Welcome to the third part of the course ‘Design borefields with confidence’.
Summary of part 2
In the last part, we got started with the thermal aspects of geothermal borefield simulations.
In Part 2.1, we introduced the concept of the temperature profile (monthly and hourly), explaining what can be observed from them. The borefield quadrants were introduced to provide additional insight without the need for detailed simulations.
In Part 2.2, we introduced the important concept of the effective borehole thermal resistance, which is the parameter that determines the relationship between the borehole wall temperature (i.e. the ground temperature) and the fluid temperature. We saw that this parameter can be influenced by changing, for example, the grout conductivity, the number of pipes and the flow regime (laminar or turbulent).
Part 2.3 introduced the concept of the g functions, which determine the long term behaviour of the borehole wall temperature over seasons and years. We discussed that these long term aspects can be influenced by changing the borehole to borehole spacing as well as the configuration of the borefield (line versus rectangular configuration).
In Part 2.4, we concluded the second part with our first simulation in GHEtool Cloud, where the different aspects of the previous sections were illustrated based on a real life case.
Content of part 3
In this part, we will dive deeper into the thermal aspects of borefield simulation, explaining how you can improve upon standard design assumptions and truly get the most out of your geothermal simulation. In the first section, we will discuss the difference in results when working with a monthly or hourly load profile. In addition to these two load types, we will discuss three major improvements to the overall accuracy of your simulation: variable fluid properties, variable flow rates and variable efficiencies.