Simulation-based performance analysis of a modular heat pump system as an alternative to gas-fired boilers in apartments

To reduce the greenhouse gas emissions of the existing housing stock, electrification of the heating system is needed. With the modular heat pump approach from the ’Gasthermenersatz’ project, a possibility will be created to archive this goal with minimal conversion work.
This thesis should thereby help the understanding of the concept and support design decisions for the modules by creating a validated simulation of the refrigeration cycle.
For this purpose, every component of the cycle is individually depicted in the
simulation. Different modeling approaches from literature for these components
are compared and fitted to the available data with optimization procedures. To
validate the simulation, experimental temperature and pressure data, gathered from a functional model, is used. As well as temperature gradients of the heat exchanging process in the condenser, taken trough thermal imaging.
The validated model is used to analyse the efficiencies and deficiencies of the
system. Furthermore the effects of heat exchanger size changes on the system are studied. In the ’Gasthermenersatz’ project proposal an efficiency increase for a serial interconnection between the modules is claimed. This claim is reviewed with the validated model.
Finally the simulations showed that the system is able to full fill the heating
requirements for a wide range of operating conditions. With only a small reduction in the heat exchanger size, the system is able stay within legal limits, without significant performance losses. But the serial interconnection between the modules did not lead to the claimed significant efficiency increases.