The Simulation of Building Electrical Power Flows

Recent developments in photovoltaic components, small-scale combined heat and power systems and ducted wind turbines have opened up the possibility for an embedded generation approach to building design. In conjunction with demand reduction measures, embedded generation encourages a new design paradigm based on matching local supply to demand. For building simulation programs to offer effective support for embedded systems design, they must be capable of modelling the electrical energy flows in a fully integrated manner. This paper describes recent work to develop an electrical power flow model and ensure its interoperability with the other technical domains found within building simulation. Specifically, the paper describes: a) an electrical network solver for d.c., a.c. and hybrid circuits; b) the thermal/electrical models of power producing and consuming equipment; c) the nature of the interactions between the thermal, lighting, air flow and electrical power flow domains; d) aspects relating to the conflation of the power flow model with the other technical domains as found within the ESP-r system. The paper concludes with a case study of the integrated thermal, lighting, air flow and power flow modelling approach when applied to a building/ HVAC problem with an embedded generation component in the form of a photovoltaic facade operating in hybrid mode.