Methods and tools for the simulation and design of geothermal heat exchangers

Context
Geothermal systems are playing an increasingly important role in ongoing worldwide efforts to develop environmentally friendly, sustainable, and efficient ways of fulfilling space heating and cooling demands. A promising approach in this regard is based on ground-source heat pumps (GSHPs) coupled to vertical geothermal boreholes. Designing of GSHPs is facilitated by accurate predictions of the working-fluid and ground temperatures, and the related heat extraction and injection rates, during their operation. The techniques used for such predictions are often based on mathematical models that invoke the assumption of purely conductive heat transfer in the ground that surrounds the boreholes. However, ground thermal properties can see significant variations in space, and heat transfer often involves non-conductive heat transfer processes, such as groundwater movement and moisture transfer. These effects influence the energy performance of GSHPs, and need to be properly accounted for in the design and simulation of GSHPs.

The Ph.D. candidate will develop advanced methods and tools for the simulation of ground-source heat pump systems. Two factors influencing long-term energy performance of GSHPs are considered:

1. Geothermal boreholes in heterogeneous soils.
Semi-analytical models of heat transfer in geothermal borehole fields with spatially varying ground properties will be developed. The effect on energy performance of GSHP systems will be assessed. Advanced methods for sizing of geothermal boreholes will be produced.
2. Thermally driven moisture transfer.
Hybrid numerical-analytical methods for the simulation of coupled heat and mass transfer in geothermal borehole fields will be developed. The specific objectives will be to evaluate how GSHP operation affects soil moisture content and how moisture transfer affects GSHP energy performance.

Qualifications
Experience and skills in the following fields are major assets: thermodynamics (refrigeration), simulation of building energy systems, object-oriented programming (Python, Modelica). Proficiency in English (written and oral) is essential.

Application
Applications should include: (1) curriculum vitae, (2) academic transcripts, (3) letter of motivation and (4) sample of a technical text written in English.