Development and Validation of a Dynamic Air Handling Unit Model, Part I

A dynamic air handling unit (AHU) simulation model that is capable of producing operational data for commonly used AHU configurations will assist further research in AHU control and operation, as well as fault detection and diagnosis. In this study, dynamic behaviors of an AHU and four building zones that were served by the AHU were modeled using HVACSIM+ software developed by the National Institute of Standards and Technology The model (called 1312 model hereafter) was developed based on two previous ASHRAE projects (RP-825 and RP-1194.). However significant modifications, which included new parameters, new control strategies, and new component models, were made in this study to develop the 1312 model. The 1312 model structure, model parameter development process, and two new component models, namely a new coil valve model and a new fan energy model, are introduced in this paper The new coil valve model considers nonlinear behaviors of a three way valve. The new fan energy model outputs fan energy consumption that includes energy consumptions for fan, belt, motor and VFD. Coefficients for the new fan energy model can directly be estimated from the total fan energy measurement. The 1312 model was also validated using real building operation data obtained from a large scale building laboratory facility. The validation process and results are introduced in a companion paper