Integration of the CEN/ISO Monthly Building Energy Model into OpenStudio

Modeling of the energy use of buildings is an extremely complicated endeavor. Modeling existing buildings is difficult because the model parameters must match the details of an existing building, many of which are unknown. Modeling buildings to be constructed is also difficult because many details of the building have not yet been designed. Fast and reasonably accurate building energy models allow designers and analysts to rapidly assess the inherent range of building energy consumption when many model parameters are uncertain. One such building model is the monthly model developed the by European Committee for Standardization (CEN) and the International Standards Organization (ISO). The CEN/ISO building model is the basis for the Energy Performance in Buildings Directive (EPBD) of the European Union. The paper describes the development and application of a specific implementation of the CEN/ISO monthly energy method as C++ code that has been integrated into the OpenStudio building energy modeling platform and software development kit. The new code has the potential to greatly improve automated modeling and calibration of existing buildings, especially for buildings where limited data are available. Because the model runs extremely fast, it is also especially suitable for parametric and/or Monte Carlo studies that can be used to evaluate the possible range of energy use of a building yet to be constructed.