Model-based control of renewable energy systems in buildings

This paper summarises the output of the EPSRC project “Optimal supervisory control of renewable energy systems in buildings” (GR/S30467) which was rated by referees as Tending to Internationally Leading for both its Research Quality and Scientific Impact. Zhang was the lead author. Hanby was his line manager and the PI on the grant.The paper describes a research project concerned with the problem of supervisory control of systems which combine a range of heat sources with active and passive thermal storage. The work is based around a prototype building which includes a ventilated PV array, solar air and water heating, biomass-fired boiler and a stratified thermal store. The supervisory control problem is, for each source, whether to deploy the received energy directly into the building, store for later use or to reject to the environment. These decisions are currently made by a building management system programmed with a complex, arbitrary set of rules and setpoints. The considerable number of operational states means that such a control system is very difficult to commission. Analysis of the data for the early stages of building operation indicate strongly that it is unlikely that optimal use is being made of the renewable energy sources with this approach. The objective of the research is to investigate the potential effectiveness of replacing the rule-based control scheme with one based on a combination of building/system model with an optimization algorithm. The existing building, plant and control systems were modeled using a commercial simulation environment and calibrated against measured data from the building. A period of swing-season operation was used to compare the existing control with that based on an optimal approach. Results indicate that significant improvements in system operation are possible, but also that significant improvement in execution time will be needed for any future on-line deployment.Engineering and Physical Sciences Research Council GR/S 30467-0