Modeling and identification of a passive air-conditioning unit using the operating point dependent parameters-structure

A mathematical description is given for heat-and moisture-transfer process of an air-conditioning unit and the parameters of its dynamic discrete models are identified. The air conditioning unit studied is passive and does not use the more typical compression system or absorption-refrigeration cycle. The purpose of the unit is to produce a microclimate with controlled relative humidity for crop growth chambers. It is very important to control relative humidity values because their variations can strongly influence crop growing conditions. The different system models are identified for the main operating points and the variation of outdoor disturbance is taken into account. These models are parameterized using polynomial functions in order to provide a single structure for the system. It makes it possible to define an input-output model for simulation of the system dynamics.