HPC (Heat Pumping Systems Control) – Model-based control of absorption heat pumping systems

Thermally driven absorption heat pumping systems are able to provide heat (absorption heat pump) and cold (absorption chillers) in a wide range of systems and applications. This technology could increase the efficiency of the energy system and the share of renewable energy. Currently the control system of absorption heat pumping systems is focussed on coverage of base load. These systems cannot handle dynamic operation behaviour, or only to an insufficient extent.

For this reason, this project aims at improving the control of absorption heat pumping systems. The control system should be capable to explicitly consider and compensate the coupled and partly non-linear correlations between the different processes and process variables, all internal and external manipulated variables as well as the fluctuations of the external disturbances, e.g. the temperature of the incoming streams. For this, a method for the model-based control of absorption heat pumping systems shall be developed. The method should be as systematic and modular as possible in order to provide a broad basis for further development of the control for both common working fluid pairs (ammonia / water or water / lithium bromide) as well as for cooling and heating applications.

In the end, the control should be able to provide the heat very accurately at the required temperature levels even in the case of strongly varying operation conditions. This would contribute to an increase of the possible range of use as well as increase the reliability of absorption heat pumping systems and thus lead to a smaller number of emergency shut downs.

Beside the experimental validation, test runs based on practical requirements are carried out to show the potential of improvement.