Description and Validation of a Dynamic Tool for the Modelling of a Solar Assisted Absorption Cooling Machine
Abstract
In recent years, the electricity consumption due to buildings air-conditioning has relevantly increased. As an alternative to conventional air-conditioning systems, solar cooling processes can satisfactorily meet the cooling load and the comfort demand at a very low energy cost. In the context of the French research project ORASOL, a small-size solar-assisted cooling system based on a water-cooled H20-LiBr absorption machine is being tested at INES (Institut National de l’Energie Solaire). The absorption machine is distributed by Rotartica, with a nominal cooling power as high as 4.5 kW, powered by 30 m2 flat plate solar collectors. The heat rejection is carried out through a horizontal ground heat exchanger. The installation has been built in the framework of the European project SOLERA (www.solera-project.eu), coordinated by Fraunhaufer ISE. In this paper the analytical model for the dynamic simulation of the entire system is presented. Special attention is paid to the simulation of the storage tank, by accounting for thermal stratification, and the flat-plate solar collectors, which are modelled by means of a slightly simplified but very reliable approach. The experimental results, collected during summer 2009, are used for the validation of the models, both for the components and the whole installation.