Propane Heat Pump Modelling and Monitoring for System Control Analysis

Sammanfattning: The objective of this master thesis was the performance analysis of a non-conventional heating system layout based on a propane heat pump unit. The objective had been pursued by monitoring and modelling the system. First, the project focused on monitoring the system, since for a correct modelling it was necessary to have all the data of the system. For this, the first step was to identify the necessary variables for the complete analysis, being temperatures and pressures as necessary as data for the calculation of power, flows and energetic analyses. The system, located in Åkersberga (Sweden), was instrumented for monitoring purposes with a combination of ClimaCheck solution and prototypes of low-cost wireless temperature sensors designed and developed at KTH Energy Technology lab. The second phase of the project was the collection of this data as well as its storage, these measures that also include multiple weather sources of ambient temperatures, relative humidity, wind speed and solar radiation are collected in a database. In addition, a web interface had been developed at KTH for displaying and processing the measurements. Once the installation was correctly monitored, the project focused on the modelling of the installation. The Heat Pump unit was modelled by means of IMST-ART. IMST-ART is an advanced software developed by the Polytechnic University of Valencia for the analysis and optimization of refrigeration equipment and components. With IMST-ART, therefore, the construction of a model with which to obtain results that approximates as much as possible to the data measured in the installation was carried out. IV The model of the heating systems was modelled by means of TRNSYS. This model included the heat pump, previously modelled with IMST-ART, the two storage tanks and all the other components of the system. Finally, this model was used to perform a parametric study to investigate the possibility of adopting this system layout to a system with storage tanks of more conventional sizes. So, starting from a system layout that was the result of a partial heating system renovation, after analysing the performance through the monitoring and modelling activity, a parametric study was performed to analyse the system performance with focus on possible improvement of the system control and optimization of components.