Future trends of the neutral model format (NMF)

The Neutral Model Format for building simulation was proposed in 1989 as a means for documentation and exchange of models. It has attracted much interest and an acceptance as a potential standard, maintained by ASHRAE's TC 4.7 technical committee. So far, the format has only been directed towards component (leaf) models, but many suggestions have been made to extend it to also cater for systems; of component models. A brief review of NMF is given. This paper makes detailed proposals for NMF extensions covering hierarchical. modeling, inheritance, equation-based function definitions, link types with associated equations, and a general method to handle non-standard extensions. A future development of NMF towards STEP/EXPRESS is also discussed.