A semi-physical TRNSYS model for H2O/LiBr-absorption chillers and heat pumps

The industrial sector holds considerable potential for reducing energy consumption and greenhouse gas emissions. An effective strategy for achieving this is the use of absorption chillers and heat pumps (ACHP) for cooling and heating, allowing to reduce the dependence on fossil fuels, when the absorption cycle is driven with heat from renewable energy sources or waste heat. However, the efficiency of ACHPs strongly depends on their hydraulic integration and control. In this context, simulation-based studies provide a valuable approach to explore ACHPs’ performance considering its interaction with other subsystems, e. g. industrial processes and volatile renewable energy sources. Therefore, simulations can serve as a useful tool to pinpoint optimization opportunities. However, as the complexity of calculations and the effort needed for model parameterization increase with the level of detail, certain simplifications have to be made. This publication describes the development of a simplified semi-physical ACHP model for TRNSYS allowing easy parametrization and short computation times but considering property data of H2O and aqueous LiBr. For this purpose, different simplified model approaches concerning heat and mass transfer are investigated and evaluated through a comparative analyses of simulation quality. To verify the reliability and accuracy of the ACHP-model, it is validated against measurement data of several ACHPs at varying operating conditions.