data from a building to create a predictive model it is essential to ensure the quality of the data is appropriate. In order to assess the data available from buildings during normal operation four studies were carried out in different buildings. The data collected from these studies represent a range of natural ventilation scenarios and building types in different locations in the UK. To test the impact of identification procedures upon the resulting neural network models, an identification experiment was carried out using dynamic thermal simulation. Neural network models were trained using both the data from real buildings and the simulation data. Results showed that neural network models trained using data from real buildings were capable of good predictions. However, the lack of input excitation during normal operation resulted in models which did not capture the effect of the window opening control. The identification experiment demonstrated that by exciting the control input the resulting neural network models captured the effect of the control, making them suitable for MPC. The main focus of this thesis is the investigation of techniques to develop predictive models which can be utilised as part of an MPC strategy. However, to demonstrate the potential benefits of MPC a controller designed to maintain a suitable internal temperature is demonstrated. The controller utilised the neural network models developed using the data from the system identification experiment and a non-linear optimiser. The MPC method showed the potential to reduce overheating and improve upon the typical control used in the majority of buildings. Findings in this thesis demonstrate that empirical models capable of good predictions can be trained and could be successfully applied to the control of natural ventilation systems. Furthermore, the potential advantages of adopting an MPC approach to natural ventilation control are shown

Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm

Abstract— Online transportation has become a basic requirement of the general public in support of all activities to go to work, school or vacation to the sights. Public transportation services compete to provide the best service so that consumers feel comfortable using the services offered, so that all activities are noticed, one of them is the search for the shortest route in picking the buyer or delivering to the destination. Node Combination method can minimize memory usage and this methode is more optimal when compared to A* and Ant Colony in the shortest route search like Dijkstra algorithm, but can’t store the history node that has been passed. Therefore, using node combination algorithm is very good in searching the shortest distance is not the shortest route. This paper is structured to modify the node combination algorithm to solve the problem of finding the shortest route at the dynamic location obtained from the transport fleet by displaying the nodes that have the shortest distance and will be implemented in the geographic information system in the form of map to facilitate the use of the system. Keywords— Shortest Path, Algorithm Dijkstra, Node Combination, Dynamic Location (key words