Modeling of Rooftop Packaged Air Conditioning Equipment

Abstract

A large amount of the operating costs of a building is determined by the energy requirements and the fuel consumptions of its heating, ventilation and air conditioning system (HVAC-system). Simulation programs are used to determine the energy use in buildings. These simulation programs are based on models for the type of HVAC equipment used and models for determining the internal and external loads of the building. In this project a model for rooftop packaged air conditioning units has been developed. The model uses generally available manufacturer's catalog data information to determine the model parameters. Thus, the model is easy applicable. The system is modeled by describing the performance of each component with mechanistic models. This method has been successfully used to predict the performance of rooftop packaged air conditioning systems and allows certain extrapolation of performance data. The model has been developed with the Engineering Equation Solver (EES) software package. A program has been written that allows determining the characteristic model parameters based on manufacturer's performance data and also allows creating extrapolated performance data for different operating conditions. Originally developed with EES the program can be also called directly by TRNSYS, a transient simulation program.