Simulation of air conditioning systems with different tools - minimum requirements for different applications

Stephan, W., and Dentel, A.
December 2006

System Simulation in Buildings 2006 - Proceedings of the Seventh International Conference, Liege, Belgium

For the energy analysis of non residential buildings two new simulation tools for the evaluation of air conditioning systems are presented. A first tool is based on idealized processes within the Mollier h,x-diagram. This tool is implemented in the simulation environment of TRNSYS. A second tool is based on the simulation of individual component models, coupled by an overall control strategy. Here the simulation environment of EES is used. The first model calculates, for a perfect control behavior and a perfect sized system, the minimum energy demand for the air treatment in the air handling unit. Seven system types are modeled in this way and can quickly be compared to each other.
The second model is component based. Each individual component is described in detail. The characteristics of the components can easily be changed. Thus undersizing or oversizing effects can be shown. Also the effects of different operating conditions, like a low supply water temperature for the heating coils, are considered and can be evaluated. Until now the calculations for the air handling models are done in sequence to a building load calculation. No direct coupling with feed back is realized. This leads to an overestimation of the zonal loads. In further work this effects will have to be integrated in the software tools.