DYNAMIC MODELLING APPROACH OF A THERMAL COMPRESSOR AND VALIDATION BASED ON EXPERIMENTAL TESTS

A thermal compressor uses thermal energy to increase the pressure of the working gas, while
maintaining a temperature difference as an essential factor for its effective functioning. The design of
the thermal compressor is similar to a gamma type Stirling engine but it replaces the power piston with
input and outlet valves. It also shares some technical features of a Stirling engine such as heating source
flexibility, low operating noise, and potential for broad applicability in today’s thermodynamic cycles.
This paper first introduces the tested thermal compressor. The behavior of the instantaneous state of the
fluid inside the thermal compressor is mimicked by a detailed dynamic modelling approach. A finite
volume method is used to spatially discretize the system into several control volumes (CVs), and energy,
mass and momentum balance equations are expressed for each control volume. This approach results
in several ordinary differential equations (ODEs) that are solved and simulated in a python written
script. The model is then validated with experimental data collected from a thermal compressor
implemented in a real heat pump test bench.